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FEATURES

DESCRIPTION

APPLICATIONS

+

−

100

2.5

ADS8320

10 nF

500

V BAT

Load

+IN

−IN

V OUT = I RSENSE

0.2

I

RSENSE

THS4281

470 pF

470 pF

VBAT

VBAT

W

kW

W

2.5 kW

500 W

W

VBAT/2

High-Side, Low Power Current-Sensing System

THS4281

SLOS432 – APRIL 2004

VERY LOW-POWER, HIGH-SPEED, RAIL-TO-RAIL INPUT AND OUTPUT

VOLTAGE-FEEDBACK OPERATIONAL AMPLIFIER

•

Very Low Quiescent Current: 750 µA (at 5 V)

Fabricated using the BiCom-II process, the THS4281

is a low-power, rail-to-rail input and output volt-

•

Rail-to-Rail Input and Output:

age-feedback

operational

amplifier

designed

to

– Common-Mode Input Voltage Extends

operate over a wide power supply range of 2.7-V to

400 mV Beyond the Rails

15-V single supply, and

±1.35-V to ±7.5-V dual

– Output Swings Within 150 mV From the

supply. Consuming only 750 µA with a unity gain

Rails

bandwidth of 90 MHz and a high 35-V/µs slew rate,

the THS4281 allows portable or other power-sensitive

•

Wide -3 dB Bandwidth at 5 V:

applications to realize high performance with minimal

– 90-MHz @ Gain = +1, 40 MHz @ Gain = +2

power. To ensure long battery life in portable appli-

•

High Slew Rate: 35 V/µs

cations, the quiescent current is trimmed to be less

than 900 µA at 25

°C, and 1 mA from –40°C to 85°C.

•

Fast Settling Time (2-V Step):

– 78 ns to 0.1%

The THS4281 is a true single-supply amplifier with a

specified common-mode input range of 400 mV

– 150 ns to 0.01%

beyond the rails. This allows for high-side current

•

sensing applications without phase reversal con-

– -91 dBc at 100 kHz, -67 dBc at 1 MHz

cerns. Its output swings to within 40 mV from the rails

with 10-k

Ω loads, and 150 mV from the rails with

•

Input Offset Voltage: 2.5 mV (Max at 25

°C)

1-k

Ω loads.

•

Output Current >30 mA (10-

Ω Load, 5 V)

The THS4281 has a good 0.1% settling time of 78 ns,

•

Low Voltage Noise of 12.5 nV/

√Hz

and 0.01% settling time of 150 ns. The low THD of

•

Supply Voltages: +2.7 V, 3 V, +5 V,

±5 V, +15 V

-87 dBc at 100 kHz, coupled with a maximum offset

•

Packages: SOT-23, MSOP, and SOIC

voltage of less than 2.5 mV, makes the THS4281 a

good match for high-resolution ADCs sampling less

than 2 MSPS.

•

Portable/Battery-Powered Applications

The THS4281 is offered in a space-saving SOT-23-5

•

High Channel Count Systems

package, a small MSOP-8 package, and the industry

standard SOIC-8 package.

•

ADC Buffer

•

Active Filters

•

Current Sensing

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas

Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

FilterPro is a trademark of Texas Instruments.

PRODUCTION DATA information is current as of publication date.

Copyright © 2004, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.