Home medical
Home medical
Digital thermometers
Digital thermometers
Overview
A medical thermometer measures
the temperature of the human body
over a small temperature range
centered around 37°C. Digital
thermometers have been replacing
mercury stick thermometers over
the past 10 to 15 years due to new
technologies that provide faster,
more convenient measurements
and also the environmental hazard
of mercury in legacy thermometers.
Probe and ear types are the two main
digital thermometers on the market,
with temple and forehead types
emerging as other alternatives. The
probe type is used in the same way
as a traditional mercury stick thermometer and measures oral, rectal,
or sometimes armpit temperatures.
The ear type is a noncontact ther-
Ear-type digital thermometer
Forehead-type digital thermometer
mometer and measures the infrared
energy radiated from the ear canal.
The temple and forehead types are
usually contact thermometers and
measure the infrared energy radiated
from the temple or forehead to
determine body temperature.
sometimes used along with the same
reference voltage in a separate circuit
to eliminate errors caused by the
reference voltage drifting over time.
If the thermistor-divider circuit and
the analog-to-digital converter (ADC)
use the same reference voltage, then
the precision calibration resistors are
not needed. In such a case, the
reference voltage is eliminated from
the temperature calculation, thus
easing the reference requirements.
Measurement
Probe-type thermometers usually
use a thermistor in the probe tip to
measure the temperature. A thermistor
is a resistor whose resistance varies
with temperature. A voltage-divider,
composed of a thermistor in series
with a precision resistor, is driven by a
reference voltage and measured either
single-ended at the midpoint or
differentially across the thermistor.
Additional precision resistors are
Probe-type digital thermometer
Used in
probe-/ear-/forehead-type
thermometers
A thermistor requires a calculation
involving a natural log, which can
consume a lot of computational
cycles and code space in the microcontroller. Alternatively, a lookup
table can be used to calculate the
temperature, an approach that
usually results in a faster calculation
LCD
37.0°C
VOLTAGE
REFERENCE
THERMISTOR
MUX
AMP
ADC
MCU
LED/EL
BACKLIGHTING
THERMOPILE
USER
INTERFACE
Used in
ear-/forehead-type
thermometers
AUDIBLE
INDICATOR
POWER MANAGEMENT
BATTERY
SWITCHING
REGULATOR
VOLTAGE
SUPERVISOR
MAXIM SOLUTION =
Functional block diagram of a digital thermometer. For a list of Maxim's recommended solutions for digital thermometer designs,
please go to: www.maxim-ic.com/thermometer.
www.maxim-ic.com/medical
39
Home medical
Digital thermometers
and more compact code. However,
there is a trade-off between the size
of the table and the interpolation
error between table entries where
increasing the number of points in
the table will decrease the interpolation error. An ADC with 12 bits or
more is sufficient for this measurement, and a gain stage is optional
depending on the measurement
range and desired accuracy.
Ear-type thermometers use thermopiles and thermistors to measure
the temperature. A thermopile is
composed of a number of thermocouples connected in series to
increase the output voltage.
Thermopiles generate an output
voltage proportional to the energy
absorbed. They use the principle of
black body radiation, whereby any
object above absolute zero will
radiate energy; in this case, the
infrared spectrum is being
measured. The infrared radiation
from the ear canal is focused and
directed onto a thermopile, the
low-level voltage output of which is
amplified and converted by an ADC
with 12-bit resolution or more. The
thermistor measures the cold-junction temperature of the thermopile,
and both the thermopile and thermistor measurements are used to
calculate the body temperature.
Temple- and forehead-type thermometers use the same technology
to measure infrared radiation as
ear-type thermometers—they just
measure it from a different location on the body. A specialized forehead
thermometer, called a temporal thermometer, measures the temperature of the temporal artery in the
forehead and the ambient temperature, and then uses these temperatures
to calculate the body temperature.
Digital thermometers are much
faster than mercury thermometers.
Sometimes, the thermistor is preheated so that it gets to the final
temperature faster. Often, predictive
algorithms are used to determine the
temperature. Instead of waiting for
the temperature sensor to settle
completely, the algorithm predicts
what the final temperature will be
based on the response during the
beginning of the measurement cycle
and the characteristics of the
thermistor.
Power management
Probe-type thermometers typically
use a coin-cell battery or two
button-cell batteries, and ear-type
thermometers usually use a coin-cell
battery or two AAA alkaline batteries.
Both thermometer types can run
either directly from the battery or
from a step-up switching regulator,
depending on the circuitry chosen.
requiring a step-down switching
regulator or linear regulator. Low
shutdown current and the ability to
turn the switching regulator off when
not in use are critical to long battery
life in this application. A voltage
supervisor can monitor the battery and
provide a reset to the microcontroller
if the battery falls below the microcontroller’s safe operating voltage.
Additionally, an extra input to the ADC
can measure the battery so that the
user is given a warning that the battery
will soon need to be replaced.
Audible indicators
Audible indicators are used to
indicate when the thermometer is
ready to be used and/or when the
measurement is complete. This is
usually a beeper or buzzer driven
either single-ended or differentially
from a microcontroller’s timer outputs.
Display and backlighting
All digital thermometers use a simple
LCD display that can be driven by a
microcontroller with an integrated
driver. Backlighting can be implemented by using either a single white
LED (WLED) driven by a discrete LED
driver or an electroluminescent (EL)
sheet and driver.
Some forehead-type thermometers
use 9V transistor batteries, thus
www.maxim-ic.com/thermometer
40
Maxim Medical Solutions
Home medical
Digital thermometers
1.5V to 3.6V, 1- or 2-channel, 12-bit ADCs extend battery life, reduce system cost,
and save board space
MAX1393/MAX1396
Benefits
The MAX1393/MAX1396 micropower, serial-output, 12-bit ADCs
operate from a single 1.5V to 3.6V power supply. These ADCs
feature automatic shutdown, fast wake-up (600ns), and a highspeed (up to 5MHz) 3-wire interface. Power consumption is only
0.734mW (VDD = 1.5V) at the maximum conversion rate of 312.5ksps.
AutoShutdown™ between conversions reduces power consumption
at slower throughput rates.
•• Extend battery life
–– 1.5V to 3.6V supply voltage operation
–– 3.1µW at 1ksps and 1.8V supply voltage
–– AutoShutdown between conversions
–– < 1µA shutdown current
Both ADCs require an external reference (VREF) with a wide range
from 0.6V to VDD. The MAX1393 provides one true-differential analog
input that accepts signals ranging from 0 to VREF (unipolar mode) or
±VREF/2 (bipolar mode). The MAX1396 provides two single-ended
inputs that accept signals ranging from 0 to VREF.
Excellent performance, low voltage, low power, flexible interface,
and small package size make these converters ideal for portable
battery-powered applications, as well as any applications that
demand low power consumption and minimal space.
2 x AA CELLS
•• Reduce system cost
–– Running directly off battery eliminates
need for power supply
–– Flexible interface allows use with any
MCU or DSP
•• Save board space
–– Small, 3mm x 3mm, 10-pin TDFN
package
–– Needs only minimal external
components (two ceramic capacitors)
0.1µF
VDD
CPU
OE
CONTROL
LOGIC AND
TIMING
DIFFERENTIAL +
INPUT
VOLTAGE REF
INPUT
VOLTAGE
AIN+ (AIN1)*
AIN- (AIN2)*
INPUT
MUX
AND T/H
12-BIT SAR
ADC
OUTPUT
SHIFT
REGISTER
CS
SCLK
DOUT
SS
SCL
MISO
UNI/BIP
(CH1/CH2)*
REF
0.1µF
MAX1393
MAX1396
GND
*INDICATES MAX1396 ONLY.
MAX1393/MAX1396 typical operating circuit.
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41
Home medical
Recommended solutions
Recommended solutions
Part
Description
Features
Benefits
1-Wire® products
1-Wire memory
DS2502
1-Wire 1024-bit OTP EPROM
Single-dedicated-contact operation, programmable
data protection, ±8kV HBM ESD protection
Minimal contact requirement to add nonvolatile
memory for ID, calibration, or authentication;
simplifies design
DS28E01-100/
DS28E02*
1-Wire 1024-bit EEPROM with
SHA-1 authentication
Single-dedicated-contact operation, SHA-1 secure
authentication and data protection, 1.8V operation
(DS28E02), ±8kV HBM/±15kV IEC ESD protection
Ensure consumables are OEM with crypto-strong
SHA-1 authentication; increase performance and
reliability
DS2431
1-Wire 1024-bit EEPROM
Single-dedicated-contact operation, programmable
data protection, ±8kV HBM/±15kV IEC ESD
protection
High ESD performance typically eliminates the need
to add protection to sensors, thus saving cost and
space
DS2460
SHA-1 coprocessor with EEPROM
Hardware-accelerated SHA-1 computation engine,
Simplifies host system implementation of SHA-1
secure memory to store three 64-bit master secrets authenticated sensors and probes
for use with authenticating 1-Wire SHA-1 slaves, I2C
interface
DS2480B
Single-channel 1-Wire master with
UART/RS-232 interface
UART/RS-232 to 1-Wire protocol bridging, supports
standard and overdrive 1-Wire speeds, lowimpedance strong pullup on 1-Wire I/O
DS2482-100
Single-channel 1-Wire master with
I2C interface
I2C to 1-Wire protocol bridging, supports standard
Generates 1-Wire waveforms from I2C interface,
and overdrive 1-Wire speeds, low-impedance strong greatly simplifying host software development
pullup on 1-Wire I/O
MAX1329
12-/16-bit data-acquisition system
with ADC, DACs, DPIOs, APIOs,
reference, voltage monitors, and
temp sensor
1.8V to 3.6V digital supply; internal charge pump
for analog circuits (2.7V to 5.5V); 12-bit SAR ADC;
dual, 12-bit force-sense DAC; integrated voltage
references, op amps, analog switches, temp sensor,
interrupts, and voltage monitors
MAX1358/MAX1359,
MAX11359*
16-bit data-acquisition systems with 1.8V to 3.6V supply; multichannel, 16-bit sigmaADC, DACs, UPIOs, RTC, voltage
delta ADC; 10-bit force-sense DACs; integrated op
monitors, and temp sensor
amps, analog switches, voltage reference, RTC with
alarm, temp sensor, maskable interrupts, and dual
V DD monitors
Highly configurable AFEs provide accurate results
and are compatible with most electrochemical test
strips
MAX1407–MAX1409,
MAX1414
Low-power, 16-bit multichannel
data-acquisition systems with
internal reference, 10-bit forcesense DACs, and RTC
1.15mA during operation; 2.5µA in sleep mode;
18ppm/°C (typ) reference; 2.4576MHz PLL clock
output; integrated RTC and alarm, dual voltage
monitors, comparator, interrupts, and wake-up
circuitry
Very low operating current delivers over 1500 tests
and greater than one year of battery life from a
single coin-cell battery
MAX9634
1µA, precision current-sense amp
Very low supply current reduces battery drain; tiny
28V (max) common-mode voltage, 250µV (max)
VOS, 1µA (max) quiescent current, small UCSP™ and package reduces solution size
SOT23 packages
MAX9918–MAX9920
Bidirectional current-sense amps
with wide -20V to +75V commonmode voltage
-40°C to +125°C temperature range, precision
400µV (max) VOS, ±0.45% gain error, shutdown
mode
1-Wire masters
Generates 1-Wire waveforms from UART/RS-232
command/communication, greatly simplifying host
software development
Analog front-ends (AFEs)
Integrated solution and precision measurement
simplify design for optical reflectometry and
electrochemical AC-excitation meters
Amplifiers
Current-sense amplifiers
High precision and shutdown allow small sense
resistors, which reduce power loss and BOM cost;
wide input range eliminates protection devices
(Continued on next page)
*Future product—contact factory for availability.
www.maxim-ic.com/medical
49
Home medical
Recommended solutions
Recommended solutions (continued)
Part
Description
Features
Benefits
Current-sense amplifiers (continued)
MAX9928F/
MAX9929F
Bidirectional current-sense amps
with wide 0 to 28V common-mode
voltage
Precision 400µV (max) VOS, ±1% gain error, sign
output, current output, 1mm x 1.5mm UCSP
Sign output enables full use of ADC range;
precision and small package reduce size and cost
of solution
Instrumentation amplifiers
MAX4194–MAX4197
Micropower, three-op-amp
instrumentation amps
450µV (max) VOS, 93µA quiescent current,
adjustable and fixed (1, 10, 100V/V) gain versions,
shutdown mode
Shutdown function and low-current operation save
power, thus extending battery runtime
MAX4208/MAX4209
Ultra-low offset/drift, precision
instrumentation amps with REF
buffer
20µV (max) input VOS with “zero drift,” 1pA inputbias current, 1.4µA shutdown current, fixed and
programmable gain versions available
Near-ground sensing simplifies design, while zerodrift offset preserves accuracy
MAX4464, MAX4470– Single/dual/quad, 1.8V/750nA,
MAX4472, MAX4474 SC70, rail-to-rail op amps
1.8V to 5.5V supply, 750nA/ch quiescent current,
rail-to-rail outputs, ground-sensing inputs
Low voltage, ultra-low current, and rail-to-rail
outputs extend battery life
Operational amplifiers
MAX4475–MAX4478
Precision, low-distortion, 4.5nV/√Hz 750µV (max) VOS, 10MHz op amps, 4.5nV/√Hz
op amps
noise, CMOS inputs, SOT23
MAX9617–MAX9620
High-efficiency, 1.5MHz op amps
with rail-to-rail inputs and outputs
MAX9910–MAX9913
Low-power, high-bandwidth, single/ 4µA quiescent current, 1pA IBIAS, 200kHz GBW, 1.8V
to 5.5V supply, MOS inputs, 1mV (max) VOS, SC70
dual, rail-to-rail I/O op amps with
package, independent shutdowns (dual)
shutdown
4µA quiescent current extends battery life
MAX9914–MAX9917
Low-power, high-bandwidth, single/ 20µA quiescent current, 1pA IBIAS, 1MHz GBW, 1.8V
to 5.5V supply, MOS inputs, 1mV (max) VOS, SC70
dual, rail-to-rail I/O op amps with
package, independent shutdowns (dual)
shutdown
20µA quiescent current extends battery life
MAX9060–MAX9064
Ultra-low-power single comparators
50nA/400nA comparators with and without internal
0.2V reference in space-saving UCSP
1mm2 package saves space, while 400nA current
saves power
MAX9065
Ultra-small, low-power window
comparator in UCSP/SOT23
1.0V to 5.5V supply, 1µA (max) quiescent current,
preset 3V and 4.2V thresholds
Monitoring Li+ battery voltage improves reliability
in portable applications
10µV (max) VOS with “zero drift,” 0.42µV P-P noise,
59µA quiescent current, tiny 8-pin SC70
Improve measurement accuracy when used for gain,
filtering, or driving ADC inputs
Improve measurement accuracy and reduce
calibration requirements
Comparators
Analog switches and multiplexers
Analog switches
MAX4575–MAX4577
±15kV ESD-protected, low-voltage,
dual SPST, CMOS analog switches
IEC 1000-4-2 compliant, 0.5nA (max) leakage, 2V
to 12V supply
Integrated ESD protection and low leakage improve
analog sensor measurement accuracy
MAX4624/MAX4625
1Ω, low-voltage, single-supply,
SPDT, CMOS analog switches
1Ω (5V) and 2Ω (3V) max RON, 1.8V to 5.5V supply,
SOT23
Small package enables compact design
MAX4751–MAX4753
0.9Ω, low-voltage, single-supply,
quad SPST, CMOS analog switches
0.9Ω (3V) and 2.5Ω (1.8V) max RON, 1.6V to 5.5V
supply, 1µA quiescent current
Wide operating range down to 1.6V simplifies
design and extends battery life
2mm x 2mm UCSP, 1.8V to 5.5V supply
High integration and small package shrink design
MAX4754–MAX4756* 0.85Ω, low-voltage, single-supply,
quad SPDT, analog switches in
UCSP/TQFN
Analog multiplexers
MAX4558–MAX4560
±15kV ESD-protected, low-voltage, Single 8:1 or dual 4:1 muxes, IEC 1000-4-2
CMOS analog multiplexers/switches compliant, 1.0nA (max) leakage, single 2V to 12V
supply
Integrated ESD protection simplifies design and
saves cost
(Continued on next page)
*Future product—contact factory for availability.
50
Maxim Medical Solutions
Home medical
Recommended solutions
Recommended solutions (continued)
Part
Description
Features
Benefits
Analog multiplexers (continued)
MAX4638/MAX4639
6Ω, low-voltage, analog multiplexers Single 8:1 or dual 4:1 muxes, single 1.8V to 5.5V
supply, -80dB crosstalk, -60dB off-isolation
Guaranteed specs deliver more-reliable
measurements, providing higher customer
satisfaction
MAX4734
0.8Ω, low-voltage, 4:1 analog
multiplexer in TQFN
Guaranteed specs deliver more-reliable
measurements, providing higher customer
satisfaction
MAX4781–MAX4783
0.7Ω, high-speed, low-voltage,
Excellent on/off performance up to 10MHz, 8:1
CMOS analog switches/multiplexers configuration, 1.6V to 3.6V supply
0.8Ω (3V) and 2Ω (1.8V) max RON, single 1.6V to
3.6V supply, 3mm x 3mm TQFN
Wide operating range allows use in many
applications, increasing design reuse
Audio solutions
Audio codecs
MAX9851/MAX9853
Stereo audio codecs with
microphone, DirectDrive ®
headphone amps, speaker amps, or
line outputs
1.7V to 3.3V digital supply, 2.6V to 3.3V analog
supply, 26mW playback power
Flexible solutions simplify audio design
MAX9856
Low-power audio codec with
DirectDrive headphone amps
1.71V to 3.6V supply, 30mW DirectDrive headphone
amp, 9mW playback power consumption, low noise,
clickless/popless operation, 36mm2 footprint
Complete audio-path solution improves audio
quality and extends battery life; small footprint
saves PCB space
MAX9860
16-bit, mono, audio voice codec
1.7V to 1.9V supply, 1.7V to 3.6V digital I/O supply,
30mW BTL headphone amp, dual low-noise
microphone inputs, clickless/popless operation,
16mm2 footprint
Complete audio-path solution improves audio
quality; extra-small footprint enables smaller
designs
MAX9867
Ultra-low-power stereo audio codec
1.65V to 1.95V supply, 1.65V to 3.6V digital I/O
supply, 6.7mW playback power consumption,
auxiliary battery-measurement ADC, < 6mm 2
footprint
Complete audio-path solution improves audio
quality and provides longest battery life; supersmall footprint enables smallest designs
Stereo audio DAC with DirectDrive
headphone amp
Integrated volume control, 1.8V to 3.6V supply,
clickless/popless operation
DirectDrive architecture eliminates DC-blocking
capacitors, saving board space
Shutdown and low supply voltage extend battery life
Audio DAC
MAX9850
Microphone preamplifiers
MAX4060–MAX4062
Differential microphone
preamplifiers with internal bias and
complete shutdown
2.4V to 5.5V supply, adjustable or fixed-gain
options, low input noise, 300nA shutdown, 0.04%
THD+N, TQFN
MAX9810
Electret condenser-microphone
cartridge preamplifier
2.3V to 5.5V supply, 82dB PSRR, three gain options, Tiny package shrinks design size
1mm x 1mm UCSP
MAX9812/MAX9813
Tiny, low-cost, single-/dual-input,
fixed-gain microphone amps with
integrated bias
230µA quiescent current, 20dB gain, 0.015%
THD+N, 100nA shutdown, SC70 and SOT23
Built-in bias and small package reduce solution
size; low noise and low distortion improve listening
experience
MAX4409–MAX4411
80mW, DirectDrive stereo
headphone amps with shutdown
1.8V to 3.6V supply, fixed or external gain options,
common-mode sensing option
Elimination of output capacitors improves lowfrequency audio response
MAX9720
50mW, DirectDrive stereo
headphone amp with SmartSense™
and shutdown
Auto mono/stereo detection, shutdown, fixed-gain
options, 0.003% THD+N, 1.8V to 3.6V supply
Integrated features save space and simplify design
Headphone amplifiers
(Continued on next page)
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51
Home medical
Recommended solutions
Recommended solutions (continued)
Part
Description
Features
Benefits
Headphone amplifiers (continued)
MAX9723
Stereo DirectDrive headphone amp 1.8V to 3.6V supply, 62mW DirectDrive headphone
with bass boost, volume control, and amp, 32-level volume control, 0.006% THD+N,
I²C interface
shutdown, UCSP and TQFN
Elimination of output capacitors improves lowfrequency audio response
MAX9724
60mW, fixed-gain, DirectDrive,
stereo headphone amp with low RF
susceptibility and shutdown
Click-and-pop suppression, 0.003% THD+N, shortcircuit and thermal protections, < 100nA shutdown,
UCSP and TDFN
DirectDrive architecture eliminates the need for
DC-blocking capacitors, saving board space and
cost
MAX9820
DirectDrive headphone amp with
external gain
95mW output power, high RF noise immunity,
clickless/popless operation, 3mm x 3mm TDFN
High RF immunity simplifies design
MAX9700
Mono, 1.2W, Class D audio amp
Up to 94% efficiency, filterless operation, 1.5mm x
2mm UCSP
High efficiency extends battery life; small package
minimizes solution size
MAX9705
2.3W, ultra-low-EMI, filterless,
Class D audio amp
Class D gives better efficiency, yet delivers 0.02%
THD+N
Small, efficient solution to drive headphones/
speakers
MAX9718/MAX9719
Low-cost, mono/stereo, 1.4W,
differential audio power amps
Class AB with superior THD+N down to 0.002%
Simple, high-fidelity solution reduces cost
MAX98000*
I2S, mono, Class D amp with
FLEXSOUND™ advanced audio
processing
Low EMI; 5-band parametric EQ; automatic level
control; speaker-excursion, power, and distortion
limiters
High-efficiency Class D extends battery life
MAX1736
Single-cell Li+ battery charger for
current-limited supply
Single-cell Li+, pulse topology, 4.7V to 22V input,
stand-alone or MCU controlled, 9mm2 SOT23
Smallest solution; minimal external components
saves board space and cost
MAX1811
USB-powered Li+ charger
Single-cell Li+; linear topology; charges from USB
port; 4.35V to 6.5V input
Simplest solution when USB is available
MAX8606
Dual-input (USB/AC adapter), linear
Li+ battery charger with integrated
50mΩ battery switch in TDFN
Selectable current limits, overvoltage protection,
USB or AC adapter input
Enables charging from USB or AC adapter
MAX8900A/
MAX8900B
1.2A switch-mode Li+ chargers
with ±22V input rating and JEITAcompliant battery temperature
monitoring
Single-cell Li+, switching topology, 3.4V to 6.3V or
8.7V input, 3.25MHz, small external inductor
Safest solution, less heat, highly reliable
MAX1551/MAX1555
Dual-input (USB/AC adapter),
single-cell Li+ battery chargers in
SOT23
Linear topology; automatic switchover when AC
adapter is plugged in; power-present and chargestatus indicators
Simplify design
DS2745
Low-cost, I2C battery monitor
Single-cell Li+; precision voltage, current, and
temperature monitor; works with MCU
Precision measurements increase runtime between
charges
DS2756
High-accuracy battery fuel gauge
with programmable suspend mode
Precision voltage, current, and temperature monitor;
96 bytes of EEPROM
Programmable suspend mode extends battery
runtime per charge
DS2780
Stand-alone, 1-Wire fuel-gauge IC
Single-cell Li+; FuelPack™ algorithm with precision
voltage, current, and temperature monitor; 1-Wire
multidrop interface; EEPROM storage
Stand-alone solution simplifies software
development
Speaker amplifiers
Battery management
Battery chargers
Fuel gauges
(Continued on next page)
*Future product—contact factory for availability.
52
Maxim Medical Solutions
Home medical
Recommended solutions
Recommended solutions (continued)
Part
Description
Features
Benefits
Fuel gauges (continued)
DS2782
Stand-alone fuel-gauge IC
Single-cell Li+; FuelPack algorithm with precision
voltage, current, and temperature monitor; I2C
interface; EEPROM storage
Stand-alone solution simplifies software
development
MAX17043*
Low-cost, I2C fuel-gauge IC
ModelGauge™ algorithm, 2mm x 3mm footprint,
low-battery alert, no sense resistor
Allows system μC to remain in sleep mode for
longer, thus saving power
Data converters
Analog-to-digital converters (ADCs)
MAX1162
16-bit, 200ksps SAR ADC with serial 10-pin µMAX® package, 10µA in shutdown
interface
Small package saves space, while low-power
operation reduces battery drain
MAX1226–MAX1231
12-bit, 12-channel, 300ksps SAR
ADCs with serial interface
Internal reference, internal temperature sensor,
5mm x 5mm 28-TQFN
Small package saves space for compact designs
MAX1391–MAX1396
8-/10-/12-bit SAR ADCs with serial
interface
1.5V to 3.6V supply, 305µW at 100ksps, 3.1µW at
1ksps, 3mm x 3mm TDFN
Supply voltage range eliminates regulated power
supply; low power consumption extends battery life
MAX1415/MAX1416
16-bit, 500sps sigma-delta ADCs
with serial interface
16-bit, 2-channel ADCs with PGA gains between 1
and 128; low power (1mW, max); 2µA in shutdown
Low-power operation extends battery life
MAX11600–
MAX11605
8-bit, 12-channel, 188ksps SAR
ADCs with serial interface
Internal reference
Flexible interface reduces design time and saves
space
Digital-to-analog converters (DACs)
MAX5510–MAX5515
Ultra-low-power, single/dual 8-bit
DACs
1.8V to 5.5V operation, 4µA/ch (max), internal or
Complete electrochemical sensor solutions simplify
external voltage reference, 30ppm/°C (max) tempco, design, increase accuracy, and extend battery life
voltage or force-sense outputs
MAX5520–MAX5525
Ultra-low-power, single/dual 10-bit
DACs
1.8V to 5.5V operation, 4µA/ch (max), internal or
Complete electrochemical sensor solutions simplify
external voltage reference, 30ppm/°C (max) tempco, design, increase accuracy, and extend battery life
voltage or force-sense outputs
MAX5530–MAX5535
Ultra-low-power, single/dual 12-bit
DACs
1.8V to 5.5V operation, 4µA/ch (max), internal or
Complete electrochemical sensor solutions simplify
external voltage reference, 30ppm/°C (max) tempco, design, increase accuracy, and extend battery life
voltage or force-sense outputs
Low-power digital potentiometers in
SOT23/µMAX
32 tap positions, 2.7V to 5.5V supply
Enable digital calibration at low power to save
battery life
MAX1574
180mA, 1x/2x, white LED charge
pump in 3mm x 3mm TDFN
3 LEDs (max), up to 60mA/LED, 5% to 100%
dimming via single wire, 100nA in shutdown, softstart limits inrush current
Integrated dimming saves space
MAX1848
White LED step-up converter in
SOT23
2.6V to 5.5V supply, switching topology, constantcurrent regulation, analog- or logic-controlled
intensity, soft-start
Uniform brightness provides better viewing
experience in low-light conditions
MAX1916
Low-dropout, constant-current,
triple white LED bias supply
3 LEDs (max), up to 60mA/LED, linear topology,
50nA in shutdown, SOT23
Tiny, low-cost, high-efficiency solution saves board
space and extends battery life
Digital potentiometers
MAX5160/MAX5161
Display
LED backlight drivers
(Continued on next page)
*Future product—contact factory for availability.
www.maxim-ic.com/medical
53
Home medical
Recommended solutions
Recommended solutions (continued)
Part
Description
Features
Benefits
LED backlight drivers (continued)
MAX1984–MAX1986
Ultra-efficient white LED drivers
1 to 8 LEDs; selectively enable LEDs; switching
topology; open-LED detection
Open-LED detection increases reliability
MAX8630
125mA, 1x/1.5x charge pump for 5
white LEDs in 3mm x 3mm TDFN
Up to 93% efficiency; charge-pump topology; PWM
dimming; factory-trimmed, full-scale LED current
Integrated derating function protects LEDs from
overheating, thus increasing reliability
MAX6950/MAX6951
Serially interfaced, 2.7V to 5.5V, 5and 8-digit LED display drivers
Slew-rate-limited driver ICs include blinking control
and PWM dimming with low EMI in a small 16-pin
package
Lower system cost by using simpler MCU and
offloading display control
MAX6952
4-wire-interfaced, 2.7V to 5.5V,
4-digit, 5 x 7 matrix LED display
driver
Slew-rate-limited driver IC for alphanumeric displays Lowers system cost by using simpler MCU and
includes blinking control and PWM dimming with
offloading display control
low EMI
MAX6954
4-wire-interfaced, 2.7V to 5.5V LED
display driver with I/O expander and
keyscan
Slew-rate-limited driver IC includes blinking control, Compact, low-EMI solution for medium-sized
PWM dimming, and keyscan
displays and switch arrays shortens design time
and approvals
MAX6978
8-port LED driver with fault
detection and watchdog
8 constant-current LED outputs; up to 55mA per
output; ±3% matching; serial interface; reports
open-circuit LED faults
Meets self-test requirements for displays in medical
devices, speeding design approval
MAX6979
16-port LED driver with fault
detection and watchdog
16 constant-current LED outputs; up to 55mA per
output; ±3% matching; serial interface; reports
open-circuit LED faults
Meets self-test requirements for displays in medical
devices, speeding design approval
MAX11800–
MAX11803
Low-power, ultra-small, 4-wire
resistive touch-screen controllers
with I²C/SPI™ interface
12-bit SAR ADC, 1.7V to 3.6V supply, direct and
autonomous modes, 1.6mm x 2.1mm WLP
Tiny wafer-level package enables small designs;
integration reduces cost
MAX11811
4-wire touch-screen controller with
integrated haptic motor driver
12-bit ADC, I2C interface, proximity driver, automatic Autonomous mode reduces processor burden;
power-down, direct and autonomous modes
automatic power-down extends battery life
MAX1233/MAX1234
±15kV ESD-protected, 4-wire touch- 12-bit SAR ADC, SPI interface, keypad controller,
screen controllers include DAC and low power
keypad controller
Combine touch-screen and keypad controller, which
simplifies design and saves board space; low power
extends battery life
MAX4995
50mA to 600mA adjustable current
limiter
Adjustable current limit, up to +125°C operation
Adjustability allows precision current limits, thus
enabling smaller power-supply solutions
MAX14523
250mA to 1.5A adjustable current
limiter
Adjustable current limit, up to +125°C operation
Adjustability allows precision current limits, thus
enabling smaller power-supply solutions
MAX7310
2-wire-interfaced, 8-bit I/O port
expander with reset
Bus timeout, 2.0V to 5.5V supply
Lockup-free operation increases reliability; low
supply voltage simplifies design
MAX7315
8-port I/O expander with LED
intensity control, interrupt, and hotinsertion protection
2.0V to 3.6V supply, 50mA output drive, global and
individual PWM intensity control with blinking
Ability to drive heavier loads makes designs more
robust
LED display drivers
Touch-screen controllers
Interface
Current limiters
I/O expanders
(Continued on next page)
54
Maxim Medical Solutions
Home medical
Recommended solutions
Recommended solutions (continued)
Part
Description
Features
Benefits
I/O expanders (continued)
MAX7318
2-wire-interfaced, 16-bit, I/O port
expander with interrupt and hotinsertion protection
Bus timeout, 2.0V to 5.5V supply
Lockup-free operation improves reliability; lower
supply voltage simplifies design
MAX7323
I2C port expander with four pushpull outputs and four open-drain
I/Os
1.71V to 5.5V supply, I2C interface, 20mA sink,
10mA source
Low-voltage operation and I/O flexibility make
design easier
MAX7328–MAX7329
I2C port expanders with eight I/O
ports
2.5V to 5.5V supply; address up to 16 devices with
100kHz I2C interface; 10µA quiescent current
Expand port pins without having to switch to a more
costly microcontroller
MAX13030E
6-channel, high-speed logic-level
translator
100Mbps (max) data rate, bidirectional, ±15kV HBM
ESD protection on I/O VCC lines, 2mm x 2mm UCSP
ESD protection with low capacitance enables high
data rates
MAX13101E
16-channel logic-level translator
20Mbps (max) data rate, bidirectional, ±15kV HBM
ESD protection on I/O VCC lines, 3mm x 3mm WLP
Integrates level translation with ESD protection in a
space-saving package
MAX3349E
Full-speed USB transceiver with
UART multiplexer
Full-/low-speed USB, ±15kV ESD protection on
D+/D- lines
Increases reliability and reduces size by functionally
sharing a USB connector
MAX3453E–
MAX3456E
±15kV ESD-protected USB
transceivers
Full-/low-speed USB, ±15kV ESD protection on
D+/D- lines, 1.65V to 3.6V logic supply
Increase reliability by protecting high-data-rate
interfaces
MAX13481E–
MAX13483E
±15kV ESD-protected USB
transceivers with external/internal
pullup resistors
Full-speed USB, ±15kV ESD protection on D+/Dlines, 1.6V to 3.6V logic supply
Compatible with low-voltage ASICs and ASSPs,
thus eliminating the need to add an interface chip
Low-profile, 3V, 120µA, IrDA
infrared transceiver
IrDA 1.2 compatible, 115.2kbps (max), 120µA (typ)
supply current, 10nA (typ) shutdown current
Infrared transceiver allows for optimal placement of
optical components
MAX3221E/
MAX3223E/
MAX3243E
±15kV ESD-protected RS-232
transceivers
1/1, 2/2, and 3/5 driver/receiver options
AutoShutdown™ extends battery life
MAX3224E–
MAX3227E,
MAX3244E/
MAX3245E
±15kV ESD-protected, 1µA,
1Mbps RS-232 transceivers with
AutoShutdown Plus™
1/1, 2/2, and 3/5 driver/receiver options; UCSP
option; 2.35V, 2.5V, or 3.0V to 5.5V supply options
Increased reliability; small solution size can be
located on main board or in cable
MAX3202E–
MAX3204E,
MAX3206E
Low-capacitance,
2-/3-/4-/6-channel, ±15kV ESD
protection arrays
5pF input capacitance, 1nA input-leakage current,
1nA supply current, tiny footprint
Easily comply with IEC 61000-4-2 ESD protection
MAX3205E/
MAX3207E/
MAX3208E
Low-capacitance, 2-/4-/6-channel,
±15kV ESD protection arrays with
TVS
2pF input capacitance, integrated transient-voltage
suppressor
Increase reliability by protecting high-data-rate
interfaces
MAX9940
Signal-line overvoltage protector
Small SC70, low supply current, ±4kV IEC Contact
protection
Protects low-voltage circuitry from high-voltage
faults, thus improving reliability
Logic-level translators
USB transceivers
IrDASM product
MAX3120
RS-232 drivers/receivers
ESD/line protection
(Continued on next page)
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55
Home medical
Recommended solutions
Recommended solutions (continued)
Part
Description
Features
Benefits
ESD/line protection (continued)
MAX13202E/
MAX13204E/
MAX13206E/
MAX13208E
Low-capacitance,
2-/4-/6-/8-channel, ±30kV ESD
protection arrays
6pF input capacitance, 1nA input-leakage current,
±30kV ESD protection
Increase reliability by protecting high-data-rate
interfaces
MAX7347–MAX7349
2-wire-interfaced, low-EMI keyswitch controllers
Monitor up to 24, 40, or 64 keys; low-voltage design; Independent key controllers free up microcontroller
key debounce
I/O and reduce software complexity
MAX7359
2-wire-interfaced, low-EMI keyswitch controller/GPO
Monitors up to 64 keys, low-voltage design, key
debounce, key-release detection
Independent key controller frees up microcontroller
I/O and reduces software complexity
MAX6816–MAX6818
Single, dual, and octal switch
debouncers
±15kV ESD protection
Improve reliability; ease of use simplifies design
MAX16054
Pushbutton on/off controller
±15kV ESD protection
Improves reliability; small size saves space
MAXQ610
Low-power, 16-bit microcontroller
with IR module
1.7V to 3.6V supply, up to 32 GPIOs, IR module, ring Low operating voltage for longer battery life
oscillator, wakeup timer, 200nA stop-mode current
MAXQ612/MAXQ622
Low-power, 16-bit microcontrollers
with IR module and optional USB
1.7V to 3.6V supply, 128KB flash, USB 2.0
transceiver, IR module, up to 52 GPIOs
Extended battery life and easier data transfer from
portable device
MAXQ2000
Low-power, 16-bit LCD
microcontroller
20MHz operation, 64KB flash, hardware multiplier,
132-segment LCD controller, 32-bit RTC, 700nA
stop-mode current
High integration saves board space; low-power
architecture extends battery life
MAXQ2010
Low-power, 16-bit mixed-signal
LCD microcontroller
8-channel, 12-bit SAR ADC; 64KB flash; supply
voltage monitor; hardware multiplier; 160-segment
LCD controller; 370nA stop-mode current
Powerful, integrated microcontroller saves space in
battery-powered applications
MAXQ8913
16-bit mixed-signal microcontroller
7-channel, 12-bit SAR ADC; 64KB flash; two 10-bit
DACs; two 8-bit DACs; four op amps; temp sensor;
two current sinks
Single chip integrates multiple functions to
minimize solution size
Keyboard scanners
Switch debouncers
Microcontrollers
Power management
Switching regulators
MAX1722–MAX1724
1.5µA IQ, step-up DC-DC converters 0.91V startup, 150mA output current, 90%
in thin 5-SOT23
efficiency, internal EMI suppression, 100nA in
shutdown
0.91V startup enables single-cell operation, saving
space, weight, and cost
MAX1832–MAX1835
High-efficiency step-up converters
with reverse-battery protection
4µA quiescent current, 1.5V startup, 150mA output
current, 90% efficiency, < 100nA in shutdown,
battery connected to OUT in shutdown
Simplify electromechanical design with integrated
reverse-battery protection; turn off power supply
when not in use to save power
MAX1947
Boost regulator for single alkalinebattery input
Low 0.7V input, internal synchronous switches,
2MHz switching, 94% efficiency, True Shutdown™,
reset flag
Harvests more energy from alkaline cells to extend
battery life; high switching frequency reduces
external component size
MAX8569
200mA step-up converter in 6-pin
SOT23 and TDFN
1.5V startup, 200mA output current, 95% efficiency,
< 100nA in shutdown, battery connected to OUT in
shutdown
Turns off power supply when not in use to save
power; increases efficiency by running directly off
of batteries
MAX8625
High-efficiency, seamless-transition, 2.5V to 5.5V supply, glitch-free buck-boost
step-up/down DC-DC converter
transitions, 92% efficiency, PWM or skip modes,
output overload protection
Wide input range maximizes battery life from
single-cell Li+
(Continued on next page)
56
Maxim Medical Solutions
Home medical
Recommended solutions
Recommended solutions (continued)
Part
Description
Features
Benefits
Linear regulators
MAX6469–MAX6484
300mA LDO linear regulators with
114mV dropout at 300mA, preset 1.5V to 3.3V in
Integrated reset saves cost and space by eliminating
internal microprocessor-reset circuit 100mV steps, 82µA supply current, 100nA shutdown need for a separate voltage supervisor
current
MAX8860
300mA LDO linear regulator in
µMAX®
60µV RMS output noise, 105mV dropout at 200mA,
Reverse-battery protection simplifies design; small
120µA quiescent current, reverse-battery protection, input and output capacitors save board space
small 2.2µF I/O capacitor
MAX8902A/
MAX8902B
Low-noise, 500mA LDO linear
regulators in a 2mm x 2mm TDFN
16µV RMS; 100mV (max) dropout at 500mA; ±1.5%
accuracy over load, line, and temperature; shutdown
mode; soft-start
Low noise and high accuracy enable optimal
performance from sensitive analog circuits
Power-management IC (PMIC)
MAX1565
Five-output power-supply IC
Five switching regulators at 1MHz; 1µA in shutdown; Complete power-management solution in one IC
supplies for motor, main, core, and LCD from supply saves board space
down to 0.7V
MAX6006–MAX6009
Precision shunt voltage references
in SOT23
1µA operating current, ±0.2% accuracy, wide
operating range (1µA to 2mA)
MAX6018
Precision, micropower, low-dropout, 1.263V to 2.048V VOUT, ±0.2% to ±0.4% accuracy,
1.8V supply, 5µA quiescent current
series voltage reference in SOT23
MAX6023
Precision, low-power, low-dropout
voltage reference in UCSP
1.25V to 5V VOUT, ±0.2% initial accuracy, 30ppm/°C Small package fits in space-constrained designs
tempco, 1mm x 1.5mm x 0.3mm package
MAX6029
Ultra-low-power, precision series
voltage reference
5.25μA quiescent current, 30ppm/°C tempco, no
external capacitors needed
Ultra-low operating current saves power; stability
over temperature increases reliability
MAX6034
Precision, micropower, series
voltage reference in small SC70
2.048V to 4.096V VOUT, ±0.2% accuracy, 30ppm/°C
tempco, 90µA quiescent current
Small SC70 package eases layout and saves board
space
MAX6381–MAX6390
Single/dual, low-power µP reset
circuits in SC70/µDFN
Multiple thresholds and timeout options; only a few
external components
Versatility eases design reuse; small package saves
space in small systems
MAX6443–MAX6452
Single/dual µP reset circuits with
manual-reset inputs
Two manual-reset inputs with extended setup period Avoid nuisance resets; eliminate the need for a
(6.72s), precision voltage monitoring down to 0.63V pinhole in the equipment case
MAX16056–
MAX16059
Ultra-low-power supervisory ICs
with watchdog timer
125nA supply current, capacitor-adjustable timing
Save power and battery life; adjustable timeouts
allow one IC to be used across multiple applications
MAX16060–
MAX16062
Quad-/hex-/octal-voltage µP
supervisors
Fixed and adjustable thresholds and timeouts,
margin-enable and tolerance-select inputs,
watchdog timer
Breadth of features and options provides flexibility
to meet many design needs, increasing design
reuse
MAX16072–
MAX16074
µP supervisory circuits in chip-scale 1mm x 1mm UCSP, 0.7µA supply current
package
Voltage references
Ultra-low operating current saves battery life
Low operating current extends battery life
Voltage supervisors
Small package saves space, while low-power
operation extends battery life
RF solutions
ISM transceivers
MAX2830
2.4GHz to 2.5GHz RF transceiver
with power amplifier
2.4GHz to 2.5GHz ISM band operation; IEEE �
802.11g/b compatible; complete RF transceiver, PA,
and crystal oscillator
MAX7030
Low-cost, 315MHz, 345MHz, and
433.92MHz ASK/OOK transceiver
with fractional-N PLL
2.1V to 3.6V or 4.5V to 5.5V supply, no programming Factory programmed for faster and simpler product
required, low current (< 6.7mA Rx, < 12.5mA Tx),
design; low-voltage operation and low current for
5mm x 5mm TQFN
long battery life
Saves space by eliminating the need for an external
SAW filter
(Continued on next page)
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57
Home medical
Recommended solutions
Recommended solutions (continued)
Part
Description
Features
Benefits
ISM transceivers (continued)
MAX7031
Low-cost, 308MHz, 315MHz, and
433.92MHz FSK transceiver with
fractional-N PLL
2.1V to 3.6V or 4.5V to 5.5V supply, no programming Factory programmed for faster and simpler product
required, low current (< 6.7mA Rx, < 12.5mA Tx),
design; 5mm x 5mm package enables small form
5mm x 5mm TQFN
factor
MAX7032
Low-cost, crystal-based,
programmable ASK/FSK/OOK
transceiver with fractional-N PLL
2.1V to 3.6V or 4.5V to 5.5V supply, no programming Factory programmed for faster and simpler product
required, low current (< 6.7mA Rx, < 12.5mA Tx),
design; low-voltage operation and low current for
5mm x 5mm TQFN
long battery life
ISM transmitters
MAX2900–MAX2904
200mW single-chip transmitter ICs Compliant with FCC CFR 47 Part 15.247 for the
for 868MHz and 915MHz ISM bands 902MHz to 928MHz ISM band and/or ETSI EN330220 for the European 868MHz ISM band
High level of integration minimizes the number of
external components, thus saving board space and
simplifying design
MAX1472
Low-power, 300MHz to 450MHz,
crystal-based ASK transmitter
Wide frequency range, low-current operation
(5.3mA, operating), 3mm x 3mm package
Crystal stability increases performance, while low
power consumption increases battery life
MAX1479
Low-power, 300MHz to 450MHz,
crystal-based ASK/FSK transmitter
Wide frequency range, low-current operation (6.7mA Crystal stability increases performance, while low
in ASK mode, 10.5mA in FSK mode)
power consumption increases battery life
MAX7057
300MHz to 450MHz, crystal-based
ASK/FSK transmitter
Wide frequency range, programmable synthesizer,
antenna-matching network
High efficiency in the 300MHz to 450MHz band
reduces transmit time, saving power and extending
battery life
MAX1471
Programmable, 300MHz to 450MHz
ASK/FSK receiver
High sensitivity, built-in image rejection, and
separate ASK/FSK data paths in a 5mm x 5mm
package
High sensitivity simplifies design while keeping
power low
MAX1473
300MHz to 450MHz ASK receiver
with AGC
High sensitivity, AGC, and built-in image rejection in Built-in image rejection provides a more-reliable
a 5mm x 5mm package
wireless link
MAX7042
300MHz to 450MHz FSK receiver
Best FSK sensitivity and built-in image rejection in a FSK sensitivity improves wireless reception; saves
5mm x 5mm package
board space
DS1337
I2C RTC with time-of-day alarm and
trickle charger
Single 1.8V to 5.5V supply, 1.3V timekeeping
voltage, two time-of-day alarms, leap-year
compensation, 32kHz square-wave output,
integrated-crystal option
Single supply reduces pin count where small
packages and simple routing are the primary
concerns
DS1341
Low-current, I2C RTC for high-ESR
crystals
Compatible with crystal ESR up to 100kΩ; low
timekeeping current of 250nA (typ)
Ability to drive high-ESR crystals allows use of any
commercially available crystal including smallest
surface-mount form factors, thus reducing cost and
board space
DS1372
I2C, 32-bit binary counter clock with
64-bit ID
Unique 64-bit serial number and a programmable
alarm
Serial number provides a method of identifying
systems without adding an extra component or
programming step, thus reducing board size and
simplifying design
DS1388
I2C RTC/supervisor with trickle
charger and 512 bytes of EEPROM
High level of integration (RTC, supervisor, watchdog
timer), 512 bytes of EEPROM, backup supply
voltage, trickle-charge capability
High level of integration saves board space and cost
DS1390–DS1394
Low-voltage, SPI/3-wire RTCs with
trickle charger
Separate SQW and INT outputs, trickle-charge
capability, UL® recognized, time-of-day alarm,
automatic backup power switching
Automatic backup power switching ensures reliable
timekeeping when main power fails
ISM receivers
Real-time clocks (RTCs)
(Continued on next page)
58
Maxim Medical Solutions
Home medical
Recommended solutions
Recommended solutions (continued)
Part
Description
Features
Benefits
Sensors
Temperature sensors
DS18B20
±0.5°C accurate, 1-Wire digital
temperature sensor
±0.5°C accuracy, 1-Wire interface, unique 64-bit
serial number
Simplifies interface when deploying multiple
distributed precision sensors
DS600
±0.5°C accurate analog-output
temperature sensor
Industry’s most accurate analog temperature sensor: Improves system temperature-monitoring accuracy
±0.5°C accuracy from -20°C to +100°C
and is easy to design with
DS75LV
Low-voltage, ±2.0°C accurate digital ±2°C accuracy from -25°C to +100°C, 1.7V to 3.7V
thermometer and thermostat
operation, industry-standard pinout and registers
Industry-standard pinout facilitates migration from
LM75 to lower supply voltage
DS7505
Low-voltage, ±0.5°C accurate digital ±0.5°C accuracy from 0°C to +70°C, 1.7V to 3.7V
thermometer and thermostat
operation, industry-standard pinout and registers
Industry-standard pinout allows easy accuracy
upgrade and supply voltage reduction from LM75
MAX6612
Small, low-power analog
temperature sensor
19.5mV/°C slope, ±3°C accuracy from 0°C to
+70°C, SC70, 35µA (max) quiescent current
Small, low-power solution saves board space and
extends battery life
Withstands 60V voltage transients and ±15kV ESD
spikes; built-in diagnostics; controlled ramp for
Hall-effect sensor power
Integrated ESD and diagnostics increase product
reliability while saving space
Hall-effect sensor interface
MAX9921
Dual, 2-wire Hall-effect sensor
interface with diagnostics
www.maxim-ic.com/medical
59
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