OP162_05 Datasheet, PDF (14/20 Pages) Analog Devices – 15 MHz Rail-to-Rail Operational Amplifiers

OP162/OP262/OP462
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
20
14-LEAD SOIC
14-LEAD TSSOP
45
70
95
120
AMBIENT TEMPERATURE (°C)
Figure 37. Maximum Power Dissipation vs. Temperature for
14-Lead Package Types
UNUSED AMPLIFIERS
It is recommended that any unused amplifiers in a dual or a
quad package be configured as a unity-gain follower with a
1 kΩ feedback resistor connected from the inverting input to
the output, and the noninverting input tied to the ground plane.
POWER-ON SETTLING TIME
The time it takes for the output of an op amp to settle after a
supply voltage is delivered can be an important consideration in
some power-up-sensitive applications. An example of this
would be in an A/D converter where the time until valid data
can be produced after power-up is important.
The OPx62 family has a rapid settling time after power-up.
Figure 38 shows the OP462 output settling times for a single-
supply voltage of VS = +5 V. The test circuit in Figure 39 was
used to find the power-on settling times for the device.
2V
100
90
500ns
0 TO +5V
SQUARE
1
OP462
V_OUT
10KΩ
Figure 39. Test Circuit for Power-On Settling Time
CAPACITIVE LOAD DRIVE
The OP162/OP262/OP462 are high speed, extremely accurate
devices that tolerate some capacitive loading at their outputs. As
load capacitance increases, unity-gain bandwidth of an OPx62
device decreases. This also causes an increase in overshoot and
settling time for the output. Figure 41 shows an example of this
with the device configured for unity gain and driving a 10 kΩ
resistor and 300 pF capacitor placed in parallel.
By connecting a series R-C network, commonly called a
“snubber” network, from the output of the device to ground,
this ringing can be eliminated and overshoot can be
significantly reduced. Figure 40 shows how to set up the
snubber network, and Figure 42 shows the improvement in
output response with the network added.
5V
OPx62
V_OUT
V_IN
R_X
C_L
C_X
Figure 40. Snubber Network Compensation for Capacitive Loads
V_S = 5V
A_V = 1
100
C_L = 300pF
90
R_L = 10kΩ
10
0%
50mV
VS = 5V
AV = 1
RL = 10kΩ
Figure 38. Oscilloscope Photo of VS and VOUT
10
0%
50mV
1µs
Figure 41. A Photo of a Ringing Square Wave
Rev. F | Page 14 of 20