Datasheet
LT1228
4
1228fd
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. Transconductance Amplifier, Pins 1, 2, 3, 5. ±5V ≤ V
S
≤ ±15V,
I
SET
= 100µA, V
CM
= 0V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
OS
Input Offset Voltage I
SET
= 1mA, T
A
= 25°C
l
±0.5 ±5
±10
mV
mV
Input Offset Voltage Drift
l
10 µV/°C
I
OS
Input Offset Current T
A
= 25°C
l
40 200
500
nA
nA
I
B
Input Bias Current T
A
= 25°C
l
0.4 1
5
µA
µA
e
n
Input Noise Voltage Density f = 1kHz 20 nV/√Hz
R
IN
Input Resistance-Differential Mode V
IN
≈ ±30mV
l
30 200 kΩ
Input Resistance-Common Mode V
S
= ±15V, V
CM
= ±12V
V
S
= ±5V, V
CM
= ±2V
l
l
50
50
1000
1000
MΩ
MΩ
C
IN
Input Capacitance 3 pF
Input Voltage Range V
S
= ±15V, T
A
= 25°C
V
S
= ±15V
l
±13
±12
±14 V
V
V
S
= ±5V, T
A
= 25°C
V
S
= ±5V
l
±3
±2
±4 V
V
CMRR Common Mode Rejection Ratio V
S
= ±15V, V
CM
= ±13V, T
A
= 25°C
V
S
= ±15V, V
CM
= ±12V
l
60
60
100 dB
dB
V
S
= ±5V, V
CM
= ±3V, T
A
= 25°C
V
S
= ±5V, V
CM
= ±2V
l
60
60
100 dB
dB
PSRR Power Supply Rejection Ratio V
S
= ±2V to ±15V, T
A
= 25°C
V
S
= ±3V to ±15V
l
60
60
100 dB
dB
g
m
Transconductance I
SET
= 100µA, I
OUT
= ±30µA, T
A
= 25°C 0.75 1.00 1.25 µA/mV
Transconductance Drift
l
–0.33 %/°C
I
OUT
Maximum Output Current I
SET
= 100µA
l
70 100 130 µA
I
OL
Output Leakage Current I
SET
= 0µA (+I
IN
of CFA), T
A
= 25°C
l
0.3 3
10
µA
µA
V
OUT
Maximum Output Voltage Swing V
S
= ±15V , R1 = ∞
V
S
= ±5V , R1 = ∞
l
l
±13
±3
±14
±4
V
V
R
O
Output Resistance V
S
= ±15V, V
OUT
= ±13V
V
S
= ±5V, V
OUT
= ±3V
l
l
2
2
8
8
MΩ
MΩ
Output Capacitance (Note 3) V
S
= ±5V 6 pF
I
S
Supply Current, Both Amps I
SET
= 1mA
l
9 15 mA
THD Total Harmonic Distortion V
IN
= 30mV
RMS
at 1kHz, R1 = 100k 0.2 %
BW Small-Signal Bandwidth R1 = 50Ω, I
SET
= 500µA 80 MHz
t
r
Small-Signal Rise Time R1 = 50Ω, I
SET
= 500µA, 10% to 90% 5 ns
Propagation Delay R1 = 50Ω, I
SET
= 500µA, 50% to 50% 5 ns
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: A heat sink may be required depending
on the power supply voltage.
Note 3: This is the total capacitance at Pin 1. It includes the input capacitance
of the current feedback amplifier and the output capacitance of the
transconductance amplifier.
Note 4: Slew rate is measured at ±5V on a ±10V output signal while operating
on ±15V supplies with R
F
= 1k, R
G
= 110Ω and R
L
= 400Ω. The slew rate is
much higher when the input is overdriven
, see the Applications Information
section.
Note 5: Rise time is measured from 10% to 90% on a ±500mV output signal
while operating on ±15V supplies with R
F
= 1k, R
G
= 110Ω and R
L
= 100Ω.
This condition is not the fastest possible, however, it does guarantee the
internal capacitances are correct and it makes automatic testing practical.
Note 6: AC parameters are 100% tested on the ceramic and plastic DIP
packaged parts (J
and N suffix) and are sample tested on every lot of the SO
packaged parts (S suffix).
Note 7: NTSC composite video with an output level of 2V.
Note 8: Back to back 6V Zener diodes are connected between Pins 2 and 3
for ESD protection.