ANALOG DEVICES LTC 1440 CS8 Datasheet

FEATURES

LTC1440/LTC1441/LTC1442

Ultralow Power Single/Dual

Comparator with Reference

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DESCRIPTIO

■

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)

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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.

TYPICAL APPLICATIO

Micropower 2.9V VCC Threshold Detector

3.3V

R1

1.65M
1%

R2

1.13M
1%

+

IN

3

–

4

IN

5

HYST

6

REF

7

+

V

+

–

LTC1440

–

V

21

GND

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1440 TA01

LTC1440 Supply Current vs Temperature

5.0
V+ = 5V

–

= GND = 0V

V

4.5

4.0

8

OUT

3.5

3.0

2.5

SUPPLY CURRENT (µA)

2.0

1.5

–40

–20 0

40 80

20 60

TEMPERATURE (°C)

100

1440/1/2 TA02

144012fd

1

LTC1440/LTC1441/LTC1442

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ABSOLUTE MAXIMUM RATINGS

(Note 1)

Voltage

+

V

to V–, V+ to GND, GND to V–...........12V to – 0.3V

+

, IN–, HYST ................. (V+ + 0.3V) to (V–– 0.3V)

IN

REF ................................... (V

OUT (LTC1440) .............. (V

+

+ 0.3V) to (V–– 0.3V)

+

+ 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

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PACKAGE/ORDER INFORMATION

TOP VIEW

TOP VIEW

1GND

–

V

2

+

IN

3

–

IN

4

8-LEAD (3mm × 3mm) PLASTIC DFN

UNDERSIDE METAL CONNECTED TO V

DD PACKAGE

T

= 125°C, θJA = 160°C/ W (DD)

JMAX

(PCB CONNECTION OPTIONAL)

ORDER PART

NUMBER

LTC1440CDD
LTC1440IDD

TOP VIEW

OUT A

1

–

V

2

+

IN A

3

–

IN A

4

N8 PACKAGE
8-LEAD PDIP

T

= 150°C, θJA = 130°C/ W (N8)

JMAX

= 150°C, θJA = 175°C/ W (S8)

T

JMAX

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/

8

OUT

+

V

7

REF

6

HYST

5

–

DD8 PART

MARKING*

LBTH

OUT B

8

+

V

7

+

IN B

6

–

IN B

5

S8 PACKAGE

8-LEAD PLASTIC SO

GND

1

–

V

2

+

IN

3

–

IN

4

N8 PACKAGE
8-LEAD PDIP

T

= 150°C, θJA = 130°C/ W (N8)

JMAX

T

= 150°C, θJA = 175°C/ W (S8)

JMAX

ORDER PART

NUMBER

LTC1440CN8
LTC1440CS8
LTC1440IN8
LTC1440IS8

ORDER PART

NUMBER

LTC1441CN8
LTC1441CS8
LTC1441IN8
LTC1441IS8

S8 PART

MARKING

1441
1441I

OUT

8

+

V

7

REF

6

HYST

5

S8 PACKAGE

8-LEAD PLASTIC SO

S8 PART

MARKING

1440
1440
1440I
1440I

OUT A

V

IN A

IN B

N8 PACKAGE
8-LEAD PDIP

T
T

ORDER PART

LTC1440CMS8
LTC1440IMS8

TOP VIEW

1

–

2

+

3

–

4

S8 PACKAGE

8-LEAD PLASTIC SO

= 150°C, θJA = 130°C/ W (N8)

JMAX

= 150°C, θJA = 175°C/ W (S8)

JMAX

GND

V
IN
IN

T

NUMBER

OUT B

8

+

V

7

REF

6

HYST

5

TOP VIEW

1

–

2

+

3

–

4

MS8 PACKAGE

8-LEAD PLASTIC MSOP

= 150°C, θJA = 250°C/ W

JMAX

ORDER PART

LTC1442CN8
LTC1442CS8
LTC1442IN8
LTC1442IS8

OUT

8

+

7

V

6

REF

5

HYST

MS8 PART

MARKING*

LTBX

NUMBER

S8 PART

MARKING

1442
1442I

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

temperature range, otherwise specifications are at T

The ● denotes the specifications which apply over the full operating

= 25°C. V+ = 5V and V– = GND = 0V unless otherwise noted.

A

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply

+

V
I

CC

Supply Voltage Range
Supply Current IN+ = IN– + 80mV LTC1440 0°C ≤ TA ≤ 70°C

HYST = REF (LTC1440/LTC1442) –40°C ≤ TA ≤ 85°C

LTC1441
LTC1442

●

●

●

●

●

2.0 11.0 V

2.1 4.0 µA

4.4 µA

3.5 5.7 µA

3.5 5.7 µA

Comparator

V

OS

I

IN

V

CM

Comparator Input Offset Voltage VCM = 2.5V
Input Leakage Current (IN+, IN–)V

+

= V

IN

IN

Input Leakage Current (HYST)
Comparator Input Common

–

= 2.5V

●

●

●

●

V

±3 ±10 mV

±0.01 ±1.0 nA
±0.02 ±1.0 nA

–

V+ – 1.3V V

Mode Range

CMRR Common Mode Rejection Ratio V– to V+ – 1.3V 0.1 1 mV/V

+

PSRR Power Supply Rejection Ratio V

= 2V to 11V (LTC1441) 0.1 1 mV/V

V+ = 2.5V to 11V (LTC1440/LTC1442) 0.1 1 mV/V
NOISE Voltage Noise 100Hz to 100kHz 100 µV
V
t

PD

HYST

Hysteresis Input Voltage Range LTC1440/LTC1442
Propagation Delay C

= 100pF Overdrive = 10mV 15 µs

OUT

●

REF – 50mV REF V

RMS

Overdrive = 100mV 8 µs

V

OH

V

OL

Output High Voltage IO = – 13mA
Output Low Voltage IO = 1.8mA LTC1440

LTC1441/LTC1442

●

V+ – 0.4V V

●

●

GND + 0.4V V

V– + 0.4V V

Reference

V

REF

I

SOURCE

I

SINK

∆V

NOISE Voltage Noise 100Hz to 100kHz 100 µV

Reference Voltage No Load LTC1440/LTC1442

0°C ≤ T
–40°C ≤ TA ≤ 85°C

LTC1440 (MSOP, DFN)

Reference Output Source Current ∆V
Reference Output Sink Current ∆V
Reference Source Current 0 ≤ I

REF

Reference Sink Current 0 ≤ I

≤ 1mV (LTC1442)

REF

≤ 2.5mV (LTC1442) 10 20 µA

REF

≤ 2mA (LTC1440)

SOURCE

≤ 10µA (LTC1440) 0.5 1.5 mV

SINK

≤ 70°C

A

●

1.170 1.194 V

●

1.164 1.200 V

●

1.164 1.200 V

●

100 µA

●

●

0.8 5 mV

5mV

RMS

144012fd

3

LTC1440/LTC1441/LTC1442

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at T

The ● denotes the specifications which apply over the full operating

= 25°C. V+ = 3V and V– = GND = 0V unless otherwise noted.

A

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply

+

V

I

CC

Supply Voltage Range

Supply Current IN+ = IN– + 80mV LTC1440 0°C ≤ TA ≤ 70°C

HYST = REF (LTC1440/LTC1442) –40°C ≤ TA ≤ 85°C

LTC1441
LTC1442

●

●

●

●

●

211V

2 3.9 µA

4.3 µA

3.5 5.7 µA

3.5 5.7 µA

Comparator

V

OS

I

IN

V

CM

Comparator Input Offset Voltage VCM = 1.5V
Input Leakage Current (IN+, IN–)V

+

= V

IN

IN

Input Leakage Current (HYST)
Comparator Input Common

–

= 1.5V

●

●

●

●

V

±3 ± 10 mV

±0.01 ±1nA
±0.02 ±1nA

–

V+ – 1.3V V

Mode Range

CMRR Common Mode Rejection Ratio V– to V+ – 1.3V 0.1 1 mV/V

+

PSRR Power Supply Rejection Ratio V

= 2V to 11V (LTC1441) 0.1 1 mV/V

V+ = 2.5V to 11V (LTC1440/LTC1442) 0.1 1 mV/V
NOISE Voltage Noise 100Hz to 100kHz 100 µV
V
t

HYST

PD

Hysteresis Input Voltage Range LTC1440/LTC1442
Propagation Delay C

= 100pF Overdrive = 10mV 14 µs

OUT

●

REF – 50mV REF V

RMS

Overdrive = 100mV 5 µs

V

OH

Output High Voltage IO = – 8mA

●

V+ – 0.4V V

Comparator

V

OL

Output Low Voltage IO = 0.8mA LTC1440

LTC1441/LTC1442

●

●

GND + 0.4V V

V– + 0.4V V

Reference

V

REF

I

SOURCE

I

SINK

∆V

NOISE Voltage Noise 100Hz to 100kHz 100 µV

Reference Voltage No Load LTC1440/LTC1442

0°C ≤ T
–40°C ≤ TA ≤ 85°C

LTC1440 (MSOP, DFN)

Reference Output Source Current ∆V
Reference Output Sink Current ∆V
Reference Source Current 0 ≤ I

REF

Reference Sink Current 0 ≤ I

≤ 1mV (LTC1442)

REF

≤ 2.5mV (LTC1442) 10 20 µA

REF

≤ 1mA (LTC1440)

SOURCE

≤ 10µA (LTC1440) 0.5 1.5 mV

SINK

≤ 70°C

A

●

1.170 1.182 1.194 V

●

1.164 1.200 V

●

1.164 1.200 V

●

●

●

60 120 µA

0.8 5.5 mV

5mV

RMS

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.

4

144012fd

LTC1440/LTC1441/LTC1442

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Comparator Response Time vs
Input Overdrive

5

TA = 25°C

4

3

2

1

0

0

100

INPUT VOLTAGE (mV) OUTPUT VOLTAGE (V)

–1

100mV 10mV

50mV 20mV

20108

RESPONSE TIME (µs)

Comparator Short-Circuit Sink
Current vs Supply Voltage

200

TA = 25°C

180

160

140

120

100

80

60

SINK CURRENT (mA)

40

20

0

OUT CONNECTED TO V

213579

0

4

SUPPLY VOLTAGE (V)

Comparator Response Time vs
Input Overdrive

5

TA = 25°C

4

3

2

1

0

100

0

64

1440/1/2 G01

INPUT VOLTAGE (mV) OUTPUT VOLTAGE (V)

100mV

–1

08

50mV

20mV

10mV

16

14

210

6

4

RESPONSE TIME (µs)

12

1440/1/2 G02

18

Comparator Short-Circuit Source
Current vs Supply Voltage

160

140

+

6

8

10

1440/1/2 G03

120

100

80

60

SOURCE CURRENT (mA)

40

20

0

0

OUT CONNECTED TO

12 4

SUPPLY VOLTAGE (V)

–

= GND = 0V

V

3

5

1440/1/2 G04

144012fd

5

LTC1440/LTC1441/LTC1442

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Comparator Response Time vs
Load Capacitance with 100mV
Input Overdrive

12

Comparator Response Time at
Low Supply Voltage

10000

10

8

6

RESPONSE TIME (µs)

4

2

0

t

PHL

t

PLH

20

LOAD CAPACITANCE (nF)

60

40

80

1440/1/2 G05

100

1000

RESPONSE TIME (µs)

100

20mV OVERDRIVE

10

1

1.0

100mV OVERDRIVE

1.2 1.4 1.61.1 1.3 1.5

SUPPLY VOLTAGE (V)

1440/1/2 G06

Comparator Output Voltage High
vs Load Current

5

4

3

V+ = 3V

2

OUTPUT VOLTAGE HIGH (V)

V+ = 2V

V+ = 5V

TA = 25°C

6

1

0

10 20 30 40

LOAD CURRENT (mA)

50 60

1440/1/2 G07

144012fd

LTC1440/LTC1441/LTC1442

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Comparator Output Voltage Low
vs Load Current

2.5
TA = 25°C

2.0

V+ = 2V

1.5

1.0

OUTPUT VOLTAGE LOW (V)

0.5

0

0

10 20

V+ = 3V

40

30 50 80

LOAD CURRENT (mA)

V+ = 5V

60 70

1440/1/2 G08

LTC1440
Supply Current vs Temperature

6

5

V+ = 5V

–

= –5V

4

V

LTC1440/LTC1442
Hysteresis Control

80

60

40

20

0

–20

–40

–60

POSITIVE-TO-NEGATIVE INPUT VOLTAGE (mV)

–80

10 20 40

0

V

– V

REF

OUTPUT HIGH

OUTPUT LOW

30

(mV)

HYST

50

1440/1/2 G09

3

V+ = 3V

V+ = 5V

–

= GND = 0V

V

60

–

= GND = 0V

V

100

140

1440/1/2 G10

144012fd

SUPPLY CURRENT (µA)

2

1

–20–40

–60

20 40 80 1200

TEMPERATURE (°C)

7

LTC1440/LTC1441/LTC1442

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Reference Output Voltage vs
Output Load Current

1.190
VCC = 5V

1.185

1.180

1.175

1.170

1.165

REFERENCE OUTPUT VOLTAGE (V)

1.160

1.155

0

0.5 1.0

1.5 2.5

OUTPUT LOAD CURRENT (mA)

SOURCE

2.0 3.0 3.5

1440/1/2 G11

1.186

1.184

1.182

1.180

1.178

1.176

1.174

REFERENCE VOLTAGE (V)

1.172

1.170

Reference Voltage vs
Temperature

–20–40

–60

20 40 80 1200

TEMPERATURE (°C)

Reference Output Voltage vs
Output Load Current (Sink)

1.200

VCC = 2V

1.195

1.190

1.185

1.180

1.175

REFERENCE OUTPUT VOLTAGE (V)

1.170
0

5

OUTPUT LOAD CURRENT (µA)

60

100

140

1440/1/2 G13

SINK

10 15 20

VCC = 5V

25 30

1440/1/2 G12

8

144012fd

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PIN FUNCTIONS

1

GND

V

2

IN

3

IN

4

LTC1440

–

+

+

–

–

OUT

REF

HYST

LTC1440/LTC1441/LTC1442

OUT A

8

7

+

V

6

5

OUT A

2

V

IN A

3

IN A

4

LTC14411

–

A

+

–

+

–

OUT B

8

7

+

V

B

+

–

+

IN B

6

–

IN B

5

1

2

V

IN A

3

4

IN B

LTC1442

–

A

+

–

+

–

–

V

B

–

OUT B

+

REF

HYST

+

V

1440/1/2 PD

8

7

6

5

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– (Pin 4): Inverting Comparator Input. 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 V

REF

to V

– 50mV.

REF

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 (Pin 8): Comparator CMOS Output. Swings from

+

GND to V

. Output can source up to 40mA and sink 5mA.

LTC1441

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.

LTC1442

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 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.

HYST (Pin 5): Hysteresis Input. Connect to REF if not
used. Input voltage range is from V

REF

to V

– 50mV.

REF

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.

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

–

to V+. Output can source up to 40mA and sink 5mA.

V

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9

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 oscil-
lation. The comparators’ CMOS outputs can source up to
40mA and the supply current glitches, that normally occur
when switching logic states, have been eliminated.

Power Supplies

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
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.

–

to GND on the LTC1440

capacitor of up to 0.01µF without oscillation and by
inserting a series resistor, capacitance values up to 100µF
can be used (Figure 1).

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.

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.

REFERENCE

OUTPUT

REF

R1

LTC144X

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.

Comparator Outputs

The LTC1440 comparator output swings between GND

+

and V
LTC1441 and LTC1442 outputs swing between V

to assure TTL compatibility with a split supply. The

–

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.

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

C1

Figure 1. Damping the Reference Output

1000

100

10

RESISTOR VALUE (kΩ)

1

0.1

0.001

Figure 2. Damping Resistance vs Bypass Capacitor Value

0.01 0.1 101
CAPACITOR VALUE (µF)

V

–

1440/1/2 F01

1440/1/2 F02

10

144012fd

LTC1440/LTC1441/LTC1442

U

WUU

APPLICATIONS INFORMATION

7

+

+

IN

3

–

IN

4

5V
TO
8V

R2

10k

R3

2.4M

R1
430Ω

C1
1µ F

HYST

5

REF

6

Figure 3a. Reference Transient Response Test Circuit

8V

+

V

5V

V

REF

2mV/DIV

V

+

8

–

LTC1440

–

V

21

GND

1440/1/2 F03a

OUT

up to 15%. If hysteresis is not wanted, the HYST pin
should be shorted to REF. Acceptable values for I

REF

range
from 0.1µA to 5µA. If 2.4M is chosen for R2, then the value
of R1 is equal to the value of V

6

I

REF

R1

R2

Figure 4. Programmable Hysteresis

REF

LTC1440

5

HYST

V

.

HB

V

HB

R1 =

(2)(I

)

REF

V

I

REF

1440/1/2 F04

HB

2

1.182V –

( )

–

2

R2 =

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:

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 (V

), is equal to twice

HB

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

1. Choose the V

V

IN

R2

3.4M
1%

R1

1.18M
1%

voltage trip level, in this example 4.65V.

IN

5V

7

+

V

+

–

LTC1440

–

V

21

GND

R3
15k
1%

R4

2.4M
1%

R5
430Ω
5%

C1
1µ F

+

IN

3

–

4

IN

5

HYST

6

REF

Figure 5. Glitch-Free Level Detector with Hysteresis

8

OUT

1440/1/2 F05

144012fd

11

LTC1440/LTC1441/LTC1442

U

WUU

APPLICATIONS INFORMATION

2. Calculate the required resistive divider ratio.

Ratio = V

Ratio = 1.182V/4.65V = 0.254

3. Choose the required hysteresis voltage band at the
input V
esis voltage band referred to the comparator input V

V

HB

V

HB

V

HB

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.

R

1

RR

21

REF/VIN

, in this example 60mV. Calculate the hyster-

HBIN

= (V

= (60mV)(0.254)

= 15.24mV

V

== =

I

BIAS

=

REF

⎡
⎢
⎢
⎢
⎢

⎣

HBIN

V

REF

)(Ratio)

.

1 182

µ

A

1

V

IN

V

HB

+

2

V

.

118

⎤
⎥
⎥

1

−
⎥
⎥

⎦

M

HB

.

⎡
⎢
⎢

.

2118

=

RM

⎢
⎢

⎣

.

=

RM

2340

Low Voltage Operation

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.

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.

.

1 182

.

465

+

V

V

15

mV
2

⎤
⎥
⎥

1

−
⎥
⎥

⎦

+

-

12

144012fd

U

TYPICAL APPLICATIONS

LTC1440/LTC1441/LTC1442

10-Bit 30µA A/D Converter

5V

LT®1034

1.2V

2N3809

150k

*TRW-IRC MRT–5/+120ppm/°C

100k

365k*

0.033µF
POLYSTYRENE

E

IN

0V TO 3V

10M

+

1/2 LTC1441

–

1N914

74C00

1M

5V

470k

32.768kHz

+

C2

1/2 LTC1441

–

1.2M

10pF

C1

VN2222LL

74C00

CONV

COMMAND

Q

74C74

D CLK

74C00 74C00

Q

STATUS

DATA
OUT

1440/1/2 TA03

32.768kHz “Watch Crystal” Oscillator

+

1/2

LTC1441

32.768kHz

1M

+V

470k

–

1.2M

10pF

1440/1/2 TA05

OUT

144012fd

13

LTC1440/LTC1441/LTC1442

U

PACKAGE DESCRIPTIO

8-Lead Plastic DFN (3mm × 3mm)

(Reference LTC DWG # 05-08-1698)

0.675 ±0.05

DD Package

R = 0.115

TYP

0.38 ± 0.10

85

3.5 ±0.05

1.65 ±0.05
(2 SIDES)2.15 ±0.05

PACKAGE
OUTLINE

0.25 ± 0.05

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

0.42 ± 0.038

(.0165 ± .0015)

0.50
BSC

2.38 ±0.05
(2 SIDES)

5.23

(.206)

MIN

TYP

RECOMMENDED SOLDER PAD LAYOUT

DETAIL “A”

0.254
(.010)

GAUGE PLANE

DETAIL “A”

0.18

(.007)

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

PIN 1

TOP MARK

(NOTE 6)

0.200 REF

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)

3.20 – 3.45

(.126 – .136)

3.00 ± 0.102

PLANE

(.118 ± .004)

(NOTE 3)

4.90

± 0.152

(.193 ± .006)

0.22 – 0.38

(.009 – .015)

TYP

1.10

(.043)

MAX

0.65

(.0256)

BSC

0.65

(.0256)

BSC

° – 6° TYP

0

(.021 ± .006)

0.53 ± 0.152

SEATING

3.00 ±0.10
(4 SIDES)

0.75 ±0.05

8

7

12

0.00 – 0.05

6

5

4

3

1.65 ± 0.10
(2 SIDES)

0.25 ± 0.05

BOTTOM VIEW—EXPOSED PAD

0.52

(.0205)

REF

3.00 ± 0.102

(.118 ± .004)

(NOTE 4)

0.86

(.034)

REF

0.127 ± 0.076
(.005 ± .003)

MSOP (MS8) 0204

2.38 ±0.10
(2 SIDES)

14

0.50 BSC

(DD8) DFN 1203

144012fd

14

PACKAGE DESCRIPTION

U

LTC1440/LTC1441/LTC1442

N8 Package

8-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

.400*

(10.160)

MAX

87 6

.255 ± .015*

(6.477 ± 0.381)

5

12

.300 – .325

(7.620 – 8.255)

.065

(1.651)

.008 – .015

(0.203 – 0.381)

+.035

.325

–.015
+0.889

8.255

()

–0.381

NOTE:

1. DIMENSIONS ARE

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)

INCHES

MILLIMETERS

TYP

.045 – .065

(1.143 – 1.651)

.100

(2.54)

BSC

S8 Package

8-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

.050 BSC

.045 ±.005

(4.801 – 5.004)

8

3

.189 – .197

NOTE 3

7

4

.130 ± .005

(3.302 ± 0.127)

.120

(3.048)

MIN

.018 ± .003

(0.457 ± 0.076)

5

6

.020

(0.508)

MIN

N8 1002

.245

MIN

.030 ±.005

TYP

RECOMMENDED SOLDER PAD LAYOUT

.010 – .020

(0.254 – 0.508)

.008 – .010

(0.203 – 0.254)

.016 – .050

NOTE:

1. DIMENSIONS IN

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)

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.

(0.406 – 1.270)

INCHES

(MILLIMETERS)

× 45°

.160

±.005

0°– 8° TYP

.228 – .244

(5.791 – 6.197)

.053 – .069

(1.346 – 1.752)

.014 – .019

(0.355 – 0.483)

TYP

1

2

.150 – .157

(3.810 – 3.988)

NOTE 3

3

4

.004 – .010

(0.101 – 0.254)

.050

(1.270)

BSC

SO8 0303

144012fd

15

LTC1440/LTC1441/LTC1442

U

TYPICAL APPLICATION

10kHz TRIM

200k

INPUT

0V TO 5V

1.2M*

= HP5082-2810

= 1N4148

= 2N2222

= 1% METAL FILM

*

= POLYSTYRENE

**

0.01µF

–

C1

1/2 LTC1441

+

100k

Q5

Q6

Q7

10kHz V/F Converter

+

2.2µF

50pF

2M TYP

100Hz TRIM

15k

100pF**

10M

C2

1/2 LTC1441

+V

6.2V TO 12V

LM334

2k*

Q1

LT1034-1.2

LT1034-1.2

Q2

Q3

Q4

2.7M

0.1µF

Q8

74C14

+

0.47µF

f

OUT

0kHz TO 10kHz

–

+

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 1% Accuracy, 8.5µA Maximum Current, Ref Output Drives 0.01µF

with Adjustable Hysteresis

LTC1540 1.182V Reference with Nanopower Comparator DFN Package 0.3µA Quiescent Current (Typical), Reference

with Adjustable Hysteresis 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 1% Accuracy, Open-Drain Out, Reference Drives 0.01µF

with Adjustable Hysteresis

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 SOT23, 1.4V to 18.5V Supply Range, ±2% Over Temperature
LT6700-2/LT6700-3

144012fd

LT 0806 REV D • PRINTED IN USA

16

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

[phone] ● FAX: [phone]

●

www.linear.com

© LINEAR TECHNOLOGY CORPORATION 1996