ZXCT1030 High-side current monitor with comparator Description The ZXCT1030 is a high side current sense monitor containing an internal reference and comparator with a non-latching output. Using this device eliminates the need to disrupt the ground plane when sensing a load current. The wide input voltage range of 20V down to as low as 2.2V make it suitable for a range of applications. Dynamics and supply current are optimized for the processing of fast pulses, associated with switch mode applications. Features Applications • Low cost, accurate high-side current sensing • Battery chargers • Output voltage scaling • Electronic fuse • Up to 18V output • DC motor control • 2.2V - 20V supply range • Over current monitor • Voltage reference on chip • Power management • Comparator on chip • Inrush current limiting • SO8 package Typical application circuit Ordering information Device Status Package Device marking Reel size (inches) Tape width (mm) Quantity per reel ZXCT1030X8TA Last time buy MSOP8 ZXCT1030 7 12 1000 ZXCT1030N8TA Active SO8 ZXCT1030 7 12 500 Issue 3 - June 2007 © Zetex Semiconductors plc 2007 1 www.zetex.com ZXCT1030 Absolute maximum ratings Voltage on any pin Operating temperature Storage temperature Package power dissipation MSOP8 -0.6V and VCC +0.6V -40 to 85°C -55 to 125°C (Tamb = 25°C) 500mW Recommended operating conditions Parameter VCC VSENSE+ VSENSE(a) VOUT Vcomp-in Tamb Min. 2.2 2.2 10 Max. 20 VCC 500 Unit V V mV 0 0.005 -40 VSENSE-1V 10 85 V V °C Pin-out connections VCC VSENSEVSENSE+ GND Issue 3 - June 2007 © Zetex Semiconductors plc 2007 Vcomp_out VOUT Vref_out Vcomp_in Pin name VCC Function Supply voltage VSENSE- Negative sense input VSENSE+ Positive sense input GND Vcomp_in Vref_out VOUT Ground Comparator input, usually a ratio of the reference or other control signal Reference output Current monitor output voltage Vcomp_out Open collector comparator output 2 www.zetex.com ZXCT1030 Electrical characteristics (ZXCT1030X8) - Test conditions Tamb = 25°C, VIN = VCC = 15V, Rcomp = 10kV, Vcomp_supply = 5V unless otherwise stated. Symbol Parameter Conditions VCC VSENSE+ VOUT VCC range Sense+ range Output voltage Output resistance VOUT temperature coefficient Supply current VSENSE+ input current VSENSE- input current (b) Minimum active common VCM(min) mode voltage ROUT VOUT TC ICC ISENSE+ ISENSE- ACC Gain BW Accuracy VOUT /VSENSE Bandwidth VSENSE = 0V VSENSE = 10mV VSENSE = 30mV VSENSE = 50mV VSENSE = 100mV VSENSE = 500mV VSENSE- = 15V, VOUT = 1V VSENSE- = 15V VSENSE- = 14.9V VCC =15V Vcomp_supply = 5V Vcomp_in = VREF VSENSE = 10mV VSENSE =100mV VSENSE = 100mV VSENSE =10mVp-p VSENSE = 100mVp-p Comparator Input voltage Vcomp_in VH Hysteresis Input bias IB Propagation delay TD VOL Output voltage low Output voltage high VOH Min. 2.2 2.2 0 88 284 480 970 4500 1.2 170 25 25 2.8 -3 9.7 Limits Typ. 2 100 300 500 1000 5000 1.5 30 270 48 70 10.0 3 6 0.005 5 30 Unit Max. 20 VCC 10 112 316 520 1030 5500 1.8 V mV mV mV mV mV mV k⍀ ppm/°C 350 90 220 µA µA nA V 3 10.3 % MHz MHz 10 15 80 100 150 V mV 150 nA ns 200 mV Vcomp_ V supply Output sink current Output high leakage current Voltage reference Vref IOL IOH delta Vref TC PSR Change in Vref VOL = 0.4V 2 1.0 Reference current = +300A to -5A Isource 5A to Isink 300A 1.200 1.240 10 30 0.01 Supply rejection mA µA 1.280 V mV ppm/°C %/V NOTES: (a) VSENSE = (VSENSE+) - (VSENSE-) (b) Level of VSENSE+ where comparator output defaults to 'off'. Issue 3 - June 2007 © Zetex Semiconductors plc 2007 3 www.zetex.com ZXCT1030 Electrical characteristics (ZXCT1030N8) - Test conditions Tamb = 25°C, VIN = VCC = 15V, Rcomp = 10kV, Vcomp_supply = 5V unless otherwise stated. Symbol Parameter Conditions VCC VSENSE+ VOUT VCC range Sense+ range Output voltage Output resistance VOUT temperature coefficient Supply current VSENSE+ input current VSENSE- input current (b) Minimum active common VCM(min) mode voltage ROUT VOUT TC ICC ISENSE+ ISENSE- ACC Gain BW Accuracy VOUT /VSENSE Bandwidth VSENSE = 0V VSENSE = 10mV VSENSE = 30mV VSENSE = 50mV VSENSE = 100mV VSENSE = 500mV VSENSE- = 15V, VOUT = 1V Min. 2.2 2.2 0 88 284 480 970 4500 1.2 VSENSE- = 15V 170 VSENSE- = 14.9V VCC =15V Vcomp_supply = 5V Vcomp_in = VREF VSENSE = 10mV VSENSE =100mV VSENSE = 100mV VSENSE =10mVp-p VSENSE = 100mVp-p Comparator Input voltage Vcomp_in VH Hysteresis Input bias IB Propagation delay TD VOL Output voltage low Output voltage high VOH Limits Typ. 2 100 300 500 1000 5000 1.5 30 270 48 70 Unit Max. 20 VCC 10 112 316 520 1030 5500 1.8 10.0 3 6 0.005 5 30 mV mV mV mV mV mV k⍀ ppm/°C 350 90 220 µA µA nA V 3 10.3 % 2.8 -3 9.7 V MHz MHz 10 15 80 100 150 V mV 150 nA ns 200 mV Vcomp_ V supply Output sink current Output high leakage current Voltage reference Vref IOL IOH delta Vref TC PSR Change in Vref VOL = 0.4V 2 1.0 Reference current = +300A to -5A Isource 5A to Isink 300A 1.200 1.240 10 30 0.01 Supply rejection mA µA 1.280 V mV ppm/°C %/V NOTES: (c) VSENSE = (VSENSE+) - (VSENSE-) (d) Level of VSENSE+ where comparator output defaults to 'off'. Issue 3 - June 2007 © Zetex Semiconductors plc 2007 4 www.zetex.com ZXCT1030 Typical characteristics Issue 3 - June 2007 © Zetex Semiconductors plc 2007 5 www.zetex.com ZXCT1030 Voltage output current monitor Referring to the block diagram, the current monitor takes the small voltage developed across the sense resistor (VSENSE) and transfers it from the large common mode supply voltage to a groundreferenced signal with a gain of 10. The sense input common mode range is 2.2V to 20V. In this range, a linear output voltage is delivered. Reference The bandgap reference allows the comparator to compare the translated Vsense with threshold value chosen by the user which can be any voltage from 0 to 1.24V, configured by two external resistors which forms Vcomp_in. The output current which can be drawn from the comparator reference (Iref source) is limited to 5µA, making potentiometers ⱖ250k⍀ suitable for setting a threshold level. Where a lower potentiometer resistor value is used, an additional resistor value should be inserted between Vref and VCC to maintain sufficient current for the reference. (as shown in Figure 1). Figure 1: External resistor for reference level The voltage reference has a maximum current sink capability. This magnitude of current will be influenced by the value of R1 which is inserted between Vref and VCC. The value of current flowing through R1 can be expressed as: I = (VCC -Vref) / R1 Comparator The open collector output is active low and is asserted when VSENSE x 10 (VOUT) > Vcomp_in. It can be connected to any voltage rail up to Vin via a pull-up resistor. Suggest values for the resistor are in the range of 10-100k⍀. In the case where high load currents or a short circuit occurs, thus reducing the common mode signals (V+, V-) typically below 2.2V, the comparator will default to the asserted state. This can eliminate a closed loop system 'latch-up' condition, allowing the controller to remove the applied power. Stability To ensure stable operation of the ZXCT1030, it is recommended a decoupling capacitor is placed across the VCC and ground connections. A ceramic 10F will be adequate. Issue 3 - June 2007 © Zetex Semiconductors plc 2007 6 www.zetex.com ZXCT1030 Intentionally left blank Issue 3 - June 2007 © Zetex Semiconductors plc 2007 7 www.zetex.com ZXCT1030 Package outline - SO8 DIM Inches Millimeters DIM Inches Min. Millimeters Min. Max. Min. Max. Max. A 0.053 0.069 1.35 1.75 e A1 0.004 0.010 0.10 0.25 b 0.013 0.020 0.33 0.51 D 0.189 0.197 4.80 5.00 c 0.008 0.010 0.19 0.25 H 0.228 0.244 5.80 6.20 ⍜ 0° 8° 0° 8° E 0.150 0.157 3.80 4.00 h 0.010 0.020 0.25 0.50 L 0.016 0.050 0.40 1.27 - - - - - 0.050 BSC Min. Max. 1.27 BSC Note: Controlling dimensions are in inches. Approximate dimensions are provided in millimeters Issue 3 - June 2007 © Zetex Semiconductors plc 2007 8 www.zetex.com ZXCT1030 Package outline - MSOP8 c e E E1 R1 D L R A2 b A A1 DIM A A1 A2 b c D E E1 e L R R1 Millimeters Min. 0.05 0.75 0.25 0.13 2.90 Inches Max. 1.10 0.15 0.95 0.40 0.23 3.10 Min. 0.002 0.0295 0.010 0.005 0.114 4.90 BSC 2.90 0.193 BSC 3.10 0.114 0.65 BSC 0.40 0.07 0.07 Max. 0.0433 0.006 0.0374 0.0157 0.009 0.122 0.122 0.025 BSC 0.70 - 0.0157 0.0027 0.0027 0.0192 - Note: Controlling dimensions are in millimeters. Approximate dimensions are provided in inches Issue 3 - June 2007 © Zetex Semiconductors plc 2007 9 www.zetex.com ZXCT1030 Definitions Product change Zetex Semiconductors reserves the right to alter, without notice, specifications, design, price or conditions of supply of any product or service. Customers are solely responsible for obtaining the latest relevant information before placing orders. Applications disclaimer The circuits in this design/application note are offered as design ideas. It is the responsibility of the user to ensure that the circuit is fit for the user’s application and meets with the user’s requirements. No representation or warranty is given and no liability whatsoever is assumed by Zetex with respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise. Zetex does not assume any legal responsibility or will not be held legally liable (whether in contract, tort (including negligence), breach of statutory duty, restriction or otherwise) for any damages, loss of profit, business, contract, opportunity or consequential loss in the use of these circuit applications, under any circumstances. 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Samples may be available “Active” Product status recommended for new designs “Last time buy (LTB)” Device will be discontinued and last time buy period and delivery is in effect “Not recommended for new designs” Device is still in production to support existing designs and production “Obsolete” Production has been discontinued Datasheet status key: “Draft version” This term denotes a very early datasheet version and contains highly provisional information, which may change in any manner without notice. “Provisional version” This term denotes a pre-release datasheet. It provides a clear indication of anticipated performance. However, changes to the test conditions and specifications may occur, at any time and without notice. “Issue” This term denotes an issued datasheet containing finalized specifications. However, changes to specifications may occur, at any time and without notice. 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