+

−

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

www.ti.com

SLOS432A – APRIL 2004 – REVISED NOVEMBER 2009

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

VOLTAGE-FEEDBACK OPERATIONAL AMPLIFIER

Check for Samples: THS4281

1

FEATURES

DESCRIPTION

23

•

Very Low Quiescent Current: 750

μA (at 5 V)

•

Rail-to-Rail Input and Output:

Fabricated using the BiCom-II process, the THS4281

is

a

low-power,

rail-to-rail

input

and

output,

–

Common-Mode Input Voltage Extends

voltage-feedback operational amplifier designed to

400 mV Beyond the Rails

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

–

Output Swings Within 150 mV From the

15-V single supply, and ±1.35-V to ±7.5-V dual

Rails

supply. Consuming only 750

μA with a unity gain

bandwidth of 90 MHz and a high 35-V/

μs slew rate,

•

Wide –3-dB Bandwidth at 5 V:

the THS4281 allows portable or other power-sensitive

–

90 MHz at Gain = +1, 40 MHz at Gain = +2

applications to realize high performance with minimal

•

High Slew Rate: 35 V/

μs

power. To ensure long battery life in portable

applications, the quiescent current is trimmed to be

•

Fast Settling Time (2-V Step):

less than 900

μA at +25°C, and 1 mA from –40°C to

–

78 ns to 0.1%

+85°C.

–

150 ns to 0.01%

The THS4281 is a true single-supply amplifier with a

•

specified common-mode input range of 400 mV

–

–91 dBc at 100 kHz, –67 dBc at 1 MHz

beyond the rails. This allows for high-side current

sensing

applications

without

phase

reversal

•

Input Offset Voltage: 2.5 mV (Max at +25°C)

concerns. Its output swings to within 40 mV from the

•

Output Current > 30 mA (10-

Ω Load, 5 V)

rails with 10-k

Ω loads, and 150 mV from the rails with

•

Low Voltage Noise of 12.5 nV/

√Hz

1-k

Ω loads.

•

Supply Voltages: +2.7 V, 3 V, +5 V, ±5 V, +15 V

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

•

Packages: SOT23, MSOP, and SOIC

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

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

APPLICATIONS

voltage of less than 2.5 mV, makes the THS4281 a

good match for high-resolution ADCs sampling less

•

Portable/Battery-Powered Applications

than 2 MSPS.

•

High Channel Count Systems

•

ADC Buffer

The THS4281 is offered in a space-saving SOT23-5

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

•

Active Filters

standard SOIC-8 package.

•

Current Sensing

1

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.

2

FilterPro is a trademark of Texas Instruments.

3

All other trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Copyright © 2004–2009, 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.