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Isolated mV/Thermocouple |
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Signal Conditioner |
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1B51 |
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FEATURES |
FUNCTIONAL BLOCK DIAGRAM |
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Functionally Complete Precision Conditioner |
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High Accuracy |
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Low Input Offset Tempco: 60.1 mV/8C |
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Low Nonlinearity: 60.025% |
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High CMR: 160 dB (60 Hz, G = 1000 V/V) |
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High CMV Isolation: 1500 V rms Continuous |
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240 V rms Input Protection |
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Small Package: 1.0" 3 2.1" 3 0.35" DIP |
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Isolated Power |
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Low-Pass Filter (fC = 3 Hz) |
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Pin Compatible with 1B41 Isolated RTD Conditioner |
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APPLICATIONS |
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Multichannel Thermocouple Temperature |
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Measurement |
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Low Level Data Acquisition Systems |
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Industrial Measurement & Control Systems |
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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.
REV. A
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.
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
1B51–SPECIFICATIONS (typical at +258C and VS = 615 V unless otherwise noted)
Model |
1B51AN |
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1B51BN |
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GAIN |
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RFB |
ù |
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Gain Equation |
G = ê1+ |
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ú × 2 |
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G |
û |
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Gain Error |
1% max |
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Gain Temperature Coefficient1 |
50 ppm/°C |
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Gain Nonlinearity |
± 0.035% (± 0.05% max) |
±0.025% (±0.04% max) |
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OFFSET VOLTAGES |
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Input Offset Voltage |
25 μV (100 μV max) |
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Initial, @ +25°C (Adjustable to Zero) |
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vs. Temperature |
± 0.1 μV/°C (±0.5 μV/°C max) |
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vs. Time, Noncumulative |
± 1 μV/month max |
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Output Offset Voltage |
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Initial |
–50 mV |
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–25 mV |
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vs. Temperature |
–175 μV/°C |
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–50 μV/°C |
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INPUT OFFSET CURRENT |
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Initial |
0.6 nA (2.5 nA max) |
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vs. Temperature |
± 2.5 pA/°C (12.5 pA/°C max) |
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INPUT BIAS CURRENT |
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Initial @ +25°C |
10 nA |
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vs. Temperature |
10 pA/°C |
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INPUT IMPEDANCE |
50 MΩ |
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Power On |
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Power Off |
40 kΩ min |
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INPUT VOLTAGE RANGE |
± 10 mV to ± 5 V |
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Linear Differential Input |
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Max CMV, Input to Output |
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AC, 60 Hz, Continuous |
1500 V rms |
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Continuous, DC |
± 2000 V |
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CMR @ 60 Hz, 1 kΩ Source Imbalance, G = 1000 |
160 dB min |
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NMR @ 60 Hz |
60 dB min |
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Transient Protection |
IEEE-STD 472 (SWC) |
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INPUT NOISE |
1 μV p-p |
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Voltage, 0.1 Hz to 10 Hz, 1 kΩ Source Imbalance |
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RATED OUTPUT |
± 10 V |
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Voltage, 2 kΩ Load, min |
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Current |
± 5 mA |
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Output Noise, DC to 100 kHz |
1 mV p-p |
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Impedance, DC |
0.1 Ω |
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FREQUENCY RESPONSE |
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Bandwidth, –3 dB |
dc to 3 Hz |
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ISOLATED POWER |
± 6.2 V ±5% |
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Voltage, No Load |
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Current |
2 mA |
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Regulation, No Load to Full Load |
7.5% |
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Ripple |
250 mV p-p |
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POWER SUPPLY |
± 15 V dc |
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Voltage, Rated Performance |
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Voltage, Operating |
± 13.5 V to ± 18 V |
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Current, Quiescent |
+12 mA @ +15 V, –4 mA @ –15 V |
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PSRR |
0.1%/V |
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ENVIRONMENTAL |
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Temperature Range |
–25°C to +85°C |
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Rated Performance |
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Operating |
–40°C to +85°C |
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Storage |
–40°C to +85°C |
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Relative Humidity |
0 to 95%, @ +60°C |
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CASE SIZE |
1.00" × 2.10" × 0.35" |
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(25.4 × 53.3 × 8.9) mm |
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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– |
REV. A |