ANALOG DEVICES LT 1357 CS8 Datasheet

FEATURES

■

25MHz Gain Bandwidth

■

600V/µs Slew Rate

■

2.5mA Maximum Supply Current

■

Unity-Gain Stable

■

C-LoadTM Op Amp Drives All Capacitive Loads

■

8nV/√Hz Input Noise Voltage

■

600µV Maximum Input Offset Voltage

■

500nA Maximum Input Bias Current

■

120nA Maximum Input Offset Current

■

20V/mV Minimum DC Gain, RL=1k

■

115ns Settling Time to 0.1%, 10V Step

■

220ns Settling Time to 0.01%, 10V Step

■

±12V Minimum Output Swing into 500Ω

■

±2.5V Minimum Output Swing into 150Ω

■

Specified at ±2.5V, ±5V, and ±15V

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APPLICATIONS

■

Wideband Amplifiers

■

Buffers

■

Active Filters

■

Data Acquisition Systems

■

Photodiode Amplifiers

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

C-Load is a trademark of Linear Technology Corporation

LT1357

25MHz, 600V/µs Op Amp

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DESCRIPTION

The LT®1357 is a high speed, very high slew rate opera­tional amplifier with outstanding AC and DC performance.
The LT1357 has much lower supply current, lower input
offset voltage, lower input bias current, and higher DC gain
than devices with comparable bandwidth. The circuit
topology is a voltage feedback amplifier with the
slewing characteristics of a current feedback amplifier.
The amplifier is a single gain stage with outstanding
settling characteristics which makes the circuit an ideal
choice for data acquisition systems. The output drives a
500Ω load to ±12V with ±15V supplies and a 150Ω
load to ±2.5V on ±5V supplies. The amplifier is also
stable with any capacitive load which makes it useful in
buffer or cable driver applications.

The LT1357 is a member of a family of fast, high perfor­mance amplifiers using this unique topology and employ­ing Linear Technology Corporation’s advanced bipolar
complementary processing. For dual and quad amplifier
versions of the LT1357 see the LT1358/LT1359 data
sheet. For higher bandwidth devices with higher supply
current see the LT1360 through LT1365 data sheets. For
lower supply current amplifiers see the LT1354 and LT1355/
LT1356 data sheets. Singles, duals, and quads of each
amplifier are available.

TYPICAL APPLICATION

DAC I-to-V Converter

6pF

DAC

INPUTS

12

5k

565A-TYPE

0.1µF5k

U

–

LT1357

+

VIk

+

()

OS OS

V

OUT

+<51Ω

A

VOL

1357 TA01

V

LSB

AV = –1 Large-Signal Response

OUT

1357 TA02

1

LT1357

WW

W

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ABSOLUTE MAXIMUM RATINGS

Total Supply Voltage (V+ to V–) ............................... 36V

Differential Input Voltage (Transient Only, Note 1)...

±10V

Input Voltage ............................................................±V

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

Operating Temperature Range ................ –40°C to 85°C

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PACKAGE/ORDER INFORMATION

TOP VIEW

1NULL
2

–IN
+IN

3

–

V

N8 PACKAGE, 8-LEAD PLASTIC DIP

T

= 150°C, θJA = 130°C/ W

JMAX

Consult factory for Industrial and Military grade parts.

8

NULL

+

7

V

6

V

OUT

54

NC

ORDER PART

NUMBER

LT1357CN8

Specified Temperature Range (Note 6)... –40°C to 85°C
Maximum Junction Temperature (See Below)

S

Plastic Package ................................................150°C

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

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

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TOP VIEW

1NULL
2

–IN
+IN

3

–

V

S8 PACKAGE, 8-LEAD PLASTIC SOIC

T

= 150°C, θJA = 190°C/ W

JMAX

8

NULL

7

V

6

V

54

NC

+

OUT

ORDER PART

NUMBER

LT1357CS8

S8 PART MARKING

1357

ELECTRICAL CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS V

V

OS

I

OS

I

B

e

n

i

n

R

IN

C

IN

CMRR Common Mode Rejection Ratio V

PSRR Power Supply Rejection Ratio VS = ±2.5V to ±15V 92 106 dB
A

VOL

Input Offset Voltage ±15V 0.2 0.6 mV

Input Offset Current ±2.5V to ±15V 40 120 nA
Input Bias Current ±2.5V to ±15V 120 500 nA
Input Noise Voltage f = 10kHz ±2.5V to ±15V 8 nV/√Hz
Input Noise Current f = 10kHz ±2.5V to ±15V 0.8 pA/√Hz
Input Resistance V

Input Capacitance ±15V 3 pF
Input Voltage Range

Input Voltage Range

Large-Signal Voltage Gain V

+

–

= ±12V ±15V 35 80 MΩ

CM

Differential ±15V 6 MΩ

= ±12V ±15V 80 97 dB

CM

V

= ±2.5V ±5V 78 84 dB

CM

V

= ±0.5V ±2.5V 68 75 dB

CM

OUT

V

OUT

V

OUT

V

OUT

V

OUT

V

OUT

TA = 25°C, VCM = 0V unless otherwise noted.

SUPPLY

±5V 0.2 0.6 mV
±2.5V 0.3 0.8 mV

±15V 12.0 13.4 V
±5V 2.5 3.5 V
±2.5V 0.5 1.1 V

±15V –13.2 –12.0 V
±5V – 3.3 –2.5 V
±2.5V –0.9 – 0.5 V

= ±12V, RL = 1k ±15V 20.0 65 V/mV
= ±10V, RL = 500Ω±15V 7.0 25 V/mV
= ±2.5V, RL = 1k ±5V 20.0 45 V/mV
= ±2.5V, RL = 500Ω±5V 7.0 25 V/mV
= ±2.5V, RL = 150Ω±5V 1.5 6 V/mV
= ±1V, RL = 500Ω±2.5V 7.0 30 V/mV

MIN TYP MAX UNITS

2

LT1357

ELECTRICAL CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS V

V

I

I

OUT

OUT

SC

Output Swing RL = 1k, V

RL = 500Ω, V
R

= 500Ω, V

L

RL = 150Ω, V
R

= 500Ω, V

L

Output Current V

Short-Circuit Current V

V

OUT
OUT

OUT

TA = 25°C, VCM = 0V unless otherwise noted.

SUPPLY

= ±40mV ±15V 13.3 13.8 ±V

IN

= ±40mV ±15V 12.0 12.8 ±V

IN

= ±40mV ±5V 3.5 4.0 ±V

IN

= ±40mV ±5V 2.5 3.3 ±V

IN

= ±40mV ±2.5V 1.3 1.7 ±V

IN

= ±12V ±15V 24.0 30 mA
= ±2.5V ±5V 16.7 25 mA

= 0V, V

= ±3V ±15V 30 42 mA

IN

MIN TYP MAX UNITS

SR Slew Rate AV = –2, (Note 3) ±15V 300 600 V/µs

±5V 150 220 V/µs

Full Power Bandwidth 10V Peak, (Note 4) ±15V 9.6 MHz

3V Peak, (Note 4) ±5V 11.7 MHz

GBW Gain Bandwidth f = 200kHz, RL = 2k ±15V 18 25 MHz

±5V 15 22 MHz
±2.5V 20 MHz

tr, t

f

Rise Time, Fall Time AV = 1, 10%-90%, 0.1V ±15V 8 ns

±5V 9 ns

Overshoot AV = 1, 0.1V ±15V 27 %

±5V 27 %

Propagation Delay 50% VIN to 50% V

, 0.1V ±15V 9 ns

OUT

±5V 11 ns

t

s

Settling Time 10V Step, 0.1%, AV = –1 ±15V 115 ns

10V Step, 0.01%, AV = –1 ±15V 220 ns
5V Step, 0.1%, A

= –1 ±5V 110 ns

V

5V Step, 0.01%, AV = –1 ±5V 380 ns

Differential Gain f = 3.58MHz, AV = 2, RL = 1k ±15V 0.1 %

±5V 0.1 %

Differential Phase f = 3.58MHz, AV = 2, RL = 1k ±15V 0.50 Deg

±5V 0.35 Deg

R

O

I

S

Output Resistance AV = 1, f = 100kHz ±15V 0.3 Ω
Supply Current ±15V 2.0 2.5 mA

±5V 1.9 2.4 mA

0°C ≤ TA ≤ 70°C, VCM = 0V unless otherwise noted.

SYMBOL PARAMETER CONDITIONS V

V

OS

Input Offset Voltage ±15V ● 0.8 mV

SUPPLY

±5V
±2.5V ● 1.0 mV

Input VOS Drift (Note 5) ±2.5V to ±15V ● 58 µV/°C

I

OS

I

B

CMRR Common Mode Rejection Ratio V

Input Offset Current ±2.5V to ±15V ● 180 nA
Input Bias Current ±2.5V to ±15V ● 750 nA

= ±12V ±15V ● 79 dB

CM

V

= ±2.5V ±5V ● 77 dB

CM

V

= ±0.5V ±2.5V ● 67 dB

CM

PSRR Power Supply Rejection Ratio VS = ±2.5V to ±15V ● 90 dB
A

VOL

Large-Signal Voltage Gain V

= ±12V, RL = 1k ±15V ● 15 V/mV

OUT

V

= ±10V, RL = 500Ω±15V ● 5 V/mV

OUT

V

= ±2.5V, RL = 1k ±5V ● 15 V/mV

OUT

V

= ±2.5V, RL = 500Ω±5V ● 5 V/mV

OUT

V

= ±2.5V, RL = 150Ω±5V ● 1 V/mV

OUT

V

= ±1V, RL = 500Ω±2.5V ● 5 V/mV

OUT

MIN TYP MAX UNITS

● 0.8 mV

3

LT1357

ELECTRICAL CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS V

V

I

I

OUT

OUT

SC

Output Swing RL = 1k, V

= 500Ω, V

R

L

R

= 500Ω, V

L

= 150Ω, V

R

L

= 500Ω, V

R

L

Output Current V

Short-Circuit Current V

V

OUT
OUT

OUT

0°C ≤ TA ≤ 70°C, VCM = 0V unless otherwise noted.

SUPPLY

= ±40mV ±15V ● 13.2 ±V

IN

= ±40mV ±15V ● 11.5 ±V

IN

= ±40mV ±5V ● 3.4 ±V

IN

= ±40mV ±5V ● 2.3 ±V

IN

= ±40mV ±2.5V ● 1.2 ±V

IN

= ±11.5V ±15V ● 23.0 mA
= ±2.3V ±5V ● 15.3 mA

= 0V, V

= ±3V ±15V ● 25 mA

IN

MIN TYP MAX UNITS

SR Slew Rate AV = –2, (Note 3) ±15V ● 225 V/µs

±5V

● 125 V/µs

GBW Gain-Bandwidth f = 200kHz,RL = 2k ±15V ● 15 MHz

±5V

I

S

Supply Current ±15V ● 2.9 mA

● 12 MHz

±5V ● 2.8 mA

–40°C ≤ TA ≤ 85°C, VCM = 0V unless otherwise noted. (Note 6)

SYMBOL PARAMETER CONDITIONS V

V

OS

Input Offset Voltage ±15V ● 1.3 mV

SUPPLY

±5V
±2.5V

Input VOS Drift (Note 5) ±2.5V to ±15V ● 58 µV/°C

I

OS

I

B

CMRR Common Mode Rejection Ratio V

Input Offset Current ±2.5V to ±15V ● 300 nA
Input Bias Current ±2.5V to ±15V ● 900 nA

= ±12V ±15V ● 78 dB

CM

= ±2.5V ±5V ● 76 dB

V

CM

V

= ±0.5V ±2.5V ● 66 dB

CM

PSRR Power Supply Rejection Ratio VS = ±2.5V to ±15V ● 90 dB
A

V

I

I

VOL

OUT

OUT

SC

Large-Signal Voltage Gain V

= ±12V, RL = 1k ±15V ● 10.0 V/mV

OUT

= ±10V, RL = 500Ω±15V ● 2.5 V/mV

V

OUT

= ±2.5V, RL = 1k ±5V ● 10.0 V/mV

V

OUT

V

= ±2.5V, RL = 500Ω±5V ● 2.5 V/mV

OUT

= ±2.5V, RL = 150Ω±5V ● 0.6 V/mV

V

OUT

= ±1V, RL = 500Ω±2.5V ● 2.5 V/mV

V

OUT

Output Swing RL = 1k, V

= 500Ω, V

R

L

= 500Ω, V

R

L

R

= 150Ω, V

L

= 500Ω, V

R

L

Output Current V

Short-Circuit Current V

= ±11V ±15V ● 22 mA

OUT

= ±2.1V ±5V ● 14 mA

V

OUT

= 0V, V

OUT

= ±40mV ±15V ● 13.0 ±V

IN

= ±40mV ±15V ● 11.0 ±V

IN

= ±40mV ±5V ● 3.4 ±V

IN

= ±40mV ±5V ● 2.1 ±V

IN

= ±40mV ±2.5V ● 1.2 ±V

IN

= ±3V ±15V ● 24 mA

IN

SR Slew Rate AV = –2, (Note 3) ±15V ● 180 V/µs

±5V ● 100 V/µs

GBW Gain-Bandwith f = 200kHz, R

= 2k ±15V ● 14 MHz

L

±5V ● 11 MHz

I

S

Supply Current ±15V ● 3.0 mA

±5V ● 2.9 mA

MIN TYP MAX UNITS

● 1.3 mV

● 1.5 mV

4

ELECTRICAL CHARACTERISTICS

INPUT COMMON-MODE VOLTAGE (V)

–200

INPUT BIAS CURRENT (nA)

0

–100

400

300

200

100

–15 –10 0 10 155–5

1357 G03

VS = ±15V
T

A

= 25°C

I

B

=

I

B

+

+ I

B

–



————

2

LT1357

The ● denotes specifications that apply over the full specified temperature
range.

Note 1: Differential inputs of ±10V are appropriate for transient operation
only, such as during slewing. Large, sustained differential inputs will
cause excessive power dissipation and may damage the part. See Input
Considerations in the Applications Information section of this data sheet
for more details.

Note 2: A heat sink may be required to keep the junction temperature

Note 3: Slew rate is measured between ±10V on the output with ±6V input

for ±15V supplies and ±1V on the output with ±1.75V input for ±5V supplies.
Note 4: Full power bandwidth is calculated from the slew rate

measurement: FPBW = SR/2πV

Note 5: This parameter is not 100% tested.
Note 6: The LT1357 is designed, characterized and expected to meet these

extended temperature limits, but is not tested at –40°C and at 85°C.
Guaranteed I grade parts are available; consult factory.

below absolute maximum when the output is shorted indefinitely.

W

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TYPICAL PERFORMANCE CHARACTERISTICS

Supply Current vs Supply Voltage
and Temperature

3.0

2.5

2.0

1.5

SUPPLY CURRENT (mA)

1.0

0.5
10501520

SUPPLY VOLTAGE (±V)

125°C

25°C

–55°C

1357 G01

Input Common-Mode Range vs
Supply Voltage

+

V

TA = 25°C

–0.5
–1.0
–1.5
–2.0

2.0

1.5

COMMON-MODE RANGE (V)

1.0

0.5

–

V

< 1mV

∆V

OS

SUPPLY VOLTAGE (±V)

10501520

1357 G02

.

P

Input Bias Current vs
Input Common-Mode Voltage

Input Bias Current vs
Temperature

450

400

350

300

250

200

150

INPUT BIAS CURRENT (nA)

100

50

0

–50 –25 25 100 12550 750

VS = ±15V
I

=

B

 

TEMPERATURE (°C)

+

I

+ I

B

————

2

1358/1359 G04

Open-Loop Gain vs

Input Noise Spectral Density

100

–



B

e

n

10

i

n

INPUT VOLTAGE NOISE (nV/√Hz)

1

10

FREQUENCY (Hz)

VS = ±15V
T

A

A

V

R

S

1k100 100k10k

= 25°C
= 101
= 100k

10

INPUT CURRENT NOISE (pA/√Hz)

1

0.1

1357 G05

Resistive Load

100

T

= 25°C

A

90

80

70

OPEN-LOOP GAIN (dB)

60

50

10

LOAD RESISTANCE (Ω)

VS = ±15V

VS = ±5V

100 10k

1k

1357 G06

5

LT1357

SETTLING TIME (ns)

–10

OUTPUT SWING (V)

–6

–4

–8

10

8
6
4

–2

2
0

50 150 250200100

1357 G12

VS = ±15V
A

V

= –1

10mV

10mV

1mV

1mV

OUTPUT CURRENT (mA)

+0.5

OUTPUT VOLTAGE SWING (V)

1.5

2.0

1.0

–0.5

V

–

V

+

–1.0
–1.5
–2.0

2.5

–2.5

–50 –40 –10 30 40 5001020–20–30

1357 G09

VS = ±5V
V

IN

= 100mV

85°C

85°C

25°C

25°C

–40°C

–40°C

SUPPLY VOLTAGE (±V)

18

GAIN-BANDWIDTH (MHz)

26

22

38

34

30

20

28

24

36

32

30

PHASE MARGIN (DEG)

38

34

50
48

44

40

36

32

46

42

10501520

1357 G15

TA = 25°C

PHASE MARGIN

GAIN-BANDWIDTH

W

U

TYPICAL PERFORMANCE CHARACTERISTICS

Open-Loop Gain vs Temperature

101

RL = 1k

= ±12V

V

100

O

= ±15V

V

S

99

98

97

96

OPEN-LOOP GAIN (dB)

95

94

93

–50 –25 25 100 12550 750

TEMPERATURE (°C)

Output Short-Circuit Current vs
Temperature

65

60

55

50

45

40

35

30

OUTPUT SHORT-CIRCUIT CURRENT (mA)

25

–50 –25 25 100 12550 750

SOURCE

TEMPERATURE (°C)

SINK

VS = ±5V

1357 G07

1357 G10

Output Voltage Swing vs
Supply Voltage

+

V

= 25°C

T

A

–1

–2

–3

3

2

OUTPUT VOLTAGE SWING (V)

1

+

V

10501520

SUPPLY VOLTAGE (±V)

Settling Time vs Output Step
(Noninverting)

10

10mV

8
6
4
2
0

–2

OUTPUT SWING (V)

–4
–6
–8

10mV

–10

50 150 250200100

1mV

1mV

SETTLING TIME (ns)

R

R

= 500Ω

L

RL = 1k

= 500Ω

L

R

VS = ±15V
A

V

L

= 1

Output Voltage Swing vs
Load Current

= 1k

1357 G08

Settling Time vs Output Step
(Inverting)

1357 G11

Output Impedance vs Frequency

1k

VS = ±15V
T

A

100

AV = 100

10

1

OUTPUT IMPEDANCE (Ω)

0.1

0.01
10k

6

Gain and Phase vs Frequency

70

= 25°C

AV = 10

AV = 1

1M

10M

1357 G13

100k 100M

FREQUENCY (Hz)

60

50

40

30

GAIN (dB)

20

10

0

–10

10k

PHASE

VS = ±15V

GAIN

VS = ±5V

A

= –1

V

= RG = 2k

R

F

= 25°C

T

A

100k 100M

FREQUENCY (Hz)

1M

VS = ±5V

10M

VS = ±15V

1357 G14

120

100

PHASE (DEG)

80

60

40

20

0

Gain-Bandwidth and Phase
Margin vs Supply Voltage

W

INPUT LEVEL (V

P-P

)

0

SLEW RATE (V/µs)

200

300

100

1000

900
800
700

400

600
500

0 8 16 2012421018146

1357 G24

VS = ±15V
A

V

= –1

R

F

= RG = 2k

SR =

SR+ + SR–

—————

2

T

A

= 25°C

FREQUENCY (Hz)

100k

–5

GAIN (dB)

–3
–4

5

1M 100M

1357 G18

1

–1

10M

3

–2

2

0

4

±15V

±2.5V

T

A

= 25°C

A

V

= –1

R

F

= RG = 2k

±5V

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TYPICAL PERFORMANCE CHARACTERISTICS

LT1357

Gain-Bandwidth and Phase
Margin vs Temperature

38

PHASE MARGIN

36
34

32
30
28
26
24

GAIN-BANDWIDTH (MHz)

22

GAIN-BANDWIDTH

20
18

–50 –25 25 100 12550 750

= ±15V

V

S

= ±5V

V

S

TEMPERATURE (°C)

Frequency Response vs
Capacitive Load

10

VS = ±15V

8

= 25°C

T

A

= –1

A

6

V

4

2
0

–2
–4

VOLTAGE MAGNITUDE (dB)

–6

–8

–10

100k

1M 100M10M

FREQUENCY (Hz)

PHASE MARGIN

= ±5V

V

S

GAIN-BANDWIDTH

= ±15V

V

S

C = 1000pF

C = 500pF

C = 100pF

C = 50pF

1357 G16

C = 0

1358/1359 G19

50
48
46
44

42
40

38

36
34
32

30

5
4
3

PHASE MARGIN (DEG)

2
1

0

GAIN (dB)

–1
–2

–3
–4
–5

100k

100

80

60

40

20

POWER SUPPLY REJECTION RATIO (dB)

Frequency Response vs
Supply Voltage (AV = 1)

T

= 25°C

A

= 1

A

V

= 2k

R

L

1M 100M

FREQUENCY (Hz)

±15V

±5V

±2.5V

10M

Power Supply Rejection Ratio
vs Frequency

0

–PSRR

+PSRR

100k 1M1k 10k100 10M 100M

FREQUENCY (Hz)

VS = ±15V
T

A

1357 G17

= 25°C

1357 G20

Frequency Response vs
Supply Voltage (AV = –1)

Common-Mode Rejection Ratio
vs Frequency

120

100

80

60

40

20

COMMON-MODE REJECTION RATIO (dB)

0

1k 100M10M1M100k10k

FREQUENCY (Hz)

VS = ±15V

= 25°C

T

A

1357 G21

1000

800

600

400

SLEW RATE (V/µs)

200

AV = –1

= RG = 2k

R

F

SR+ + SR–

SR =

—————

2

= 25°C

T

A

0

015105

SUPPLY VOLTAGE (±V)

1357 G22

Slew Rate vs TemperatureSlew Rate vs Supply Voltage

600

500

SR = ————— 

400

A

300

200

SLEW RATE (V/µs)

100

0

–50 –25 25 100 12550 750

V

= –2

SR+ + SR–

2

VS = ±5V

TEMPERATURE (°C)

V

= ±15V

S

Slew Rate vs Input Level

1357 G23

7

LT1357

FREQUENCY (Hz)

100k 1M

0

OUTPUT VOLTAGE (V

P-P

)

10

10M

1357 G27

6

2

4

8

AV = –1

AV = 1

VS = ±5V
R

L

= 2k

2% MAX DISTORTION

CAPACITIVE LOAD (F)

10p

0

OVERSHOOT (%)

100

1µ

1357 G30

1000p 0.01µ

50

100p 0.1µ

AV = 1

AV = –1

VS = ±15V
T

A

= 25°C

W

U

TYPICAL PERFORMANCE CHARACTERISTICS

Total Harmonic Distortion
vs Frequency

0.01
TA = 25°C

= 3V

V
R

0.001

TOTAL HARMONIC DISTORTION (%)

0.0001
10



O

RMS

= 2k

L

AV = –1

AV = 1

100 100k

1k

FREQUENCY (Hz)

2nd and 3rd Harmonic Distortion
vs Frequency

–30

VS = ±15V

= 2V

O

L

V

= 2k
= 2



P-P

FREQUENCY (Hz)

3RD HARMONIC

2ND HARMONIC

1M 2M 4M

V

–40

R
A

–50

–60

–70

HARMONIC DISTORTION (dB)

–80

–90

100k 200k 400k

10k

1357 G25

1357 G28

Undistorted Output Swing vs
Frequency (±15V)

30

25

)

P-P

20

15

10

VS = ±15V

OUTPUT VOLTAGE (V

R

5

A
A

0
100k 1M

Differential Gain and Phase
vs Supply Voltage

0.50
DIFFERENTIAL PHASE

0.45

0.40

DIFFERENTIAL PHASE (DEGREES)

0.35

10M

AV = –1

AV = 1

= 2k

L

= 1, 1% MAX DISTORTION

V

= –1, 2% MAX DISTORTION

V

AV = 2

= 1k

R

L

= 25°C

T

A



10M

1354 G29

FREQUENCY (Hz)

DIFFERENTIAL GAIN

±5 ±10 ±15

SUPPLY VOLTAGE (V)

Undistorted Output Swing vs
Frequency (±5V)

1357 G26

Capacitive Load Handling

0.15

DIFFERENTIAL GAIN (PERCENT)

0.10

0.05

8

Small-Signal Transient
(AV = 1)

Small-Signal Transient
(AV = –1)

1357 TA31 1357 TA32

Small-Signal Transient
(AV = –1, CL = 1000pF)

1357 TA33

W

U

TYPICAL PERFORMANCE CHARACTERISTICS

LT1357

Large-Signal Transient
(AV = 1)

1357 TA34 1357 TA35

U

WUU

Large-Signal Transient
(AV = –1)

APPLICATIONS INFORMATION

The LT1357 may be inserted directly into many high
speed amplifier applications improving both DC and AC
performance, provided that the nulling circuitry is
removed. The suggested nulling circuit for the LT1357 is
shown below.

Offset Nulling

+

V

3

2

Layout and Passive Components

The LT1357 amplifier is easy to apply and tolerant of less
than ideal layouts. For maximum performance (for
example, fast settling time) use a ground plane, short lead
lengths and RF-quality bypass capacitors (0.01µF to 0.1µF).
For high drive current applications use low ESR bypass
capacitors (1µF to 10µF tantalum). Sockets should be
avoided when maximum frequency performance is
required, although low profile sockets can provide
reasonable performance up to 50MHz. For more details
see Design Note 50.

+

–

1

LT1357

10k

7

6

4

8

–

V

1357 AI01

Large-Signal Transient
(AV = 1, CL = 10,000pF)

1357 TA36

The parallel combination of the feedback resistor and gain
setting resistor on the inverting input can combine with
the input capacitance to form a pole which can cause
peaking or oscillations. For feedback resistors greater
than 5kΩ, a parallel capacitor of value

CF > (RG • CIN)/R

F

should be used to cancel the input pole and optimize
dynamic performance. For unity-gain applications where
a large feedback resistor is used, CF should be greater
than or equal to CIN.

Capacitive Loading

The LT1357 is stable with any capacitive load. This is
accomplished by sensing the load induced output pole and
adding compensation at the amplifier gain node. As the
capacitive load increases, both the bandwidth and phase
margin decrease so there will be peaking in the frequency
domain and in the transient response as shown in the
typical performance curves.The photo of the small-signal
response with 1000pF load shows 50% peaking. The
large-signal response with a 10,000pF load shows the
output slew rate being limited to 5V/µs by the short-circuit
current. Coaxial cable can be driven directly, but for best
pulse fidelity a resistor of value equal to the characteristic
impedance of the cable (i.e., 75Ω) should be placed in

9

LT1357

U

WUU

APPLICATIONS INFORMATION

series with the output. The other end of the cable should
be terminated with the same value resistor to ground.

Input Considerations

Each of the LT1357 inputs is the base of an NPN and
a PNP transistor whose base currents are of opposite
polarity and provide first-order bias current cancellation.
Because of variation in the matching of NPN and PNP
beta, the polarity of the input bias current can be positive
or negative. The offset current does not depend on
NPN/PNP beta matching and is well controlled. The use of
balanced source resistance at each input is recommended
for applications where DC accuracy must be maximized.

The inputs can withstand transient differential input volt­ages up to 10V without damage and need no clamping or
source resistance for protection. Differential inputs, how­ever, generate large supply currents (tens of mA) as
required for high slew rates. If the device is used with
sustained differential inputs, the average supply current
will increase, excessive power dissipation will result and
the part may be damaged.

a comparator, peak detector or other open-loop applica­tion with large, sustained differential inputs

normal, closed-loop operation, an increase of power
dissipation is only noticeable in applications with large
slewing outputs and is proportional to the magnitude of
the differential input voltage and the percent of the time
that the inputs are apart. Measure the average supply
current for the application in order to calculate the power
dissipation.

Power Dissipation

The LT1357 combines high speed and large output drive
in a small package. Because of the wide supply voltage
range, it is possible to exceed the maximum junction
temperature under certain conditions. Maximum junction
temperature (TJ) is calculated from the ambient tempera­ture (TA) and power dissipation (PD) as follows:

The part should not be used as

. Under

Worst-case power dissipation occurs at the maximum
supply current and when the output voltage is at 1/2 of
either supply voltage (or the maximum swing if less than
1/2 supply voltage). Therefore P

P

Example: LT1357CS8 at 70°C, VS = ±15V, RL = 120Ω
(Note: the minimum short-circuit current at 70°C is
25mA, so the output swing is guaranteed only to 3V with
120Ω.)

P

T

Circuit Operation

The LT1357 circuit topology is a true voltage feedback
amplifier that has the slewing behavior of a current feed­back amplifier. The operation of the circuit can be under­stood by referring to the simplified schematic. The inputs
are buffered by complementary NPN and PNP emitter
followers which drive a 500Ω resistor. The input voltage
appears across the resistor generating currents which are
mirrored into the high impedance node. Complementary
followers form an output stage which buffers the gain
node from the load. The bandwidth is set by the input
resistor and the capacitance on the high impedance node.
The slew rate is determined by the current available to
charge the gain node capacitance. This current is the
differential input voltage divided by R1, so the slew rate
is proportional to the input. Highest slew rates are there­fore seen in the lowest gain configurations. For example,
a 10V output step in a gain of 10 has only a 1V input step,
whereas the same output step in unity-gain has a ten times
greater input step. The curve of Slew Rate vs Input Level
illustrates this relationship. The LT1357 is tested for slew
rate in a gain of –2 so higher slew rates can be expected
in gains of 1 and –1, and lower slew rates in higher gain
configurations.

= (V+ – V–)(I

DMAX

= (30V • 2.9mA) + (15V–3V)(25mA) = 387mW

DMAX

= 70°C + (387mW • 190°C/W) = 144°C

JMAX

) + (V+/2)2/R

SMAX

DMAX

is:

L

LT1357CN8: TJ = TA + (PD • 130°C/W)
LT1357CS8: TJ = TA + (PD • 190°C/W)

10

The RC network across the output stage is bootstrapped
when the amplifier is driving a light or moderate load and

LT1357

U

WUU

APPLICATIONS INFORMATION

has no effect under normal operation. When driving a
capacitive load (or a low value resistive load) the network
is incompletely bootstrapped and adds to the compensa­tion at the high impedance node. The added capacitance
slows down the amplifier which improves the phase
margin by moving the unity-gain frequency away from the

E

W

A

TI

C

R1

500Ω

W

SPL

I

IIFED S

–IN

CH

+

V

pole formed by the output impedance and the capacitive
load. The zero created by the RC combination adds phase
to ensure that even for very large load capacitances, the
total phase lag can never exceed 180 degrees (zero phase
margin) and the amplifier remains stable.

+IN

C

R

C

C

C

OUT

–

V

U

PACKAGE DESCRIPTION

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

(2.540 ± 0.254)

0.045 – 0.065

(1.143 – 1.651)

0.100 ± 0.010

Dimensions in inches (millimeters) unless otherwise noted.

N8 Package

8-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

0.130 ± 0.005

(3.302 ± 0.127)

0.125

(3.175)

MIN

0.018 ± 0.003

(0.457 ± 0.076)



0.020

(0.508)

MIN

0.255 ± 0.015*
(6.477 ± 0.381)



876



12

0.400*
(10.160)

MAX

1357 SS01

3

5

4

N8 1197

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

LT1357

PACKAGE DESCRIPTION

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°

(1.346 – 1.752)

0°– 8° TYP

0.016 – 0.050

0.406 – 1.270

U

TYPICAL APPLICATIONS

U

Dimensions in inches (millimeters) unless otherwise noted.

S8 Package

8-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

0.053 – 0.069

0.004 – 0.010

(0.101 – 0.254)

0.228 – 0.244

0.014 – 0.019

(0.355 – 0.483)

0.050

(1.270)

TYP

(5.791 – 6.197)

0.189 – 0.197*
(4.801 – 5.004)

7

8

1

2

5

6

0.150 – 0.157**
(3.810 – 3.988)

3

4

SO8 0996

Instrumentation Amplifier

R1

20k

R2
2k

–

LT1357

–

V

IN

+

+





R

4

1



A

=+ +

1

V

R

3

2





TRIM R5 FOR GAIN
TRIM R1 FOR COMMON MODE REJECTION
BW = 250kHz



RRRRRR

2



1



3

+



4



+

23

R

5

R5

432Ω

R3

2k




=

104





–

LT1357

+

R4

20k

1357 TA03

V

IN

V

OUT

5.62k3.4k

330pF

200kHz, 4th Order Butterworth Filter

3.4k

–

LT1357

+

100pF

2.61k

2.61k

5.11k

1000pF

47pF

–

LT1357

+

1357 TA04

RELATED PARTS

PART NUMBER DESCRIPTION COMMENTS

LT1358/LT1359 Dual/Quad 2mA, 25MHz, 600V/µs Op Amp Good DC Precision, Stable with All Capacitive Loads
LT1360 4mA, 50MHz, 800V/µs Op Amp Good DC Precision, Stable with All Capacitive Loads
LT1361/LT1362 Dual/Quad 4mA, 50MHz, 800V/µs Op Amp Good DC Precision, Stable with All Capacitive Loads

V

OUT

12

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

[phone] ● FAX: [phone]

●

www.linear-tech.com

1357fa LT/TP 0598 REV A 2K • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 1994