OP-160_15 Datasheet, PDF (17/24 Pages) Analog Devices – High-Speed, Current Feedback Operational Amplifier

- RNRLOGDEVICES fRX-ON-DEHRND HOTLINE
Page 18
OP-160
v+
RPOT = 1110 TO 1Okn
+15V
10j1F
~F---,
0.111F' ...L
OUT
DISABLE
~"::'
820(-1
vaJT
11<n
v-
FIGURE 14: Input Offset Voltage Nulling
~- _{OFFSET VOLTAGE ADJUSTMENT}
Offset voltage is adjusted with a 20kn potentiometer as shown
Oin Figure 14. The potentiometer should be connected between
pins 1 and 5 with its wiper connected to the V+ supply. The
B ^{typical trim range is :!::40mV.}
S _{DISABLE AMPLIFIER SHUTDOWN}
O ^{Pin 8 of the OP-160, DISABLE, is an amplifier shutdown control}
input. The OP-160 operates normally when Pin 8 is left floating.
L ^{When greater than 1O00j.1Ais drawn from the DISABLE pin, the}
OP-160 is disabled. To draw current from the DISABLE pin, an
E _{open collector output logic gate or a discrete NPN transistor can}
T ^{be used as shown in Figure 15. An internal resistor limits the}
E ^{DISABLE current to around 500j.lA if the DISABLE pin is}
2V n
ov--.J L
1011f
=1+
-:
0"11F~
-15V ':"
FIGURE 16: DISABLE Turn-On/Turn-aff Test Circuit
shifting the TTL signal to whatever supply voltage is used to
power the OP-160.
In the DISABLE mode, the OP-160 maintains 40dB of input-to-
output isolation if the input signal remains below :!::1.5V.Output
resistance is very high. over 100kn. if the output is driven by
signals of less than :t1.5V. Higher signals will be distorted.
Figure 16 shows a test circuit for measuring the turn-on and
turn-off times for the OP-160. The OP-160 is in a gain of +1 with
a + 1V DC input. As the input pulseto the inverter rises its output
grounded with the OP-160 powered by :t15V suppHes. These
falls, drawing current from the DISABLE pin and disabling the
logic interface methods have the added advantage of level
v+
v+
'ltN
vour
2V n
5110
ov--.J L
"::' _v-
.---
FIGURE 15: Simple circuits allow the OP-160 to be shutdown.
"'t'i
LOGIC GATE
WITH OPEN
COLLECTOAiDRAIN
OUTPUT
VOUT
v-
-17-