OP-41_15 Datasheet, PDF (8/11 Pages) Analog Devices – LOW BIAS CURRENT HIGH STABILITY JFET OPERATIONAL AMPLIFIER

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Page 9
OP-41
OFFSET VOLTAGE ADJUSTMENT
Offset voltage is adjusted by a potentiometer of 10kO to 100kO
resistance. This potentiometer should be connected between
pins 1 and 5 with the wiper connected to the V- supply. (See
Figure 1.) Nulling Vas will change TCVes by no more than
5J.1V1°Cper millivolt of Vas change.
FIGURE 1: INPUT OFFSET VOLTAGE NULLING
FIGURE 3: SMALL-SIGNALTRANSIENT RESPONSE
V+
v-
NOTL
vos CAN BE TRIMMEDWITH POTENTIOMETER
RANGING FROM 10kn TO lOOk!).
OB ^---------- _{APPLICATIONSINFORMATION}
S _{TYPICALAC PERFORMANCE CHARACTERISTICS}
O ^- _{Figure 2 shows the overload recovery time after the output}
saturates at each supply. A high degree of slew-rate symmetry
L _{is maintained even during severe input overload. The photo}
E ^{also shows the well controlled linear characteristics of the}
amplifier and freedom from oscillations. The OP-41's symmetry
TE _{greatly reduces the generation of large DC components in the}
FIGURE 4: SMALL-SIGNAL TRANSIENT RESPONSE WITH
1000pF LOAD
,
FIGURE 5: WIDE-DYNAMiC-RANGE LIGHTDETECTOR
'"4pF
output when the amplifier is overdriven. This significantly
reduces system recovery time after an overload.
Figure 3 shows the unity-gain small-signal transient response
1o9n
of the OP-41. Note the clean symmetrical waveform.
Figure 4 illustrates the high degree of stabiJity even when
~
loaded with 1000pF at unity-gain. Heavy capacitive loading will
va. O.5V/nW
cause stability problems with many amplifiers.
Figure 5 illustrates the use of the OP-41 in a high sensitivity,
wide-dynamic-range light detector. This circuit will produce an
0 utput voltage proportional to the light input over a GOdB range.
FIGURE 2: OVERLOAD RECOVERY TIME AT Av =10
CMR MEASUREMENT METHODS
Two separate methods are used to measure the CMR. The first
method is used over the range of 10Hz to 20kHz. This method
grounds the input circuitry and applies the common~mode
signal to the remainder of the op amp. Figure 6.
The AMP-O1 eliminates loading on the output stage. This
assures that the OP-41 output is not required to deliver current
into the feedback circuit. The effects of the OUT open-loop gain
changing with frequency are therefore significantly reduced.
The circuit does not require tight resistor matching. DC data
sheet limits may be verified using this method. Circuit accuracy
is dependent on the high CMR of the AMP-O1.
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