40 μA Micropower Instrumentation

Amplifier in WLCSP Package

AD8235

Rev. 0

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FEATURES

Low power

40 μA maximum supply current

6 nA shutdown current

Low input currents

50 pA input bias current

25 pA input offset current

High Common Mode Rejection Ratio (CMRR)

110 dB CMRR , G = 100

Space saving

WLCSP package

Zero input crossover distortion

Versatile

Rail-to-rail input and output

Shutdown

Gain set with single resistor (G = 5 to 200)

AD8236: μSOIC package version of AD8235

APPLICATIONS

Medical instrumentation

Low-side current sense

Portable electronics

GENERAL DESCRIPTION

The AD8235 is the smallest and lowest power instrumentation

amplifier in the industry. It is available in a 1.5 mm × 2.2 mm

wafer level chip scale package (WLCSP). The AD8235 draws

a maximum quiescent current of 40 μA. In addition, it draws a

maximum 500 nA of current during shutdown mode, making

it an excellent instrumentation amplifier for battery powered,

portable applications.

The AD8235 can operate on supply voltages as low as 1.8 V. The

input stage allows for wide rail-to-rail input voltage range without

the crossover distortion, common in other designs. The rail-to-

rail output enables easy interfacing to ADCs.

The AD8235 is an excellent choice for signal conditioning. Its

low input bias current of 50 pA and high CMRR of 110 dB

(G = 100) offer tremendous value for its size and low power.

It is specified over the extended industrial temperature range of

−40°C to 125°C.

CONNECTION DIAGRAM

RG

RG

REF

–IN

+IN

210kΩ

210kΩ

52.5kΩ

52.5kΩ

AD8235

C3

B3

A1

D1

ESD

PROTECTION

ESD

PROTECTION

A3

D3

B1

SDN

A2

C1

NC B2

NC D2

ESD

PROTECTION

ESD

PROTECTION

ESD

PROTECTION

OP AMP

A

OP AMP

B

ESD

PROTECTION

TOP VIEW

(BALL SIDE DOWN)

Not to Scale

Figure 1.

PIN CONFIGURATION

BALL A1

INDICATOR

SDN

–IN

RG

REF

NC

RG

NC

NC = NO CONNECT

+IN

1

A

B

C

D

23

Figure 2. 11-Ball WLCSP (CB-11-1)

1.0

2.0

4.0

3.0

0.5

1.5

3.5

2.5

0

OUTPUT VOLTAGE (V)

5.0

4.5

5.5

5.0

0.5

–0.5

1.5 2.0

3.0

4.0

4.5

0

1.0

2.5

3.5

G = 5

G = 5

Figure 3. Wide Common-Mode Voltage Range vs. Output Voltage