LT1208 Linear Technology, LT1208 Datasheet - Page 7

• Manufacturer Part Number: LT1208
• Description: Dual and Quad 45MHz/ 400V/us Op Amps
• Manufacturer: Linear Technology

A
Input Considerations
Resistors in series with the inputs are recommended for
the LT1208/LT1209 in applications where the differential
input voltage exceeds 6V continuously or on a transient
basis. An example would be in noninverting configura-
tions with high input slew rates or when driving heavy
capacitive loads. The use of balanced source resistance at
each input is recommended for applications where DC
accuracy must be maximized.
Transient Response
The LT1208/LT1209 gain-bandwidth is 45MHz when mea-
sured at 100kHz. The actual frequency response in unity-
gain is considerably higher than 45MHz due to peaking
PPLICATI
A
C
A
C
V
L
V
L
= –1
= 1000pF
= 10,000pF
= 1
Small-Signal Capacitive Loading
Large-Signal Capacitive Loading
O
U
S
I FOR ATIO
U
W
1208/09 AI01
1208/09 AI02
U
caused by a second pole beyond the unity-gain crossover.
This is reflected in the 50 phase margin and shows up as
overshoot in the unity-gain small-signal transient re-
sponse. Higher noise gain configurations exhibit less
overshoot as seen in the inverting gain of one response.
The large-signal response in both inverting and non-
inverting gain show symmetrical slewing characteristics.
Normally the noninverting response has a much faster
rising edge due to the rapid change in input common-
mode voltage which affects the tail current of the input
differential pair. Slew enhancement circuitry has been
added to the LT1208/LT1209 so that the falling edge slew
rate is balanced.
A
A
V
V
= 1
= –1
Small-Signal Transient Response
Small-Signal Transient Response
LT1208/LT1209
1208/09 AI03
1208/09 AI04
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