Current Sensors Model CMR-25 Magneto-Resistive Description The CMR-25 current sensor builds on patented company technology to offer superior sensor performance and accuracy in current measuring applications. The current sensor utilizes an ASIC (Application Specific Integrated Circuit) and a magnetoresistive (MR) magnetic sensor to provide extremely low offset drift with temperature, resulting in stable, repeatable, accurate measurements. It operates from a +5V unipolar power and has an accessible internal 2.5V voltage reference. It can operate from either the internal or external voltage reference, enabling several sensors to be used without offset imbalance. Three primary pins enable the sensor to be configured for different measuring ranges and the current output signal allows different load resistors to be used depending on the application. Features Applications • Ultra low offset drift with temperature • Servo drives • Unipolar Voltage Supply • Variable speed drives • Superior global accuracy over temperature range • Frequency converters • Customer adjustable gain • Power supply systems • Customer accessible voltage reference • Over current protection • Self calibrating • Power metering • Designed for auto assembly • Uninterruptible power supplies (UPS) • Current output CMR-25 Electrical Specifications Nominal current (IN) ....................................... 25 Amp rms (1) 0 to ± 56 Amp Measuring range ........................................... 2 Measuring resistance ( ) ................................ R. min. R. max. with + 5V at ± 25 Amp rms............... 0 ohms 80 ohms at ± 40 Amp rms............... 31 ohms 0 ohms Nominal analog output current ....................... 12.5 mA rms Turns ratio .................................................... 1-2-3:2000 3 ° Overall accuracy at 25 C ( ) ........................... ± 0.24 % of IN max. 3 ° ° Overall accuracy at -40 C to +85 C ( ) ........... ± 0.32 % of IN max. Supply voltage (Vdc) ...................................... + 5 Vdc (± 5 %) Internal reference voltage .............................. + 2.5 Vdc (± 10 mV) Galvanic Isolation . . . ....................................... 5.0 kV rms / 50 Hz / 1 minute) Accuracy-Dynamic Performance ° Zero current offset at 25 C............................. < ± 30 uA (= 0.24 % of 25A) Offset current temperature drift ° ° < ± 5 uA (= 0.04 % of 25A) between +10 C and +50 C .............. ° ° < ± 10 uA (= 0.08 % of 25A) between -40 C and +85 C................ Linearity ........................................................ < ± 0.1 % Response time @ 90% ................................... better than 200 ns ................................ di/dt accurately followed greater than 100 A/us Bandwidth (-1 dB) DC to 200 kHz ........................................... General Information ° ° Operating temperature ................................... -40 C to + 85 C ° ° Storage temperature...................................... -40 C to + 90 C Current drain (plus output current) ................... 12 mA (+5V) Secondary internal resistance ......................... ° 50 ohms (at 70 C) Package ....................................................... Glass - filled Polyamide (UL94-VO) Approvals ..................................................... EN 50082-2, EN 50081-2, UL, CE Rated insulation voltage /insulation classification 400V / Reinforced Environment .................................................. Polution degree 2, category III Weight .......................................................... 20 grams Mounting ...................................................... Designed to mount directly on PCB via thru hole connect pins Output reference ........................................... To obtain a positive output on the terminal marked "O/P", current must flow in the direction of the arrow (conventional flow) Notes: 1. ac peak. Maximum dc or ac rms range is 40 amps. 2. Higher resistance (Rm) values can be used with reduced measuring range. R Specified values conditional on 70°C ambient and no power supply tolerance. 3. Excludes the effects of tolerances of reference voltage and external load resistance. 4. Due to continuous process improvements, specifications are subject to change without notice. 6120 Hanging Moss Road • Orlando, FL 32807 Phone (407) 678-6900 • Fax (407) 677-5765 • www.fwbell.com Rev. date 04/2005 Current Sensors Mechanical Dimensions All dimensions are in millimeters (inches) PIN 3 PIN 2 Vcc Model CMR-25 GND PIN 1 F.W. BELL BOTTOM CMR-25 0408 O/P VIEW EXT REF REF PIN 6 PIN 5 PIN 4 34 TYP. (1.339) 12.55±0.2 (0.494) 25.9 TYP. (1.020) including label 4±0.3 (0.157) 0.64 SQUARE TYP. 0.8 SQUARE (0.025) (0.032) SECONDARY PINS (5) PRIMARY PINS (6) 5.3 (0.209) 10.55 2.54 (0.1) (0.415) Primary Current Nominal Primary 2.54 (0.1) Output Primary Pin Connection Nom I Max I pn p 1.92 4.06 (0.16) Turns (A) (A) (mA) (0.076) 3 2 1 in 1 25 56 12.5 4 5 6 out 11.75 2.54 (0.1) 2.7 (0.463) 3 2 1 (0.106) in 2 12 27 12 out 4 5 6 2.54 (0.1) 2.54 in 2.54 (0.1) 3 2 1 (0.1) out 2.54 3 8 18 12 4 5 6 (0.1) External voltage reference mode Electrical wiring diagram primary pins power supply Internal voltage reference mode 0V +5V primary pins power supply 0V +5V 0V Output External 2.5V reference Rm load resistor voltage source Output Output 0V Rm load resistor External 2.5V reference 2.5V reference Output voltage source voltage Notes: 1. For internal 2.5V reference mode 'Ext Ref' pin must be connected to ground. 2. For external 2.5V reference voltage mode, apply voltage in the range +1.0V to 3.0V to the 'Ext Ref' pin, R 3. Housing material: Glass filled polyamide, fully encapsulated construction. 4. Due to continuous process improvement, specifications are subject to change without notice. 6120 Hanging Moss Road • Orlando, FL 32807 r Phone (407) 678-6900 • Fax (407) 677-5765 • www.fwbell.com Rev. date 04/2005