THS4031, THS4032

100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS

SLOS224C – JULY 1999 – REVISED APRIL 2000

26

POST OFFICE BOX 655303

APPLICATION INFORMATION

offset nulling

The THS403x has very low input offset voltage for a high speed amplifier. However, if additional correction is

required, the designer can make use of an offset nulling function provided on the THS4031. By placing a

potentiometer between terminals 1 and 8 of the device and tying the wiper to the negative supply, the input offset

can be adjusted. This is shown in Figure 50.

_

+

THS4031

VCC –

VCC+

0.1

µF

0.1

µF

10 k

Ω

Figure 50. Offset Nulling Schematic

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

) RS 1 )

R

F

R

G

" I

IB–

R

F

+

–

VI

+

RG

RS

RF

IIB–

VO

IIB+

Figure 51. Output Offset Voltage Model