null  User manual
POWER SUPPLIES ANALOG
DESIGN GUIDE
Data Sheets
Applications Notes
•
N
DITIO
E
d
22n
Free Samples
•
Smallest Dual-Output Supply
for PDAs: Logic Step-Down and
LCD Step-Up
4
High-Efficiency Hand-Held Supply Fits Internal Switches into a
12-Pin QFN Package
STEPS DOWN TO 1.25V FOR NEWEST LOGIC CHIPS
10µH
INPUT
2.0V TO 5.5V
IN QFN
2-P
4m m x
0.1µF
FBLCD
AIN1
mm
4mm
x
LCD OUTPUT
UP TO 28V
UP TO 10mA
LXLCD
AIN2
85
1
IN
0.
MAX1878
LOGIC
OFF
LCD
OFF
10µH
ON
ON
LX
ON
ONLCD
LOGIC OUTPUT
1.25V TO VIN
UP TO 500mA
FB
PGND AGND PGNDLCD
Packaged in a 0.85mm high, 4mm x 4mm QFN, the MAX1878 is the
simplest and smallest single-chip solution providing both logic and LCD
power for PDAs and hand-held products. For the logic supply, it uses a
high-efficiency (90%) step-down DC-DC converter with synchronous rectification that eliminates the need for an external diode, saving cost and size.
For the LCD supply, the internal switch is capable of supplying outputs as
high as 28V. Each output has its own logic-controlled enable.
• Dual-Output:
• Step-Down: Logic Supply Down
to 1.25V
• Step-Up: LCD Supply Up to 28V
• Smallest Package: 4mm x 4mm
12-Pin QFN
• Small External Components:
10µF and 10µH
• 90% Efficiency
• Low 19µA Quiescent
Supply Current
• Evaluation Kit
Available to Speed
Designs
• Priced at $1.57†
†1000-up recommended resale. Price provided is for design guidance and is FOB USA. International prices will differ due to local duties,
taxes, and exchange rates. Not all packages are offered in 1k increments, and some may require minimum order quantities.
is a registered trademark of Maxim Integrated Products, Inc. © 2002 Maxim Integrated Products.
ANALOG
DESIGN GUIDE
1
2
3
Multiplexers, Switches
Interface Products
4
DC-DC Converters,
Power Supplies
µP Supervisory
5
6
7
8
9
10
11
12
Op Amps, Comparators
Analog Filters
A/D Converters
Video/High-Speed Amps
D/A Converters
Analog Functions
Voltage References
Temperature Sensors
13
High-Speed
ADCs & DACs
14
Signal Conditioners
Smallest, Highest Efficiency
Multi-Output DC-DC Converter
Compact, Cost-Effective, Integrated Power Supply Solutions for
Digital Cameras and PDAs
Use the MAX1800 step-up master or the MAX1802 step-down master to provide all the voltage
outputs required in your digital camera and PDA designs from a single IC. They include high-efficiency DC-DC converters with synchronous rectifiers to give over 90% efficient power conversion for
the logic supply, which uses >50% of the power in a camera system. They come in a small 32-pin
5mm x 5mm TQFP, which is 40% smaller than existing TQFP solutions. The MAX1800 and MAX1802
also eliminate external components such as power diodes, power switches, and at least one
transformer to save cost and size. For flexibility, add the low-cost, 8-pin SOT23 MAX1801 “slave”
controller to create optional features like a motor control supply for zooming and focusing. The
MAX1800/MAX1802 can provide all the voltages for logic, core, backlighting, LCD, and expansion
port of PDAs.
EXAMPLE OF A COMPLETE DIGITAL CAMERA POWER SUPPLY
(CAN ALSO BE USED IN PDAs)
INPUT
0.7V TO 5.5V
EIGHT OUTPUTS
P OUT1
3.3V
LOGIC
1.8V
CORE
7.0V
CCFL MODULE
N
P
LDO
OUT2
VIN
N
VIN
MAX1800
15.0V
CCD BIAS
STEP-UP
MASTER
MAX1800 STEP-UP MASTER
MAX1802 STEP-DOWN MASTER
OUT3
MAX1801 SLAVE CONTROLLER
8-PIN SOT23
2.8mm x 2.9mm
32-PIN TQFP—5x5*
7mm x 7mm x 1mm
-7.5V
N
VIN
18.0V
LCD BIAS
12.0V
(DIMENSION INCLUDES LEADS)
VIN
OUT4
OUT1 ON
ON
OFF
1-, 2-, 3-, or 4-Cell Designs
MAX1800
N
OUT2 ON
OUT3 ON
OSC
OUT4 ON
LDO ON
REF
OSC SLAVE
CONTROLLER
REF
DL
MAX1802
Step-Down
0.7V to 5.5V Input
2.5V to 11V Input
One Li+,
Two or Three Alkaline
Two Li+,
Four Alkaline
Internal Step-Up,
Three Step-Up Controllers,
LDO Controller
Step-Down Controller,
Three Step-Up Controllers,
Internal Step-Down
N
VIN
GND
Step-Up,
Step-Up/Down
5.0V
MAX1801
*Dimensions include 5mm body plus 1mm for the length of each lead for a total of 7mm.
DL
ADD UP
TO FIVE SLAVE
CONTROLLERS
5.0V
MAX1801
OSC SLAVE
CONTROLLER
REF
N
ZOOM
MOTOR DRIVE
(OPTIONAL)
LENS COVER
DRIVE
(OPTIONAL)
Lowest Cost Three- and Five-Output
xDSL and Cable Modem Power Supplies
High-Efficiency Step-Down Controller Plus Multiple LDO Controllers
on a Single IC
COMPLETE, LOW-COST, FIVE-OUTPUT xDSL MODEM SUPPLY
FIVE OUTPUTS
DH
V+
3.3V
1A
DL
Q
-PIN S
2.5V
500mA CORE
LDO1
m x .9 m
4
5V
100mA AFE
MAX1865T
12V
POSITIVE
100mA LINE DRIVER
1865
OP
20
LDO2
Q
-PIN S
LDO3
m
-12V
NEGATIVE
100mA LINE DRIVER
m
6m
m
I/O
N
m
1864
N
OP
16
INPUT
LOW-COST
ADAPTER
4.5V TO 28V
6m
• No Current-Sense
Resistors Mean
Less Cost
• Step-Down Output:
1.25V to 5.5V
• LDO Outputs:
±1.25V to ±15V
• Power-OK Checks All
Outputs
• EV Kit Available to
Speed Designs
x 8.65
LDO4
GND
POK
POWER OK
SIGNAL
Use the MAX1864 and MAX1865 power-supply controller ICs to build the lowest cost xDSL and
cable modem consumer premises equipment (CPE) power supplies. They integrate a high-efficiency
step-down DC-DC controller and two to four linear regulator controllers that provide all the required
voltages for CPE. The current-mode step-down controller uses an external, dual N-channel MOSFET to
provide low-cost synchronous rectification for high efficiency and low heat. To further save cost, no
external current-sense resistor is required. Switching frequencies of 100kHz and 200kHz permit the
use of low-cost magnetics and aluminum electrolytic capacitors. The linear regulator controllers drive
inexpensive external bipolar junction transistors (B JTs).
MAX1864
• Step-Down Controller
• Two Positive LDO Controllers
• 16-Pin QSOP Package
MAX1865
• Step-Down Controller
• Three Positive LDO Controllers
• One Negative LDO Controller
• 20-Pin QSOP Package
110V Power Supply Controller
Integrates High-Voltage Startup FET
Optimized for Telecom and
• Up to 300kHz Operation for Smaller
Magnetics and Capacitors
Data Communications Applications
• Wide 11V to 110V Input Voltage Range
VIN (UP TO 110V)
• Guaranteed ±2.5% VREF Accuracy
• Only 2.2mA Supply Current
V
• Input Feed-Forward
Compensation for Fast LineV
Q
N
I
Transient Response
S
N_DRV
-P
• Programmable: Current
CS
0m
Limit, Maximum Duty
m x 5.84
R
Cycle, Oscillator
MAX5003
43% SMALLER FOOTPRINT
THAN COMPETITOR’S SO-14
Frequency, Undervoltage
Lockout, and Soft-Start
HV PWM
INTERNAL
CONTROLLER
OPTOCOUPLER
• External Frequency Synchronization
110V STARTUP
FEEDBACK
TRANSISTOR
ISOLATION
• MAX5003 EV Kit Available to Speed
Designs
CC
OP
4.8
m
m
16
IN
SENSE
Low-Cost, Dual-Output SLIC Supply
Uses Standard Transformer
STANDARD TRANSFORMER FROM
MULTIPLE VENDORS
REDUCES COST
OUTPUT 1
-72V, 100mA RING BATTERY
INPUT
8V TO 24V
VCC
LOW-COST
UNREGULATED
AC-DC
ADAPTER
OUTPUT 2
-24V, 400mA TALK BATTERY
MAX1856
SYNC
SYNC SIGNAL
(OPTIONAL)
FREQ
DIGITAL
SOFT-START
OUTPUT VOLTAGE CAN BE SET
TO OPTIMIZE SHORT-LOOP OR
LONG-LOOP OPERATION WITH
VARIOUS SLIC ICs
FREQUENCY
SELECT
(100kHz TO 500kHz)
EXT
GND
N
FLYBACK TOPOLOGY REDUCES
INPUT RIPPLE CURRENT
EVALUATION KIT AVAILABLE TO SPEED DESIGNS. The MAX1856 can be configured to work with different input and
output voltages from those shown in this block diagram. For further information, please contact your local Maxim FAE or email us
at [email protected]
VOUT
5V
Industry’s First Hot-Swap Switches
for Power-Over-LAN
Simple-Swappers™ Require No Design and No External Components
65V SWITCH IS IEEE802.3af COMPATIBLE
DATA TERMINAL EQUIPMENT
BACKPLANE
(+10V TO +65V)
• IP Phone
MAX5910
MAX5917
VIN
VOUT
ENABLE
SAFELY CONNECT YOUR
DATA TERMINAL EQUIPMENT
TO A SWITCH/ROUTER
POWER SOURCE.
N.C.
• Wireless LAN Access Node
(Eliminates AC Adapter)
GND
UVLO
• Security Camera
(Eliminates AC Adapter)
FAULT
PGOOD
Beats Competition 3 Ways
1) First IEEE802.3af-Compatible
Hot-Swap Switch
2) Highest Integration
• Drives 500µF at Startup
• Internal Switch Delivers 26W
of Power
• 500mA Output Current at
Startup
• Built-In Undervoltage Lockout
(UVLO)
• Input Voltage Range:
+10V to +65V
• Power Good Output Monitors:
UVLO, Power Not Good, and
Thermal Shutdown
3) Smallest Board Space and
Lowest Cost
• Requires No External
Components
• 60% Less Board Space than
Discrete Solutions
• 8-Pin or 16-Pin SO Packages
-48V SWITCH DELIVERS POWER AND DATA OVER
STANDARD CATEGORY 5 CABLE
MONITORS UVLO
POWER NOT GOOD,
LOAD DISCONNECT
& THERMAL SHUTDOWN
-16V to -65V
COMPATIBLE WITH
3.3V AND 5V LOGIC
♦ 2Ω INTERNAL POWER
SWITCH
♦ DELIVERS 13W POWER
(20W FOR MAX5912)
♦ DISCONNECTS LOAD AT
“ZERO CURRENT”
♦ SAFE HOT SWAP
WITHSTANDS
-70V TRANSIENTS
ON/OFF
UVLO
ADJUST DEFAULT
UVLO THRESHOLD
WITH EXTERNAL
RESISTOR DIVIDER
Part
GATE
VIN
FAULT OUTPUT
MAX5911/
MAX5912
SIMPLE
SWAPPER™
VOUT
AGND
DGND
Output Current Limit
(mA)
CAN VARY ±5V
WITH RESPECT
TO AGND
Pin-Package
MAX5910
280
8-SO
MAX5911
280
8-SO
MAX5912
415
16-SO
MAX5917A
567
16-SO
MAX5917B
420
16-SO
Simple-Swapper is a trademark of Maxim Integrated Products, Inc.
Highest Power Step-Up DC-DC
Delivers 20W to Replace Modules
Drop-In, Internal Switch 20W PWM Design in SO Package
MAX1708
16-PIN QSOP
NETWORK OR TELECOM CARD
INPUT
0.7V to 5V
LOCAL ISOLATED
3.3V POWER BUS
1µH
5A MOSFET
MAX1709
MAX1709
ON
16-PIN NSO
OFF
600kHz OR
SYNCHRONIZABLE
PROGRAMMABLE
CURRENT LIMIT
AND SOFT-START
RACK-MOUNTED
TELECOMMUNICATIONS
SYSTEM
28-PIN QSOP
OUTPUT
5V/4A
LOCAL
POWER BUS
9A MOSFET
The MAX1708 and MAX1709 set a new standard of space savings for high-power step-up DC-DC
conversion. The MAX1709 packs a 22mΩ, 9A, power MOSFET into a small SO package. It operates
from inputs in the 0.7V to 5V range, and provides up to 20W at fixed (3.3V or 5V) or adjustable (2.5V
to 5.5V) voltages. For lower power applications, choose the MAX1708, which provides up to 10W (5V at
2A) in a smaller 16-pin QSOP package. For added flexibility, both devices include programmable softstart and current limit, allowing external components to be optimized when less than full-power
capability is required.
Simplest SOT23 Step-Up Controllers
Use Fewest Components
SIMPLEST AND SMALLEST BOOST CONTROLLER CIRCUIT
ELIMINATES INRUSH CURRENT
POWER INPUT
1V TO VOUT
SOFT-START RESPONSE
VCC INPUT
2.5V TO 5.5V
OUTPUT
>VIN
UP TO
30W
MAX1522
MAX1523
MAX1524
EXT
ON
SHDN
OFF
GND
FB
N
VOUT, 5V/div
VSHDN, 5V/div
SO
PIN T
23
6-
VIN = 3V
VOUT = 12V
RLOAD = 200Ω
ILOAD = 60mA
VCC
m
2.9
m
m
IL, 1A/div
m x 2.8
400µs/div
Built-in soft-start eliminates inrush current spikes, permitting use of a smaller and lower
cost input capacitor and inductor. The costly sense resistor is also eliminated.
Use the MAX1522/MAX1523/MAX1524 DC-DC controllers to build the simplest and smallest
step-up circuits. These SOT23 controllers have an internal digital soft-start that eliminates the inrush
current spikes that shorten useful battery life. Soft-start also permits a smaller input capacitor. These
controllers eliminate the sense resistor to increase efficiency while saving space and cost. Finally, they
switch at up to 1MHz, permitting the use of a small inductor.
Highest Power, Low-Voltage, Boost
DC-DCs Are Now Smaller
50% Smaller Packages, 0.7V Startup Voltage, Up to 1.5A Output,
1MHz Switching (or Synchronize from 500kHz to 1.25MHz)
The MAX1760/MAX1763/MAX1765 are 50% smaller upgrades to the popular MAX1700 family of
low-voltage, high-power, high-efficiency PWM step-up DC-DC converters. The MAX1760 family
features smaller external components, adjustable current limit, and soft-start. They deliver more
power from low voltages than any other step-ups available: 1.5A from 3.6VIN (single Li+) and 400mA
from 1.2VIN (single NiMH or alkaline). Input range is 0.7V to 5.5V. Switcher output range is 2.5V to
5.5V. The MAX1763 and MAX1765 include a linear regulator for a second output.
HIGHEST POWER
INPUT
LX
DC/DC OUT
ON
DC/DC
OFF
ON
IN QSO
6-P
GND
P
16
IN QSO
6-P
OR
m
m
mm
m
1m
m
m
.
5m
.3 m m x 1
m
x6
4.9
m
x 6 m m x 1.
5m
m
m
1
mm x
1.5W
PACKAGE
S
IN T SOP-E
-P
P
1.5W
PACKAGE
S
IN T SOP-E
-P
OUTPUT
3.3V
UP TO 500mA
ON
OFF
P
1
LDO DR
FB
LX
OUT
OR
4.9
4.9
GND
P
X
1
LDO
OFF
IN µMA
0-P
3mm
x
ON
GND
OFF
7m
ON
.1
ON
MAX1765
m
MAX1763
OUTPUT
UP TO 5.5V
UP TO 500mA
OUT
x 6 m m x 1.
x6
1m
LX
MAX1760
INPUT
DUAL OUTPUTS
1 x Li+
SYSTEM POWER
2.5V TO
5V OR 3.3V
4.2V
UP TO 1.5A
CORE POWER
3.3V OR 1.5V
UP TO 1.5A
INL
1 x Li+
OR
2AA
7m
1 x Li+
OR
2AA
16
INPUT
STEP-UP/DOWN
1
SMALLEST PACKAGE
.3 m m x 1
.
EVALUATION KIT AVAILABLE TO SPEED DESIGNS. Conceptual schematics; not all components are shown.
Regulated Step-Up/Down Charge
Pump Delivers Guaranteed 125mA
STEP-UP/DOWN REGULATION
NO INDUCTOR, ALL CERAMIC CAPACITORS
0,22µF
EINGANG
1,8V
BIS
5,5V
GEREGELTE AUFWÄRTS-/ABWÄRTSWANDLUNG MIT 1 KONDENSATOR
CXP
MAX1595-33
MAX1595-50
IN
AUSGANG
5V ODER 3,3V
125mA
OUT
ON
1µF
1µF
SHDN
GND
1,48W
Verlustleistung
€1,69*
1mm
6.0
VOUT = 5.0V, ILOAD = 125mA
5.0
4.0
3.0
VOUT = 3.3V, ILOAD = 75mA
2.0
1.0
1,
3,1
x 4mm x
x
m
1m
ODER
N µMA
-PI
5mm
4m
m
8
IN QFN
2-P
X
1
OFF
Delivers 5V or 3.3V from a 1.8V to 5.5V
Input with No Inductors
OUTPUT VOLTAGE (V)
CXN
mm x
Preisgünstig mit
0,36W Verlustleistung
€1,60*
0
0
1.0
2.0
3.0
4.0
5.0
INPUT VOLTAGE (V)
WÄHLEN SIE
LEISTUNG ODER
PREIS
†1000-up recommended resale. Price provided is for design guidance and is FOB USA. International prices will differ due to local duties, taxes, and exchange rates.
6.0
New! Schematics and Bills of
Materials Online
Choose Proven, Lab-Tested Circuits from Maxim’s Growing Library of
Applications
Maxim has placed over 30 useful power-supply application circuits on our website for you to
browse and download. You can sort the list by topology, input voltage, or output voltage and download
schematics and component bills of materials, including part numbers and vendor names. You can also
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additions. Visit http://dbserv.maxim-ic.com/PowerSupplies.cfm
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Current
Input Voltage
(V)
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(V)
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(A)
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Schematic and
Bill of Materials
Key Attributes
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Evaluation
Board
Schematic and
Bill of Materials
Evaluation
Board
5
1.2
6
Tracking supply for DDR termination
Download
Request
Step-Up
2.5
5
3
Internal switch, smallest size, synchronization
Download
Request
Inverter
3.3
-5.2
0.3
<3mm profile, very low ripple
Download
Request
Multi-Output
12
3.3, 2.5, 1.8, -4.8
1, 0.3, 0.2, 0.06
Low-cost, single controller design
Download
Request
Step-Down
USB Power Management IC
Integrates ±15kV Transient
Voltage Suppressors
Highest Integration Saves Board Space, Cost, and Design Time, Fits
in a 10-Pin µMAX Package
LOW QUIESCENT CURRENT LDO REGULATOR
ROBUST TRANSIENT VOLTAGE
SUPPRESSORS FOR DATA LINES
♦ 3.3V/150mA OUTPUT
MAX5005
MAX5006
MAX5007
♦ IEC 1000-4-2 AIR DISCHARGE
VOLTAGE TO ±15kV
♦ IEC 1000-4-2 CONTACT DISCHARGE
VOLTAGE TO ±8kV
VBUS
♦ 30µA SUPPLY CURRENT INDEPENDENT OF LOAD
3.3V
LDO
REGULATOR
5V
RST
OPEN
USB PORT
D+
SUPERVISORY
RESET
INTERNAL D+ AND D- TERMINATION
RESISTOR AND CONTROL
♦ USE SELR PIN TO CONFIGURE USB
PERIPHERAL FOR FULL SPEED OR
LOW SPEED
♦ USE ENABLE PIN TO DESELECT INTERNAL
TERMINATION RESISTOR
♦ STABLE WITH 1µF CERAMIC OUTPUT CAPACITOR
1µF
CERAMIC
1.5kΩ
D+
DGND
♦ 6A SURGE CURRENT RATING
VCC
D-
3.3V USB
CONTROLLER
ENABLE SELR
Part
Reset Output
MAX5005
Open Drain
MAX5006
Push-Pull Active Low
MAX5007
Push-Pull Active High
µP RESET CIRCUIT
♦ ENABLES USB CONTROLLER
WHEN VOUT IS IN
REGULATION
♦ 200ms TIMEOUT PERIOD
Smart Dual USB Switch Reduces
Software Overhead with
Auto Turn-Off/-On
1
2
5
SHORT APPLIED
SHORT-CIRCUIT
FAULT RESPONSE
FAULT INDICATOR
TRIPS AFTER 20ms BLANKING
TO PREVENT HOT-SWAP GLITCHES
5V, VIN
MAX1823
5V
0
3
VOUT
6
5V
FAULT-CONDITION
CURRENT LIMITED TO 350mARMS
BY PULSING (COMPETITOR'S
CURRENT SHOOTS TO ISHORT)
0
FAULT
INDICATOR
20ms RESET SIGNAL ALLOWS
PROPER SYSTEM START-UP
1A
0
IOUT
7
t = 10ms/div
4
SHORT-CIRCUIT REMOVED AND
AUTOMATICALLY DETECTED BY MAX1823
(COMPETITION REQUIRES DETECTION
CIRCUIT & MANUAL POWER RECYCLING)
SWITCH TURNS ITSELF OFF
AFTER 20ms (COMPETITION WAITS
FOR MICROPROCESSOR SIGNAL,
WASTING POWER & RISKING DAMAGE)
SWITCH TURNS ITSELF ON 20ms
AFTER DETECTING FAULT REMOVAL
(COMPETITION REQUIRES MICROPROCESSOR SIGNAL)
World’s Smallest, Dual, CurrentLimited Switch with Fault-Blanking
The MAX1812 is the world’s smallest, dual, current-limited switch for USB applications. Each
channel is guaranteed to supply 500mA and meets all USB specifications. Internal fault-blanking
prevents momentary faults (capacitive loads) from resetting the host system and eliminates the need
for external components.
INTERNAL FAULT-BLANKING SAVES COMPONENTS AND PREVENTS HOT-SWAP GLITCHES
TO USB
PORT A
INTERNAL
BLANKING
ELIMINATES FOUR
EXTERNAL
COMPONENTS
HOST
µP
5V
FAULTB
20ms
DELAY
INB
500mA
SWITCH
MAX1812
OUTB
TO USB
PORT B
x4
X
20ms
DELAY
3mm
FAULTA
IN µMA
0-P
mm
OUTA
.1
500mA
SWITCH
1
5V
INA
.9 m m x 1
AREA = 2.95mm x 4.9mm
HEIGHT = 1.11mm, MAX
NEW
36V Input, 20W Output Step-Downs
Save Space
B
A
EFFICIENCY (%)
m
80
m
3
• High-Voltage Operation
(Up to 36VIN)
• 10-Pin µMAX Package
• Up to 330kHz Switching
Frequency Reduces
Component Sizes
• Output Power >20W
• High Efficiency
• 90µA Quiescent Supply
Current
• 4µA Shutdown Current
• Output Voltage: 3.3V/5V
(MAX1744) Adj. 1.25V to
18V (MAX1745)
100
Nµ
-PI M
AX
10
EFFICIENCY vs. LOAD CURRENT
(VOUT = 5.0V)
m x 5m
INPUT
4.5V TO 36V
D
C
60
40
A: VIN = 7.2V
B: VIN = 12.0V
C: VIN = 24.0V
D: VIN = 36.0V
20
47µF
4.7µF
OFF
EXT
CS
REF
0.01
0.1
1
10
LOAD CURRENT (A)
MAX1744
4.7µF
0.001
VH
SHDN
VL
0
0.0001
V+
ON
OUTPUT
3.3V/5V
UP TO 4A
22µH
40mΩ
220µF
OUT
GND
0.1µF
Smallest Step-Down Converter with
24V Internal MOSFET Switch
3-/4-Cell Li+ Powered, Low IQ, Keep Alive, and Wake-On LAN Supply
The MAX1837 delivers up to 250mA, the MAX1836 delivers up to 125mA, and the MAX1776
delivers up to 500mA, permitting optimal inductor selection. The MAX1836/MAX1837 come in a 6-pin
SOT23 package, and the MAX1776 comes in an 8-pin µMAX package. Both convert directly from 24V
inputs, eliminating the intermediate step-down voltage that wastes over 15% of the battery life and
increases complexity. Applications include I/O, audio, keep-alive, WLAN, and video supplies in
notebook and hand-held systems powered by up to four lithium batteries and AC-DC adapters.
DIRECT STEP-DOWN FROM 24V WITHOUT 2-STAGE EFFICIENCY LOSS
INTERNAL
24V P-CHANNEL
MOSFET
WLAN
RTC
AUDIO
P
OUTPUT
1.25V TO VIN
UP TO 500mA
90% EFFICIENCY
VIDEO
I/O
IQ = 12µA
MAX1836/MAX1837
DIRECT CONVERSION
FROM 4.5V TO 24V
(FOUR Li+ OR AC-DC
ADAPTER)
MAX1836
IQ = 15µA
MAX1776
125mA/250mA
6-PIN SOT23
500mA
8-PIN µMAX
Direct conversion from 24V to 3.3V saves 15% power by eliminating compound efficiency losses generated when converting
from 24V to 5V and then from 5V to 3.3V.
1MHz, 600mA Step-Down Powers DSP
Cores Using Inexpensive Capacitors
High-Speed Converter Provides Excellent Line and Load Regulation
Using Tiny, 4.7µF Ceramic Capacitors Instead of Expensive, HighESR Tantalum Capacitors
INPUT
2.5V to 5.5V
4.7µF
4.7µH
BATT
LX
OUTPUT 1.8V AT 600mA
ADJUSTS DOWN TO 1.25V
4.7µF
ON
OFF
SHDN
SKIP
PWM
MAX1821
FB
PFM
REF
COMP
GND
• 600mA Guaranteed Output
Current
• 1MHz PWM Switching Frequency
• Requires only 4.7µF Ceramic
Capacitor
• Excellent Line and Load Regulation
• Synchronize to 2.5G (19.8MHz)
or 3G (13MHz) System Clock
• Programmable Output Voltage
from 1.25V to 5.5V
• No Schottky Diode Required
The MAX1821 is the first 1MHz PWM converter capable of delivering precision line and load regulation for the latest DSP cores using low-ESR ceramic input and output capacitors. The precision line
and load regulation is achieved through an innovative current-mode control algorithm. Its unique
slope compensation and high-bandwidth error amplifier, combined with a simple external compensation circuit, stabilize the converter with only a small 4.7µF ceramic capacitor. The MAX1821
can operate in PWM or PFM mode to maximize standby and operational efficiencies. To maximize
battery life, the MAX1821 delivers > 93% efficiency using an integrated low RDSON switch and synchronous rectifier.
Smallest 250mA Step-Downs Achieve
95% Efficiency for Sub-2V Logic
5-
23
3
m
The MAX1733/MAX1734 step-down DCOUTPUT
1.25V TO 2.5V (M
INPUT
AX
DC converters deliver over 250mA to outputs
1.5V OR 1.8V (M 1733)
2.7V TO 5.5V
AX1734)
as low as 1.25V and have 1.5% output voltage
UP
TO 250mA
10µH
IN
LX
accuracy. The input voltage range of 2.7V to
5.5V makes these devices ideal for portable
MAX1734
applications powered from a single lithium cell,
ON
from three alkaline or NiCd/NiMH cells, or
SHDN
OUT
OFF
SO
from a regulated 3.3V or 5V supply.
PIN T
These converters use a unique proprietary
GND
current-limited control scheme that maintains
m
m x 3m
a low 40µA quiescent supply current, while
their high 1.2MHz (max) switching frequency
and internal synchronous rectification significantly improve efficiency and minimize solution size. This
reduces external component size and eliminates the external Schottky diode required with conventional step-down converters. Only three small external components are needed for a complete DC-DC
solution.
The MAX1733 provides a resistor-adjustable output voltage, while the MAX1734 is available in a
variety of preset output voltages. Both devices are available in space-saving 5-pin SOT23 packages.
Reduce WCDMA PA Current Draw
83% with Dynamically Controlled
Step-Down DC-DC
High-Speed DC-DC Adjusts 2.5G and 3G PA Supplies to Match
Transmit Power
1000
BATTERY CURRENT (mA)
The MAX1820 is the first step-down
converter designed specifically for PAs in 2.5G
and 3G cellular phones. The baseband
processor dynamically programs the converter
output voltage based on the variable power
required by the PA. The high-speed MAX1820
converter varies its output voltage from 0.4V to
3.4V in less than 30µs, tracking the PA transmit
power envelope. By matching the PA supply
voltage envelope, the PA minimizes power loss
and maximizes battery life. The MAX1820 is
equipped
with
a
divide-by-13
or
divide-by-18 phase-locked-loop (PLL) to
synchronize to a 2.5G or 3G system clock. An
actual test with a WCDMA PA proved this
synchronization method does not add spurious
noise into the RF band.
REDUCE BATTERY CURRENT
FROM 62mA TO 11mA
PA CONNECTED TO BATTERY
100
SAVE 83% BATTERY CURRENT
PA CONNECTED
TO MAX1820
10
-10
-5
0
5
10
15
20
25
TRANSMIT POWER (dBm)
OUTPUT OF HIGH-SPEED DC-DC
TRACKS PA POWER ENVELOPE WITHIN 30µs
DATA MODE
PA SUPPLY
VOLTAGE
FAST 30µs
SETTLING TIME
500mV/div
ONLY SUPPLY WITH
DAC INPUT FOR DIRECT
COMMUNICATION
FROM BB PROCESSOR
VOICE MODE
400µs/div
INPUT
2.7V TO 4.2V
BATT
Li+ BATTERY
4.7µH
SYNC
LX
4.7µF
MAX1820
VOUT CONTROL
DAC
REF
GND
OUT
13MHz OR 18MHz
SYSTEM CLOCK
CLOCK SYNC
REDUCES NOISE
MAX1820Z
NO SYNC
MAX1820Y*
÷ 18 PLL
MAX1820X*
÷ 13 PLL
*Future product—contact factory for availability.
RF TRANSMIT SECTION
BASEBAND
PROCESSOR
RF RECEIVE SECTION
2.5G AND 3G
FIXED-GAIN
LINEAR PA
DYNAMIC OUTPUT
0.4V TO 3.4V IN 30µs
UP TO 600mA
Triple, Low-Noise, Low-Dropout
Linear Regulators Provide Complete
RF Power
67dB PSRR, Low-Crosstalk Voltage, and 45µVRMS Noise Provide
Flawless Transmission
The MAX8890 contains three identical 100mA, low-noise linear regulators in a low-profile 4mm x
4mm x 0.85mm QFN package. Their 67dB PSRR, low-crosstalk voltage, and 45µVRMS noise make
them ideal for the noise-sensitive RF sections of cellular phones and wireless PDAs. Low 50mV
dropout at 100mA load maximizes battery life. Output voltages are preset from 1.8V to 3.3V in 50mV
increments. The MAX8890 is priced at $0.99†.
3 LOW-NOISE LDOs IN A SINGLE QFN PACKAGE
67dB POWER-SUPPLY
REJECTION RATIO
CERAMIC INPUT AND
OUTPUT CAPACITORS
SAVE COST
IN1
4.7µF
60
OUT1
50
40
30
2.2µF
IN2
CROSSTALK (µVp-p)
OUT2
10
0
0
0.1
1
2.2µF
ON
10
100
0.1
1000
1
10
100
1000
FREQUENCY (kHz)
FREQUENCY (kHz)
EN2
OFF
1.8V TO 3.3V
100mA
OUT3
GND
4mm
BP
0.01µF
FACTORY PRESET
OUTPUTS SAVE
SPACE
2.2µF
IN QFN
2-P
mm
EN3
1
INDEPENDENT
CONTROLS
1.8V TO 3.3V
100mA
MAX8890
10
CIN = 1µF + 0.1µF
IOUT = 10mA
20
IN3
EN1
100
x
85
Li+
BATTERY
LOW-IMPEDANCE INPUT
IOUT1 = 100mA SINUSOIDAL LOAD
IOUT3 = 10mA
70
3 OUTPUTS
1.8V TO 3.3V
100mA
PSRR (dB)
INPUT
2.5V TO 5.5V
LOW-CROSSTALK VOLTAGE
1000
80
4 m m x 0.
†1000-up recommended resale. Price provided is for design guidance and is FOB USA. International prices will differ due to local duties, taxes, and exchange rates.
First Dual 160mA LDOs in SOT23
PSRR VS. FREQUENCY
50% SPACE SAVINGS AND EXCELLENT AC PERFORMANCE
80
70
60
PSRR (dB)
INCREDIBLE 1.0Ω
MOSFET PASS SWITCHES
>75dB
at up to 10kHz!
50
40
>65dB
at up to 100kHz!
30
INPUT
2.5V TO 5.5V
20
OFF
0.7W ION
IPAT
S
I
D S
SHDNA
OUTA
MAX8883
OUTB
ON
OFF
SHDNB
G
GND
m
m
6-
23
m x 2.9
DUAL LDOs IN
TINY SOT23 PACKAGE
0
R
0.01
UP TO 160mA
1.8V TO 3.3V
SO
PIN T
m
G R EA T P S R
UP TO 160mA
1.8V TO 3.3V
UP TO 160mA
FROM EACH OUTPUT
RE
AT
IS O
L A TI O N
CHANNEL-TO-CHANNEL ISOLATION (dB)
ON
10
DUAL
OUTPUTS
IN
2.8
The MAX8882/MAX8883 are
dual, low-noise, low-dropout
linear regulators that operate
from a 2.5V to 6.5V input and
deliver up to 160mA of continuous output current from each
output. These devices are less
than half the size of their closest
competition, yet their ultralow 1.0Ω on-resistance is lower
than most single-LDO competition in the same package. Each
LDO has only 72mV dropout at
80mA for longest battery life.
Both devices are available in fixed
output voltages of 2.85V/2.85V,
3.3V/2.5V, 3.3V/1.8V, 3V/3V
and 2.5V/1.8V.
0.1
1
10
100
FREQUENCY (kHz)
1000
CHANNEL-TO-CHANNEL
ISOLATION VS. FREQUENCY
100
90
80
>90dB
at up to 10kHz
70
60
50
>85dB
at up to 100kHz
40
30
>65dB
at up to 1MHz
20
10
0
0.01
0.1
1
10
100
FREQUENCY (kHz)
These dual linear regulators offer better AC performance
and lower dropout voltages than single devices requiring twice the board space.
1000
First 500mA Linear Regulator with
0.8V Output in 1.3W µMAX Package
The MAX1806 delivers outputs down to 0.8V at 500mA for new and future processor core power
supplies. The small µMAX package is specially constructed to dissipate 1.3W, which is 3.6 times more
than the competitor’s parts in the same package. Output voltage tolerance is ±1% and is preset (to
save space and cost) or adjustable from 0.8V to 4.5V (for flexibility). A Power-OK output signal
indicates when the output voltage drops from its nominal value by more than 7%. It includes current
limiting and shuts off in the event of short-circuit or thermal-overload faults. The MAX1806 uses a
P-channel MOSFET power switch so there is no large base current draw, even in dropout.
OPERATING RANGE, VOUT = 0.8V
600
500
OUTPUT CURRENT (mA)
• Guaranteed 500mA Output
• Regulated Outputs Down to 0.8V
• ±1% Voltage Accuracy:
Preset Voltages: 0.8V, 1.5V,
1.8V, 2.5V, or 3.3V
Adjustable Range: 0.8V to 4.5V
• Power-OK Output
• 1.3W, 1.1mm-High 8-Pin µMAX
Package
• 2.25V to 5.5V Input Range
• Low 175mV Dropout at 500mA
• 210µA Quiescent Supply Current
• 0.02µA Shutdown Current
400
MAX1806
1.3W µMAX
RANGE
300
200
100
COMPETITOR’S
RANGE
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
INPUT VOLTAGE (V)
World’s Smallest 0.5A and 1A
Linear Regulators
Special High-Power Packages Dissipate 1.3W and 1.5W
MAX1792
MAX1793
0.5A, LOW-DROPOUT
LINEAR REGULATOR IN 1.3W µMAX
1A, LOW-DROPOUT
LINEAR REGULATOR IN 1.5W TSSOP
x = 5.0mm
x = 6.2mm
SM 51%
ALL
ER
x = 6.5mm
x = 6.7mm
y = 3.1mm
y = 7.5mm
y = 5.1mm
8-PIN SO
AREA = 31mm2
8-PIN µMAX
AREA = 15mm2
1.1mm
HIGH
• ±1% Output Voltage Accuracy
• Fixed Outputs (1.5V, 1.8V, 2.5V,
3.3V, 5.0V) or Adjustable from
2V to 5V
SOT223
AREA = 50.3mm2
SM 34%
ALL
ER
y = 5.1mm
16-PIN TSSOP
AREA = 33.2mm2
ONLY 1.1mm
HIGH
• Low 130mV Dropout at 0.5A (MAX1792)
• Low 210mV Dropout at 1.0A (MAX1793)
• Thermal Overload Protection
Lowest Dropout and Lowest Cost
SOT23 and QFN LDOs for Baseband
and RF Chipsets
Output
Capacitance (µF)
Output Voltages (V)
1
1.8, 2.5, 3.3, 5, or Adj 1.5 to 5
3.3
1.5, 1.8, 2.0, 2.5, 3.3, 5, or Adj 1.25 to 5
120mA output, reverse-battery protection
1
2.8, 2.84, 3.15, or Adj 1.25 to 6.5
MAX8867/8
150mA output, reverse-battery protection
1
Fixed 2.5 to 5 in 100mV increments
MAX8875
150mA output with POK, reverse-battery protection
1
Fixed 2.5 to 5 in 100mV increments
MAX8877/8
150mA output, thin 1.1mm (max) height, reverse-battery
protection
1
Fixed 2.5 to 5 in 100mV increments
MAX8880/1
200mA output, reverse-battery protection
1
1.8, 2.5, 3.3, 5, or Adj 1.25 to 5
MAX8882/3
Dual 160mA output LDOs in SOT23
2.2
Fixed 1.8 to 3.3 in 100mV increments
MAX8887/8
150mV dropout at 300mA, thin 1.1mm (max) height
2.2
Fixed 1.5 to 3.3 in 100mV increments
MAX8890
Triple 100mA output LDOs in 4mm x 4mm QFN
2.2
Fixed 1.8 to 3.3 in 50mV increments
Part
Features
MAX1725/6
20mA output, 2µA quiescent current,
reverse-battery protection
MAX1818
120mV dropout at 500mA
MAX8863/4
CUSTOMIZED
OUTPUT
VOLTAGES
Battery Chargers Selector Table
No. of Series
Li+ Cells
Cell
Chemistry
Charge
Rate
Charge
Termination
Method
EV
Kit
MAX745
1 to 4
Li+
Fast
Voltage and
current limit
Yes
MAX1645A
1 to 4
Independent
Fast
—
Yes
MAX1647
—
Independent
Fast, up to 4A
MAX1667
4
Independent
Fast, up to 4A
MAX1737
1 to 4
Li+
Fast, up to 4A
MAX1757
1 to 3
Li+
Fast, up to 1.5A
MAX1758
1 to 4
Li+
Fast, up to 1.5A
MAX1811
1
Li+
Fast, up to
500mA
Voltage and
current limit
MAX1879
1
Li+
Fast, up to
800mA
MAX1873R/S/T
2/3/4
Li+/Ni
Fast, up to 4A
Voltage and
current limit
Voltage and
current limit
MAX1772
2 to 4
Independent
Fast, up to 4A
DS2770*
1
Li+/Ni
Fast
Part
*Future product—contact factory for availability.
Features
High-efficiency switch-mode controller
Pin-Package
20-SSOP
SBS Level 2 (1.0 compliant) smart battery charger,
SMBus interface, current-limiting input
SMBus serial interface, Level 2 Duracell/
Intel-compliant charger
SMBus serial interface, Level 2 Duracell/
Intel-compliant charger
16-NSO,
20-SSOP
Yes
28VIN external switches, sync rectified step-down
controller, input-current-limit loop, timers
28-SSOP
Yes
14VIN internal switches, sync rectified step-down,
input-current-limit loop, timers
28-SSOP
Yes
28VIN internal switches, sync rectified step-down,
input-current-limit loop, timers
28-SSOP
—
Linear charger, internal switch,
power through USB port, 0.5% precision
—
Pulse charger, ext switch, no heat
dissipation, upgrade to MAX1679
8-µMAX
Yes
28VIN lowest cost step-down controller,
300kHz PWM, input-current-limit loop
16-QSOP
Voltage and
current limit
Yes
28VIN ext switches, sync rectified
step-down controller, input-current-limit loops
28-QSOP
IMIN, timer
DS2770K*
15VIN, ext switch pulse charger
integrated with fuel gauge
16-TSSOP
SMBus
controlled
SMBus
controlled
Voltage and
current limit
Voltage and
current limit
Voltage and
current limit
Yes
Yes
28-SSOP
20-SSOP
8-SO (1.4W)
Cool Li+ Battery Charger Has
Virtually No Power Dissipation
Safe, Simple, and Inexpensive Pulse Charger Dissipates No Heat
PULSE CHARGING DECREASES SYSTEM
HEAT AND INCREASES RELIABILITY
INPUT
CURRENT-LIMITED
WALL-CUBE
5V TO 22V
800mA
OPTIONAL
LED
ONLY ONE EXTERNAL FET
REQUIRED FOR COMPLETE
Li+ CHARGER
P-Ch
IN
GATE
CHG
BATT
MAX1879
THERM
0.75% VOLTAGE
ACCURACY
Li+
SINGLE Li+
BATTERY
GND
TEMPERATURE
PROTECTION
(OPTIONAL)
Safety Features Include:
• Continuous Over/Undervoltage
Protection
• ±0.75% Charge Voltage Tolerance
• 6.25-Hour Charging Time-Out
Prevents Infinite Trickle-Charge
• Safely Precharges Near-Dead Cell
• Over/Undertemperature Protection
• Automatic Charging Restart at 4V
• Safe, Simple, and Inexpensive Pulse
Charger Dissipates No Heat
• Evaluation Kit Available to
Speed Designs
RE
FUTU CT
U
D
O
R
P
Single-Cell Li+ Protector Enables
Power Control Function in
Battery Pack
The DS2720* single-cell Li+ protection IC integrates memory, overtemperature protection, and the
ability to communicate with the host processor, along with the standard over/undervoltage and overcharge protection found in popular standalone protectors. Because the host can communicate with the
DS2720, it can control the protection MOSFETs in software, enabling power control through the
DS2720 and MOSFET.
• Li+ Safety Circuit;
• Overvoltage Protection
• Overcurrent/Short-Circuit
Protection
• Undervoltage Protection
• Overtemperature Protection
• Controls High-Side N-Channel
Power MOSFETs
• System Power Management and
Control Feature Support
• 8 Bytes of Lockable EEPROM
• 1-Wire®, Multinode Digital
Communication Interface
• 8-Pin µSOP Package
*Future product—contact factory for availability.
1-Wire is a registered trademark of Dallas Semiconductor.
PACK +
HOST
DS2720
DATA
PLS
DQ
PACK POWER
SWITCH
DC
PS
CC
VDD
VSS
CP
+
-
Electronically Label Battery Packs
with Low-Cost, 1-Wire Digital
Interface ICs
V+
4.7kΩ
BASEBAND
PROCESSOR/
ASIC
64-BIT
ROM
DATA
V-
TIME
ADC
TEMP
E2
PROTECTOR
(Lithium only)
BATTERY PACK
HANDSET
• Real-Time Clock (DS2415)
• Local Temperature Sensor:
9 Bit to 12 Bit (DS1822),
13 Bit (DS2436)
• Battery-Voltage ADC:
10 Bit (DS2436)
• 512-Bit SHA-1 Encryption
Engine (DS2432)
• 1-Wire Digital Interface
• Unique 64-Bit Serial Number
• Reduces Battery Contacts
Reduced to Three, Regardless
of Device Chosen
• User-Programmable EEPROM:
16 Bits (DS1822), 256 Bits
(DS2436) 1024 Bits (DS2432)
Dallas Semiconductor silicon label ICs tag a unique and unchangeable electronic label to the battery
pack. Each offers an array of feature functions to fit different cellular phone applications. The low-cost
DS2401 is the base model of this series, containing a 64-bit ROM accessible from the 1-Wire serial digital
interface. The DS2415 adds a real-time clock to the serial number, eliminating the need to have a backup battery for the real-time clock in the host product. The DS1822 replaces thermistors in the battery
pack by integrating a local digital thermometer and 16 bits of EEPROM to the 64-bit ROM. The DS2432
features 1024 bits of user EEPROM and a 512-bit SHA-1 algorithm that encrypts the EEPROM array.
The security offered in the DS2432 deters non-OEM battery packs, thus enhancing accessory revenue
and more importantly, increasing the safety to the user of the product with lithium-based packs. The
DS2436 provides data storage in the form of the 64-bit ROM and 256-bit user EEPROM, and replaces the
pack thermistor and ADCs in the host reserved for measuring pack voltage.
Battery Pack ID Solutions Selector Table
Pin-Package
(mm2)
TO-92, 6-TSOC,
CSP (1.4 x 0.7)
6-TSOC,
Flip Chip (1.4 x 1.1)
6-TSOC,
Flip Chip (2.5 x 1.8)
TO-92, 8-SO,
Flip Chip (2.0 x 1.4)
64-Bit
ROM
Real-Time
Clock
1-Wire
Interface
EEPROM
(Bytes)
Local Temp
Sensor (Bits)
Voltage
ADC (Bits)
Fuel
Gauge
Li+
Protector
EV Kit
DS2401
—
—
—
—
—
—
—
DS2415
—
—
—
—
—
—
DS2432
—
1024 bits
—
—
—
—
—
DS1822
—
2
12
—
—
—
DS1701K
DS2436
—
32
13
10
—
—
DS2436K
TO-92, 8-SO
DS2438
40
13
10
—
DS2438K
8-SO
DS2760
NEW
—
32
11
11
Single
cell
DS2760K
16-TSSOP,
Flip Chip (3.2 x 2.7)
E DS2770*
FUTUR
—
32
11
11
—
DS2770K*
16-TSSOP
E DS2720*
FUTUR
—
8
—
—
—
Single
cell
DS2720K*
8-µSOP
Part
*Future product—contact factory for availability.
Power 3 White LEDs from Single Li+
with 0.3% Brightness Matching
Lowest Dropout (200mV) Current Regulator Fits in 1mm-Thin SOT23
The MAX1916 triple-output current regulator provides significantly better matching than traditional ballast resistor schemes and provides longer battery life. Ballast resistors only provide 2:1 LED
matching. The MAX1916 regulates three LED currents with 0.3% matching, eliminating costly factory
calibration and the need to purchase LEDs with matched forward voltages (VF). 200mV dropout allows
LEDs to be powered directly from a single-cell lithium-ion (Li+) battery for a longer time, extending
battery life.
TRIPLE WHITE LED SUPPLY IS SUPERIOR TO BALLAST RESISTORS
200mV
DROPOUT EXTENDS
BATTERY LIFE
THIN SOT23
1mm HEIGHT
+
LED2
LED3
SET
ON
EN
ADDS 350mV
TO BATTERY LIFE
25
VCNTL
LED1
OFF
BETTER MATCHING, LONGER BATTERY LIFE
30
LED CURRENT (mA)
Li+
BATTERY
2.5V, 5.5V
BETTER THAN
0.3% LED-TO-LED
MATCHING
MAX1916
SIMPLE
BRIGHTNESS
CONTROL
GOOD CURRENT
MATCHING
3 RANDOM LEDs
USING MAX1916
20
350mV
POOR CURRENT
MATCHING
15
SAME 3 LEDs USING
34.8Ω BALLAST RESISTORS
10
GND
5
3.0
3.2
3.4
3.6
3.8
4.0
4.2
BATTERY VOLTAGE (V)
The MAX1916 eliminates costly factory calibration and special batch ordering while improving battery life and brightness matching.
High-Efficiency SOT23 Step-Up
Current Source Powers Up to 6 White
LEDs with Uniform Brightness
SERIES LEDs HAVE MATCHED LED
CURRENT AND UNIFORM BRIGHTNESS
33µH
3.3µF
LX
V+
90
OUTPUT
UP TO 13V
UP TO 60mA
MATCHED CURRENT
=
UNIFORM BRIGHTNESS
1µF
LOGIC OR
DAC
GND
CNTL
CS
COMP
0.15µF
20Ω
85
80
75
OUT
MAX1848
40% MORE EFFICIENT,
1.8x LONGER BATTERY LIFE
25Ω
RSENSE
5Ω
EFFICIENCY (%)
INPUT
2.6V TO 5.5V
LOWER INPUT RIPPLE
THAN CHARGE PUMP
65
60
m
m
8m
23
SO
PIN T
m x 2.9
NO CALIBRATION:
5% CURRENT TOLERANCE WITH
STANDARD LOW-COST
CHIP RESISTOR
NEW
MAX1848
WITH THREE LEDs
IN SERIES
55
50
45
35
PROGRAMMABLE
BRIGHTNESS
1.8x
LONGER
BATTERY
LIFE
70
40
2.8
The MAX1848 is the
first high-efficiency step-up
DC-DC converter that
regulates current instead of
voltage to power white LEDs
for backlights in cell phones
and PDAs. It powers two or
three white LEDs in series
(up to 6 total), instead of in
parallel, to eliminate brightness mismatch caused by
different threshold voltages.
An internal N-channel
MOSFET switch provides
85% efficiency, 40% better
than traditional doubling
charge-pump solutions.
30
3.0
DOUBLING CHARGE
PUMP WITH THREE
LEDs IN PARALLEL
3.5
IOUT = 15mA
4.0
INPUT VOLTAGE (V)
NO BALLAST RESISTORS AND
NO FACTORY CALIBRATION
4.5
Most Efficient 1.4MHz SOT23
Current-Mode Step-Up DC-DC
Converter
0.7Ω On-Resistance and 200µA IQ—Highest Efficiency
The MAX1896 uses current-mode control and 1.4MHz fixed-frequency pulse-width modulation
(PWM) to provide over 90% efficiency, fast transient response, and operation with physically smaller
components. It features 200µA quiescent supply current, low RON (on-resistance), 0.01µA logiccontrolled shutdown current, and programmable soft-start. The MAX1896 is intended for PDAs, LCD
panels, and hand-held equipment.
MOST EFFICIENT & SMALLEST SOT23 13V STEP-UP CONVERTER
INPUT
2.6V to 5.5V
BETTER EFFICIENCY
LX
MAX1896
SHDN
SS
3
6-
FB
GND
SO
PIN T
23
OPTIONAL
SOFT-START
5
R1
R2
3.0
2
m
80
70
COMPETITION
60
VIN = 3.3V
VOUT = 5V
50
0
m
4
ON
MAX1896
90
100
200
300
400
m
OFF
IN
1
EFFICIENCY (%)
6
100
OUTPUT
UP TO 13V,
UP TO 600mA
m x 3.0
OUTPUT CURRENT (mA)
The MAX1896 is pin compatible with the LT1613 and has higher efficiency due to lower switch on-resistance and lower quiescent
supply current.
World’s First Step-Up Converters
with “Reverse-Battery” Protection
SOT23 Boost Converters Use Only 4µA and Integrate Protection to
Save Cost
PROTECTION INTEGRATED; SYNCHRONOUS RECTIFIER INTEGRATED
INTERNAL SWITCH
OPENS IF BATTERY
IS REVERSED
NO REVERSE CURRENT
(IN-FAULT CONDITION)
OUTPUT
2V TO 5.5V
UP TO 150mA
PART
NUMBER
IN SHUTDOWN
OUTPUT
MAX1832
Battery connects
to load
Adjustable (2V to 5.5V)
MAX1833
Battery connects
to load
Fixed 3.3V
MAX1834
Battery and load
disconnect
Adjustable (2V to 5.5V)
MAX1835
Battery and load
disconnect
Fixed 3.3V
P
N
BATTERY
ACCIDENTLY
REVERSED
FAULT
CONDITION
+
INPUT
RANGE
1.5V TO 5.5V
ON
SHDN
OFF
MAX1832
MAX1833
MAX1834
MAX1835
GND
TINY
6-PIN SOT23
SAVES SPACE
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