Linear Technology LT1122 Datasheet

1

LT1122

Fast Settling, JFET Input

Operational Amplifier

■

100% Tested Settling Time 340ns Typ
to 1mV at Sum Node, 10V Step 540ns Max
Tested with Fixed Feedback Capacitor

■

Slew Rate 60V/µs Min

■

Gain Bandwidth Product 14MHz

■

Power Bandwidth (20Vp-p) 1.2 MHz

■

Unity Gain Stable; Phase Margin 60°

■

Input Offset Voltage 600µV Max

■

Input Bias Current 25°C 75pA Max

70°C 600pA Max

■

Input Offset Current 25°C 40pA Max

70°C 150pA Max

■

Low Distortion

DUESCRIPTIO

S

F

EATU

RE

The LT1122 JFET input operational amplifier combines
high speed and precision performance.

A unique poly-gate JFET process minimizes gate series
resistance and gate-to-drain capacitance, facilitating wide
bandwidth performance, without degrading JFET transis­tor matching.

It slews at 80V/µs and settles in 340ns. The LT1122 is
internally compensated to be unity gain stable, yet it has a
bandwidth of 14MHz at a supply current of only 7mA. Its
speed makes the LT1122 an ideal choice for fast settling
12-bit data conversion and acquisition systems.

The LT1122 offset voltage of 120µV, and voltage gain of
500,000 also support the 12-bit accurate applications.

The input bias current of 10pA and offset current of 4pA
combined with its speed allow the LT1122 to be used in
such applications as high speed sample and hold amplifi­ers, peak detectors, and integrators.

■

Fast 12-Bit D/A Output Amplifiers

■

High Speed Buffers

■

Fast Sample and Hold Amplifiers

■

High Speed Integrators

■

Voltage to Frequency Converters

■

Active Filters

■

Log Amplifiers

■

Peak Detectors

12-Bit Voltage Output D/A Converter

Large-Signal Response

5V/DIV

200ns/DIV
AV = –1

1122 TA07

U
S

A

O

PPLICATI

U

A

O

PPLICATITYPICAL

0mA TO 2mA

OR 4mA

+

2

3

6

C

f

V
0V TO 10V

OUT

12-BIT CURRENT OUTPUT D/A CONVERTER
C = 5pF TO 17pF
(DEPENDING ON D/A CONVERTER USED)

+

–

f

LT1122

LT1122•TA01

2

LT1122

Supply Voltage .................................................... ± 20V

Differential Input Voltage ...................................... ± 40V

Input Voltage ........................................................ ±20V

Output Short Circuit Duration .......................... Indefinite

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

Operating Temperature Range

LT1122AM/BM/CM/DM ....................– 55°C to 125°C

LT1122AC/BC/CC/DC/CS/DS .............. – 40°C to 85°C

Storage Temperature Range

All Devices....................................... – 65°C to 150°C

WU

U

PACKAGE

/

O

RDER I FOR ATIO

LT1122AMJ8 LT1122CCJ8
LT1122BMJ8 LT1122DCJ8
LT1122CMJ8 LT1122ACN8
LT1122DMJ8 LT1122BCN8
LT1122ACJ8 LT1122CCN8
LT1122BCJ8 LT1122DCN8

ORDER PART

NUMBER

ORDER PART

NUMBER

LT1122CS8
LT1122DS8

PART MARKING

1122C
1122D

A

U
G

W

A

WUW

ARB

S

O

LUTEXI T

I

S

8
7
6
54

3

2

1

V

TRIM

–IN
+IN

V

V TRIM

OUT

+

V

SPEED BOOST/
OVERCOMP

TOP VIEW

N8 PACKAGE

8-LEAD PLASTIC DIP

–

OS

OS

LT1122

J8 PACKAGE

8-LEAD HERMETIC DIP

T

JMAX

= 150°C, θJA = 130°C/W (N8)

T

JMAX

= 175°C, θJA = 100°C/W (J8)

8
7
6
54

3

2

1

–IN

V

TRIM

+IN

–

V TRIM

OUT

OS

V

SPEED BOOST/
OVERCOMP

TOP VIEW

S8 PACKAGE

8-LEAD PLASTIC SOIC

+

OS

V

LT1122

T

JMAX

= 150°C, θJA = 190°C/W

Consult factory for Industrial grade parts.

E

LECTRICAL C CHARA TERIST

ICS

VS = ± 15V, TA = 25°C, VCM = 0V unless otherwise noted. (Note 1)

LT1122CM/DM

LT1122AM/BM LT1122CC/DC

LT1122AC/BC LT1122CS/DS

SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

V

OS

Input Offset Voltage 120 600 130 900 µV

I

OS

Input Offset Current 4 40 5 50 pA

I

B

Input Bias Current 10 75 12 100 pA
Input Resistance

Differential 10

12

10

12

Ω

Common Mode V

CM

= – 10V to + 8V 10

12

10

12

Ω

V

CM

= + 8V to + 11V 10

11

10

11

Ω

Input Capacitance 44pF

S

R

Slew Rate AV = – 1 60 80 50 75 V/µs
Settling Time (Note 2) + 10V to 0V, – 10V to 0V

100% Tested: A and C Grades

to 1mV at Sum Node 340 540 350 590 ns
B and D Grades to 1mV at Sum Node 350 360 ns
All Grades to 0.5mV at Sum Node 450 470 ns

GBW Gain Bandwidth Product 14 13 MHz

Power Bandwidth V

OUT

= 20Vp-p 1.2 1.1 MHz

A

VOL

Large Signal Voltage Gain V

OUT

= ±10V, RL = 2kΩ 180 500 150 450 V/mV

V

OUT

= ± 10V, RL = 600Ω 130 250 110 220 V/mV

CMRR Common Mode Rejection Ratio VCM = ± 10V 83 99 80 98 dB

Input Voltage Range (Note 3) ±10.5 ±11 ± 10.5 ± 11 V

PSRR Power Supply Rejection Ratio VS = ±10V to ± 18V 86 103 82 101 dB

Input Noise Voltage 0.1Hz to 10Hz 3.0 3.3 µV

P-P

Input Noise Voltage Density fO = 100Hz 25 27 nV/√Hz

fO = 10kHz 14 15 nV/√Hz

Input Noise Current Density fO = 100Hz, fO = 10kHz 2 2 fA/√Hz

3

LT1122

E

LECTRICAL C CHARA TERIST

ICS

LT1122CM/DM

LT1122AM/BM LT1122CC/DC

LT1122AC/BC LT1122CS/DS

SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

VS = ± 15V, TA = 25°C, VCM = 0V unless otherwise noted.

LT1122CC/DC

LT1122AC/BC LT1122CS/DS

SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

V

OS

Input Offset Voltage • 350 1400 400 2000 µV

Average Temperature Coefficient • 518 6 25 µV/°C

of Input Offset Voltage

I

OS

Input Offset Current • 12 150 15 200 pA

I

B

Input Bias Current • 80 600 90 800 pA

A

VOL

Large Signal Voltage Gain V

OUT

= ± 10V, R

L

≥ 2kΩ • 120 380 100 340 V/mV

CMRR Common Mode Rejection Ratio V

CM

= ±10V • 82 98 78 96 dB

PSRR Power Supply Rejection Ratio V

S

= ±10V to ± 17V • 84 101 80 99 dB

Input Voltage Range • ±10 ± 10.8 ± 10 ±10.8 V

V

OUT

Output Voltage Swing R

L

= 2kΩ • ±11.5 ±12.4 ± 11.5 ± 12.4 V

S

R

Slew Rate A

V

= – 1 • 50 70 40 65 V/µs

VS = ± 15V, VCM = 0V, 0°C ≤ TA ≤ 70°C, unless otherwise noted. (Note 1)

LT1122AM/BM LT1122CM/DM

SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

V

OS

Input Offset Voltage • 650 2400 800 3400 µV
Average Temperature Coefficient • 618 725 µV/°C

of Input Offset Voltage

I

OS

Input Offset Current • 0.5 6 0.6 9 nA

I

B

Input Bias Current • 625 735 nA

A

VOL

Large Signal Voltage Gain V

OUT

= ± 10V, R

L

≥ 2kΩ • 70 230 60 200 V/mV

CMRR Common Mode Rejection Ratio V

CM

= ±10V • 80 97 76 94 dB

PSRR Power Supply Rejection Ratio V

S

= ±10V to ± 17V • 83 100 78 98 dB

Input Voltage Range • ±10 ± 10.5 ± 10 ±10.5 V

V

OUT

Output Voltage Swing R

L

= 2kΩ • ±11.3 ±12.1 ± 11.3 ± 12.1 V

S

R

Slew Rate A

V

= – 1 • 45 60 35 55 V/µs

VS = ± 15V, VCM = 0V, – 55°C ≤ TA ≤ 125°C, unless otherwise noted. (Note 1)

The • denotes the specifications which apply over the full operating
temperature range.
Note 1: The LT1122 is measured in an automated tester in less than one
second after application of power. Depending on the package used, power
dissipation, heat sinking, and air flow conditions, the fully warmed up chip
temperature can be 10°C to 50°C higher than the ambient temperature.
Note 2: Settling time is 100% tested for A and C grades using the settling
time test circuit shown. This test is not included in quality assurance
sample testing.

Note 3: Input voltage range functionality is assured by testing offset
voltage at the input voltage range limits to a maximum of 4mV (A, B
grades), to 5.7mV (C, D grades).
Note 4: Minimum supply voltage is tested by measuring offset voltage to
7mV maximum at ±5V supplies.
Note 5: The LT1122 is not tested and not quality-assurance-sampled at
–40°C and at 85°C. These specifications are guaranteed by design,
correlation and/or inference from – 55°C, 0°C, 25°C, 70°C and/or 125°C
tests.

V

OUT

Output Voltage Swing RL = 2kΩ±12 ±12.5 ± 12 ± 12.5 V

RL = 600Ω±11.5 ± 12 ± 11.5 ±12 V

I

S

Supply Current 7.5 10 7.8 11 mA
Minimum Supply voltage (Note 4) ± 5 ±5V
Offset Adjustment Range R

POT

≥ 10k, Wiper to V

+

±4 ±10 ±4 ± 10 mV