OP-44_15 Datasheet, PDF (7/9 Pages) Analog Devices – HIGH SPEED PRECISION OPERATIONAL AMPLIFIER

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IPMI) OP-44 HIGH-SPEED, PRECISION OPERATIONAL AMPLIFIER
APPLICATIONS INFORMATION
The OP-44 is a high-speed amplifier internally compensated for
closed-loop gains of 3 or more. Slew rate is typically 120V/J.ts,
Supply decoupling must be used to overcome inductance and
resistance associated with the supply lines to the amplifier. For
most applications, a 0.1J.tF to 0.01J.tF placed between each
which allows the OP-44 output to handle a 20Vp_psine wave at
supply pin and ground is adequate. Ifsupply lines are extremely
2MHz. Stability is ensured by the OP-44's guaranteed capacitive
long and/or noisy, an additional tantalum capacitor between
load drive ability of 50pF.
3.3J.tF and 10J.tFshould be placed in parallel with each of the
smaller decoupling capacitors.
The input capacitance of high-speed op amps often causes a
noticeable degradation of pulse response, resulting in exces-
sive overshoot and ringing. The pole introduced by the input
The OP-44 displays excellent resistance to radiation. Radiation
hardness data is available by contacting the factory.
capacitance can be compensated by placing a similar capaci-
tance in the feedback loop of the amplifier. For the OP-44, the
FIGURE 3: Transient Response Test Circuit
input capacitance is typically 6pF.
Small-signal and large-signal transient responses are shown in
V,N
Figures 1 and 2. These photos were taken using the gain of 3
VOUT
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test circuit shown in Figure 3.
As with most JFET-input op amps, the output of the OP-44 may
undergo phase inversion if either input exceeds the specified
input voltage range. Phase inversion will not damage the
amplifier, nor will it cause an internal latch-up.
O_{FIGURE 1: Small-Signal Transient Response}
. ^{BSOLETE = (AVCL +3, CL=50pF)}
SpF
OFFSET VOLTAGEADJUSTMENT
Offset voltage is adjusted with a 10kD to 100kD potentiometer
as shown in Figure 4. The potentiometer is connected between
pins 1 and 5 with its wiper connected to the V- supply. Nulling
Vas in this manner changes TCVas by no more than 5J.tV/oCper
millivolt of Vas change. Alternately, Vas may be nulled by
attaching the potentiometer wiper through a 1MD resistor to the
positive supply rail.
FIGURE 4: Input Offset Voltage Nulling
FIGURE 2: Large-Signal Transient Response
(AVCL= +3, CL= 50pF)
V-
V+
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v-
STANDARD METHOD
1MH
v-
ALTERNATE METHOD
NOTE,
Vos CAN BE TRIMMED WITH
POTENTIOMETER RANGING
FROM 10W TO 100k!1.
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10/87, Rev. 81