THS4011, THS4012

290-MHz LOW-DISTORTION HIGH-SPEED AMPLIFIERS

SLOS216B – JUNE 1999 – FEBRUARY 2000

18

POST OFFICE BOX 655303

APPLICATION INFORMATION

offset voltage

the corresponding gains. The following schematic and formula can be used to calculate the output offset

voltage:

V

OO +

V

IO

1

)

R

F

R

G

" I

IB

)

R

S

1

)

R

F

R

G

" I

IB–

R

F

+

–

VI

+

RG

RS

RF

IIB–

VO

IIB+

Figure 29. Output Offset Voltage Model

optimizing unity gain response

Internal frequency compensation of the THS401x was selected to provide very wideband performance yet still

maintain stability when operated in a noninverting unity gain configuration. When amplifiers are compensated

in this manner there is usually peaking in the closed loop response and some ringing in the step response for

very fast input edges, depending upon the application. This is because a minimum phase margin is maintained

for the G=+1 configuration. For optimum settling time and minimum ringing, a feedback resistor of 100

Ω should

be used as shown in Figure 30. Additional capacitance can also be used in parallel with the feedback resistance

if even finer optimization is required.

_

+

THS401x

100

Ω

Input

Output

Figure 30. Noninverting, Unity Gain Schematic