Analog Devices 1B51BN, 1B51AN Datasheet

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Isolated mV/Thermocouple

Signal Conditioner

 

 

 

 

 

1B51

 

 

 

 

FEATURES

FUNCTIONAL BLOCK DIAGRAM

 

Functionally Complete Precision Conditioner

 

 

High Accuracy

 

 

Low Input Offset Tempco: 60.1 mV/8C

 

 

Low Nonlinearity: 60.025%

 

 

High CMR: 160 dB (60 Hz, G = 1000 V/V)

 

 

High CMV Isolation: 1500 V rms Continuous

 

 

240 V rms Input Protection

 

 

Small Package: 1.0" 3 2.1" 3 0.35" DIP

 

 

Isolated Power

 

 

Low-Pass Filter (fC = 3 Hz)

 

 

Pin Compatible with 1B41 Isolated RTD Conditioner

 

 

APPLICATIONS

 

 

Multichannel Thermocouple Temperature

 

 

Measurement

 

 

Low Level Data Acquisition Systems

 

 

Industrial Measurement & Control Systems

 

GENERAL DESCRIPTION

The 1B51 is a precision, mV/thermocouple signal conditioner that incorporates a circuit design utilizing transformer based isolation and automated surface mount manufacturing technology. It provides an unbeatable combination of versatility and performance in a compact plastic package. Designed for measurement and control applications, it is specially suited for harsh environments with extremely high common-mode interference. Unlike costlier solutions that require separate dc/dc converters, each 1B51 generates its own input side power, providing true, low cost channel-to-channel isolation.

Functionally, the signal conditioner consists of three basic sections: chopper stabilized amplifier, isolation and output filter. The chopper amplifier features a highly stable offset tempco of

±0.1 μV/°C and resistor programmable gains from 2 to 1000. Wide range zero suppression can be implemented at this stage.

The isolation section has complete input to output galvanic isolation of 1500 V rms continuous using transformer coupling techniques. Isolated power of 2 mA at ±6.2 V is provided for ancillary circuits such as zero suppression and open-input detection. Filtering at 3 Hz is implemented by a passive antialiasing filter at the front end and a two-pole active filter at the output.

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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 otherwise under any patent or patent rights of Analog Devices.

Overall NMR is 60 dB and CMR is 160 dB min @ 60 Hz, G = 1000.

The 1B51 is specified over –25°C to +85°C and operates over the industrial (–40°C to +85°C) temperature range.

DESIGN FEATURES AND USER BENEFITS

High Noise Rejection: The combination of a chopper stabilized front end with a low-pass filter provides high system accuracy in harsh industrial environments as well as excellent rejection of 50 Hz/60 Hz noise.

Input Protection: The input is internally protected against continuous application of 240 V rms.

Low Cost: The 1B51 offers a very low cost per channel for high performance, isolated, low level signal conditioners.

Wide Range Zero Suppression: This input referred function is a convenient way to null large input offsets.

Low-Pass Filter: The three pole active filter (fC = 3 Hz) reduces 60 Hz noise and aliasing errors.

Small Size: The 1B51 package size (1.0" × 2.1" × 0.35") and functional completeness make it an excellent choice in systems with limited board space and clearance.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 617/329-4700 Fax: 617/326-8703

Analog Devices 1B51BN, 1B51AN Datasheet

1B51–SPECIFICATIONS (typical at +258C and VS = 615 V unless otherwise noted)

Model

1B51AN

 

 

1B51BN

 

 

 

 

 

 

GAIN

 

 

 

 

 

 

é

 

RFB

ù

 

Gain Equation

G = ê1+

 

 

ú × 2

*

 

R

 

ë

 

G

û

 

Gain Error

1% max

 

 

*

Gain Temperature Coefficient1

50 ppm/°C

 

*

Gain Nonlinearity

± 0.035% (± 0.05% max)

±0.025% (±0.04% max)

 

 

 

 

 

 

OFFSET VOLTAGES

 

 

 

 

 

Input Offset Voltage

25 μV (100 μV max)

 

Initial, @ +25°C (Adjustable to Zero)

*

vs. Temperature

± 0.1 μV/°C (±0.5 μV/°C max)

*

vs. Time, Noncumulative

± 1 μV/month max

*

Output Offset Voltage

 

 

 

 

 

Initial

–50 mV

 

 

–25 mV

vs. Temperature

–175 μV/°C

 

–50 μV/°C

 

 

 

 

 

 

INPUT OFFSET CURRENT

 

 

 

 

 

Initial

0.6 nA (2.5 nA max)

*

vs. Temperature

± 2.5 pA/°C (12.5 pA/°C max)

*

 

 

 

 

 

 

INPUT BIAS CURRENT

 

 

 

 

 

Initial @ +25°C

10 nA

 

 

*

vs. Temperature

10 pA/°C

 

*

 

 

 

 

 

 

INPUT IMPEDANCE

50 MΩ

 

 

 

Power On

 

 

*

Power Off

40 kΩ min

 

*

 

 

 

 

 

 

INPUT VOLTAGE RANGE

± 10 mV to ± 5 V

 

Linear Differential Input

*

Max CMV, Input to Output

 

 

 

 

 

AC, 60 Hz, Continuous

1500 V rms

 

*

Continuous, DC

± 2000 V

 

 

*

CMR @ 60 Hz, 1 kΩ Source Imbalance, G = 1000

160 dB min

 

*

NMR @ 60 Hz

60 dB min

 

*

Transient Protection

IEEE-STD 472 (SWC)

*

 

 

 

 

 

 

INPUT NOISE

1 μV p-p

 

 

 

Voltage, 0.1 Hz to 10 Hz, 1 kΩ Source Imbalance

 

 

*

 

 

 

 

 

 

RATED OUTPUT

± 10 V

 

 

 

Voltage, 2 kΩ Load, min

 

 

*

Current

± 5 mA

 

 

*

Output Noise, DC to 100 kHz

1 mV p-p

 

*

Impedance, DC

0.1 Ω

 

 

*

 

 

 

 

 

 

FREQUENCY RESPONSE

 

 

 

 

 

Bandwidth, –3 dB

dc to 3 Hz

 

*

 

 

 

 

 

 

ISOLATED POWER

± 6.2 V ±5%

 

 

Voltage, No Load

 

*

Current

2 mA

 

 

*

Regulation, No Load to Full Load

7.5%

 

 

 

*

Ripple

250 mV p-p

 

*

 

 

 

 

 

 

POWER SUPPLY

± 15 V dc

 

 

 

Voltage, Rated Performance

 

 

*

Voltage, Operating

± 13.5 V to ± 18 V

*

Current, Quiescent

+12 mA @ +15 V, –4 mA @ –15 V

*

PSRR

0.1%/V

 

 

*

 

 

 

 

 

 

ENVIRONMENTAL

 

 

 

 

 

Temperature Range

–25°C to +85°C

 

Rated Performance

*

Operating

–40°C to +85°C

*

Storage

–40°C to +85°C

*

Relative Humidity

0 to 95%, @ +60°C

*

CASE SIZE

1.00" × 2.10" × 0.35"

*

 

(25.4 × 53.3 × 8.9) mm

 

 

 

 

 

 

 

NOTES

•Specifications same as 1B51AN. 1See graph in text.

Specifications subject to change without notice.

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

PIN DESIGNATIONS

Pin Designation

1HI

2PROT HI

4ICOM

5LO

16+15 V

17–15 V

22VO

23GND

34–VISO

35+VISO

37GAIN

38FB

–2–

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