Analog Devices AD22055 Datasheet

Single Supply Bridge

a

FEATURES
Gain of 400. Alterable from 40 to 1000
Output Span 20 mV to (VS – 0.25) V
1 Pole Low-Pass Filtering Available
Offset Capability
Differential Input Resistance 230 kV
Drives 1 kV Load to +4 V Using V
Supply Voltage: +3 V to +36 V
Transient Spike Protection and RFI Filters Included
Peak Input Voltage (40 ms): 60 V
Reversed Supply Protection: –34 V
Operating Temperature Range: –408C to +1258C

APPLICATIONS
Interface for Pressure Transducers, Position

Indicator, Strain Gages and Other Low Level Signal
Sources

= +5 V

S

Transducer Amplifier

FUNCTIONAL BLOCK DIAGRAM

IN+
IN–

AD22055

8
1

+V

S

6

A1

OFS

7

2

GND

FILT

3

A2

AD22055

OUT

5

4

GAIN

GENERAL DESCRIPTION

The AD22055 accepts a differential signal from a bridge trans­ducer whose common-mode signal can be anywhere between
the power supplies.

V

REF

IN+ OFS +VSOUT

AD22055

IN– GND FILT GAIN

1234

Figure 1. Typical Application Circuit for a Pressure Sensor Interface

The extended temperature range allows for local signal condi­tioning for oil and hydraulic pressure sensors as well as other
automotive sensors.

The use of an external gain resistor allows the user to compen­sate transducer gain error and temperature drift.

+5 VOLT

OUTPUT

5678

GAIN = 400

1kΩ

ANALOG
GROUND

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Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
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Fax: [phone] © Analog Devices, Inc., 1997

AD22055–SPECIFICATIONS

(@ TA = + 258C, VS = +5 V, VCM = 0, unless otherwise noted)

Parameter Comments Test Conditions Min Typ Max Units

INPUTS (PINS 1 AND 8)

V

CM

CMRR

LF

CMRR

HF

R

INCM

R

MATCH

R

INDIFF

PREAMPLIFIER

G

CL

V

O

R

O

OUTPUT BUFFER

G

CL

V

O

R

O

OVERALL SYSTEM

G

CL

Common-Mode Range 0 5 V
Common-Mode Rejection Ratio f ≤ 10 Hz –80 –90 dB
Common-Mode Rejection Ratio f = 10 kHz –60 –75 dB
Common-Mode Input Resistance Pin 1 or Pin 8 to Pin 2 180 230 kΩ
Matching of Input Resistances ±0.5 %
Differential Input Resistance Pin 1 to Pin 8 180 230 300 kΩ

Closed-Loop Gain
Output Voltage Range (Pin 3) +0.02 +4.75 V
Output Resistance

Closed-Loop Gain

1

2

1

R

≥ 10 kΩ 9.95 10 10.05 V/V

LOAD

77.6 80 82.4 kΩ

40 V/V

Output Voltage Range +0.02 +4.75 V
Output Resistance (Pin 5) V

1

Gain

≥ 0.1 V dc 2.0 Ω

O

V

≥ 0.1 V dc 398 400 402 V/V

O

Gain Drift –40°C to +125°C –60 ppm/°C
Gain Drift –125°C to +150°C –500 ppm/°C

V

OS

Initial Offset Voltage

3

–1 0.05 1 mV

Offset Drift –40°C to +125°C1µV/°C
Offset Drift –125°C to +150°C –10 µV/°C
Input Resistance Pin 7 to Pin 2 2.5 3.0 kΩ

I

OSC

BW

–3 dB

SR Slew Rate 0.2 V/µs
N

SD

Short-Circuit Output Current 7 11 25 mA
–3 dB Bandwidth VO = + 1 V dc 20 30 kHz

Noise Spectral Density

3

f = 100 Hz to 10 kHz 0.2 µV/√Hz

POWER SUPPLY

V

S

I

S

Operating Range TA = T
Quiescent Supply Current

4

MIN

to T

MAX

3 5 36 V

200 500 µA

TEMPERATURE RANGE

T

OP

NOTES

1

A2 gain is trimmed to ±0.5% with a 0.01% 1 kΩ resistor to ground from Pin 4. The overall gain is trimmed to a gain of 400 ±0.5% with the same 1 kΩ resistor. The
gain of A1 (the ratio of overall gain to A2 gain) is used to adjust the overall gain and, therefore, is not trimmed explicitly to 40. Note that the actual gain to a particu­lar application can be modified by the use of an external resistor at Pin 4.

2

The actual output resistance of A1 is only a few ohms, but access to this output, via Pin 3, is always through an 80 k Ω resistor, which is trimmed to ±3%.

3

Referred to the input (Pins 1 and 8).

4

With VDM = 0 V. Differential mode signals are referred to as VDM, while VCM refers to common-mode voltages.

All min and max specifications are guaranteed, although only those marked in boldface are tested on all production units at final test.
Specifications subject to change without notice.

Operating Temperature Range –40 +125 °C

–2–

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