OP490GSZ-REEL Analog Devices Inc, OP490GSZ-REEL Datasheet - Page 12

• Manufacturer Part Number: OP490GSZ-REEL
• Description: IC,Operational Amplifier,QUAD,BIPOLAR,SOP,16PIN,PLASTIC
• Manufacturer: Analog Devices Inc

Specifications of OP490GSZ-REEL

• Amplifier Type: General Purpose
• Number Of Circuits: 4
• Slew Rate: 0.012 V/µs
• Gain Bandwidth Product: 20kHz
• Current - Input Bias: 4.2nA
• Voltage - Input Offset: 600µV
• Current - Supply: 60µA
• Voltage - Supply, Single/dual (±): 1.6 V ~ 36 V, ±0.8 V ~ 18 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.300", 7.5mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Output Type: -
• Current - Output / Channel: -
• -3db Bandwidth: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: OP490GSZ-REELTR

OP490
HIGH OUTPUT AMPLIFIER
The amplifier shown in Figure 24 is capable of driving 25 V p-p
into a 1 kΩ load. Design of the amplifier is based on a bridge
configuration. A amplifies the input signal and drives the load
with the help of B. Amplifier C is a unity-gain inverter which
drives the load with help from D. Gain of the high output
amplifier with the component values shown is 10, but can easily
be changed by varying R1 or R2.
SINGLE-SUPPLY MICROPOWER QUAD
PROGRAMMABLE GAIN AMPLIFIER
The combination of a quad OP490 and the DAC8408 quad 8-bit
CMOS DAC creates a quad programmable-gain amplifier with
a quiescent supply drain of only 140 μA. The digital code
present at the DAC, which is easily set by a microprocessor,
V
IN
1kΩ
R1
2
3
+
–
OP490
1/4
+15V
–15V
A
11
4
1
6
5
9kΩ
R2
–
+
OP490
1/4
B
50Ω
R3
Figure 24. High Output Amplifier
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Rev. E | Page 12 of 16
50Ω
R4
R
determines the ratio between the fixed DAC feedback resistor
and the resistance of the DAC ladder seen by the op amp feed-
back loop. The gain of each amplifier is:
where n equals the decimal equivalent of the 8-bit digital code
present at the DAC. If the digital code present at the DAC
consists of all zeros, the feedback loop opens causing the op
amp output to saturate. The 10 MΩ resistors placed in parallel
with the DAC feedback loop eliminate this problem with a very
small reduction in gain accuracy. The 2.5 V reference biases the
amplifiers to the center of the linear region providing maximum
output swing.
L
V
V
OUT
50Ω
IN
R8
=
−
256
n
14
50Ω
R7
OP490
1/4
D
5kΩ
R6
–
+
13
12
5kΩ
R5
8
OP490
1/4
C
–
+
10
9