Datasheet OP490 (Analog Devices) - 10

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OP490 APPLICATIONS INFORMATION –18V BATTERY-POWERED APPLICATIONS
The OP490 can be operated on a minimum supply voltage of 1.6 V or with dual supplies of ±0.8 V drawing only 60 μA of
14 13 12 11 10 9 8
supply current. In many battery-powered circuits, the OP490 can be continuously operated for hundreds of hours before
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requiring battery replacement, thereby reducing equipment downtime and operating costs.
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High performance portable equipment and instruments frequently use lithium cells because of their long shelf life, light
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weight, and high energy density relative to older primary cells. Most lithium cells have a nominal output voltage of 3 V and are noted for a flat discharge characteristic. The low supply current 9
GND
01 8- requirement of the OP490, combined with the flat discharge 30
+18V
00 characteristic of the lithium cell, indicates that the OP490 can Figure 19. Burn-In Circuit be operated over the entire useful life of the cell. Figure 21 shows the typical discharge characteristic of a 1 Ah lithium cell
+15V
powering an OP490 with each amplifier, in turn, driving full
+15V
output swing into a 100 kΩ load.
) 4 + V ( 1/4 E OP490 + G A 1kΩ A T – OP37 V2 L O A 3 V – L L 100Ω 10kΩ CE E –15V ID X 2 –15V O VIN + 1/4 HUR DI P V1 OP490 UL 1 B -S – 20V p-p @ 10Hz UM HI IT L
1
0
-02
0 250 500 750 1000 1250 1500 V1
308
CHANNEL SEPARATION = 20 log + V2/1000 HOURS
00
1/4
Figure 21. Lithium-Sulphur Dioxide Cell Discharge Characteristic with
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OP490 and 100 kΩ Loads
– SINGLE-SUPPLY OUTPUT VOLTAGE RANGE
In single-supply operation the input and output ranges of the OP490 include ground. This allows true zero-in, zero-out
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operation. The output stage provides an active pull-down to
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around 0.8 V above ground. Below this level, a load resistance of up
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20 to 1 MΩ to ground is required to pull the output down to zero. 0 8- 30 00 In the region from ground to 0.8 V, the OP490 has voltage gain Figure 20. Channel Separation Test Circuit equal to the data sheet specification. Output current source capability is maintained over the entire voltage range including ground. Rev. E | Page 9 of 16 Document Outline FEATURES GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAMS TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ELECTRICAL CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION TYPICAL PERFORMANCE CHARACTERISTICS APPLICATIONS INFORMATION BATTERY-POWERED APPLICATIONS SINGLE-SUPPLY OUTPUT VOLTAGE RANGE INPUT VOLTAGE PROTECTION MICROPOWER VOLTAGE-CONTROLLED OSCILLATOR MICROPOWER SINGLE-SUPPLY QUAD VOLTAGE-OUTPUT 8-BIT DAC HIGH OUTPUT AMPLIFIER SINGLE-SUPPLY MICROPOWER QUAD PROGRAMMABLE GAIN AMPLIFIER OUTLINE DIMENSIONS ORDERING GUIDE