datasheet for LTC1441 by Linear Technology

datasheet for LTC1441 by Linear Technology
LTC1440/LTC1441/LTC1442
Ultralow Power Single/Dual
Comparator with Reference
U
DESCRIPTIO
FEATURES
■
■
■
■
■
■
■
■
■
■
■
Ultralow Quiescent Current: 2.1µA Typ (LTC1440)
Reference Output Drives 0.01µF Capacitor
Adjustable Hysteresis (LTC1440/LTC1442)
Wide Supply Range:
Single: 2V to 11V
Dual: ±1V to ±5.5V
Input Voltage Range Includes the Negative Supply
TTL/CMOS Compatible Outputs
12µs Propagation Delay with 10mV Overdrive
No Crowbar Current
40mA Continuous Source Current
Pin Compatible Upgrades for MAX921/922/923
3mm x 3mm x 0.75mm DFN Package (LTC1440)
U
APPLICATIO S
■
■
■
■
Battery-Powered System Monitoring
Threshold Detectors
Window Comparators
Oscillator Circuits
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
The LTC ®1440/LTC1441/LTC1442 are ultralow power
single and dual comparators with built-in references. The
comparators feature less than 3.7µA supply current over
temperature (LTC1440), a 1.182V ±1% reference, programmable hysteresis (LTC1440/LTC1442) and TTL/CMOS
outputs that sink and source current. The reference output
can drive a bypass capacitor of up to 0.01µF without
oscillation.
The comparators operate from a single 2V to 11V supply
or a dual ±1V to ±5.5V supply (LTC1440). Comparator
hysteresis is easily programmed by using two resistors
and the HYST pin (LTC1440/LTC1442). Each comparator’s
input operates from the negative supply to within 1.3V of
the positive supply. The comparator output stage can
continuously source up to 40mA. By eliminating the
cross-conducting current that normally happens when the
comparator changes logic states, the power supply glitches
are eliminated.
The LTC1440 is available in 8-pin PDIP, SO, MSOP and
DFN packages. The LTC1441/LTC1442 are available in
8-pin PDIP and SO packages.
U
TYPICAL APPLICATIO
Micropower 2.9V VCC Threshold Detector
LTC1440 Supply Current vs Temperature
3.3V
5.0
R2
1.13M
1%
7
4.5
V+
3 IN +
+
8
4 IN–
–
5 HYST
V + = 5V
V – = GND = 0V
4.0
3.5
3.0
2.5
2.0
LTC1440
6 REF
OUT
SUPPLY CURRENT (µA)
R1
1.65M
1%
1.5
–40 –20
V–
2
GND
1
40
20
60
0
TEMPERATURE (°C)
80
100
1440/1/2 TA02
1440 TA01
144012fd
1
LTC1440/LTC1441/LTC1442
U
W W
W
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Voltage
V + to V –, V + to GND, GND to V – ...........12V to – 0.3V
IN +, IN –, HYST ................. (V + + 0.3V) to (V – – 0.3V)
REF ................................... (V + + 0.3V) to (V – – 0.3V)
OUT (LTC1440) .............. (V + + 0.3V) to (GND – 0.3V)
OUT (LTC1441/LTC1442) ... (V + + 0.3V) to (V – – 0.3V)
Current
IN +, IN –, HYST ................................................. 20mA
REF ................................................................... 20mA
OUT .................................................................. 50mA
OUT Short-Circuit Duration (V + ≤ 5.5V) .......Continuous
Power Dissipation .............................................. 500mW
Operating Temperature Range
LTC144XC ............................................... 0°C to 70°C
LTC144XI ........................................... – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Storage Temperature Range
(DD Package) ................................... – 65°C to 125°C
Junction Temperature ........................................... 150°C
Junction Temperature (DD Package) .................... 125°C
Lead Temperature (Soldering, 10 sec).................. 300°C
W
U
U
PACKAGE/ORDER INFORMATION
TOP VIEW
TOP VIEW
GND
1
8
OUT
V–
2
7
V+
IN +
3
6
REF
IN –
4
5
HYST
TJMAX = 125°C, θJA = 160°C/ W (DD)
UNDERSIDE METAL CONNECTED TO V–
(PCB CONNECTION OPTIONAL)
DD8 PART
MARKING*
LBTH
TOP VIEW
OUT A 1
8
OUT B
V– 2
7
V+
IN A + 3
6
IN B +
4
5
–
N8 PACKAGE
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
IN A
–
IN B
TJMAX = 150°C, θJA = 130°C/ W (N8)
TJMAX = 150°C, θJA = 175°C/ W (S8)
TOP VIEW
8
OUT
2
7
V+
IN + 3
6
REF
IN –
4
5
HYST
N8 PACKAGE
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
V
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
ORDER PART
NUMBER
LTC1440CDD
LTC1440IDD
GND 1
–
OUT
V+
REF
HYST
TJMAX = 150°C, θJA = 250°C/ W
S8 PART
MARKING
1440
1440
1440I
1440I
ORDER PART
NUMBER
LTC1440CMS8
LTC1440IMS8
TOP VIEW
OUT A 1
8
OUT B
V– 2
7
V+
IN A+ 3
6
REF
–
4
5
HYST
N8 PACKAGE
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
IN B
8
7
6
5
MS8 PACKAGE
8-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 130°C/ W (N8)
TJMAX = 150°C, θJA = 175°C/ W (S8)
ORDER PART
NUMBER
LTC1440CN8
LTC1440CS8
LTC1440IN8
LTC1440IS8
ORDER PART
NUMBER
LTC1441CN8
LTC1441CS8
LTC1441IN8
LTC1441IS8
S8 PART
MARKING
1441
1441I
1
2
3
4
GND
V–
IN +
IN –
TJMAX = 150°C, θJA = 130°C/ W (N8)
TJMAX = 150°C, θJA = 175°C/ W (S8)
MS8 PART
MARKING*
LTBX
ORDER PART
NUMBER
LTC1442CN8
LTC1442CS8
LTC1442IN8
LTC1442IS8
S8 PART
MARKING
1442
1442I
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
* The temperature grade is identified by a label on the shipping container.
2
144012fd
LTC1440/LTC1441/LTC1442
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. V + = 5V and V – = GND = 0V unless otherwise noted.
SYMBOL PARAMETER
Power Supply
V+
Supply Voltage Range
Supply Current
ICC
Comparator
VOS
Comparator Input Offset Voltage
Input Leakage Current (IN +, IN –)
IIN
Input Leakage Current (HYST)
Comparator Input Common
VCM
Mode Range
CMRR
Common Mode Rejection Ratio
PSRR
Power Supply Rejection Ratio
NOISE
VHYST
tPD
Voltage Noise
Hysteresis Input Voltage Range
Propagation Delay
VOH
VOL
Output High Voltage
Output Low Voltage
Reference
Reference Voltage
VREF
CONDITIONS
MIN
IN + = IN – + 80mV
LTC1440 0°C ≤ TA ≤ 70°C
HYST = REF (LTC1440/LTC1442)
–40°C ≤ TA ≤ 85°C
LTC1441
LTC1442
VCM = 2.5V
VIN + = VIN – = 2.5V
●
●
●
●
V – to V + – 1.3V
V + = 2V to 11V (LTC1441)
V + = 2.5V to 11V (LTC1440/LTC1442)
100Hz to 100kHz
LTC1440/LTC1442
COUT = 100pF
Overdrive = 10mV
Overdrive = 100mV
IO = – 13mA
IO = 1.8mA
LTC1440
LTC1441/LTC1442
No Load
ISOURCE
ISINK
∆VREF
Reference Output Source Current
Reference Output Sink Current
Reference Source Current
Reference Sink Current
∆VREF ≤ 1mV (LTC1442)
∆VREF ≤ 2.5mV (LTC1442)
0 ≤ ISOURCE ≤ 2mA (LTC1440)
0 ≤ ISINK ≤ 10µA (LTC1440)
NOISE
Voltage Noise
100Hz to 100kHz
●
●
●
●
●
LTC1440/LTC1442
0°C ≤ TA ≤ 70°C
–40°C ≤ TA ≤ 85°C
LTC1440 (MSOP, DFN)
●
TYP
MAX
UNITS
11.0
4.0
4.4
5.7
5.7
V
µA
µA
µA
µA
±3
±0.01
±0.02
±10
±1.0
±1.0
V + – 1.3V
mV
nA
nA
V
0.1
0.1
0.1
100
1
1
1
2.0
2.1
3.5
3.5
V–
REF – 50mV
15
8
●
●
●
V + – 0.4V
●
●
●
●
1.170
1.164
1.164
100
10
●
mV/V
mV/V
mV/V
µVRMS
REF
V
µs
µs
V
GND + 0.4V
V
V – + 0.4V
V
1.194
1.200
1.200
20
0.8
0.5
●
100
5
1.5
5
V
V
V
µA
µA
mV
mV
mV
µVRMS
144012fd
3
LTC1440/LTC1441/LTC1442
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. V + = 3V and V – = GND = 0V unless otherwise noted.
SYMBOL PARAMETER
Power Supply
Supply Voltage Range
V+
CONDITIONS
ICC
IN + = IN –
Supply Current
Comparator
VOS
Comparator Input Offset Voltage
Input Leakage Current (IN +, IN –)
IIN
Input Leakage Current (HYST)
Comparator Input Common
VCM
Mode Range
CMRR
Common Mode Rejection Ratio
PSRR
Power Supply Rejection Ratio
NOISE
VHYST
tPD
Voltage Noise
Hysteresis Input Voltage Range
Propagation Delay
VOH
Output High Voltage
Comparator
Output Low Voltage
VOL
Reference
Reference Voltage
VREF
MIN
●
+ 80mV
HYST = REF (LTC1440/LTC1442)
LTC1440 0°C ≤ TA ≤ 70°C
–40°C ≤ TA ≤ 85°C
LTC1441
LTC1442
VCM = 1.5V
VIN + = VIN – = 1.5V
V – to V + – 1.3V
V + = 2V to 11V (LTC1441)
V + = 2.5V to 11V (LTC1440/LTC1442)
100Hz to 100kHz
LTC1440/LTC1442
COUT = 100pF
Overdrive = 10mV
Overdrive = 100mV
IO = – 8mA
IO = 0.8mA
LTC1440
LTC1441/LTC1442
No Load
LTC1440/LTC1442
0°C ≤ TA ≤ 70°C
–40°C ≤ TA ≤ 85°C
LTC1440 (MSOP, DFN)
ISOURCE
ISINK
∆VREF
Reference Output Source Current
Reference Output Sink Current
Reference Source Current
Reference Sink Current
∆VREF ≤ 1mV (LTC1442)
∆VREF ≤ 2.5mV (LTC1442)
0 ≤ ISOURCE ≤ 1mA (LTC1440)
0 ≤ ISINK ≤ 10µA (LTC1440)
NOISE
Voltage Noise
100Hz to 100kHz
2
●
MAX
V
3.9
4.3
5.7
5.7
µA
µA
µA
µA
±3
±0.01
±0.02
±10
±1
±1
V + – 1.3V
mV
nA
nA
V
0.1
0.1
0.1
100
1
1
1
3.5
3.5
V–
REF – 50mV
REF
14
5
●
V + – 0.4V
GND + 0.4V
V – + 0.4V
●
●
●
●
●
●
●
1.170
1.164
1.164
60
10
UNITS
11
2
●
●
●
●
●
●
●
●
TYP
1.182
120
20
0.8
0.5
●
100
1.194
1.200
1.200
5.5
1.5
5
mV/V
mV/V
mV/V
µVRMS
V
µs
µs
V
V
V
V
V
V
µA
µA
mV
mV
mV
µVRMS
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
144012fd
4
LTC1440/LTC1441/LTC1442
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Comparator Response Time vs
Input Overdrive
Comparator Response Time vs
Input Overdrive
3
100mV
50mV
OUTPUT VOLTAGE (V)
TA = 25°C
4
10mV
20mV
2
1
0
0
100
0
–1
2
4
6
RESPONSE TIME (µs)
8
10
INPUT VOLTAGE (mV)
INPUT VOLTAGE (mV)
OUTPUT VOLTAGE (V)
5
5
TA = 25°C
4
100mV
3
50mV
20mV
10mV
2
1
0
100
0
–1
0
2
4 6 8 10 12 14 16 18
RESPONSE TIME (µs)
1440/1/2 G01
1440/1/2 G02
Comparator Short-Circuit Sink
Current vs Supply Voltage
Comparator Short-Circuit Source
Current vs Supply Voltage
200
160
TA = 25°C
180
140
140
SOURCE CURRENT (mA)
SINK CURRENT (mA)
160
OUT CONNECTED TO V +
120
100
80
60
120
OUT CONNECTED TO
V – = GND = 0V
100
80
60
40
40
20
20
0
0
0
1
2
3 4 5 6 7 8
SUPPLY VOLTAGE (V)
9
10
1440/1/2 G03
0
1
2
3
SUPPLY VOLTAGE (V)
4
5
1440/1/2 G04
144012fd
5
LTC1440/LTC1441/LTC1442
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Comparator Response Time vs
Load Capacitance with 100mV
Input Overdrive
Comparator Response Time at
Low Supply Voltage
12
10000
t PHL
RESPONSE TIME (µs)
RESPONSE TIME (µs)
10
8
t PLH
6
1000
20mV OVERDRIVE
100
4
2
0
20
60
80
40
LOAD CAPACITANCE (nF)
10
100mV OVERDRIVE
1
100
1.0
1440/1/2 G05
1.1
1.2
1.3
1.4
SUPPLY VOLTAGE (V)
1.5
1.6
1440/1/2 G06
Comparator Output Voltage High
vs Load Current
5
OUTPUT VOLTAGE HIGH (V)
TA = 25°C
V + = 5V
4
3
V + = 3V
2
V + = 2V
1
0
10
20
30
40
LOAD CURRENT (mA)
50
60
1440/1/2 G07
144012fd
6
LTC1440/LTC1441/LTC1442
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Comparator Output Voltage Low
vs Load Current
LTC1440/LTC1442
Hysteresis Control
POSITIVE-TO-NEGATIVE INPUT VOLTAGE (mV)
2.5
2.0
V + = 3V
V + = 2V
1.5
V + = 5V
1.0
0.5
0
0
10
50 60
20 30 40
LOAD CURRENT (mA)
70
80
80
60
OUTPUT HIGH
40
20
0
OUTPUT LOW
–20
–40
–60
–80
0
10
20
30
VREF – VHYST (mV)
40
50
1440/1/2 G09
1440/1/2 G08
LTC1440
Supply Current vs Temperature
6
5
SUPPLY CURRENT (µA)
OUTPUT VOLTAGE LOW (V)
TA = 25°C
V + = 5V
V – = –5V
4
3
2
V + = 3V
V – = GND = 0V
V + = 5V
V – = GND = 0V
1
–60 –40 –20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
1440/1/2 G10
144012fd
7
LTC1440/LTC1441/LTC1442
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Reference Output Voltage vs
Output Load Current (Sink)
Reference Output Voltage vs
Output Load Current
1.200
1.190
REFERENCE OUTPUT VOLTAGE (V)
REFERENCE OUTPUT VOLTAGE (V)
VCC = 5V
1.185
SOURCE
1.180
1.175
1.170
1.165
1.160
1.155
V CC = 2V
1.195
V CC = 5V
1.190
1.185
SINK
1.180
1.175
1.170
0
0.5 1.0 1.5 2.0 2.5 3.0
OUTPUT LOAD CURRENT (mA)
3.5
0
10
15
20
25
5
OUTPUT LOAD CURRENT (µA)
30
1440/1/2 G12
1440/1/2 G11
Reference Voltage vs
Temperature
1.186
REFERENCE VOLTAGE (V)
1.184
1.182
1.180
1.178
1.176
1.174
1.172
1.170
–60 –40 –20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
1440/1/2 G13
144012fd
8
LTC1440/LTC1441/LTC1442
U
U
U
PIN FUNCTIONS
1
GND
LTC1440
–
2 V
OUT 8
1
OUT A
7
2
V–
V+
3 IN
4 IN–
+
REF 6
–
HYST
5
OUT B 8
V+
+
+
LTC1441
A
–
+
–
B
7
1 OUT A
2
V–
+
LTC1442
3 IN A
IN B
4 IN A–
IN B– 5
6
–
–
V+
7
+
3 IN A+
4 IN B–
8
B
A
+
+
OUT B
REF 6
V–
HYST 5
1440/1/2 PD
LTC1440
GND (Pin 1): Ground. Connect to V – for single supply
operation.
V – (Pin 2): Negative Supply. Connect to ground for single
supply operation. Potential should be more negative than
GND.
IN + (Pin 3): Noninverting Comparator Input. Input common mode range from V – to V + –1.3V. Input current
typically 10pA at 25°C.
IN B – (Pin 5): Inverting Input of Comparator B. Input
common mode range from V – to V + –1.3V. Input current
typically 10pA at 25°C.
IN B + (Pin 6): Noninverting Input of Comparator B. Input
common mode range from V – to V + –1.3V. Input current
typically 10pA at 25°C.
V + (Pin 7): Positive Supply. 2V to 11V.
OUT B (Pin 8): Comparator B CMOS Output. Swings from
V – to V +. Output can source up to 40mA and sink 5mA.
IN – (Pin 4): Inverting Comparator Input. Input common
mode range from V – to V + –1.3V. Input current typically
10pA at 25°C.
LTC1442
HYST (Pin 5): Hysteresis Input. Connect to REF if not
used. Input voltage range is from VREF to VREF – 50mV.
V – (Pin 2): Negative Supply.
OUT A (Pin 1): Comparator A CMOS Output. Swings from
V – to V +. Output can source up to 40mA and sink 5mA.
REF (Pin 6): Reference Output. 1.182V with respect
to V –. Can source up to 200µA and sink 15µA at 25°C.
Drive 0.01µF bypass capacitor without oscillation.
IN A+ (Pin 3): Noninverting Input of Comparator A. Input
common mode range from V – to V + –1.3V. Input current
typically 10pA at 25°C.
V + (Pin 7): Positive Supply. 2V to 11V.
IN B– (Pin 4): Inverting Input of Comparator B. Input
common mode range from V – to V + –1.3V. Input current
typically 10pA at 25°C.
OUT (Pin 8): Comparator CMOS Output. Swings from
GND to V +. Output can source up to 40mA and sink 5mA.
LTC1441
OUT A (Pin 1): Comparator A CMOS Output. Swings from
V – to V +. Output can source up to 40mA and sink 5mA.
V – (Pin 2): Negative Supply.
IN A+ (Pin 3): Noninverting Input of Comparator A. Input
common mode range from V – to V + –1.3V. Input current
typically 10pA at 25°C.
HYST (Pin 5): Hysteresis Input. Connect to REF if not
used. Input voltage range is from VREF to VREF – 50mV.
REF (Pin 6): Reference Output. 1.182V with respect
to V –. Can source up to 200µA and sink 15µA at 25°C.
Drive 0.01µF bypass capacitor without oscillation.
V + (Pin 7): Positive Supply. 2V to 11V.
OUT B (Pin 8): Comparator B CMOS Output. Swings from
V – to V +. Output can source up to 40mA and sink 5mA.
IN A– (Pin 4): Inverting Input of Comparator A. Input
common mode range from V – to V + –1.3V. Input current
typically 10pA at 25°C.
144012fd
9
LTC1440/LTC1441/LTC1442
U
W
U
U
APPLICATIONS INFORMATION
LTC1440/LTC1441/LTC1442 are a family of micropower
comparators with built-in 1.182V reference. Features
include programmable hysteresis (LTC1440/LTC1442),
wide supply voltage range (2V to 11V) and the ability of the
reference to drive up to a 0.01µF capacitor without oscillation. The comparators’ CMOS outputs can source up to
40mA and the supply current glitches, that normally occur
when switching logic states, have been eliminated.
capacitor of up to 0.01µF without oscillation and by
inserting a series resistor, capacitance values up to 100µF
can be used (Figure 1).
Power Supplies
Figure 3 shows the bypassed reference output with a
square wave applied to the V + pin. Resistors R2 and R3 set
10mV of hysteresis voltage band while R1 damps the
reference response. Note that the comparator output
doesn’t trip.
The comparator family operates from a single 2V to 11V
supply. The LTC1440 includes a separate ground for the
comparator output stage, allowing a split supply ranging
from ±1V to ±5.5V. Connecting V – to GND on the LTC1440
will allow single supply operation. If the comparator output is required to source more than 1mA, or the supply
source impedance is high, V + should be bypassed with a
0.1µF capacitor.
Figure 2 shows the resistor value required for different
capacitor values to achieve critical damping. Bypassing
the reference can help prevent false tripping of the comparators by preventing glitches on V + or reference load
transients from disturbing the reference output voltage.
REFERENCE
OUTPUT
REF
R1
Comparator Inputs
The comparator inputs can swing from the negative supply V – to within 1.3V max of the positive supply V +. The
inputs can be forced 300mV below V – or above V + without
damage and the typical input leakage current is only
±10pA.
C1
LTC144X
V–
1440/1/2 F01
Figure 1. Damping the Reference Output
Comparator Outputs
Voltage Reference
The internal bandgap reference has a voltage of 1.182V
referenced to V –. The reference accuracy is 1.5% from
– 40°C to 85°C. It can source up to 200µA and sink up to
20µA with a 5V supply. The reference can drive a bypass
1000
RESISTOR VALUE (kΩ)
The LTC1440 comparator output swings between GND
and V + to assure TTL compatibility with a split supply. The
LTC1441 and LTC1442 outputs swing between V – and V +.
The outputs are capable of sourcing up to 40mA and
sinking up to 5mA while still maintaining microampere
quiescent currents. The output stage does not generate
crowbar switching currents during transitions which helps
minimize parasitic feedback through the supply pins.
100
10
1
0.1
0.001
0.01
0.1
1
CAPACITOR VALUE (µF)
10
1440/1/2 F02
Figure 2. Damping Resistance vs Bypass Capacitor Value
144012fd
10
LTC1440/LTC1441/LTC1442
U
U
W
U
APPLICATIONS INFORMATION
7
V+
3 IN +
+
8
4 IN–
5V
TO
8V
OUT
up to 15%. If hysteresis is not wanted, the HYST pin
should be shorted to REF. Acceptable values for IREF range
from 0.1µA to 5µA. If 2.4M is chosen for R2, then the value
of R1 is equal to the value of VHB.
–
5 HYST
R2
10k
R3
2.4M
2
C1
1µF
HYST
R2 =
V–
R2
GND
VHB
(2)(IREF)
(
1.182V –
VHB
2
)
IREF
2
1
1440/1/2 F04
Figure 4. Programmable Hysteresis
1440/1/2 F03a
Figure 3a. Reference Transient Response Test Circuit
Level Detector
The LTC1440 is ideal for use as a micropower level
detector as shown in Figure 5. R1 and R2 form a voltage
divider from VIN to the noninverting comparator input. R3
and R4 set the hysteresis voltage, and R5 and C1 bypass
the reference output. The following design procedure can
be used to select the component values:
8V
V+
5V
2mV/DIV
LTC1440
5
V–
R1 =
REF
R1
LTC1440
6 REF
R1
430Ω
6
IREF
VREF
1. Choose the VIN voltage trip level, in this example 4.65V.
OUT
2ms/DIV
1440/1/2 F03b
Figure 3b. Reference and Comparator Output
Transient Response
Hysteresis
Hysteresis can be added to the LTC1440 by connecting a
resistor (R1) between the REF and HYST pins and a
second resistor (R2) from HYST to V – (Figure 4).
The difference between the upper and lower threshold
voltages, or hysteresis voltage band (VHB), is equal to twice
the voltage difference between the REF and HYST pins.
When more hysteresis is added, the upper threshold
increases the same amount as the low threshold decreases. The maximum voltage allowed between REF and
HYST pins is 50mV, producing a maximum hysteresis
voltage band of 100mV. The hysteresis band could vary by
V IN
5V
R2
3.4M
1%
7
V+
3 IN +
+
8
R1
1.18M
1%
4
IN–
OUT
–
5 HYST
R3
15k
1%
R4
2.4M
1%
LTC1440
6 REF
R5
430Ω
5%
C1
1µF
V–
2
GND
1
1440/1/2 F05
Figure 5. Glitch-Free Level Detector with Hysteresis
144012fd
11
LTC1440/LTC1441/LTC1442
U
W
U
U
APPLICATIONS INFORMATION
2. Calculate the required resistive divider ratio.
Ratio = VREF/ VIN
Ratio = 1.182V/4.65V = 0.254
3. Choose the required hysteresis voltage band at the
input VHBIN, in this example 60mV. Calculate the hysteresis voltage band referred to the comparator input VHB.
⎤
⎡
⎥
⎢
4.65V
− 1⎥
R2 = 1.18M ⎢
15mV ⎥
⎢
⎥⎦
⎢⎣ 1.182V + 2
R2 = 3.40M
VHB = (VHBIN)(Ratio)
Low Voltage Operation
VHB = (60mV)(0.254)
It is important to note that the voltage references internal
to the LTC1440 and LTC1442 can exceed the common
mode range of the comparators at low supply voltages.
The input common mode range of the LTC1440/LTC1441/
LTC1442 comparators is guaranteed to extend up to (V+ 1.3V). Therefore, if one of the comparator inputs is at the
1.182V reference voltage, the minimum supply voltage is
2.5V for a valid output reading.
VHB = 15.24mV
4. Choose the values for R3 and R4 to set the hysteresis.
R4 = 2.4M
R3(kΩ) = VHB = 15k
5. Choose the values for R1 and R2 to set the trip point.
V
1.182V
= 1.18M
R1 = REF =
IBIAS
1µA
⎤
⎡
⎥
⎢
VIN
R2 = R1⎢
− 1⎥
VHB ⎥
⎢
⎥⎦
⎢⎣ VREF + 2
The guaranteed minimum operating voltage for the
LTC1440/LTC1441/LTC1442 is 2V (or ±1V). However,
both the reference and comparator(s) will function with a
supply voltage as low as 1.5V, but performance will
degrade as the voltage goes below 2V. The voltage reference temperature coefficient will degrade slightly, and the
comparators will have less output drive with an increase in
propagation delay. At the reduced supply voltages, the
input common mode range of the comparator(s) will still
typically extend from the negative supply to approximately
1.1V below the positive supply.
144012fd
12
LTC1440/LTC1441/LTC1442
U
TYPICAL APPLICATIONS
10-Bit 30µA A/D Converter
32.768kHz
1M
5V
470k
+
C2
1/2 LTC1441
5V
EIN
0V TO 3V
–
1.2M
®
LT 1034
1.2V
100k
365k*
10pF
+
C1
1/2 LTC1441
2N3809
STATUS
–
150k
0.033µF
POLYSTYRENE
VN2222LL
1N914
74C00
10M
Q
74C00
74C00
DATA
OUT
Q
74C74
74C00
D
CLK
CONV
COMMAND
*TRW-IRC MRT–5/+120ppm/°C
1440/1/2 TA03
32.768kHz “Watch Crystal” Oscillator
32.768kHz
1M
+V
470k
+
1/2
LTC1441
OUT
–
1.2M
10pF
1440/1/2 TA05
144012fd
13
LTC1440/LTC1441/LTC1442
U
PACKAGE DESCRIPTIO
DD Package
8-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698)
R = 0.115
TYP
5
0.38 ± 0.10
8
0.675 ±0.05
3.5 ±0.05
1.65 ±0.05
2.15 ±0.05 (2 SIDES)
1.65 ± 0.10
(2 SIDES)
3.00 ±0.10
(4 SIDES)
PIN 1
TOP MARK
(NOTE 6)
PACKAGE
OUTLINE
(DD8) DFN 1203
0.75 ±0.05
0.200 REF
0.25 ± 0.05
4
0.25 ± 0.05
1
0.50 BSC
0.50
BSC
2.38 ±0.05
(2 SIDES)
2.38 ±0.10
(2 SIDES)
0.00 – 0.05
BOTTOM VIEW—EXPOSED PAD
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON TOP AND BOTTOM OF PACKAGE
MS8 Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1660)
0.889 ± 0.127
(.035 ± .005)
5.23
(.206)
MIN
3.20 – 3.45
(.126 – .136)
3.00 ± 0.102
(.118 ± .004)
(NOTE 3)
0.65
(.0256)
BSC
0.42 ± 0.038
(.0165 ± .0015)
TYP
8
7 6 5
0.52
(.0205)
REF
RECOMMENDED SOLDER PAD LAYOUT
0.254
(.010)
3.00 ± 0.102
(.118 ± .004)
(NOTE 4)
4.90 ± 0.152
(.193 ± .006)
DETAIL “A”
0° – 6° TYP
GAUGE PLANE
1
0.53 ± 0.152
(.021 ± .006)
DETAIL “A”
2 3
4
1.10
(.043)
MAX
0.86
(.034)
REF
0.18
(.007)
SEATING
PLANE
0.22 – 0.38
(.009 – .015)
TYP
0.65
(.0256)
BSC
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
0.127 ± 0.076
(.005 ± .003)
MSOP (MS8) 0204
144012fd
14
LTC1440/LTC1441/LTC1442
U
PACKAGE DESCRIPTION
N8 Package
8-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
.400*
(10.160)
MAX
8
7
6
5
1
2
3
4
.255 ± .015*
(6.477 ± 0.381)
.300 – .325
(7.620 – 8.255)
.065
(1.651)
TYP
.008 – .015
(0.203 – 0.381)
+.035
.325 –.015
(
8.255
+0.889
–0.381
.130 ± .005
(3.302 ± 0.127)
.045 – .065
(1.143 – 1.651)
.120
(3.048) .020
MIN
(0.508)
MIN
.018 ± .003
.100
(2.54)
BSC
)
(0.457 ± 0.076)
N8 1002
NOTE:
1. DIMENSIONS ARE
INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
.189 – .197
(4.801 – 5.004)
NOTE 3
.045 ±.005
.050 BSC
8
.245
MIN
7
6
5
.160 ±.005
.150 – .157
(3.810 – 3.988)
NOTE 3
.228 – .244
(5.791 – 6.197)
.030 ±.005
TYP
1
RECOMMENDED SOLDER PAD LAYOUT
.010 – .020
× 45°
(0.254 – 0.508)
.008 – .010
(0.203 – 0.254)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
NOTE:
1. DIMENSIONS IN
.053 – .069
(1.346 – 1.752)
.014 – .019
(0.355 – 0.483)
TYP
INCHES
(MILLIMETERS)
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
2
3
4
.004 – .010
(0.101 – 0.254)
.050
(1.270)
BSC
SO8 0303
144012fd
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
15
LTC1440/LTC1441/LTC1442
U
TYPICAL APPLICATION
10kHz V/F Converter
+V
6.2V TO 12V
LM334
2k*
INPUT
0V TO 5V
1.2M*
Q8
Q1
+
LT1034-1.2
2.2µF
10kHz TRIM
200k
C1
1/2 LTC1441
0.01µF
+
LT1034-1.2
–
0.47µF
Q2
+
50pF
Q3
100k
Q4
2M TYP
100Hz TRIM
= HP5082-2810
15k
= 1N4148
Q7
Q5
= 2N2222
100pF**
fOUT
0kHz TO 10kHz
* = 1% METAL FILM
** = POLYSTYRENE
Q6
74C14
10M
2.7M
0.1µF
–
C2
1/2 LTC1441
+
1440/1/2 TA04
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC1443
1.182V Reference with Micropower Quad Comparators
1% Accuracy, 8.5µA Maximum Current, Ref Output Drives 0.01µF
LTC1444/LTC1445
1.2V Reference with Quad Comparator
with Adjustable Hysteresis
1% Accuracy, 8.5µA Maximum Current, Ref Output Drives 0.01µF
LTC1540
1.182V Reference with Nanopower Comparator
with Adjustable Hysteresis
DFN Package 0.3µA Quiescent Current (Typical), Reference
Drives 0.01µF
LTC1541
1.2V Reference with Micropower Amplifier and Comparator
DFN Package 1.25% Accuracy, Rail-to-Rail Out, Low Offset Amplifier
LTC1842/LTC1843
1.82V Reference with Dual Comparators
with Adjustable Hysteresis
1% Accuracy, Open-Drain Out, Reference Drives 0.01µF
LTC1998
1.2 Reference with Comparator with Adjustable Thesholds
Li-Ion Low Battery Monitor, SOT23, 1% Accuracy
LT6700-1
0.4 Reference with Low Voltage Dual Comparators
LT6700-2/LT6700-3
SOT23, 1.4V to 18.5V Supply Range, ±2% Over Temperature
144012fd
16
Linear Technology Corporation
LT 0806 REV D • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 1996
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertising