9

LT1358/LT1359

Small-Signal Transient

Small-Signal Transient

Small-Signal Transient

1358/1359 G31

1358/1359 G32

Large-Signal Transient

Large-Signal Transient

Large-Signal Transient

1358/1359 G36

1358/1359 G35

1358/1359 G33

1358/1359 G34

Layout and Passive Components

The LT1358/LT1359 amplifiers are easy to use and toler-

ant of less than ideal layouts. For maximum performance

(for example, fast 0.01% settling) use a ground plane,

short lead lengths, and RF-quality bypass capacitors

(0.01

µF to 0.1µF). For high drive current applications use

low ESR bypass capacitors (1

µF to 10µF tantalum).

The parallel combination of the feedback resistor and gain

setting resistor on the inverting input combine with the

input capacitance to form a pole which can cause peaking

or oscillations. If feedback resistors greater than 5k are

used, a parallel capacitor of value

should be used to cancel the input pole and optimize

dynamic performance. For unity-gain applications where

Capacitive Loading

The LT1358/LT1359 are stable with any capacitive load.

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. 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., 75

Ω) should be placed in 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 LT1358/LT1359 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.