16

LT1498/LT1499

14989f LT/TP 0397 7K • PRINTED IN USA

© LINEAR TECHNOLOGY CORPORATION 1996

RELATED PARTS

PART NUMBER

DESCRIPTON

COMMENTS

LTC

Rail-to-Rail Input and Output, Zero-Drift Op Amp

High DC Accuracy, 10

1V/

µs Slew Rate, Max Supply Current 2.2mA

LT1211/LT1212

Dual/Quad 14MHz, 7V/

µs, Single Supply Precision Op Amps

Input Common Mode Includes Ground, 275

6

µV/°C Max Drift, Max Supply Current 1.8mA per Op Amp

LT1213/LT1214

Dual/Quad 28MHz, 12V/

µs, Single Supply Precision Op Amps

Input Common Mode Includes Ground, 275

6

µV/°C Max Drift, Max Supply Current 3.5mA per Op Amp

LT1215/LT1216

Dual/Quad 23MHz, 50V/

µs, Single Supply Precision Op Amps

Input Common Mode Includes Ground, 450

Max Supply Current 6.6mA per Op Amp

LT1366/LT1367

Dual/Quad Precision, Rail-to-Rail Input and Output Op Amps

475

Max Supply Current 520

µA per Op Amp

LT1490/LT1491

Dual/Quad Micropower, Rail-to-Rail Input and Output Op Amps

Max Supply Current 50

µA per Op Amp, 200kHz GBW, 0.07V/µs

Linear Technology Corporation

Bidirectional Current Sensor

A bidirectional current sensor for battery-powered sys-

tems is shown in Figure 3. Two outputs are provided: one

proportional to charge current, the other proportional to

discharge current. The circuit takes advantage of the

LT1498’s rail-to-rail input range and its output phase

reversal protection. During the charge cycle, the op amp

voltage is then amplified at the Charge Out by the ratio of

keeping Q2 off and the Discharge Out low, even though the

(+) input of A2 exceeds the positive power supply. During

the discharge cycle, A2 and Q2 are active and the operation

is similar to the charge cycle.

–

+

–

+

A1

1/2 LT1498

A2

1/2 LT1498

Q2

MTP23P06

= 1V/A

DISCHARGE

OUT

CHARGE

OUT

Q1

MTP23P06

1498/99 F03

DISCHARGE

CHARGE

0.1

Ω

()

Figure 3. Bidirectional Current Sensor