Datasheet

LT1210
11
1210fb
For more information www.linear.com/LT1210
applicaTions inForMaTion
bandwidth is reduced. The photos in Figures 5a, 5b and 5c
show the large-signal response of the LT1210 for various
gain configurations. The slew rate varies from 770V/µs
for a gain of 1, to 1100V/µs for a gain of –1.
When the LT1210 is used to drive capacitive loads, the
available output current can limit the overall slew rate.
In the fastest configuration, the LT1210 is capable of a
slew rate of over 1V/ns. The current required to slew a
capacitor at this rate is 1mA per picofarad of capacitance,
so 10,000pF would require 10A! The photo (Figure 6)
shows the large-signal behavior with C
L
= 10,000pF. The
slew rate is about 150V/µs, determined by the current
limit of 1.5A.
Differential Input Signal Swing
The differential input swing is limited to about ±6V by
an ESD protection device connected between the inputs.
In normal operation, the differential voltage between the
input pins is small, so this clamp has no effect; however,
in the shutdown mode the differential swing can be the
same as the input swing. The clamp voltage will then set
the maximum allowable input voltage. To allow for some
margin, it is recommended that the input signal be less
than ±5V when the device is shut down.
Capacitance on the Inverting Input
Current feedback amplifiers require resistive feedback from
the output to the inverting input for stable operation. Take
care to minimize the stray capacitance between the output
and the inverting input. Capacitance on the inverting input
to ground will cause peaking in the frequency response
(and overshoot in the transient response), but it does not
degrade the stability of the amplifier.
Figure 5a. Large-Signal Response, A
V
= 1
Figure 5b. Large-Signal Response, A
V
= –1
Figure 5c. Large-Signal Response, A
V
= 2
Figure 6. Large-Signal Response, C
L
= 10,000pF
R
F
= 825Ω
R
L
= 10Ω
V
S
= ±15V
1210 F05a
R
F
= R
G
= 750Ω
R
L
= 10Ω
V
S
= ±15V
1210 F05b
R
F
= R
G
= 750Ω
R
L
= 10Ω
V
S
= ±15V
1210 F05c
R
F
= R
G
= 3k
R
L
= ∞
V
S
= ±15V
1210 F06
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