ZXCT1080 HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR Description Pin Assignments The ZXCT1080 is a high side current sense monitor with a gain of 10 and a voltage output. Using this device eliminates VCC the need to disrupt the ground plane when sensing a load current. 1 5 S- GND 2 The wide input voltage range of 60V down to as low as 3V make it suitable for a range of applications; including systems OUT 3 operating from industrial 24 to 28V rails and 48V rails. 74 S+ The separate supply pin (VCC) allows the device to continue functioning under short circuit conditions, giving an end stop voltage at the output. The ZXCT1080 has an extended ambient operating temperature range of -40°C to 125°C enabling it to be used in a wide range of applications including automotive. Features Applications • 3V to 60V continuous high side voltage • Industrial applications current measurement • Accurate high-side current sensing • Battery management • -40 to 125°C temperature range • Over-current measurement • AEC-Q100 Grade 1 qualified • Power management • Output voltage scaling x10 • Automotive current measurement • 4.5V to 12V VCC range • Low quiescent current: • o 80μA supply pin o 27μA IS+ SOT25 package Typical Application Circuit RSENSE VIN 5 4 VCC ZXCT1080 Document number: DS33454 Rev. 4 - 2 S+ 1 S- ZXCT1080 GND OUT 2 3 1 of 11 www.diodes.com VOUT December 2011 © Diodes Incorporated ZXCT1080 HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR Pin Descriptions Pin Name 1 VCC This is the analogue supply and provides power to internal circuitry Description 2 3 GND OUT 4 S+ 5 S- Ground pin Output voltage pin. NMOS source follower with 20μA bias to ground This is the positive input of the current monitor and has an input range from 60V down to 3V. The current through this pin varies with differential sense voltage This is the negative input of the current monitor and has an input range from 60V down to 3V Absolute Maximum Ratings (TA = 25°C) Parameter Continuous voltage on S- and S+ Voltage on all other pins Rating Unit -0.6 and 65 -0.6 and +14 V V Differential sense voltage, VSENSE (Note 1) 800 mV Operating temperature -40 to +125 °C Storage Temperature -55 to +150 °C 125 300 °C Maximum Junction Temperature Package Power Dissipation (Note 2) mW (@ TA = 25°C) Operation above the absolute maximum rating may cause device failure. Operation at the absolute maximum ratings, for extended periods, may reduce device reliabilty. Note: 1. VSENSE is defined as the differentail voltage between S+ and S- pins 2. Assumes θJA = 420°C/W Recommended Operating Conditions Symbol Common-mode Sense+ Input Range VCC Supply Voltage Range VSENSE Note: Parameter VIN Differential Sense Input Voltage Range Min Max Units 3 60 V 4.5 12 V 0 0.15 V VOUT Ouput Voltage Range (Note 3) 0 1.5 V TA Ambient Temperature Range -40 125 °C 3. Based on 10x VSENSE ZXCT1080 Document number: DS33454 Rev. 4 - 2 2 of 11 www.diodes.com December 2011 © Diodes Incorporated ZXCT1080 HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR Electrical Characteristics TA = 25°C, VIN = 12V, VCC = 5V, VSENSE (Note 4) = 100mV (unless otherwise specified) Symbol Parameter ICC VCC Supply Current IS+ S+ Input Current IS- S- Input Current VO(0) Zero VSENSE error (Note 4, 6) VO(10) Output Offset Voltage (Note 7) Gain ΔVOUT/ΔVSENSE (Note 4) VOUT TC (Note 8) Conditions VCC = 12V, VSENSE =0V (Note 4) TA Min (Note 5) Typ. 25°C 40 80 Full range Max Units (Note 5) 120 145 µA 25°C Full range 15 27 42 60 µA 25°C 15 40 80 nA 25°C 0 35 mV 25°C -25 +25 VSENSE = 10mV to 150mV Full range 25°C -55 9.9 +55 10.1 (Note 4) Full range 9.8 VSENSE = 0V (Note 4) VSENSE = 10mV (Note 4) VOUT variation with temperature 10 10.2 30 mV V/V ppm/°C ACC Total output error IOH Output Source Current ΔVOUT = -30mV 1 mA 20 µA -3 3 % Output Sink Current ΔVOUT = +30mV PSRR VCC Supply Rejection Ration VCC = 4.5V to 12V 54 60 dB CMRR Common-Mode Sense Rejection Ratio VIN = 60V to 3V 68 80 dB -3dB small signal bandwidth VSENSE (AC) = 10mVpp (Note 4) 500 kHz IOL BW Notes: 4. VSENSE = "VS+" - "VS-" 5. All Min and Max specifications over full temperature range are guaranteed by design and characterization 6. The ZXCT1080 operates from a positive power rail and the internal voltage-current converter current flow is unidirectional; these result in the output offset voltage for VSENSE = 0V always being positive. 7. For VSENSE > 10mV, the internal voltage-current converter is fully linear. This enables a true offset to be defined and used. VO(10) is expressed as the variance about an output voltage of 100mV> 8. Temperature dependent measurements are extracted from characterization and simulation results. ZXCT1080 Document number: DS33454 Rev. 4 - 2 3 of 11 www.diodes.com December 2011 © Diodes Incorporated ZXCT1080 HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR Typical Characteristics Test conditions unless otherwise stated:TA = 25°C, VIN = 12V, VCC = 5V, VSENSE+ = 12V, VSENSE = 100mV 70 20 IS+ INPUT CURRENT (µA) ICC, SUPPLY CURRENT (µA) TA = 125°C 65 TA = 85°C 60 T A = 25°C TA = 0°C 55 TA = -40°C TA = 125°C TA = 25°C TA = -40°C 10 VCC = 5V VSENSE = 0mV VS+ = 12V VSENSE = 0mV 50 2 15 4 6 8 10 VCC, SUPPLY VOLTAGE (V) Fig. 1 Supply Current 5 12 0 5 10 15 20 25 30 35 VS+, INPUT CURRENT (V) Fig. 2 Input Current 40 40 35 IS- SENSE CURRENT (nA) IS+ INPUT CURRENT (µA) 20 15 10 30 25 20 15 10 VCC = 5V VSENSE = 0mV T AMB = 25°C 5 5 -50 -25 0 25 50 75 100 TA, TEMPERATURE(°C) Fig. 3 Input Current 0 0 125 1.6 1.8 1.4 1.6 5 10 15 20 25 30 VS+, INPUT VOLTAGE (V) Fig. 4 Sense Current 1.2 1.0 0.8 0.6 0.4 VOUT, OUTPUT VOLTAGE (V) VOUT, OUTPUT VOLTAGE (V) VSENSE = 150mV 0.2 ZXCT1080 Document number: DS33454 Rev. 4 - 2 VCC = 5V VS+ = 12V 1.2 VSENSE = 100mV 1.0 0.8 0.6 VSENSE = 50mV 0.4 0.0 -50 4 of 11 www.diodes.com 40 1.4 0.2 0.0 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 VSENSE,SENSE VOLTAGE (V) Fig. 5 Output Voltage 35 VSENSE = 10mV -25 0 25 50 75 100 TA, TEMPERATURE (°C) Fig. 6 Output Voltage 125 December 2011 © Diodes Incorporated ZXCT1080 HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR Typical Characteristics (cont.) Test conditions unless otherwise stated:TA = 25°C, VIN = 12V, VCC = 5V, VSENSE+ = 12V, VSENSE = 100mV 0 VIN = 12V VCC = 5V VSENSE = 100mV 25 TA = 125°C -1 ΔOUTPUT VOLTAGE (mV) ΔVOUT, OUTPUT VOLTAGE (mV) 30 T A = 85°C 20 TA = 25°C TA = 0°C 15 TA = -40°C 10 5 -2 TA = -40°C -3 TA = 0°C -4 TA = 25°C -5 TA = 85°C VIN = 12V VCC = 5V VSENSE = 100mV -6 0 0 -7 0.0 5 10 15 20 25 30 IOL , OUTPUT SINK CURRENT (µA) Fig. 7 Output Current Sink T A = 125°C 0.2 0.4 0.6 0.8 1.0 1.2 1.4 IOH, OUTPUT SOURCE CURRENT (mA) Fig. 8 Output Current Source 10.1 12m ΔOUTPUT VOLTAGE (V) GAIN 10.0 9.9 9.8 9.7 0 VSENSE = 150mV 10m 8m VSENSE = 100mV VSENSE = 50mV VSENSE = 10mV 6m 4m 2m VCC = 5V TAMB = 25°C 0 50m 100m VSENSE, SENSE VOLTAGE (V) Fig. 9 Differential gain 150m 0 5 10 15 20 25 30 VS+, INPUT VOLTAGE (V) Fig. 10 Output Voltage 35 40 ΔOUTPUT VOLTAGE (V) 6m 4m 2m 0 -2m -4m 0 5 10 15 20 25 30 VS+, INPUT VOLTAGE (V) Fig. 11 Output Voltage ZXCT1080 Document number: DS33454 Rev. 4 - 2 35 40 5 of 11 www.diodes.com December 2011 © Diodes Incorporated ZXCT1080 HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR Typical Characteristics (cont.) Test conditions unless otherwise stated:TA = 25°C, VIN = 12V, VCC = 5V, VSENSE+ = 12V, VSENSE = 100mV 8 14 VIN = 12V T A = 25°C 12 6 TA = 125°C TA = 85°C 10 ΔVOUT (mV) ΔVOUT (mV) 8 4 2 T A = 25°C 6 TA = 0°C T A = -40°C 4 2 VSENSE = 10mV to 150mV 0 0 -2 VIN = 12V VSENSE = 5V -4 -2 6 8 10 VCC, SUPPLY VOLTAGE (V) Fig. 12 Normalized Output Voltage 20 1.5 15 1.0 10 VIN = 12V VCC = 5V TA = 25C VSENSE = 10mVp-p 5 1k 10k 100k 1M FREQUENCY (Mhz) Fig. 14 Small Signal Bandwidth 60 6 8 10 VCC, SUPPLY VOLTAGE (V) Fig. 13 Normalized Output Voltage 12 0.5 0.0 -2 10M VIN = 12V VIN PEAK = 60V VCC = 5V 50 0 2 4 6 8 10 12 14 TIME (µs) Fig. 15 Large Signal Pulse Response 0 2 4 1.00 RSENSE = 0.1Ω RLOAD = 30Ω VIN 40 VOLTAGE (V) VOLTAGE (V) 4 12 VOLTAGE (V) GAIN (dB) 4 30 20 0.95 VOUT 10 0.90 0 0 200 400 600 TIME (ms) Fig. 16 Load Dump Waveform ZXCT1080 Document number: DS33454 Rev. 4 - 2 -2 6 of 11 www.diodes.com 6 8 10 12 14 TIME (µs) Fig. 17 Small Signal Pulse Response December 2011 © Diodes Incorporated ZXCT1080 HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR Typical Characteristics (cont.) Test conditions unless otherwise stated:TA = 25°C, VIN = 12V, VCC = 5V, VSENSE+ = 12V, VSENSE = 100mV 70 80 70 60 50 50 PSRR (dB) CMRR (dB) 60 40 30 0 10 30 20 20 10 40 VIN = 12V VSENSE = 100mV VCC = 5V 100 1k 10k 100k FREQUENCY (Hz) Fig. 18 Common Mode Rejection ZXCT1080 Document number: DS33454 Rev. 4 - 2 10 1M 7 of 11 www.diodes.com 0 100 VIN = 12V VSENSE = 100mV VCC = 5V 1k 10k 100k FREQUENCY (Hz) Fig. 19 Supply Rejection 1M December 2011 © Diodes Incorporated ZXCT1080 HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR Application Information The ZXCT1080 has been designed to allow it to operate with 5V supply rails while sensing common mode signals up to 60V. This makes it well suited to a wide range of industrial and power supply monitoring applications that require the interface to 5V systems while sensing much higher voltages. To allow this its VCC pin can be used independently of S+. Figure 1 shows the basic configuration of the ZXCT1080. Fig. 20 Typical Configuration of ZXCT1080 Load current from the input is drawn through RSENSE developing a voltage VSENSE across the inputs of the ZXCT1080. The internal amplifier forces VSENSE across internal resistance RGT causing a current to flow through MOSFET M1. This current is then converted to a voltage by RG. A ratio of 10:1 between RG and RGT creates the fixed gain of 10. The output is then buffered by the unity gain buffer. The gain equation of the ZXCT1080 is: V OUT = IL RSENSE RG × 1 = IL x RSENSE × 10 RGT The maximum recommended differential input voltage, VSENSE, is 150mV; it will however withstand voltages up to 800mV. This can be increased further by the inclusion of a resistor, RLIM, between S- pin and the load; typical value is of the order of 10k. ZXCT1080 Document number: DS33454 Rev. 4 - 2 8 of 11 www.diodes.com December 2011 © Diodes Incorporated ZXCT1080 HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR Application Information (cont.) Fig. 21 Protection/Error Sources for ZXCT1080 Capacitor CD provides high frequency transient decoupling when used with RLIM; typical values are of the order 10pF. For best performance RSENSE should be connected as close to the S+ (and SENSE) pins; minimizing any series resistance with RSENSE. When choosing appropriate values for RSENSE a compromise must be reached between in-line signal loss (including potential power dissipation effects) and small signal accuracy. Higher values for RSENSE gives better accuracy at low load currents by reducing the inaccuracies due to internal offsets. For best operation the ZXCT1080 has been designed to operate with VSENSE of the order of 50mV to 150mV. Current monitors' basic configuration is that of a unipolar voltage to current to voltage converter powered from a single supply rail. The internal amplifier at the heart of the current monitor may well have a bipolar offset voltage but the output cannot go negative; this results in current monitors saturating at very low sense voltages. As a result of this phenomenon the ZXCT1080 has been specified to operate in a linear manner over a VSENSE range of 10mV to 150mV range, however it will still be monotonic down to VSENSE of 0V. It is for this very reason that Diodes has specified an input offset voltage (VO(10)) at 10mV. The output voltage for any VSENSE voltage from 10mV to 150mV can be calculated as follows: VOUT = (VSENSE ) × G + V (10 ) Alternatively the load current can be expressed as: IL = (VOUT − VO(10 )) GxRSENSE ZXCT1080 Document number: DS33454 Rev. 4 - 2 9 of 11 www.diodes.com December 2011 © Diodes Incorporated ZXCT1080 HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR Ordering Information Device AEC-Q100 Package Part Mark Reel Size Tape Width (mm) Quantity per Reel ZXCT1080E5TA Grade 1 SOT25 1080 7 8 3000 Package Outline Dimensions (All Dimensions in mm) SOT25 A B C H K J ZXCT1080 Document number: DS33454 Rev. 4 - 2 M N D L 10 of 11 www.diodes.com SOT25 Dim Min Max Typ A 0.35 0.50 0.38 B 1.50 1.70 1.60 C 2.70 3.00 2.80 D ⎯ ⎯ 0.95 H 2.90 3.10 3.00 J 0.013 0.10 0.05 K 1.00 1.30 1.10 L 0.35 0.55 0.40 M 0.10 0.20 0.15 N 0.70 0.80 0.75 0° 8° α ⎯ All Dimensions in mm December 2011 © Diodes Incorporated ZXCT1080 HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 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