Datasheet LT1637 Datasheet (Linear Technology)

FEATURES

LT1637

1.1MHz, 0.4V/µs

Over-The-Top Micropower, Rail-To-Rail

Input and Output Op Amp

U

DESCRIPTIO

■

Operates with Inputs Above V

■

Rail-to-Rail Input and Output

■

Micropower: 250µA Supply Current Max

■

Gain-Bandwidth Product: 1.1MHz

■

Slew Rate: 0.4V/µs

■

Low Input Offset Voltage: 350µV Max

■

Single Supply Input Range: –0.4V to 44V

■

High Output Current: 25mA Min

■

Specified on 3V, 5V and ±15V Supplies

■

Output Shutdown

■

Output Drives 4700pF with Output Compensation

■

Reverse Battery Protection to 25V

■

High Voltage Gain: 800V/mV

■

High CMRR: 110dB

+

U

APPLICATIO S

■

Battery or Solar Powered Systems: Portable Instrumentation Sensor Conditioning

■

Supply Current Sensing

■

Battery Monitoring

■

MUX Amplifiers

■

4mA to 25mA Transmitters

The LT®1637 is a rugged op amp that operates on all single and split supplies with a total voltage of 2.7V to 44V. The LT1637 has a gain-bandwidth product of 1.1MHz while

drawing less than 250µA of quiescent current. The LT1637

can be shut down, making the output high impedance and

reducing the quiescent current to only 3µA. The LT1637 is

reverse supply protected: it draws virtually no current for reverse supply up to 25V. The input range of the LT1637 includes both supplies and the output swings to both supplies. Unlike most micropower op amps, the LT1637 can drive heavy loads; its rail-to-rail output drives 25mA. The LT1637 is unity-gain stable into all capacitive loads up

to 4700pF when optional 0.22µF and 150Ω compensation

is used.

The LT1637 has a unique input stage that operates and remains high impedance when above the positive supply. The inputs take 44V both differential and common mode, even when operating on a 3V supply. Built-in resistors protect the inputs for faults below the negative supply up to 22V. There is no phase reversal of the output for inputs 5V below VEE or 44V above VEE, independent of VCC.

The LT1637 op amp is available in the 8-pin MSOP, PDIP and SO packages.

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

Over-The-Top is a trademark of Linear Technology Corporation.

TYPICAL APPLICATIO

Switchable Precision Current Source Current Source Timing

+

R*

SHDN

LT1004-1.24.7µF

2k

+

LT1637

–

*OPTIONAL FOR LOW OUTPUT CURRENTS, R* = R

U

Over-The-TopTM Current Source with Shutdown

I

OUT

R

TP0610

4V TO 44V

1.2

=

I

OUT

R

e.g., 10mA = 120Ω

1637 TA01

V

SHDN

I

OUT

6V

4V

2V

0V

10mA

5mA

0mA

100µs/DIV 1637 TA01b

1

LT1637

1

2

3

4

8

7

6

5

TOP VIEW

NULL

V

+

OUT

SHDN

NULL

–

IN

+

IN

V

–

S8 PACKAGE

8-LEAD PLASTIC SO

N8 PACKAGE 8-LEAD PDIP

1 2 3 4

NULL

–

IN

+

IN

V

–

8 7 6 5

NULL V

+

OUT SHDN

TOP VIEW

MS8 PACKAGE

8-LEAD PLASTIC MSOP

WW

W

U

ABSOLUTE AXI U RATI GS

(Note 1)

Total Supply Voltage (V+ to V–) .............................. 44V

Input Differential Voltage ......................................... 44V

Input Current ...................................................... ±25mA

Shutdown Pin Voltage Above V

–

.....................................

32V

Shutdown Pin Current ........................................ ±10mA

Output Short-Circuit Duration (Note 2) ......... Continuous

UUW

PACKAGE/ORDER I FOR ATIO

ORDER PART

NUMBER

LT1637CMS8

T

= 150°C, θJA = 250°C/W

JMAX

MS8 PART

MARKING

Operating Temperature Range (Note 3) .. – 40°C to 85°C Specified Temperature Range (Note 4) ... –40°C to 85°C

Junction Temperature........................................... 150°C

Storage Temperature Range ................. –65°C to 150°C

Lead Temperature (Soldering, 10 sec).................. 300°C

ORDER PART

NUMBER

LT1637CN8 LT1637CS8 LT1637IN8 LT1637IS8

T

= 150°C, θJA = 130°C/W (N8)

JMAX

= 150°C, θJA = 190°C/W (S8)

T

JMAX

S8 PART

MARKING

LTIE

1637 1637I

Consult factory for Military grade parts.

3V 5VAUD ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the specified temperature range, otherwise specifications are at TA = 25°C. VS = 3V, 0V; VS = 5V, 0V; V

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

OS

I

OS

I

B

e

n

i

n

2

Input Offset Voltage N8, S8 Packages 100 350 µV

Input Offset Voltage Drift (Note 9) N8, S8 Packages, – 40°C ≤ TA ≤ 85°C ● 13µV/°C

Input Offset Current ● 0.4 6.0 nA

Input Bias Current ● 20 50 nA

Input Noise Voltage 0.1Hz to 10Hz 0.6 µV Input Noise Voltage Density f = 1kHz 27 nV/√Hz Input Noise Current Density f = 1kHz 0.08 pA/√Hz

= V–,VCM = V

SHDN

= Half Supply unless otherwise specified. (Note 4)

OUT

≤ 70°C ● 550 µV

0°C ≤ T

A

–40°C ≤ T MS8 Package 100 350 µV

0°C ≤ T –40°C ≤ T

MS8 Package, – 40°C ≤ T

V

CM

V

CM

= 0V 0.1 nA

V

S

≤ 85°C ● 700 µV

A

≤ 70°C ● 750 µV

A

≤ 85°C ● 900 µV

A

≤ 85°C ● 26µV/°C

A

= 44V (Note 5) ● 2.5 µA

= 44V (Note 5) ● 23 60 µA

P-P

LT1637

3V 5VAUD ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the specified temperature range, otherwise specifications are at TA = 25°C. VS = 3V, 0V; VS = 5V, 0V; V

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

R

IN

C

IN

CMRR Common Mode Rejection Ratio VCM = 0V to (VCC – 1V) ● 88 110 dB

A

VOL

V

OL

V

OH

I

SC

PSRR Power Supply Rejection Ratio VS = 3V to 12.5V, VCM = VO = 1V ● 90 98 dB

I

S

I

SHDN

t

ON

t

OFF

t

SETTLING

GBW Gain-Bandwidth Product f = 10kHz 650 1000 kHz

SR Slew Rate AV = – 1, R

Input Resistance Differential 1 2.6 MΩ

Input Capacitance 4pF Input Voltage Range ● 044V

(Note 5) V

Large-Signal Voltage Gain VS = 3V, VO = 500mV to 2.5V, RL = 10k 150 400 V/mV

Output Voltage Swing LOW No Load ● 38 mV

Output Voltage Swing HIGH VS = 3V, No Load ● 2.94 2.975 V

Short-Circuit Current (Note 2) VS = 3V, Short Output to Ground 10 14 mA

Minimum Supply Voltage ● 2.7 V

Reverse Supply Voltage I

Supply Current 190 250 µA

(Note 6)

Supply Current, SHDN V

Shutdown Pin Current V

Output Leakage Current V

Maximum Shutdown Pin Current V

Turn-On Time V

Turn-Off Time V

Settling Time 0.1% A

(Note 5) 0°C ≤ T

(Note 7) 0°C ≤ T

= V–, VCM = V

SHDN

= Half Supply unless otherwise specified. (Note 4)

OUT

Common Mode, V

= 0V to 44V (Note 8) ● 80 98 dB

CM

V

= 3V, 0°C ≤ TA ≤ 70°C ● 100 V/mV

S

= 3V, –40°C ≤ TA ≤ 85°C ● 75 V/mV

V

S

= 0V to 44V 0.7 1.4 MΩ

CM

VS = 5V, VO = 500mV to 4.5V, RL = 10k 300 800 V/mV

= 5V, 0°C ≤ TA ≤ 70°C ● 200 V/mV

V

S

V

= 5V, –40°C ≤ TA ≤ 85°C ● 150 V/mV

S

I

= 5mA ● 325 700 mV

SINK

V

S

V

S

= 5V, I

= 3V, I

= 10mA ● 580 1300 mV

SINK

= 5mA ● 2.25 2.67 V

SOURCE

VS = 5V, No Load ● 4.94 4.975 V V

= 5V, I

S

= 3V, Short Output to V

V

S

= 10mA ● 3.80 4.45 V

SOURCE

CC

15 45 mA

VS = 5V, Short Output to Ground 15 22 mA

= 5V, Short Output to V

V

S

= –100µA ● 25 40 V

S

= 2V, No Load (Note 6) ● 312 µA

PIN5

= 0.3V, No Load (Note 6) ● 0.2 15 nA

PIN5

= 2V, No Load (Note 5) ● 1.0 5 µA

V

PIN5

V

= 3.3V 2.5 µA

PIN5

= 5V 4.3 µA

V

PIN5

= 2V, No Load (Note 6) ● 0.02 1 µA

PIN5

= 32V, No Load (Note 5) ● 20 150 µA

PIN5

= 5V to 0V, R

PIN5

= 0V to 5V, R

PIN5

= 1, ∆VO = 2V 9 µs

V

≤ 70°C ● 550 kHz

A

–40°C ≤ T

≤ 85°C ● 500 kHz

A

= ∞ 0.210 0.35 V/µs

L

≤ 70°C ● 0.185 V/µs

A

≤ 85°C ● 0.170 V/µs

A

CC

= 10k 45 µs

L

= 10k 3 µs

L

15 60 mA

● 295 µA

3

LT1637

±15V ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the specified temperature range, otherwise specifications are at TA = 25°C. V

= ±15V, V

S

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

OS

I

OS

I

B

e

n

i

n

R

IN

C

IN

CMRR Common Mode Rejection Ratio VCM = –15V to 29V ● 80 110 dB

A

VOL

V

OL

V

OH

I

SC

PSRR Power Supply Rejection Ratio V

I

S

I

SHDN

V

L

V

H

t

ON

t

OFF

= 0V, V

CM

OUT

= 0V, V

= V– unless otherwise specified. (Note 4)

SHDN

Input Offset Voltage N8, S8 Packages 100 450 µV

≤ 70°C ● 650 µV

0°C ≤ T

A

–40°C ≤ T

≤ 85°C ● 800 µV

A

MS8 Package 100 450 µV

≤ 70°C ● 800 µV

0°C ≤ T

A

–40°C ≤ T

≤ 85°C ● 950 µV

A

Input Offset Voltage Drift (Note 9) N8, S8 Packages, – 40°C ≤ TA ≤ 85°C ● 13µV/°C

MS8 Package, – 40°C ≤ T

≤ 85°C ● 26µV/°C

A

Input Offset Current ● 16 nA Input Bias Current ● 17 50 nA Input Noise Voltage 0.1Hz to 10Hz 0.6 µV

P-P

Input Noise Voltage Density f = 1kHz 27 nV/√Hz Input Noise Current Density f = 1kHz 0.08 pA/√Hz Input Resistance Differential 1 3 MΩ

Common Mode, V

= –15V to 14V 2200 MΩ

CM

Input Capacitance 4pF Input Voltage Range ● –15 29 V

Large-Signal Voltage Gain V

= ±14V, R

O

0°C ≤ T –40°C ≤ T

= 10k 100 400 V/mV

L

≤ 70°C ● 75 V/mV

A

≤ 85°C ● 50 V/mV

A

Output Voltage Swing LOW No Load ● –14.997 –14.95 V

= 5mA ● –14.680 –14.25 V

I

SINK

= 10mA ● –14.420 –13.65 V

I

SINK

Output Voltage Swing HIGH No Load ● 14.9 14.967 V

I

= 5mA ● 14.2 14.667 V

SOURCE

= 10mA ● 13.7 14.440 V

I

SOURCE

Short-Circuit Current (Note 2) Short Output to GND ±25 ±31.7 mA

≤ 70°C ● ±20 mA

0°C ≤ T

A

–40°C ≤ T

= ±1.5V to ±22V ● 90 115 dB

S

≤ 85°C ● ±15 mA

A

Minimum Supply Voltage ● ±1.35 V Supply Current 230 300 µA

● 370 µA

Positive Supply Current, SHDN V

Shutdown Pin Current V

Maximum Shutdown Pin Current V

Output Leakage Current V

Shutdown Pin Input Low Voltage V

Shutdown Pin Input High Voltage V

Turn-On Time V

Turn-Off Time V

= – 20V, V

PIN5

= – 21.7V, V

PIN5

V

= – 20V, V

PIN5

= 32V, V

PIN5

= – 20V, V

PIN5

= ±22V ● – 21.7 –21.6 V

S

= ±22V ● – 20.8 –20.0 V

S

= – 10V to – 15V, R

PIN5

= – 15V to – 10V, R

PIN5

= ±22V, No Load ● 640 µA

S

= ±22V, No Load ● 0.3 15 nA

S

= ±22V, No Load ● 0.9 8 µA

S

= ±22V ● 20 150 µA

S

= ±22V, No Load ● 0.02 2 µA

S

= 10k 35 µs

L

= 10k 3 µs

L

4

LT1637

±15V ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the specified temperature range, otherwise specifications are at TA = 25°C. V

= ±15V, V

S

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

GBW Gain-Bandwidth Product f = 10kHz 750 1100 kHz

SR Slew Rate AV = – 1, R

Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.

Note 2: A heat sink may be required to keep the junction temperature below absolute maximum.

Note 3: The LT1637 is guaranteed functional over the operating

temperature range of – 40°C to 85°C.

Note 4: The LT1637C is guaranteed to meet specified performance from

0°C to 70°C. The LT1637C is designed, characterized and expected to meet specified performance from –40°C to 85°C but is not tested or QA

sampled at these temperatures. The LT1637I is guaranteed to meet

specified performance from –40°C to 85°C.

= 0V, V

CM

OUT

= 0V, V

= V– unless otherwise specified. (Note 4)

SHDN

≤ 70°C ● 650 kHz

0°C ≤ T

A

–40°C ≤ T

0°C ≤ T –40°C ≤ T

≤ 85°C ● 600 kHz

A

= ∞, VO = ±10V, Measure at VO = ±5V 0.225 0.4 V/µs

L

≤ 70°C ● 0.200 V/µs

A

≤ 85°C ● 0.180 V/µs

A

Note 5: V V

S

Note 6: V V

S

Note 7: Guaranteed by correlation to slew rate at V V

S

Note 8: This specification implies a typical input offset voltage of 650µV at

V

CM

Note 9: This parameter is not 100% tested.

= 5V limits are guaranteed by correlation to VS = 3V and

S

= ±15V or VS = ±22V tests.

= 3V limits are guaranteed by correlation to VS = 5V and

S

= ±15V or VS = ±22V tests.

= ±15V and GBW at

= 3V and V

= ±15V tests.

S

= 44V and a maximum input offset voltage of 5.4mV at VCM = 44V.

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Supply Current vs Supply Voltage

400

350

300

T

250

200

150

SUPPLY CURRENT (µA)

100

50

0

0 10203040

TOTAL SUPPLY VOLTAGE (V)

= 125°C

A

T

= 25°C

A

T

= –55°C

A

1637 G01

Minimum Supply Voltage

400

300

200

100

0

T

= 125°C

A

–100

–200

–300

CHANGE IN INPUT OFFSET VOLTAGE (µV)

–400

1 2 3 4 5

0

TOTAL SUPPLY VOLTAGE (V)

T

= –55°C

A

T

= 25°C

A

1637 G02

Input Bias Current vs Common Mode Voltage

40

VS = 5V, 0V

30

20

10

T

= –55°C

0.12

0.08

0.04

INPUT BIAS CURRENT (µA)

0.04

0.08

A

T

= 125°C

A

T

= 25°C

0

4 4.2 4.4 4.6 4.8 5 10 20 30 40 50

A

COMMON MODE VOLTAGE (V)

1637 G03

5

LT1637

TEMPERATURE (°C)

–50

SLEW RATE (V/µs)

25

1637 G12

–25 0 50 75 100 125

0.7

0.6

0.5

0.4

0.3

0.2

0.1

FALLING, V

S

= ±1.5V

FALLING, V

S

= ±15V

RISING, V

S

= ±15V

RISING, V

S

= ±1.5V

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Output Saturation Voltage vs Load Current (Output High)

1

VS = 5V, 0V

= 30mV

V

OD

0.1

OUTPUT SATURATION VOLTAGE (V)

0.01

0.0001 0.001

T

= 125°C

A

T

= 25°C

A

T

= –55°C

A

0.01 0.1 1 10 100

SOURCING LOAD CURRENT (mA)

0.1Hz to 10Hz Noise Voltage

V

= ±2.5V

S

1637 G04

Output Saturation Voltage vs Load Current (Output Low)

10

VS = 5V, 0V

= 30mV

V

OD

1

0.1

T

= 125°C

A

T

= 25°C

0.01

OUTPUT SATURATION VOLTAGE (V)

0.001

A

0.0001 0.001

T

= –55°C

A

0.01 0.1 1 10 100

SINKING LOAD CURRENT (mA)

Noise Voltage Density vs Frequency

70

V

= ±15V

S

60

50

1637 G05

Output Saturation Voltage vs Input Overdrive

100

VS = 5V, 0V

90

NO LOAD

80

70

60

50

40

30

20

OUTPUT SATURATION VOLTAGE (mV)

10

0

20

30

10 90

0

INPUT OVERDRIVE (mV)

40

OUTPUT HIGH

OUTPUT LOW

60

50

70

Input Noise Current vs Frequency

1.4

V

= ±15V

S

1.2

1.0

0.8

80

100

1637 G06

INPUT NOISE CURRENT DENSITY (pA/√Hz)

0.6

0.4

0.2

0

1

10 100 1000

FREQUENCY (Hz)

1637 G09

40

NOISE VOLTAGE (200nV/DIV)

2

0

3

19

4

TIME (s)

6

7

8

5

10

1637 G07

Open-Loop Gain and Phase Shift vs Frequency Slew Rate vs Temperature

70

V

= ±2.5V

60

50

40

30

20

GAIN (dB)

10

0

–10

–20

–30

1k

GAIN

10k 100k 1M

FREQUENCY (Hz)

S

PHASE

120

100

80

60

40

20

0

1637 G10

30

INPUT NOISE VOLTAGE DENSITY (nV/√Hz)

20

1

10 100 1000

FREQUENCY (Hz)

Gain-Bandwidth Product vs Temperature

1300

1200

PHASE SHIFT (DEG)

1100

1000

900

800

GAIN-BANDWIDTH PRODUCT (kHz)

700

–50

–25 0

V

= ±15V

S

V

= ±1.5V

S

50 100 125

25 75

TEMPERATURE (°C)

1637 G08

1637 G11

6

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Gain-Bandwidth Product and Phase Margin vs Supply Voltage CMRR vs Frequency PSRR vs Frequency

1300

1250

1200

1150

1100

1050

GAIN-BANDWIDTH PRODUCT (kHz)

1000

515

0

PHASE MARGIN

GAIN BANDWIDTH

10

TOTAL SUPPLY VOLTAGE (V)

25 45

20

55

50

45

40

35

30

40

1637 G13

25

35

30

100

90

PHASE MARGIN (DEG)

80

70

60

50

40

30

20

10

COMMON MODE REJECTION RATIO (dB)

0

1k

V

= ±15V

S

V

= ±1.5V

S

10k 100k 1M

FREQUENCY (Hz)

1637 G14

90

V

= ±2.5V

S

80

70

60

50

40

30

NEGATIVE SUPPLY

20

10

0

POWER SUPPLY REJECTION RATIO (dB)

–10

1k

LT1637

POSITIVE SUPPLY

10k 100k 1M

FREQUENCY (Hz)

1637 G15

Gain-Bandwidth Product and Phase Margin vs Load Resistance

1400

V

= ±2.5V

S

1300

1200

1100

1000

900

800

GAIN-BANDWIDTH PRODUCT (kHz)

700

600

GAIN BANDWIDTH

1k

LOAD RESISTANCE (Ω)

PHASE MARGIN

10k 100k

Settling Time to 0.1% vs Output Step

10

V

= ±15V

S

8

6

AV = 1

4

2

0

–2

OUTPUT STEP (V)

–4

–6

–8

–10

0

AV = 1

10

SETTLING TIME (µs)

AV = –1

20

Undistorted Output Swing

Output Impedance vs Frequency

50

45

40

35

30

25

20

15

10

1637 G16

10k

V

S

PHASE MARGIN (DEG)

1k

100

10

OUTPUT IMPEDANCE (Ω)

1

0.1 100

= ±2.5V

AV = 100

AV = 10

AV = 1

1k 100k 1M10k

FREQUENCY (Hz)

1637 G17

Capacitive Load Handling, Overshoot vs Capacitive Load

100

V

= ±2.5V

S

90

NO OUTPUT COMPENSATION

80

70

60

50

40

OVERSHOOT (%)

30

20

10

30

40

1637 G19

0

10

AV = 1

100 1000 10000

CAPACITIVE LOAD (pF)

AV = 2

AV = 5

AV = 10

1637 G20

vs Frequency

35

V

= ±15V

s

30

)

25

P-P

20

15

10

OUTPUT SWING (V

V

= ±2.5V

s

5

0

100

1k 10k 100k

FREQUENCY (Hz)

DISTORTION ≤ 1%

= 1

A

V

Total Harmonic Distortion + Noise vs Frequency

10

VS = 3V, 0V

= 1.8V

V

OUT

=10k

L

AV = –1

AV = 1

100 10k 100k1k

P-P

FREQUENCY (Hz)

VCM = 1.2V

1

R

0.1

0.01

THD + NOISE (%)

0.001

0.0001 10

1637 G18

1637 G21

7

LT1637

OUTPUT VOLTAGE (V

P-P

)

0.01

THD + NOISE (%)

1

10

023

1637 G23

0.001 1

0.1

RL = 10k V

CM

= HALF SUPPLY f = 1kHz FOR A

V

= –1, RG = 100k

AV = –1, VS = 3V, 0V

AV = 1 V

S

= ±1.5V

AV = 1 V

S

= 3V, 0V

AV = 1 V

S

= 3V, 0V

AV = –1 V

S

= ±1.5V

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Total Harmonic Distortion + Noise vs Load Resistance

1

V

= ±1.5V

S

= ±0.9V

V

0.1

0.01

THD + NOISE (%)

0.001

0.0001

IN

VS = 3V, 0V V

IN

VS = 3V, 0V V

IN

100

LOAD RESISTANCE TO GROUND (Ω)

Open-Loop Gain

A

B

C

(50µV/DIV)

A: RL = 2k B: RL = 10k

= 50k

C: R

CHANGE IN INPUT OFFSET VOLTAGE

L

–10V

OUTPUT VOLTAGE (5V/DIV)

0V 10V

VS = 3V TOTAL

= 1

A

V

= 1.8V

P-P

AT 1kHz

V

IN

= 0.6V TO 2.4V

= 0.3V TO 2.1V

1k 10k 100k

V

= ±15V

S

A

B

C

1637 G24

1637 G22

Large-Signal Response

= ±15V

V

S

AV = –1

10V

– 10V

Total Harmonic Distortion + Noise vs Output Voltage

Small-Signal Response

V

= ±15V

S

AV = 1

50mV

–50mV

1637 G25

1637 G26

U

APPLICATIO S I FOR ATIO

Supply Voltage

The positive supply pin of the LT1637 should be bypassed

with a small capacitor (about 0.01µF) within an inch of the pin. When driving heavy loads an additional 4.7µF electro-

lytic capacitor should be used. When using split supplies, the same is true for the negative supply pin.

The LT1637 is protected against reverse battery voltages up to 25V. In the event a reverse battery condition occurs, the supply current is typically less than 1nA.

When operating the LT1637 on total supplies of 30V or

more, the supply must not be brought up faster than 1µs.

This is especially true if low ESR bypass capacitors are used. A series RLC circuit is formed from the supply lead

inductance and the bypass capacitor. 5Ω of resistance in

the supply or the bypass capacitor will dampen the tuned circuit enough to limit the rise time.

8

WUU

Inputs

The LT1637 has two input stages, NPN and PNP (see the Simplified Schematic), resulting in three distinct operating regions as shown in the Input Bias Current vs Common Mode typical performance curve.

For input voltages about 0.9V or more below V+, the PNP input stage is active and the input bias current is typically –20nA. When the input voltage is about 0.5V or less from V+, the NPN input stage is operating and the input bias current is typically 80nA. Increases in temperature will cause the voltage at which operation switches from the PNP stage to the NPN stage to move towards V+. The input offset voltage of the NPN stage is untrimmed and is

typically 600µV.

LT1637

U

WUU

APPLICATIO S I FOR ATIO

A Schottky diode in the collector of each NPN transistor of the NPN input stage allows the LT1637 to operate with either or both of its inputs above V+. At about 0.3V above V+ the NPN input transistor is fully saturated and the input

bias current is typically 23µA at room temperature. The input offset voltage is typically 600µV when operating

above V+. The LT1637 will operate with its input 44V above V– regardless of V+.

The inputs are protected against excursions as much as 22V below V– by an internal 1.3k resistor in series with each input and a diode from the input to the negative supply. There is no output phase reversal for inputs up to 5V below V–. There are no clamping diodes between the inputs and the maximum differential input voltage is 44V.

Output

The output voltage swing of the LT1637 is affected by input overdrive as shown in the typical performance curves. When monitoring input voltages within 100mV of V+, gain should be taken to keep the output from clipping.

The output of the LT1637 can be pulled up to 25V beyond V+ with less than 1nA of leakage current, provided that V is less than 0.5V.

The normally reverse biased substrate diode from the output to V– will cause unlimited currents to flow when the output is forced below V–. If the current is transient and limited to 100mA, no damage will occur.

The LT1637 is internally compensated to drive at least 200pF of capacitance under any output loading condi-

tions. A 0.22µF capacitor in series with a 150Ω resistor

between the output and ground will compensate these amplifiers for larger capacitive loads, up to 4700pF, at all output currents.

+

Lower load resistance increases the output crossover distortion, but has no effect on the input stage transition distortion. For lowest distortion the LT1637 should be operated single supply, with the output always sourcing current and with the input voltage swing between ground and (V+ – 0.9V). See the Typical Performance Characteristics curves.

Gain

The open-loop gain is less sensitive to load resistance when the output is sourcing current. This optimizes performance in single supply applications where the load is returned to ground. The typical performance photo of Open-Loop Gain for various loads shows the details.

Shutdown

The LT1637 can be shut down two ways: using the shutdown pin or bringing V+ to within 0.5V of V–. When V

+

is brought to within 0.5V of V– both the supply current and output leakage current drop to less than 10nA. When the shutdown pin is brought 1.2V above V–, the supply

current drops to about 3µA and the output leakage current is less than 1µA, independent of V

+

. In either case the input bias current is less than 0.1nA (even if the inputs are 44V above the negative supply).

The shutdown pin can be taken up to 32V above V–. The shutdown pin can be driven below V–, however the pin current through the substrate diode should be limited with an external resistor to less than 10mA.

Input Offset Nulling

The input offset voltage can be nulled by placing a 10k potentiometer between Pins 1 and 8 with its wiper to V

–

(see Figure 1). The null range will be at least ±3mV.

Distortion

There are two main contributors of distortion in op amps: output crossover distortion as the output transitions from sourcing to sinking current and distortion caused by nonlinear common mode rejection. Of course, if the op amp is operating inverting there is no common mode induced distortion. When the LT1637 switches between input stages there is significant nonlinearity in the CMRR.

LT1637

8

1

10k

–

V

Figure 1. Input Offset Nulling

1637 F01

9

LT1637

–

+

LT1637

5k

1M

5V TO 44V

3V

100k

0.5Ω

LAMP

ON/OFF

OUT

1637 TA05

OUT = 0V FOR GOOD BULB

3V FOR OPEN BULB

SI PLIFIED

SHDN

5

R1 1M

Q3

10µA

WW

SCHE ATIC

R2 6k

–IN

Q2

+IN

R3

1.3k

2

R4

1.3k

3

Q9

Q11

D1 D2

Q12

Q14

+

7

Q25

Q26

V

6

OUT

Q13Q1

Q15Q10

Q16

Q18

Q17

Q19

Q23

D3

Q20

Q21

Q22

Q24

Q4

Q6

Q5

Q7

Q8

U

TYPICAL APPLICATIO S

Positive Supply Rail Current Sense

+

V

200Ω

5V

0.2Ω

200Ω

LOAD

I

LOAD

V

+

–

OUT

LT1637

= (2Ω)(I

LOAD

Q1 2N3904

0V TO 4.3V

2k

1637 TA02

)

D4

D5

Optional Output Compensation for

Capacitive Loads Greater Than 200pF

V

IN

+

LT1637

–

0.22µF

150Ω

1637 TA03

R5 7k

R7 400Ω

C

≤ 4700pF

L

R6 7k

R8 400Ω

81

NULLNULL

Lamp Outage Detector

1637 SS

–

4

V

10

Over-The-Top Comparator with Hysteresis

(0V TO 44V)

10k

IN1

10k

IN2

HYSTERESIS =

V

CC

100

3V TO 44V

+

LT1637

–

1M

2N5087

2N5210

1637 TA04

1M

Over-The-Top Current Sense

0.1V TO 44V R1

200Ω

5V

R

LOAD

S

0.2Ω

I

LOAD

V

OUT

I

LOAD

+

LT1637

–

V

=

(RS)(R2/R1)

OUT

Q1 2N3904

R2 2k

1637 TA06

V

OUT

(0V TO 4.3V)

PACKAGE DESCRIPTIO

0.007 (0.18)

0.021

± 0.006

(0.53 ± 0.015)

* DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH,

PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.

INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

° – 6° TYP

0

U

Dimensions in inches (millimeters) unless otherwise noted.

MS8 Package

8-Lead Plastic MSOP

(LTC DWG # 05-08-1660)

0.118 ± 0.004* (3.00 ± 0.102)

0.193 ± 0.006

(4.90 ± 0.15)

SEATING

PLANE

0.040

± 0.006

(1.02 ± 0.15)

0.012

(0.30)

0.0256

REF

(0.65)

BSC

0.034 ± 0.004

(0.86 ± 0.102)

0.006 ± 0.004

(0.15 ± 0.102)

N8 Package

8-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

8

7

12

6

5

0.118 ± 0.004**

4

3

LT1637

(3.00 ± 0.102)

MSOP (MS8) 1098

0.300 – 0.325

(7.620 – 8.255)

0.065

(1.651)

0.009 – 0.015

(0.229 – 0.381)

+0.035

0.325 –0.015

+0.889

8.255

()

–0.381

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)

TYP

0.045 – 0.065

(1.143 – 1.651)

0.100 (2.54)

BSC

8-Lead Plastic Small Outline (Narrow 0.150)

0.010 – 0.020

(0.254 – 0.508)

0.008 – 0.010

(0.203 – 0.254)

*

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

× 45°

0.016 – 0.050

(0.406 – 1.270)

0.053 – 0.069

(1.346 – 1.752)

0°– 8° TYP

0.014 – 0.019

(0.355 – 0.483)

TYP

0.130 ± 0.005

(3.302 ± 0.127)

0.125

(3.175)

MIN

0.018 ± 0.003

(0.457 ± 0.076)

S8 Package

(LTC DWG # 05-08-1610)

0.004 – 0.010

(0.101 – 0.254)

0.050

(1.270)

BSC

0.020

(0.508)

MIN

0.228 – 0.244

(5.791 – 6.197)

0.255 ± 0.015* (6.477 ± 0.381)

87 6

12

0.189 – 0.197* (4.801 – 5.004)

7

8

1

2

0.400*

(10.160)

MAX

6

3

5

4

3

N8 1098

5

0.150 – 0.157** (3.810 – 3.988)

4

SO8 1298

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.

11

LT1637

U

TYPICAL APPLICATIO S

3V

V

SAMPLE

0V

DROOP (LT1636 BUFFER): 200mV/s DROOP INTO HIGH IMPEDANCE : LESS THAN 0.625mV/s

Sample-and-Hold

3V

+

LT1636

–

3V

V

OUT

1637 TA07

V

+

IN

LT1637

–

SHDN

150Ω

0.22µF

MUX Amplifier Waveforms

0.2ms/DIV

1637 TA08

5kHz AT 4V

10kHz AT 2V

INPUT SELECT 1kHz AT 5V

MUX Amplifier

5V

V

IN1 P-P

V

IN2

P–P

SHDN

74HC04

+

LT1637

–

SHDN

–

LT1637

+

V

OUT

V

OUT

2V/DIV

5V

INPUT

SELECT

5V/DIV

1637 TA09

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PART NUMBER DESCRIPTION COMMENTS

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Output Op Amps per Amplifier, Rail-to-Rail Input and Output, 200kHz GBW

LT1636 Single Over-The-Top Micropower Rail-to-Rail Input and Output 55µA Supply Current, V

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LT1782 Micropower, Over-The-Top, SOT-23, Rail-to-Rail SOT-23, 800µV V

OS(MAX)

, I

=55µA (Max),

S

Input and Output Op Amp Gain-Bandwidth = 200kHz, Shutdown Pin

LT1783 1.2MHz, Over-The-Top, Micropower, Rail-to-Rail SOT-23, 800µV V

OS(MAX)

, I

=300µA (Max),

S

Input and Output Op Amp Gain-Bandwidth = 1.2MHz, Shutdown Pin

OS(MAX)

12

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507

●

www.linear-tech.com

1637f LT/TP 0100 4K • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 1999