ANALOG DEVICES AD8553 Service Manual

1.8 V to 5 V Auto-Zero, In-Amp

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FEATURES

Low offset voltage: 20 μV max Low input offset drift: 0.1 μV/°C max High CMR: 120 dB min @ G = 100 Low noise: 0.7 μV p-p from 0.01 Hz to 10 Hz Wide gain range: 0.1 to 10,000 Single-supply operation: 1.8 V to 5.5 V Rail-to-rail output Shutdown capability

APPLICATIONS

Strain gauge Weigh scales Pressure sensors Laser diode control loops Portable medical instruments Thermocouple amplifiers

with Shutdown

AD8553

PIN CONFIGURATION

RGA

1

2

VINP

VCC

VFB

AD8553

3

TOP VIEW

(Not to Scale)

VO

4

5

Figure 1. 10-Lead MSOP

10

9

8

7

6

RGB

VINN

GND

V

REF

ENABLE

05474-001

GENERAL DESCRIPTION

The AD85531 is a precision instrumentation amplifier featuring low noise, rail-to-rail output and a power-saving shutdown mode. The AD8553 also features low offset voltage and drift coupled with high common-mode rejection. In shutdown mode, the total supply current is reduced to less than 4 µA. The AD8553 is capable of operating from 1.8 V to 5.5 V.

With a low offset voltage of 20 µV, an offset voltage drift of

0.1 µV/°C, and 10 Hz), the AD8553 is ideal for applications where error sources cannot be tolerated. Precision instrumentation, position and pressure sensors, medical instrumentation, and strain gauge amplifiers benefit from the low noise, low input bias current, and high common-mode rejection. The small footprint and low cost are ideal for high volume applications.

a voltage noise of only 0.7 µV p-p (0.01 Hz to

The small package and low power consumption allow max

imum channel density and minimum board size for

space-critical equipment and portable systems.

The AD8553 is specified over the industrial temperature range

rom −40°C to +85°C. The AD8553 is available in a Pb-free,

f 10-lead MSOP.

1

Patent pending.

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.

AD8553

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REVISION HISTORY

10/05—Revision 0: Initial Version

Rev. 0 | Page 2 of 20

AD8553

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SPECIFICATIONS

ELECTRICAL CHARACTERISTICS

VCC = 5.0 V, VCM = 2.5 V, V resistor values. Temperature specifications guaranteed by characterization.

Table 1.

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Input Offset Voltage V G = 100 4 20 μV G = 10 15 50 μV G = 1 120 375 μV

vs. Temperature ΔVOS/ΔT G = 1000, −40°C ≤ TA ≤ +85°C 0.02 0.1 μV/°C G = 100, −40°C ≤ TA ≤ +85°C 0.02 0.1 μV/°C G = 10, −40°C ≤ TA ≤ +85°C 0.1 0.3 μV/°C G = 1, −40°C ≤ TA ≤ +85°C 1 3 μV/°C

Input Bias Current I

−40°C ≤ TA ≤ +85°C 2 nA

Input Offset Current I

VREF Pin Current I

Input Operating Impedance

Differential 50||1 MΩ||pF

Common Mode 10||10 GΩ||pF Input Voltage Range 0 3.3 V Common-Mode Rejection CMR G = 100, VCM = 0 V to 3.3 V, −40°C ≤ TA ≤ +85°C 120 140 dB G = 10, VCM = 0 V to 3.3 V, −40°C ≤ TA ≤ +85°C 100 120 dB Gain Error G = 100, VCM = 12.125 mV, VO = 0.075 V to 4.925 V 0.10 0.3 %

G = 10, VCM = 121.25 mV , VO = 0.075 V to 4.925 V 0.15 0.4 %

Gain Drift G = 10, 100, 1000, −40°C ≤ TA ≤ +85°C 5 25 ppm/°C G = 1, −40°C ≤ TA ≤ +85°C 30 50 ppm/°C Nonlinearity G = 100, VCM = 12.125 mV, VO = 0.075 V to 4.925 V 0.001 0.003 % FS G = 10, VCM = 121.25 mV, VO = 0.075 V to 4.925 V 0.040 0.060 % FS V

Range 0.8 4.2 V

REF

OUTPUT CHARACTERISITICS

Output Voltage High V Output Voltage Low V Short-Circuit Current I

POWER SUPPLY

Power Supply Rejection PSR G = 100, VS = 1.8 V to 5.5 V, VCM = 0 V 100 120 dB G = 10, VS = 1.8 V to 5.5 V, VCM = 0 V 90 110 dB Supply Current I

−40°C ≤ TA ≤ +85°C 1.5 mA Supply Current Shutdown Mode I

ENABLE INPUTS

Logic High Voltage 2.40 V Logic Low Voltage 0.80 V

NOISE PERFORMANCE

Voltage Noise e Voltage Noise Density e G = 10, f = 1 kHz 150 nV/√Hz Internal Clock Frequency 60 kHz Signal Bandwidth

1

Higher bandwidths result in higher noise.

1

= VCC/2, VIN = V

REF

G = 1 to 1000 1 kHz

B

OS

REF

SC

SY

SD

OS

OH

OL

n p-p

n

− V

, R

INP

INN

G = 1000 4 20 μV

0.4 1 nA

2 nA

0.01 1 nA

4.925 V

0.075 V ±35 mA

IO = 0 mA, VIN = 0 V 1.1 1.3 mA

2 4 μA

f = 0.01 Hz to 10 Hz 0.7 μV p-p G = 100, f = 1 kHz 30 nV/√Hz

= 10 kΩ, TA = 25°C, G = 100, unless specified. See Tab l e 5 for gain setting

LOAD

Rev. 0 | Page 3 of 20

AD8553

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= 1.8 V, VCM = -0 V, V

V

S

= VS/2, VIN = V

REF

INP

− V

INN

, R

= 10 kΩ, TA = 25°C, G = 100, unless specified. See Ta b le 5 for gain setting

LOAD

resistor values. Temperature specifications guaranteed by characterization.

Table 2.

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Input Offset Voltage V

OS

G = 1000 3 20 μV G = 100 3 20 μV G = 10 14 50 μV G = 1 130 375 μV Vs. Temperature ΔVOS/ΔT G = 1000, −40°C ≤ TA ≤ +85°C 0.02 0.25 μV/°C

G = 100, −40°C ≤ TA ≤ +85°C 0.02 0.25 μV/°C G = 10, −40°C ≤ TA ≤ +85°C 0.1 3 μV/°C G = 1, −40°C ≤ TA ≤ +85°C 1 10 μV/°C

Input Bias Current I

B

0.05 1 nA

−40°C ≤ TA ≤ +85°C 2 nA Input Offset Current I VREF Pin Current I

OS

REF

2 nA

0.02 1 nA Input Operating Impedance Differential 50||1 MΩ||pF Common Mode 10||10 GΩ||pF

Input Voltage Range 0 0.15 V Common-Mode Rejection CMR G = 100, VCM = 0 V to 0.15 V, −40°C ≤ TA ≤ +85°C 100 110 dB G = 10, VCM = 0 V to 0.15 V, −40°C ≤ TA ≤ +85°C 90 110 dB Gain Error G = 100, VCM =4.125 mV, VO = 0.075 V to 1.725 V 0.2 0.4 %

G = 10, VCM = 41.25 mV, VO = 0.075 V to 1.725 V 0.2 0.4 %

Gain Drift G = 10, 100, 1000, −40°C ≤ TA ≤ +85°C 25 ppm/°C G = 1, −40°C ≤ TA ≤ +85°C 50 ppm/°C Nonlinearity G = 100, VCM = 4.125 mV, VO = 0.075 V to 1.725 V 0.003 % FS G = 10, VCM = 41.25 mV, VO = 0.075 V to 1.725 V 0.010 % FS V

Range 0.8 1.0 V

REF

OUTPUT CHARACTERISITICS

Output Voltage High V Output Voltage Low V Short-Circuit Current I

OH

OL

SC

1.725 V

0.075 V

±5 mA

POWER SUPPLY

Power Supply Rejection PSR G = 100, VS = 1.8 V to 5.5 V, VCM = 0 V 100 120 dB Supply Current I

SY

IO = 0 mA, VIN = 0 V 0.8 1.2 mA

−40°C ≤ TA ≤ +85°C 1.4 mA Supply Current Shutdown Mode I

SD

2 4 μA

ENABLE INPUTS

Logic High Voltage 1.4 V Logic Low Voltage 0.5 V

NOISE PERFORMANCE

Voltage Noise e Voltage Noise Density e

n p-p

n

f = 0.01 Hz to 10 Hz 0.7 μV p-p

G = 100, f = 1 kHz 30 nV/√Hz G = 10, f = 1 kHz 150 nV/√Hz Internal Clock Frequency 60 kHz Signal Bandwidth

1

Higher bandwidths result in higher noise.

1

G = 1 to 1000 1 kHz

Rev. 0 | Page 4 of 20

AD8553

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ABSOLUTE MAXIMUM RATINGS

Table 3.

Parameter Ratings

Supply Voltage 6 V Input Voltage +V Differential Input Voltage Output Short-Circuit Duration to GND Indefinite Storage Temperature Range (RM Package) −65°C to +150°C Operating Temperature Range −40°C to +85°C Junction Temperature Range (RM Package) −65°C to +150°C Lead Temperature Range (Soldering, 10 sec) 300°C

1

Differential input voltage is limited to ±5.0 V, the supply voltage, or

whichever is less.

1

±V

SUPPLY

Stresses above those listed under Absolute Maximum Ratings may 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

θ JA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages.

Table 4.

Package Type θ

10-Lead MSOP (RM) 110 32.2 °C/W

1

θJA is specified for the nominal conditions, that is, θJA is specified for the

device soldered on a circuit board.

1

JA

θ

JC

Unit

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.

Rev. 0 | Page 5 of 20

AD8553

√

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TYPICAL PERFORMANCE CHARACTERISTICS

TA = 25°C, G = 100, unless specified, see Tab l e 5 for gain setting resistor values. Filters as noted are the combination of R2/C2 and R3/C3 as in Figure 31.

80

GAIN = 1000

60

VCC = 1.8V AND 5V FILTER = 1kHz

80

GAIN = 1000

60

VCC = 1.8V AND 5V FILTER = 10kHz

GAIN = 100

40

GAIN = 10

20

GAIN (dB)

GAIN = 1

0

–20

–40

10 100 1k 10k 100k

FREQUENCY ( Hz)

Figure 2. Gain vs. Frequency

180

VCC = 5V FILTER = 1kHz

160

GAIN = 100

140

GAIN = 10

120

GAIN = 1

100

CMR (dB)

80

60

40

20

10 100 1k 10k 100k

FREQUENCY ( Hz)

Figure 3. Common-Mode Rejection (CMR) vs. Frequency

160

GAIN = 100

140

GAIN = 10

120

GAIN = 1

100

80

PSR (dB)

60

40

GAIN = 100

40

GAIN = 10

20

GAIN (dB)

GAIN = 1

0

–20

05474-002

–40

10 100 1k 10k 100k

FREQUENCY ( Hz)

05474-003

Figure 5. Gain vs. Frequency

180

VCC = 5V FILTER = 10kHz

160

GAIN = 100

140

GAIN = 10

120

GAIN = 1

100

CMR (dB)

80

60

40

05474-004

20

10 100 1k 10k 100k

FREQUENCY ( Hz)

05474-005

Figure 6. Common-Mode Rejection (CMR) vs. Frequency

10k

GAIN = 1

1k

Hz)

100

NOISE (nV/

10

GAIN = 10

GAIN = 100, 1000

20

FILTE R = 10kHz FILTER = 1kHz

10

10 100 1k 10k 100k

FREQUENCY (Hz)

Figure 4. Power Supply Rejection vs. Frequency

VCC=5VAND1.8V

05474-006

1

0.01 1001010.1 1k 10k 100k

Figure 7. Voltage Noise Density

Rev. 0 | Page 6 of 20

FREQUENCY (Hz)

05474-007

ANALOG DEVICES AD8553 Service Manual

FEATURES

APPLICATIONS

PIN CONFIGURATION

GENERAL DESCRIPTION

TABLE OF CONTENTS

REVISION HISTORY

SPECIFICATIONS

ELECTRICAL CHARACTERISTICS

ABSOLUTE MAXIMUM RATINGS

THERMAL RESISTANCE

ESD CAUTION

TYPICAL PERFORMANCE CHARACTERISTICS