OP492 Analog Devices, OP492 Datasheet - Page 13

• Manufacturer Part Number: OP492
• Description: Quad Single Supply Operational Amplifier
• Manufacturer: Analog Devices

Specifications of OP492

• -3db Bandwidth: 4MHz
• Slew Rate: 4V/µs
• Vos: 1.4mV
• Ib: 375nA
• # Opamps Per Pkg: 4
• Input Noise (nv/rthz): 15nV/rtHz
• Vcc-vee: 4.5V to 33V
• Isy Per Amplifier: 1.4mA
• Packages: SOIC

APPLICATIONS INFORMATION
PHASE REVERSAL
The OP492 has built-in protection against phase reversal when
the input voltage goes to either supply rail. In fact, it is safe for
the input to exceed either supply rail by up to 0.6 V with no risk
of phase reversal. However, the input should not go beyond the
positive supply rail by more than 0.9 V; otherwise, the output
will reverse phase. If this condition occurs, the problem can be
fixed by adding a 5 kΩ current limiting resistor in series with
the input pin. With this addition, the input can go to more than
5 V beyond the positive rail without phase reversal.
An input voltage that is as much as 5 V below the negative rail
will not result in phase reversal.
0V
11.8V p-p
OP492
Figure 34. Output Phase Reverse If Input Exceeds
5V
the Positive Supply (V+) by More Than 0.9 V
2kΩ
100
10
0%
90
1V
5µs
Rev. C | Page 13 of 20
POWER SUPPLY CONSIDERATIONS
The OP292/OP492 are designed to operate equally well at single
+5 V or ±15 V supplies. The lowest supply voltage recommended
is 4.5 V.
It is a good design practice to bypass the supply pins with a
0.1 μF ceramic capacitor. It helps improve filtering of high
frequency noise.
For dual-supply operation, the negative supply (V−) must be
applied at the same time, or before V+. If V+ is applied before V−,
or in the case of a loss of the V− supply, while either input is
connected to ground or another low impedance source, excessive
input current may result. Potentially damaging levels of input
current can destroy the amplifier. If this condition can exist,
simply add a l kΩ or larger resistor in series with the input to
eliminate the problem.
0V
10V p-p
Figure 35. No Negative Rail Phase Reversal, Even with Input Signal
OP492
5V
2kΩ
at 5 V Below Ground
1V/DIV
OP292/OP492
4ms/DIV