ANALOG DEVICES AD8228 Service Manual

Low Gain Drift

+

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FEATURES

Easy to use Pin strappable gains of 10 and 100 Wide power supply range: ±2.3 V to ±18 V DC specifications (B Grade, G = 10)

2 ppm/°C gain drift

0.02% gain error 50 μV maximum input offset voltage

0.8 μV/°C maximum input offset drift

0.6 nA maximum input bias current 100 dB CMRR

AC specifications

650 kHz, –3 dB bandwidth (G = 10) 2 V/μs slew rate

Low noise

8 nV/√Hz, @ 1 kHz (G = 100)

0.3 μV p-p from 0.1 Hz to 10 Hz (G = 100)

APPLICATIONS

Weigh scales Industrial process controls Bridge amplifiers Precision data acquisition systems Medical instrumentation Strain gages Transducer interfaces

GENERAL DESCRIPTION

The AD8228 is a high performance instrumentation amplifier with very high gain accuracy. Because all gain setting resistors are internal and laser trimmed, gain accuracy and gain drift are better than can be achieved with typical instrumentation amplifiers.

Low voltage offset, low offset drift, low gain drift, high gain acc

uracy, and high CMRR make this part an excellent choice in applications that demand the best dc performance possible, such as bridge signal conditioning.

Precision Instrumentation Amplifier

AD8228

CONNECTION DIAGRAM

1

–IN

2

G1

3

G2

4

IN

AD8228

TOP VIEW

(Not to Scale)

Figure 1.

Table 1. Instrumentation Amplifiers by Category

General Purpose

Zero Drift

Military Grade

AD82201 AD82311 AD620 AD6271 AD8250 AD8221 AD85531 AD621 AD6231 AD8251 AD8222 AD85551 AD524 AD8253 AD82241 AD85561 AD526 AD8228 AD85571 AD624

1

Rail-to-rail output.

The AD8228 operates on both single and dual supplies. Because

he part can operate on supplies up to ±18 V, it is well suited for

t applications where high common-mode input voltages are encountered. The AD8228 is available in 8-lead MSOP and SOIC packages.

Performance is specified over the entire industrial temperature

nge of −40°C to +85°C for all grades. Furthermore, the AD8228

ra is operational from −40°C to +125°C. For a pin-compatible amplifier with similar specifications, but with a gain range of 1 to 1000, see the

AD8221.

8

+V

7

V

OUT

6

REF

5

–V

Low Power

S

07035-001

High Speed PGA

Rev. 0

Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners.

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REVISION HISTORY

7/08—Revision 0: Initial Version

Rev. 0 | Page 2 of 24

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SPECIFICATIONS

GAIN = 10

VS = ±15 V, V

Table 2.

Conditions A Grade B Grade Parameter (Gain = 10) Min Typ Max Min Typ Max Unit

COMMON-MODE REJECTION RATIO

CMRR DC to 60 Hz with 1 kΩ

Source Imbalance

CMRR at 2 kHz VCM = −10 V to +10 V 90 100 dB

NOISE

Voltage Noise f = 1 kHz 15 15 nV/√Hz f = 0.1 Hz to 10 Hz 0.5 0.5 μV p-p Current Noise f = 1 kHz 40 40 fA/√Hz

f = 0.1 Hz to 10 Hz 6 6 pA p-p

VOLTAGE OFFSET Referred to input,

Offset 90 50 μV

Over Temperature T = −40°C to +85°C 180 100 μV Average TC T = −40°C to +85°C 1.5 0.8 μV/°C

Offset vs. Supply (PSR) 104 120 106 120 dB

INPUT CURRENT

Input Bias Current 0.5 1.5 0.4 0.6 nA

Over Temperature T = −40°C to +85°C 2.0 1 nA Average TC T = −40°C to +85°C 1 1 pA/°C

Input Offset Current 0.2 0.6 0.1 0.4 nA

Over Temperature T = −40°C to +85°C 0.8 0.6 nA Average TC T = −40°C to +85°C 1 1 pA/°C

REFERENCE INPUT

RIN 20 20 kΩ IIN V Voltage Range −VS +VS −VS +VS V Gain to Output 1 ± 0.0001 1 ± 0.0001 V/V

DYNAMIC RESPONSE

Small Signal −3 dB Bandwidth 650 650 kHz Settling Time 0.01% 10 V step 6 6 μs Settling Time 0.001% 10 V step 9 9 μs Slew Rate 2 2.5 2 2.5 V/μs

GAIN V

Gain Error 0.07 0.02 % Gain Nonlinearity

RL = 10 kΩ 3 10 3 10 ppm RL = 2 kΩ 3 10 3 10 ppm

Gain vs. Temperature 1 10 1 2 ppm/°C

INPUT

Input Impedance

Differential 100||2 100||2 GΩ||pF Common Mode 100||2 100||2 GΩ||pF

Input Operating Voltage Range

Over Temperature T = −40°C to +85°C −VS + 2.0 +VS − 1.2 −VS + 2.0 +VS − 1.2 V

Input Operating Voltage Range1 VS = ±5 V to ±18 V −VS + 1.9 +VS − 1.2 −VS + 1.9 +VS − 1.2 V

Over Temperature T = −40°C to +85°C −VS + 2.0 +VS − 1.2 −VS + 2.0 +VS − 1.2 V

= 0 V, TA = 25°C, RL = 2 kΩ, all specifications referred to input, unless otherwise noted.

REF

VCM = −10 V to +10 V 94 100 dB

V

= V

IN+

= ±5 V to ±15 V

V

S

= V

IN+

= −10 V to +10 V

OUT

1

VS = ±2.3 V to ±5 V −VS + 1.9 +VS − 1.1 −VS + 1.9 +VS − 1.1 V

= 0 V

IN−

REF

= V

= 0 V 50 60 50 60 μA

IN−

REF

Rev. 0 | Page 3 of 24

AD8228

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Conditions A Grade B Grade Parameter (Gain = 10) Min Typ Max Min Typ Max Unit

OUTPUT RL = 10 kΩ

Output Swing VS = ±2.3 V to ±5 V −VS + 1.1 +VS − 1.2 −VS + 1.1 +VS − 1.2 V

Over Temperature T = −40°C to +85°C −VS + 1.4 +Vs − 1.3 −VS + 1.4 +VS − 1.3 V

Output Swing VS = ±5 V to ±18 V −VS + 1.2 +VS − 1.4 −VS + 1.2 +VS − 1.4 V

Over Temperature T = –40°C to +85°C −VS + 1.6 +VS − 1.5 −VS + 1.6 +VS − 1.5 V

Short-Circuit Current 18 18 mA

POWER SUPPLY

Operating Range VS = ±2.3 V to ±18 V ±2.3 ±18 ±2.3 ±18 V Quiescent Current 0.85 1 0.85 1 mA

Over Temperature T = −40°C to +85°C 1 1.2 1 1.2 mA

TEMPERATURE RANGE

Specified Performance −40 +85 −40 +85 °C Operating Range

1

Operating near the input voltage range limit may reduce the available output range. See Figure 10 and Figure 11 for the input common-mode range vs. output

voltage.

2

See the Typical Performance Characteristics section for expected operation between 85°C to 125°C.

2

−40 +125 −40 +125 °C

Rev. 0 | Page 4 of 24

AD8228

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GAIN = 100

VS = ±15 V, V

Table 3.

Conditions A Grade B Grade Parameter (Gain = 100) Min Typ Max Min Typ Max Unit

COMMON-MODE REJECTION RATIO

CMRR DC to 60 Hz with 1 kΩ

Source Imbalance

CMRR at 2 kHz VCM = −10 V to +10 V 100 105 dB

NOISE

Voltage Noise f = 1 kHz 8 8 nV/√Hz f = 0.1 Hz to 10 Hz 0.3 0.3 μV p-p Current Noise f = 1 kHz 40 40 fA/√Hz

f = 0.1 Hz to 10 Hz 6 6 pA p-p

VOLTAGE OFFSET Referred to input,

Offset 90 50 μV

Over Temperature T = −40°C to +85°C 140 80 μV Average TC T = −40°C to +85°C 0.9 0.5 μV/°C

Offset vs. Supply (PSR) 118 140 124 140 dB

INPUT CURRENT

Input Bias Current 0.5 1.5 0.4 0.6 nA

Over Temperature T = −40°C to +85°C 2.0 1 nA Average TC T = −40°C to +85°C 1 1 pA/°C

Input Offset Current 0.2 0.6 0.1 0.4 nA

Over Temperature T = −40°C to +85°C 0.8 0.6 nA Average TC T = −40°C to +85°C 1 1 pA/°C

REFERENCE INPUT

RIN 20 20 kΩ IIN V Voltage Range −VS +VS −VS +VS V Gain to Output 1 ± 0.0001 1 ± 0.0001 V/V

DYNAMIC RESPONSE

Small Signal −3 dB Bandwidth 110 110 kHz Settling Time 0.01% 10 V step 13 13 μs Settling Time 0.001% 10 V step 15 15 μs Slew Rate 2 2.5 2 2.5 V/μs

GAIN V

Gain Error 0.1 0.05 % Gain Nonlinearity

RL = 10 kΩ 5 15 5 15 ppm RL = 2 kΩ 15 45 15 45 ppm

Gain vs. Temperature 1 10 1 2 ppm/°C

INPUT

Input Impedance

Differential 100||2 100||2 GΩ||pF Common Mode 100||2 100||2 GΩ||pF

Input Operating Voltage Range1 VS = ±2.3 V to ±5 V −VS + 1.9 +VS − 1.1 −VS + 1.9 +VS − 1.1 V

Over Temperature T = −40°C to +85°C −VS + 2.0 +VS − 1.2 −VS + 2.0 +VS − 1.2 V

Input Operating Voltage Range1

Over Temperature T =−40°C to +85°C −VS + 2.0 +VS − 1.2 −VS + 2.0 +VS − 1.2 V

= 0 V, TA = 25°C, RL = 2 kΩ, all specifications referred to input, unless otherwise noted.

REF

VCM = −10 V to +10 V 114 120 dB

V

= V

IN+

= ±5 V to ±15 V

V

S

= V

IN+

= −10 V to +10 V

OUT

= ±5 V to ±18 V −VS + 1.9 +VS − 1.2 −VS + 1.9 +VS − 1.2 V

V

S

= 0 V

IN−

REF

= V

= 0 V 50 60 50 60 μA

IN−

REF

Rev. 0 | Page 5 of 24

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Conditions A Grade B Grade Parameter (Gain = 100) Min Typ Max Min Typ Max Unit

OUTPUT RL = 10 kΩ

Output Swing VS = ±2.3 V to ±5 V −VS + 1.1 +VS − 1.2 −VS + 1.1 +VS − 1.2 V

Over Temperature T = −40°C to +85°C −VS + 1.4 +Vs − 1.3 −VS + 1.4 +VS − 1.3 V

Output Swing VS = ±5 V to ±18 V −VS + 1.2 +VS − 1.4 −VS + 1.2 +VS − 1.4 V

Over Temperature T = −40°C to +85°C −VS + 1.6 +VS − 1.5 −VS + 1.6 +VS − 1.5 V

Short-Circuit Current 18 18 mA

POWER SUPPLY

Operating Range VS = ±2.3 V to ±18 V ±2.3 ±18 ±2.3 ±18 V Quiescent Current 0.85 1 0.85 1 mA

Over Temperature T = −40°C to +85°C 1 1.2 1 1.2 mA

TEMPERATURE RANGE

Specified Performance −40 +85 −40 +85 °C Operating Range

1

Operating near the input voltage range limit may reduce the available output range. See Figure 12 and Figure 13 for the input common-mode range vs. output

voltage.

2

See the Typical Performance Characteristics section for expected operation between 85°C to 125°C.

2

−40 +125 −40 +125 °C

Rev. 0 | Page 6 of 24

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ABSOLUTE MAXIMUM RATINGS

Table 4.

Parameter Rating

Supply Voltage ±18 V Output Short-Circuit Current Indefinite Input Voltage (Common Mode) ±VS Differential Input Voltage ±VS Storage Temperature Range −65°C to +150°C Operating Temperature Range1 −40°C to +125°C Maximum Junction Temperature 140°C ESD

Human Body Model 2 kV Charge Device Model 1 kV

1

Temperature range for specified performance is −40°C to +85°C. See the

Typical Performance Characteristics section for expected operation from 85°C to 125°C.

Stresses above those listed under Absolute Maximum Ratings ma

y cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

THERMAL RESISTANCE

θJA is specified for a device in free air.

Table 5.

Package θJA Unit

8-Lead MSOP, 4-Layer JEDEC Board 135 °C/W 8-Lead SOIC, 4-Layer JEDEC Board 121 °C/W

ESD CAUTION

Rev. 0 | Page 7 of 24

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PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

1

–IN

2

G1

3

G2

4

+IN

AD8228

TOP VIEW

(Not to Scale)

Figure 2. Pin Configuration

8

+V

S

7

V

OUT

6

REF

5

–V

S

07035-004

Table 6. Pin Function Descriptions

Pin No. Mnemonic Description

1 −IN Negative Input. 2, 3 G1, G2 Gain Pins. Short together for a gain of 100. Leave unconnected for a gain of 10. 4 +IN Positive Input. 5 −VS Negative Supply. 6 REF Reference. 7 V

Output.

OUT

8 +VS Positive Supply.

Rev. 0 | Page 8 of 24

ANALOG DEVICES AD8228 Service Manual

FEATURES

APPLICATIONS

GENERAL DESCRIPTION

CONNECTION DIAGRAM

TABLE OF CONTENTS

REVISION HISTORY

SPECIFICATIONS

GAIN = 10

GAIN = 100

ABSOLUTE MAXIMUM RATINGS

THERMAL RESISTANCE

ESD CAUTION

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS