Datasheet

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LTC1440/LTC1441/LTC1442

144012fd

APPLICATIO S

Ultralow Power Single/Dual

Comparator with Reference

1.65M

1.13M

3.3V

–

GND

OUT

LTC1440

1440 TA01

–

HYST

REF

–

TEMPERATURE (°C)

–40

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

20 60

1440/1/2 TA02

–20 0

40 80

100

SUPPLY CURRENT (µA)

= 5V

–

= GND = 0V

Micropower 2.9V V

Threshold Detector

LTC1440 Supply Current vs Temperature

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, pro-

grammable 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.

■

Battery-Powered System Monitoring

■

Threshold Detectors

■

Window Comparators

■

Oscillator Circuits

■

Ultralow Quiescent Current: 2.1

A Typ (LTC1440)

■

Reference Output Drives 0.01

F 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)

FEATURES

DESCRIPTIO

TYPICAL APPLICATIO

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Summary of content (16 pages)

PAGE 1
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.
PAGE 2
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 ...........................................
PAGE 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 + = 5V and V – = GND = 0V unless otherwise noted.
PAGE 4
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.
PAGE 5
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
PAGE 6
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.
PAGE 7
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.
PAGE 8
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.
PAGE 9
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.
PAGE 10
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.
PAGE 11
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 = VHB (2)(IREF) ( 1.182V – VHB 2 ) IREF V– R2 GND 2 1 1440/1/2 F04 Figure 4. Programmable Hysteresis 1440/1/2 F03a Figure 3a.
PAGE 12
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.
PAGE 13
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.
PAGE 14
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 0.25 ± 0.05 4 0.25 ± 0.05 0.75 ±0.05 0.200 REF 0.50 BSC 2.38 ±0.05 (2 SIDES) 1 0.50 BSC 2.38 ±0.10 (2 SIDES) 0.00 – 0.
PAGE 15
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.
PAGE 16
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.