LINER LTC1440IN8

LTC1440/LTC1441/LTC1442
Ultralow Power Single/Dual
Comparator with Reference
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DESCRIPTION
FEATURES
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Ultralow Quiescent Current: 2.1µA Typ (LTC1440)
Wide Supply Range:
Single: 2V to 11V
Dual: ±1V to ±5.5V
Input Voltage Range Includes the Negative Supply
Reference Output Drives 0.01µF Capacitor
Adjustable Hysteresis (LTC1440/LTC1442)
TTL/CMOS Compatible Outputs
12µs Propagation Delay with 10mV Overdrive
No Crowbar Current
40mA Continuous Source Current
Pin Compatible Upgrades for MAX921/922/923
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APPLICATIONS
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Battery-Powered System Monitoring
Threshold Detectors
Window Comparators
Oscillator Circuits
, LTC and LT are registered trademarks of Linear Technology Corporation.
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 and MSOP
packages. The LTC1441/LTC1442 are available in 8-pin
PDIP and SO packages.
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TYPICAL APPLICATION
Micropower 2.9V VCC Threshold Detector
LTC1440 Supply Current vs Temperature
3.3V
5.0
R2
1.13M
1%
7
V+
3 IN +
4.5
+
8
4 IN–
–
5 HYST
LTC1440
6 REF
V–
2
OUT
SUPPLY CURRENT (µA)
R1
1.65M
1%
V + = 5V
V – = GND = 0V
4.0
3.5
3.0
2.5
2.0
1.5
–40 –20
GND
1
40
20
60
0
TEMPERATURE (°C)
80
100
1440/1/2 TA02
1440 TA01
1
LTC1440/LTC1441/LTC1442
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ABSOLUTE MAXIMUM RATINGS
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
Lead Temperature (Soldering, 10 sec).................. 300°C
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PACKAGE/ORDER INFORMATION
ORDER PART NUMBER
TOP VIEW
8
OUT
2
7
V
+
IN + 3
6
REF
–
4
5
HYST
N8 PACKAGE
8-LEAD PDIP
S8 PACKAGE
8-LEAD PLASTIC SO
GND 1
V
IN
–
LTC1440CN8
LTC1440CS8
LTC1440IN8
LTC1440IS8
1
2
3
4
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 B
TJMAX = 150°C, θJA = 130°C/ W (N8)
TJMAX = 150°C, θJA = 175°C/ W (S8)
S8 PART MARKING
LTC1440CMS8
OUT
V+
REF
HYST
MS8 PART MARKING
TJMAX = 150°C, θJA = 250°C/ W
LTC1441CN8
LTC1441CS8
LTC1441IN8
LTC1441IS8
S8 PART MARKING
1441
1441I
8
7
6
5
MS8 PACKAGE
8-LEAD PLASTIC MSOP
ORDER PART NUMBER
TOP VIEW
IN A
TOP VIEW
GND
V–
IN +
IN –
1440
1440I
TJMAX = 150°C, θJA = 130°C/ W (N8)
TJMAX = 150°C, θJA = 175°C/ W (S8)
–
ORDER PART NUMBER
LTBX
ORDER PART NUMBER
TOP VIEW
LTC1442CN8
LTC1442CS8
LTC1442IN8
LTC1442IS8
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
S8 PART MARKING
1442
1442I
TJMAX = 150°C, θJA = 130°C/ W (N8)
TJMAX = 150°C, θJA = 175°C/ W (S8)
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
Power Supply
V+
Supply Voltage Range
ICC
Supply Current
2
V + = 5V, V – = GND = 0V, TA = 25°C unless otherwise noted.
CONDITIONS
MIN
●
IN + = IN – = 80mV
HYST = REF (LTC1440/LTC1442)
LTC1440
LTC1441
LTC1442
●
●
●
TYP
MAX
UNITS
2.1
3.5
3.5
11.0
3.7
5.7
5.7
V
µA
µA
µA
2.0
LTC1440/LTC1441/LTC1442
ELECTRICAL CHARACTERISTICS
V + = 5V, V – = GND = 0V, TA = 25°C unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
Comparator
VOS
Comparator Input Offset Voltage
VCM = 2.5V
Input Leakage Current (IN +, IN –)
VIN + = VIN – = 2.5V
IIN
Input Leakage Current (HYST)
VCM
Comparator Input Common Mode Range
CMRR
Common Mode Rejection Ratio
V – to V + – 1.3V
PSRR
Power Supply Rejection Ratio
V + = 2V to 11V
NOISE
Voltage Noise
100Hz to 100kHz
VHYST
Hysteresis Input Voltage Range
LTC1440/LTC1442
tPD
Propagation Delay
COUT = 100pF
VOH
VOL
Output High Voltage
Output Low Voltage
Reference
VREF
Reference Voltage
IO = – 13mA
IO = 1.8mA
MIN
●
●
●
●
TYP
MAX
UNITS
±3
±0.01
±0.02
±10
±1.0
±1.0
V + – 1.3V
1
1
mV
nA
nA
V
mV/V
mV/V
µVRMS
V
µs
µs
V
V
V
V–
0.1
0.1
100
●
REF – 50mV
Overdrive = 10mV
Overdrive = 100mV
●
LTC1440
LTC1441/LTC1442
ISOURCE
ISINK
∆VREF
Reference Output Source Current
Reference Output Sink Current
Reference Source Current
Reference Sink Current
No Load
C Temp Range
LTC1440/LTC1442
I Temp Range
No Load LTC1440 (MSOP) C Temp Range
∆VREF ≤ 1mV (LTC1442)
∆VREF ≤ 2.5mV (LTC1442)
0 ≤ ISOURCE ≤ 2mA (LTC1440)
0 ≤ ISINK ≤ 10µA (LTC1440)
NOISE
Voltage Noise
100Hz to 100kHz
REF
15
8
V + – 0.4V
GND + 0.4V
V – + 0.4V
●
●
●
●
●
●
1.170
1.164
1.164
100
10
●
1.182
200
20
0.8
0.5
●
V + = 2V to 11V
100Hz to 100kHz
LTC1440/LTC1442
COUT = 100pF
VOH
VOL
IO = – 8mA
IO = 0.8mA
Output High Voltage
Output Low Voltage
●
LTC1440
LTC1441
LTC1442
VCM = 1.5V
VIN + = VIN – = 1.5V
2
2
3.5
3.5
●
●
●
±3
±0.01
±0.02
●
●
●
●
V – to
5
1.5
5
V–
V + – 1.3V
0.1
0.1
100
●
REF – 50mV
Overdrive = 10mV
Overdrive = 100mV
LTC1440
LTC1441/LTC1442
11
3.6
5.7
5.7
±10
±1
±1
V + – 1.3V
1
1
REF
14
5
●
●
●
V
V
V
µA
µA
mV
mV
mV
µVRMS
100
V + = 3V, V – = GND = 0V, TA = 25°C unless otherwise noted.
Power Supply
V+
Supply Voltage Range
ICC
Supply Current
IN + = IN – = 80mV
HYST = REF (LTC1440/LTC1442)
Comparator
VOS
Comparator Input Offset Voltage
Input Leakage Current (IN +, IN –)
IIN
Input Leakage Current (HYST)
VCM
Comparator Input Common Mode Range
CMRR
Common Mode Rejection Ratio
PSRR
Power Supply Rejection Ratio
NOISE
Voltage Noise
VHYST
Hysteresis Input Voltage Range
tPD
Propagation Delay
1.194
1.200
1.200
V + – 0.4V
GND + 0.4V
V – + 0.4V
V
µA
µA
µA
mV
nA
nA
V
mV/V
mV/V
µVRMS
V
µs
µs
V
V
V
3
LTC1440/LTC1441/LTC1442
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
Reference
VREF
Reference Voltage
ISOURCE
ISINK
∆VREF
V + = 3V, V – = GND = 0V, TA = 25°C unless otherwise noted.
CONDITIONS
No Load
C Temp Range
LTC1440/LTC1442
I Temp Range
No Load LTC1440 (MSOP) C Temp Range
∆VREF ≤ 1mV (LTC1442)
∆VREF ≤ 2.5mV (LTC1442)
0 ≤ ISOURCE ≤ 1mA (LTC1440)
0 ≤ ISINK ≤ 10µA (LTC1440)
Reference Output Source Current
Reference Output Sink Current
Reference Source Current
Reference Sink Current
●
●
●
●
MIN
TYP
MAX
UNITS
1.170
1.164
1.164
60
10
1.182
1.194
1.200
1.200
V
V
V
µA
µA
mV
mV
mV
120
20
0.8
0.5
●
●
NOISE
Voltage Noise
100Hz to 100kHz
5.5
1.5
5
µVRMS
100
The ● denotes specifications which apply over the full operating
temperature range.
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TYPICAL PERFORMANCE CHARACTERISTICS
Comparator Response Time vs
Input Overdrive
Comparator Response Time vs
Input Overdrives
3
100mV
50mV
10mV
20mV
2
1
0
0
100
–1
0
2
4
6
RESPONSE TIME (µs)
8
10
200
5
TA = 25°C
4
TA = 25°C
180
100mV
3
50mV
160
20mV
SINK CURRENT (mA)
4
OUTPUT VOLTAGE (V)
TA = 25°C
INPUT VOLTAGE (mV)
INPUT VOLTAGE (mV) OUTPUT VOLTAGE (V)
5
Comparator Short-Circuit Sink
Current vs Supply Voltage
10mV
2
1
0
100
140
OUT CONNECTED TO V +
120
100
80
60
40
0
20
0
–1
0
4 6 8 10 12 14 16 18
RESPONSE TIME (µs)
2
1440/1/2 G01
0
1
2
3 4 5 6 7 8
SUPPLY VOLTAGE (V)
Comparator Response Time vs
Load Capacitance with 100mV
Input Overdrive
Comparator Response Time at
Low Supply Voltage
10000
12
160
10
1440/1/2 G03
1440/1/2 G02
Comparator Short-Circuit Source
Current vs Supply Voltage
9
140
OUT CONNECTED TO
V – = GND = 0V
100
80
60
40
t PHL
RESPONSE TIME (µs)
RESPONSE TIME (µs)
SOURCE CURRENT (mA)
10
120
8
t PLH
6
1000
20mV OVERDRIVE
100
10
100mV OVERDRIVE
4
20
0
1
2
3
SUPPLY VOLTAGE (V)
4
5
1440/1/2 G04
4
1
2
0
0
20
60
80
40
LOAD CAPACITANCE (nF)
100
1440/1/2 G05
1.0
1.1
1.2
1.3
1.4
SUPPLY VOLTAGE (V)
1.5
1.6
1440/1/2 G06
LTC1440/LTC1441/LTC1442
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TYPICAL PERFORMANCE CHARACTERISTICS
Comparator Output Voltage Low
vs Load Current
Comparator Output Voltage High
vs Load Current
TA = 25°C
TA = 25°C
OUTPUT VOLTAGE HIGH (V)
V + = 5V
4
3
V + = 3V
2
V + = 2V
1
20
30
40
LOAD CURRENT (mA)
50
2.0
V + = 2V
1.5
V + = 5V
1.0
0.5
0
60
V + = 3V
0
10
20 30 40 50 60
LOAD CURRENT (mA)
1440/1/2 G07
70
80
80
60
OUTPUT HIGH
40
20
0
OUTPUT LOW
–20
–40
–60
–80
0
10
20
30
VREF – VHYST (mV)
1440/1/2 G08
LTC1440
Supply Current vs Temperature
40
50
1440/1/2 G09
Reference Output Voltage vs
Output Load Current
1.190
6
5
V + = 5V
V – = –5V
4
3
V + = 3V
–
V = GND = 0V
2
V + = 5V
–
REFERENCE OUTPUT VOLTAGE (V)
VCC = 5V
SUPPLY CURRENT (µA)
1.185
SOURCE
1.180
1.175
1.170
1.165
1.160
V = GND = 0V
1.155
1
–60 –40 –20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
0
0.5 1.0 1.5 2.0 2.5 3.0
OUTPUT LOAD CURRENT (mA)
1440/1/2 G10
Reference Output Voltage vs
Output Load Current (Sink)
Reference Voltage vs
Temperature
1.186
1.200
V CC = 2V
1.184
1.195
V CC = 5V
1.190
1.185
SINK
1.180
1.175
1.170
3.5
1440/1/2 G11
REFERENCE VOLTAGE (V)
10
REFERENCE OUTPUT VOLTAGE (V)
0
POSITIVE-TO-NEGATIVE INPUT VOLTAGE (mV)
2.5
5
OUTPUT VOLTAGE HIGH (V)
LTC1440/LTC1442
Hysteresis Control
1.182
1.180
1.178
1.176
1.174
1.172
0
25
10
15
20
5
OUTPUT LOAD CURRENT (µA)
30
1440/1/2 G12
1.170
–60 –40 –20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
1440/1/2 G13
5
LTC1440/LTC1441/LTC1442
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PIN FUNCTIONS
1
GND
LTC1440
–
2 V
OUT 8
1
OUT A
7
2
V–
V+
+
3 IN+
4 IN–
OUT B 8
V+
+
–
LTC1441
A
–
–
B
7
2
V–
LTC1442
+
3 IN A+
IN B+ 6
5
4 IN A–
IN B– 5
–
–
8
V+
7
+
+
REF 6
3 IN A
4 IN B–
OUT B
B
A
+
REF 6
HYST
1 OUT A
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.
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.
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.
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OUT A (Pin 1): Comparator A CMOS Output. Swings from
V – to V +. Output can source up to 40mA and sink 5mA.
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.
LTC1440/LTC1441/LTC1442
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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
7
LTC1440/LTC1441/LTC1442
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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
6
IREF
R2
10k
R3
2.4M
R1
430Ω
5
V–
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
R1
LTC1440
6 REF
R1 =
REF
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
8
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
LTC1440/LTC1441/LTC1442
U
W
U
U
APPLICATIONS INFORMATION
2. Calculate the required resistive divider ratio.




4.65V
R2 = 1.18M 
− 1
15mV 

 1.182V + 2

R2 = 3.40M
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.
VHB = (VHBIN)(Ratio)
Low Voltage Operation
VHB = (60mV)(0.254)
The guaranteed minimum operating voltage is 2V or
(±1V). As the total supply voltage is reduced below 2V, the
performance degrades and the supply current falls. Both
the reference and the comparator are still functioning with
supply voltage down to 1.5V. The reference will have
slightly worse temperature coefficient. While the comparator would have less output drive and the propagation
delay increases. The useful input voltage range extends
from the negative supply to a little under 1V below the
positive supply, which is slightly closer to the positive rail
than the device operating from higher supply voltages.
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
R1 = REF =
= 1.18M
IBIAS
1µA




VIN
R2 = R1
− 1
VHB 

 VREF + 2

U
TYPICAL APPLICATIONS
Low Battery Detect Operates Down to 1.5V
7
2-CELL
NiCd
V+
2.6M
3 IN +
LTC1440
+
8
1M
4 IN–
–
OUT
V+
6 REF
20k
5
1.3M
HYST
GND
1
V–
1440 TA06
2
1M
9
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
10pF
365k*
+
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
10
LTC1440/LTC1441/LTC1442
U
PACKAGE DESCRIPTION
Dimensions in inches (millimeters) unless otherwise noted.
N8 Package
8-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
0.400*
(10.160)
MAX
8
7
6
5
1
2
3
4
0.255 ± 0.015*
(6.477 ± 0.381)
0.300 – 0.325
(7.620 – 8.255)
0.065
(1.651)
TYP
0.009 – 0.015
(0.229 – 0.381)
(
+0.635
–0.381
0.125
(3.175)
MIN
0.005
(0.127)
MIN
+0.025
0.325 –0.015
8.255
0.130 ± 0.005
(3.302 ± 0.127)
0.045 – 0.065
(1.143 – 1.651)
)
0.015
(0.380)
MIN
0.018 ± 0.003
(0.457 ± 0.076)
0.100 ± 0.010
(2.540 ± 0.254)
N8 0695
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.189 – 0.197*
(4.801 – 5.004)
8
7
6
5
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
1
0.010 – 0.020
× 45°
(0.254 – 0.508)
0.008 – 0.010
(0.203 – 0.254)
2
3
4
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0°– 8° TYP
0.016 – 0.050
0.406 – 1.270
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
0.014 – 0.019
(0.355 – 0.483)
0.050
(1.270)
BSC
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.
SO8 0695
11
LTC1440/LTC1441/LTC1442
U
TYPICAL APPLICATION
10kHz V/F Converter
+V
6.2V TO 12V
LM334
2k*
INPUT
0V TO 5V
Q8
Q1
+
LT1034-1.2
2.2µF
10kHz TRIM
200k
1.2M*
C1
1/2 LTC1441
0.01µF
+
LT1034-1.2
–
0.47µF
Q2
+
50pF
Q3
100k
Q4
2M TYP
100Hz TRIM
= HP5082-2810
15k
= 1N4148
Q5
= 2N2222
Q7
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
LT1178/LT1179
Dual/Quad 17µA Precision Single Supply Op Amps
70µV Max VOS, 5nA Max IBIAS
LT1351
Single 250µA, 3MHz, 200V/µs Op Amp with Shutdown
C-LoadTM Op Amp Stable Driving Any Capacitive Load
LT1352/LT1353
Dual/Quad 250µA, 3MHz, 200V/µs Op Amps
C-Load Op Amps Stable Driving Any Capacitive Load
LTC1443/LTC1444/LTC1445
Micropower Quad Comparator with 1% Reference
LTC1443 Has 1.182V Reference, LTC1444/LTC1445 Have
1.221V Reference and Adjustable Hysteresis
C-Load is a trademark of Linear Technology Corporation.
12
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900
FAX: (408) 434-0507● TELEX: 499-3977 ● www.linear-tech.com
144012fa LT/TP 0298 REV A 2K • PRINTED IN USA
●
 LINEAR TECHNOLOGY CORPORATION 1996