ISL21440_11_技术文档

Micropower Voltage Reference with Comparator

ISL21440

Features

• 1.8µA Supply Current Over Full Temperature Range

• Wide Supply Range . . . . . . . . . . . . . . . . . . . . . . . . . .2V to 11V

• Precision 1.182V ±0.5% Voltage Reference

• Comparator with User Programmable Hysteresis

• Temperature Range. . . . . . . . . . . . . . . . . . . .-40°C to +125°C

• 8 Ld MSOP and 8 Ld TDFN Packages

The ISL21440 is a micropower, FGA™ reference and comparator

on a single chip. Drawing less than 1.8µA supply current over the

full operating temperature range, the ISL21440 operates from a

single 2V to 11V supply and can also be used with split bipolar

supplies.

The ISL21440’s on-board reference provides a 1.182V ±0.5%

output. It features programmable hysteresis and TTL/CMOS

compatible outputs that sink and source current. Low Bias

currents permit high value divider resistors for typical circuit

current drains of <2.5µA.

• Pin Compatible Upgrade to MAX921 and LTC1440

Applications

• Low Battery Detector

• Low Voltage Reset

• Overvoltage Monitor

• Window Comparator

The low supply current makes the ISL21440 ideal for battery

powered devices in battery level or low voltage monitors circuits.

The ISL21440 is a pin-compatible, performance upgrade of both

the LTC1440, LTC1540, MAX921 and MAX931.

Vdd

VBAT

1.190

V+ = 3V

1.188

V+

2.4M

IN+

IN-

1.186

+

-

OUT

LoBAT-

V+ = 5V

1.184

1.182

1.180

1.8M

HYST

REF

ISL21440

20k

1.178

V+ = 2V

1.176

1.174

1.172

2.4M

V-

GND

-40

-20

0

20

40

60

80

100

120

LOW BATTERY DETECTOR

TEMPERATURE (°C)

FIGURE 1. TYPICAL APPLICATION

FIGURE 2. REFERENCE VOLTAGE vs TEMPERATURE

February 23, 2011

FN6532.2

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.

All other trademarks mentioned are the property of their respective owners.

1

ISL21440

Block Diagram

V+

IN+

+

-

OUT

IN-

HYST

REF

ISL21440

V-

GND

Pin Configuration

Pin Descriptions

PIN SYMBOL

ISL21440

DESCRIPTION

(8 LD MSOP, 8 LD TDFN)

TOP VIEW

1

2

GND

V-

Ground pin. Sets the Comparator output low level.

Negative Supply Input for Voltage Reference and

Comparator.

OUT

V+

GND

V-

1

2

3

4

8

7

6

5

3

IN+

Comparator non-inverting input pin. Range: V- to

V+ -1.5V.

IN+

IN-

REF

4

5

IN-

Comparator inverting input pin. Range: V- to V+ -1.5V

HYST

Comparator Hysteresis input. Accepts a voltage divided

from the Reference output. Range is VREF - 50mV to

VREF. Connect directly to VREF for zero hysteresis.

6

7

REF

V+

Reference output. Source 2mA and Sink 10µA.

Positive Supply Input for Comparator and Reference.

Range is 2.0V to 11.0V

8

OUT

Comparator output, CMOS push-pull. Output swing

referenced to V+ and GND.

FN6532.2

February 23, 2011

2

ISL21440

Ordering Information

PART NUMBER

V

RANGE

(V)

TEMP RANGE

(°C)

PACKAGE

(Pb-free)

PKG.

DWG. #

DD

(Notes 1, 2, 3)

PART MARKING

1440Z

ISL21440IUZ

ISL21440IRTZ

NOTES:

2 to 11

-40 to +125

8 Ld MSOP

8 Ld TDFN

M8.118

L8.3x3G

1440

1. Add “-T*” suffix for tape and reel. Please refer to TB347 for details on reel specifications.

2. These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte

tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations). Intersil Pb-

free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.

3. For Moisture Sensitivity Level (MSL), please see device information page for ISL21440. For more information on MSL please see techbrief TB363.

FN6532.2

February 23, 2011

3

ISL21440

Table of Contents

Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Thermal Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Environmental Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Recommended Operating Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Analog Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Analog Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Typical Performance Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Device Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Comparator Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Voltage Reference Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Applications Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Handling and Board Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Hysteresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Board Assembly Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Special Applications Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Typical Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Low Battery Detector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Window Comparator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Revision History. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Package Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Package Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

FN6532.2

February 23, 2011

4

ISL21440

Absolute Maximum Ratings

Thermal Information

Supply Voltage Range, V+ to GND . . . . . . . . . . . . . . . . . . . . . .-0.5V to +12V

IN+, IN- with Respect to V- . . . . . . . . . . . . . . . . . . . . . . . -0.3V to (V+) +0.3V

GND with Respect to V- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.0V to -0.3V

V+ with Respect to V- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12V to -0.3V

REF, HYST with Respect to V- . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 1.5V

Out with Respect to GND. . . . . . . . . . . . . . . . . . . . . . . . . (V+) +0.3V to -0.3V

Thermal Resistance (Typical)

8 Ld MSOP Package (Notes 5, 7) . . . . . . . . . .

8 Ld TDFN Package (Notes 5, 6). . . . . . . . . . .

Maximum Junction Temperature (Plastic Package) . . . . . . . . . . . .+150°C

Storage Temperature Range. . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C

Pb-Free Reflow Profile (Note 8). . . . . . . . . . . . . . . . . . . . . . . . see link below

http://www.intersil.com/pbfree/Pb-FreeReflow.asp

θ

_JA(°C/W)

154

θ

_JC(°C/W)

55

8

68

Voltage on All Other Pins. . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to V + 0.3V

CC

ESD Rating

Human Body Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4000V

Machine Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350V

Charged Device Model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2000V

Latch Up (Tested Per JESD-78B; Class 1, Level A) . . . . . . . . . . . . . . 100mA

Recommended Operating Conditions

Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +125°C

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7V to 5.5V

Environmental Operating Conditions

X-Ray Exposure (Note 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mRem

CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product

reliability and result in failures not covered by warranty.

NOTES:

4. Measured with no filtering, distance of 10” from source, intensity set to 55kV and 70mA current, 30s duration. Other exposure levels should be

analyzed for Output Voltage drift effects. See “Applications Information” on page 11.

5. θ_JAis measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.

6. For θ , the “case temp” location is the center of the exposed metal pad on the package underside.

JC

7. For θ , the “case temp” location is taken at the package top center.

JC

8. Post-reflow drift for the ISL21440 device voltage reference output will range from 100mV to 1.0mV based on experimental results with devices on

FR4 double sided boards. The design engineer must take this into account when considering the reference voltage after assembly.

Analog Specifications V+= +5.0V. V- = GND = 0V unless otherwise specified, T = +25°C. Boldface limits apply over the operating

A

temperature range, -40°C to +125°C.

MIN

TYP

MAX

SYMBOL

PARAMETER

TEST CONDITIONS

(Note 10) (Note 9) (Note 10) UNITS

POWER SUPPLY

V

Supply Voltage Range

Supply Current

V- = GND

2.0

11.0

0.75

0.85

V

+

I

IN+ = IN- +80mV,

HYST = REF

0.46

µA

CC

COMPARATOR

V

OS

Input Offset Voltage

V

= 2.5V

MSOP Package

TDFN Package

±3

±3.25

±3.6

±3.75

1.4

mV

CM

IN+

mV

I

Input Leakage Current (IN+, IN-, HYST)

V

= V = 2.5V

IN-

MSOP Package

TDFN Package

0.1

nA

IN

1.5

nA

3

nA

V

Common-Mode Input Range

V-

(V+) - 1.5

3

V

CM

CMRR

Common-Mode Rejection Ratio

V- to (V+ - 1.5V)

MSOP Package

TDFN Package

1.2

mV/V

3.5

4.5

5

FN6532.2

February 23, 2011

5

ISL21440

Analog Specifications V+= +5.0V. V- = GND = 0V unless otherwise specified, T = +25°C. Boldface limits apply over the operating

A

temperature range, -40°C to +125°C. (Continued)

MIN

TYP

MAX

SYMBOL

PSRR

PARAMETER

TEST CONDITIONS

MSOP Package

(Note 10) (Note 9) (Note 10) UNITS

Power Supply Rejection Ratio

V+ = 2V to 11V

0.25

1.1

1.2

mV/V

V

TDFN Package

1.5

1.6

V

Hysteresis Input Voltage

REF - 50mV

REF

HYST

t

Propagation Delay - High to Low Transition

C

= 100pF

Overdrive = 10mV

Overdrive = 100mV

Overdrive = 10mV

Overdrive = 100mV

100

50

µs

PHL

L

µs

t

Propagation Delay - Low to High Transition

200

100

µs

PLH

µs

V

Output High Voltage

Output Low Voltage

I

= -10mA

= 3mA

O

(V+) - 0.4

1.176

V

OH

O

V

I

GND + 0.4

V

OL

REFERENCE

V

Reference Voltage

No Load

1.188

-2.0

-2.5

2.0

V

REF

ΔV

Output Load Regulation

0 ≤ I

≤ 2mA

SOURCE

-0.5

0.1

mV

REF

0 ≤ I

≤ 10µA

SINK

2.5

Analog Specifications V+= +3.0V. V- = GND = 0V unless otherwise specified, T = +25°C. Boldface limits apply over the operating

A

temperature range, -40°C to +125°C.

MIN

TYP

MAX

SYMBOL

PARAMETER

TEST CONDITIONS

(Note 10) (Note 9) (Note 10) UNITS

V+ = 3.0V, V- = GND = 0V

I

Supply Current

IN+ = IN- +80mV,

HYST = REF

0.40

0.7

0.8

µA

CC

COMPARATOR

V Input offset Voltage

V

= 1.5V

MSOP Package

TDFN Package

±2.3

0.1

±3.4

±3.5

±4.2

±4.3

1.1

mV

OS

CM

IN+

mV

I

Input Leakage Current (IN+, IN-, HYST)

V

= V = 1.5V

IN-

nA

IN

3

nA

V

Common-Mode Input Range

V-

(V+) - 1.5

5

V

CM

CMRR

Common-Mode Rejection Ratio

V- to (V+ - 1.5V)

MSOP Package

TDFN Package

1.2

mV/V

5.5

7.5

8

FN6532.2

February 23, 2011

6

ISL21440

Analog Specifications V+= +3.0V. V- = GND = 0V unless otherwise specified, T = +25°C. Boldface limits apply over the operating

A

temperature range, -40°C to +125°C. (Continued)

MIN

TYP

MAX

SYMBOL

PSRR

PARAMETER

TEST CONDITIONS

MSOP Package

(Note 10) (Note 9) (Note 10) UNITS

Power Supply Rejection Ratio

V+ = 2V to 11V

0.25

1.1

1.2

mV/V

V

TDFN Package

1.5

1.6

V

Hysteresis Input Voltage

REF - 50mV

REF

HYST

t

Propagation Delay - High to Low Transition

C

= 100pF

Overdrive = 10mV

Overdrive = 100mV

Overdrive = 10mV

Overdrive = 100mV

100

50

µs

PHL

L

µs

t

Propagation Delay - Low to High Transition

200

100

µs

PLH

µs

V

Output High Voltage

Output Low Voltage

I

= -6mA

O

(V+) - 0.4

1.176

V

OH

V

I

= 1.8mA

O

GND + 0.4

V

OL

REFERENCE

V

Reference Voltage

No Load

1.188

-2.0

-2.5

2.0

V

REF

ΔV

Output Load Regulation

0 ≤ I

≤ 2mA

SOURCE

-0.5

0.1

mV

REF

0 ≤ I

≤ 10µA

SINK

-2.5

NOTES:

9. Over the specified temperature range. Temperature coefficient is measured by the box method whereby the change in V

temperature range; in this case, -40°C to +125°C = +165°C.

is divided by the

OUT

10. Parts are 100% tested at +25°C and +85°C. The -40°C and +125°C temperature limits are established by characterization and are not production

tested.

Typical Performance Curves

0.49

0.48

0.47

0.46

0.45

0.44

0.43

0.42

0.41

0.40

1.2

1.0

0.8

0.6

0.4

0.2

0

V+ = 5V

V+ = 3V

2

3

4

5

6

7

8

9

10

11

-40

-20

0

20

40

60

80

100

120

V

(V)

TEMPERATURE (°C)

DD

FIGURE 4. I

vs V

DD

FIGURE 3. I

vs TEMPERATURE

DD

FN6532.2

February 23, 2011

7

ISL21440

Typical Performance Curves (Continued)

1.190

1.188

1.186

1.184

1.182

1.180

1.178

1.176

1.174

1.172

1.190

1.188

1.186

1.184

1.182

1.180

1.178

1.176

1.174

1.172

V+ = 3V

V+ = 5V

V+ = 2V

-40

-20

0

20

40

60

80

100

120

2

3

4

5

6

7

8

9

10

11

12

V

(V)

TEMPERATURE (°C)

DD

FIGURE 6. V

vs SUPPLY VOLTAGE

FIGURE 5. V

vs TEMPERATURE

REF

1.183

1.182

1.181

1.180

1.179

1.178

1.177

1.176

1.175

1.188

1.187

1.186

1.185

1.184

1.183

1.182

V+ = 5V

V+ = 3V

V+ = 2V

1.5

0

0.5

1.0

2.0

2.5

3.0

0

0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50

LOAD (mA)

FIGURE 7. V

vs LOAD (SOURCE)

FIGURE 8. V

vs LOAD (SINK)

REF

1.30

1.25

1.20

1.15

1.10

1.05

1.00

3.0

2.5

2.0

1.5

1.0

0.5

0

NO

LOAD

10mA

LOAD

100mA

LOAD

V+ = 5V

V+ = 3V

V+ = 2V

V+ = 11V

1.00 1.25

1.50

1.75

2.00 2.25

(V)

2.50

2.75

3.00

0

2

4

6

I

8

10

12

14

V

(mA)

DD

LOAD

FIGURE 10. COMPARATOR OUTPUT LOW VOLTAGE vs LOAD

FIGURE 9. DROPOUT - V

OUTPUT

REF

FN6532.2

February 23, 2011

8

ISL21440

Typical Performance Curves (Continued)

12

6

5

4

3

2

1

0

10

8

V+ = 11V

V+ = 5V

6

4

2

0

V+ = 3V

V+ = 2V

10

0

5

15

20

25

30

35

40

45

50

-60 -55-50 -45 -40 -35-30 -25 -20-15 -10 -5

0 5 10 15 20 25 30 35 40 45 50 55 60

I

(mA)

IN+ - IN- (mV)

LOAD

FIGURE 11. COMPARATOR OUTPUT HIGH VOLTAGE vs LOAD

FIGURE 12. HYSTERESIS - 0mV (V+ = 5V)

6

5

4

3

2

1

0

5

4

3

2

1

0

-60-55-50-45-40-35-30-25-20-15-10 -5

0 5 10 15 20 25 30 35 40 45 50 55 60

-60-55 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5

0 5 10 15 20 25 30 35 40 45 50 55 60

IN+ - IN- (mV)

FIGURE 14. HYSTERESIS - 25mV (V+ = 5V)

FIGURE 13. HYSTERESIS - 12.5mV (V+ = 5V)

6

5

4

3

2

1

0

6

5

4

3

2

1

0

-60-55-50-45-40-35-30-25-20-15-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60

IN+ - IN- (mV)

FIGURE 16. HYSTERESIS - 50mV (V+ = 5V)

FIGURE 15. HYSTERESIS - 37.5mV (V+ = 5V)

FN6532.2

February 23, 2011

9

ISL21440

Typical Performance Curves (Continued)

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

-60-55-50-45-40-35-30-25-20-15-10 -5 0

5 10 15 20 25 30 35 40 45 50 55 60

-60-55-50-45-40-35-30-25-20-15-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60

IN+ - IN- (mV)

FIGURE 17. HYSTERESIS - 0mV (V+ = 3V)

FIGURE 18. HYSTERESIS - 12.5mV (V+ = 3V)

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

-60-55-50-45-40-35-30-25-20-15-10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60

-60-55-50-45-40-35-30-25-20-15-10 -5

0 5 10 15 20 25 30 35 40 45 50 55 60

IN+ - IN- (mV)

FIGURE 20. HYSTERESIS - 37.5mV (V+ = 3V)

FIGURE 19. HYSTERESIS - 25mV (V+ = 3V)

90

80

70

60

50

40

30

20

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

3V

5V

10

20

30

40

50

60

70

80

90 100 110 120

-60-55-50-45-40-35-30-25-20-15-10 -5

0 5 10 15 20 25 30 35 40 45 50 55 60

INPUT VOLTAGE (mV)

IN+ - IN- (mV)

FIGURE 22. OUTPUT RESPONSE TIME vs INPUT OVERDRIVE

(t

FIGURE 21. HYSTERESIS - 50mV (V+ = 3V)

)

PHL

FN6532.2

February 23, 2011

10

ISL21440

Typical Performance Curves (Continued)

270

245

220

195

170

145

120

95

5.5

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

3V

OUT

V+

70

45

5V

20

-0.5

0

10

30

40

50

60

70

80

90 100 110 120

0.2

0.4

0.6 0.8

1.0 1.2 1.4

1.6 1.8

2.0

INPUT VOLTAGE (mV)

TIME (ms)

FIGURE 23. OUTPUT RESPONSE TIME vs INPUT OVERDRIVE

(t

FIGURE 24. POWER-UP/DOWN OUTPUT RESPONSE

)

PLH

(V+ = 5V, IN+ = V+, IN- = V

)

REF

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

OUT

V+

-0.5

0

0.2

0.4

0.6

0.8

1.0 1.2

1.4

1.6

1.8

2.0

TIME (ms)

FIGURE 25. POWER-UP/DOWN OUTPUT RESPONSE (V+ = 3V, IN+ = V+, IN- = V

)

REF

1mA are expected, then a 0.1µF decoupling capacitor at the V+

pin should be added.

Functional Description

Device Power

Voltage Reference Section

The ISL21440 device has a single positive supply pin, V+, and

two other supply pins, V- and GND. Normally for single supply

applications the V- pin is tied to system ground as well as the

GND pin. The separate ground pin allows the comparator to be

powered by split supplies from ±1.0V to ±5.5V. Note that the

minimum supply voltage will be 0.8V above the comparator

maximum input level for accurate operation.

The voltage reference is a micropower FGA reference and is set

to 1.182V ±0.5% at the factory. The reference output can source

up to 2mA but the sink capability is very limited at only 10µA,

maximum. Small value capacitors, up to 10nF, can be used on

the reference output to lower noise if desired.

Applications Information

Handling and Board Mounting

FGA references provide excellent initial accuracy and low

temperature drift at the expense of very little power drain. There

are some precautions to take to insure this accuracy is not

compromised. Excessive heat during solder reflow can cause

excessive initial accuracy drift, so the recommended +260°C

max temperature profile should not be exceeded. Expect up to

1mV drift from the solder reflow process.

Comparator Section

The comparator inputs can swing from the negative supply (GND

pin) to within 0.8V of the positive supply (V+). Alternatively, with

the comparator input set at the 1.182V reference level, the

minimum input voltage for accurate operation is 2.0V. If the

inputs are expected to see voltage levels above V+ or below

ground, they should be clamped with low leakage Schottky

diodes.

The CMOS output swings essentially from the GND potential to

V+ potential, depending on load current. If loads in excess of

FGA references are susceptible to excessive X-radiation like that

used in PC board manufacturing. Initial accuracy can change

FN6532.2

February 23, 2011

11

ISL21440

10mV or more under extreme radiation. If an assembled board

needs to be X-rayed, care should be taken to shield the FGA

reference device.

the received dose by over 90%. The lead frame for the device

which is on the bottom also provides similar shielding.

If a device is expected to pass through luggage X-ray machines

numerous times, it is advised to mount a 2-layer (minimum) PC

board over the top of the package, which along with a ground

plane underneath will effectively shield it from 50 to 100 passes

through the machine. Since these machines vary in X-ray dose

delivered, it is difficult to produce an accurate maximum pass

recommendation.

Hysteresis

The Hysteresis function allows for changing the value of the

reference switchover point depending on the previous state of

the comparator. This works to remove the effects of noise or

glitches in the voltage detection input and provide more reliable

output transitions.

Typical Applications

Low Battery Detector

Hysteresis is added to the ISL21440 by connecting one resistor

between the REF and HYST pins (R

), and another

REF

resistor(R

) between the HYST pin and ground. The hysteresis

HYST

voltage (V ) is designed to be twice the voltage difference

Figure 26 shows a typical implementation for the ISL21440, a

H

between the HYST pin and REF pin (V = 2 * (V )).

- V

low battery detector. The values for R

and R

provide

H

REF HYST

REF

HYST

Since the reference voltage is 1.182V (V

), Equations 1 and 2

20mV of hysteresis and 0.5µA I . The input trip point for

REF

for these two resistors are shown as follows:

V

is the same as the reference voltage, 1.182V, and a

detect

resistor divider at the input sets the Lo

(EQ. 1)

trip point at 2.7V. The

∗

R

= V ⁄ (2 I

) = (V

– V

) ⁄ I

HYST REF

BAT

total current draw for the circuit is going to be 1.1µA for V and

REF

H

REF

DD

0.6µA for V

.

BAT

(EQ. 2)

R

= (1.182 – V ⁄ 2) ⁄ I

= V ⁄ I

HYST REF

V_DD

HYST

H

REF

V_BAT

I

is chosen to be less than the maximum output of the

REF

V+

2.4M

reference, usually 5µA is a safe value but for lowest power, 0.1µA

can be used.

IN+

IN-

+

Lo_BAT-

OUT

-

If the hysteresis is not used, the HYST pin should be tied to the

REF pin.

1.8M

HYST

REF

20k

ISL21440

V- GND

Board Assembly Considerations

FGA references provide high accuracy and low temperature drift

but some PC board assembly precautions are necessary. Normal

Output voltage shifts of 100µV to 1mV can be expected with

Pb-free reflow profiles or wave solder on multi-layer FR4 PC

boards. Precautions should be taken to avoid excessive heat or

extended exposure to high reflow or wave solder temperatures,

this may reduce device initial accuracy.

2.4M

FIGURE 26. LOW BATTERY DETECTOR WITH HYSTERESIS

Post-assembly X-ray inspection may also lead to permanent

changes in device output voltage and should be minimized or

avoided. If X-ray inspection is required, it is advisable to monitor

the reference output voltage to verify excessive shift has not

occurred. If large amounts of shift are observed, it is best to add

an X-ray shield consisting of thin zinc (300µm) sheeting to allow

clear imaging, yet block x-ray energy that affects the FGA

reference.

Window Comparator

The ISL21440 can be combined with a micropower comparator

to produce a window comparator circuit. The circuit in Figure 27

uses a 3 resistor divider to produce high and low trip points, and

the ISL28197 (800nA supply current) comparator is added to

give the second output. The two outputs can be used separately

for over or undervoltage indication, or a gate can be added as

shown to report either in-window or out-of window condition.

Special Applications Considerations

The resistors are shown as Equations 3, 4 and 5 as follows.

In addition to post-assembly examination, there are also other

X-ray sources that may affect the FGA reference long term

accuracy. Airport screening machines contain X-rays and will

have a cumulative effect on the voltage reference output

accuracy. Carry-on luggage screening uses low level X-rays and is

not a major source of output voltage shift, although if a product

is expected to pass through that type of screening over 100x it

may need to consider shielding with copper or aluminum.

Checked luggage X-rays are higher intensity and can cause

output voltage shift in much fewer passes, so devices expected to

go through those machines should definitely consider shielding.

Note that just two layers of 1/2 ounce copper planes will reduce

Set:

(EQ. 3)

R

= 1M(1%)

3

2

= R [V ⁄ V – 1]

(EQ. 4)

(EQ. 5)

3

H

L

R

= R ([V ⁄ V

– 1] – R )

REF 2

1

3

H

Example: For V = 3.8V, V = 2.7V (3.3V ± 0.5V)

H

L

R = 402k, R = 1.82M (can be 1%)

2

1

The resulting circuit draws about 3µA and works down to V

2.2V.

=

DD

FN6532.2

February 23, 2011

12

ISL21440

V_BATOR V_DD

V_BAT

R1

V+

IN+

V_LOW

-

+

-

OUT

IN-

V_WINDOW

HYST

REF

R2

V_HI-

ISL21440

V-

GND

+

-

ISL28197

R3

FIGURE 27. WINDOW COMPARATOR CIRCUIT

FN6532.2

February 23, 2011

13

ISL21440

Revision History

The revision history provided is for informational purposes only and is believed to be accurate, but not warranted. Please go to web to make

sure you have the latest Rev.

DATE

REVISION

FN6532.2

CHANGE

1/24/11

On page 3:

Updated Tape & Reel note in “Ordering Information” to add new standard "Add “-T*” suffix for tape and reel."

The "*" covers all possible tape and reel options

On page 6:

Separated “Analog Specifications” tables into 2 tables. Put specs from "V+ = 3.0V, V- = GND = 0V" to end of table

into separate table and added following common conditions:

"V+= +3.0V. V- = GND = 0V unless otherwise specified, T = +25°C. Boldface limits apply over the operating

A

temperature range, -40°C to +125°C."

On page 6:

Changed conditions for “V ” from Io = -7mA to Io = -6mA

OH

Changed conditions for “V ” from Io = 3mA to Io = 1.8mA

OL

3/31/10

3/2/10

In “Window Comparator” on page 12, changed "with a micropower to.." to: "with a micropower comparator to.."

Page 14, replaced POD M8.118 with newest revision. Updated to new intersil format by adding land pattern and

moving dimensions from table onto drawing

FN6532.1

FN6532.0

Updated datasheet with the TDFN spec.

Spec added on pages 5-6 are: VOS, IIN, CMRR and PSRR. Each spec has an added row for the TDFN package

and the original limit for the MSOP package.

12/7/09

Initial Release

Products

Intersil Corporation is a leader in the design and manufacture of high-performance analog semiconductors. The Company's products

address some of the industry's fastest growing markets, such as, flat panel displays, cell phones, handheld products, and notebooks.

Intersil's product families address power management and analog signal processing functions. Go to www.intersil.com/products for a

complete list of Intersil product families.

*For a complete listing of Applications, Related Documentation and Related Parts, please see the respective device information page

on intersil.com: ISL21440

To report errors or suggestions for this datasheet, please go to www.intersil.com/askourstaff

FITs are available from our website at http://rel.intersil.com/reports/search.php

FN6532.2

February 23, 2011

14

ISL21440

Package Outline Drawing

M8.118

8 LEAD MINI SMALL OUTLINE PLASTIC PACKAGE

Rev 3, 3/10

5

3.0±0.05

A

8

DETAIL "X"

D

1.10 MAX

SIDE VIEW 2

0.09 - 0.20

4.9±0.15

3.0±0.05

5

0.95 REF

PIN# 1 ID

1

2

B

0.65 BSC

GAUGE

PLANE

TOP VIEW

0.25

3°±3°

0.55 ± 0.15

DETAIL "X"

0.85±010

H

C

SEATING PLANE

0.10 C

0.25 - 0.036

0.10 ± 0.05

0.08

C A-B D

M

SIDE VIEW 1

(5.80)

NOTES:

1. Dimensions are in millimeters.

(4.40)

(3.00)

2. Dimensioning and tolerancing conform to JEDEC MO-187-AA

and AMSEY14.5m-1994.

3. Plastic or metal protrusions of 0.15mm max per side are not

included.

(0.65)

4. Plastic interlead protrusions of 0.15mm max per side are not

included.

(0.40)

(1.40)

5. Dimensions are measured at Datum Plane "H".

6. Dimensions in ( ) are for reference only.

TYPICAL RECOMMENDED LAND PATTERN

FN6532.2

February 23, 2011

15

ISL21440

Package Outline Drawing

L8.3x3G

8 LEAD THIN DUAL FLAT NO-LEAD PLASTIC PACKAGE (TDFN)

Rev 0, 5/07

PIN 1 INDEX AREA

3.00

A

1.45

PIN 1 INDEX AREA

B

0.075 C

4X

6X 0.50 BSC

1.50

REF

3.00

1.75

8X 0.25

0.10 M C A B

8X 0.40

2.20

TOP VIEW

BOTTOM VIEW

SEE DETAIL X''

0.10 C

(8X 0.60)

(1.75)

(8X 0.25)

0.75

C

SEATING PLANE

0.08 C

(6X 0.50 BSC)

SIDE VIEW

(1.45)

(2.20)

5

TYPICAL RECOMMENDED LAND PATTERN

0.20 REF

c

0~0.05

DETAIL “X”

NOTES:

1. Controlling dimensions are in mm.

Dimensions in ( ) for reference only.

2. Unless otherwise specified, tolerance : Decimal ±0.05

Angular ±2°

3. Dimensioning and tolerancing conform to JEDEC STD MO220-D.

4. The configuration of the pin #1 identifier is optional, but must be located

within the zone indicated. The pin #1 identifier may be either a mold or

mark feature.

5. Tiebar shown (if present) is a non-functional feature.

For additional products, see www.intersil.com/product_tree

Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted

in the quality certifications found at www.intersil.com/design/quality

Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time

without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be

accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third

parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.

For information regarding Intersil Corporation and its products, see www.intersil.com

FN6532.2

February 23, 2011

16


型号：	ISL21440_11
厂家：	Intersil
描述：	Micropower Voltage Reference with Comparator 微功耗电压参考与比较
文件：	总16页 (文件大小：845K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

ISL21440_11 [INTERSIL]

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