ZXCT1023 MICROPOWER FIXED GAIN OF 50 CURRENT MONITOR Description Pin Assignments The ZXCT1023 is a precision high-side current sense monitor. Using this type of device eliminates the need to disrupt the ground plane when sensing a load current. TDFN1218-4L The ZXCT1023 has a fixed internal gain of 50 and the only external component required is the external current sense resistor; this combined with its 1.2mm x 1.8mm TDFN package more than quarters the solution size of the ZXCT1010. OUT 1 4 S+ GND 2 3 STop View The wide input voltage range of 20V down to as low as 2.5V makes it suitable for a range of applications. The combination of operation down to 2.5V and just 3.5µA quiescent current makes it ideal for single cell Li-Ion/polymer battery charge/discharge measurement applications. Features Applications • • • • • • • • Accurate high-side current sensing Fixed gain of 50 output scaling 2.5V – 20V operating range 3.5µA quiescent current TDFN1218 package Battery capacity measurement Battery chargers Over-current monitor Typical Application Circuit S+ RS S- RGT – + VOUT RG ZXCT1023 Document number: DS31997 Rev. 3 - 2 GND 1 of 8 www.diodes.com June 2011 © Diodes Incorporated ZXCT1023 MICROPOWER FIXED GAIN OF 50 CURRENT MONITOR Pin Descriptions Pin Name Pin Number 1 OUT 2 3 4 GND SS+ Central Paddle Description Voltage output. The output voltage is referenced to GND. The overall voltage gain is 50, i.e., VOUT = 50 x VSENSE where VSENSE = VS+ - VSGround and substrate connection of device High impedence negative sense voltage input Positive sense input. Also acts as power supply pin to ZXCT1023 Substrate. Connect to GND Absolute Maximum Ratings Description Rating Unit -0.5 to 20 V Voltage on S- (Note 1, 2), OUT(Note 1) -0.5 VS++0.5 V VSENSE (Note 3) -0.5 to +2.5 V Junction Temperature Storage Temperature -40 to 125 -55 to 150 °C °C Voltage on S+ (Note 1) Package Power Dissipation (TA = 25°C) TDFN1218 ESD Ratings mW Human Body Model Machine Model 2000 150 V V These are stress ratings only. Operation outside the absolute maximum ratings may cause device failure. Operation at the absolute maximum rating for extended periods may reduce device reliability. Semiconductor devices are ESD sensitive and may be damaged by exposure to ESD events. Suitable ESD precautions should be taken when handling and transporting these devices. Notes: 1. Measured with respect to GND pin 2. Subject to absolute maximum VSENSE not being exceeded. 3. VSENSE is defined as the voltage difference across the sense resistor, RS. 4. The usable VSENSE range is limited by the output voltage range; and as such will be reduced at lower VS+ values. Recommended Operating Conditions (TA = 25°C) Symbol VS+ (Note 1) VSENSE VOUT TA Parameter Max Unit 2.5 20 V Differential Sense Input Voltage Range 0 380 (Note 4) mV Output Voltage Range 0 VS- - 1 V -40 85 °C Common-Mode Sense Input Range Ambient Temperature Range ZXCT1023 Document number: DS31997 Rev. 3 - 2 2 of 8 www.diodes.com Min June 2011 © Diodes Incorporated ZXCT1023 MICROPOWER FIXED GAIN OF 50 CURRENT MONITOR Electrical Characteristics (TA = 25°C, VS+ = 3.6V, VSENSE = 50mV, unless otherwise stated) Symbol Min. Limits Typ. 0.3 50 425 500 575 VSENSE = 30mV 1.41 1.5 1.59 VSENSE = 50mV 2.425 2.5 2.575 VSENSE = 100mV, VS+ = 20V 4.85 5 5.15 50 300 ppm/°C 8 μA 100 nA Parameter Conditions VSENSE = 0mV VSENSE = 10mV VOUT TC (Note 5) Output voltage Output voltage temperature coefficient IQ Ground pin current VSENSE = 0V IS- SENSE- input current VSENSE = 0V 3.5 Acc Accuracy VSENSE = 50mV Gain VOUT/VSENSE VSENSE = 50mV ROUT Output resistance BW PSRR (Note 6) Notes 5. 6. Bandwidth -3 Max. 3 Unit mV V % 50 V/V 15 kΩ VSENSE (DC) = 10mV 300 kHz VSENSE (DC) = 50mV 1 MHz 60 dB Power supply rejection ratio VSENSE = 30mV, VS+ = 2.5 to 20V 50 TC limits are determined by characterization. PSRR is defined as change in output voltage per change in S+ voltage, VS+. ZXCT1023 Document number: DS31997 Rev. 3 - 2 3 of 8 www.diodes.com June 2011 © Diodes Incorporated ZXCT1023 MICROPOWER FIXED GAIN OF 50 CURRENT MONITOR Typical DC Characteristics 2.5 3% VSENSE = 0V, VS+ = 3.6V TA = 85°C TA = -40°C Differential Gain Error 2 IS+ (µA) TA = 0°C 1.5 TA = 85°C 1 2% TA = -40°C 1% TA = 25°C 0% TA = 0°C -1% 0.5 -2% 0 2 4 6 8 10 12 14 16 18 0 20 10 20 30 VSENSE (mV) VS+ (V) S+ Input Current vs. Supply voltage 40 3.5 TA = 0°C VS+ = 3.6V TA = 85°C VS+ = 3.6V -40°C 3 TA = 25°C 60 25°C 50 50 Normalised Gain Error vs. Sense Voltage 2.5 VOUT (V) Differential Gain (ΔVOUT/ΔVSENSE) 70 85°C TA = 0°C 2 TA = -40°C 1.5 40 1 30 0.5 0 20 0 2 4 6 8 0 10 10 20 VSENSE (mV) Differential Gain vs. Sense Voltage 30 VSENSE (mV) 40 50 60 Output Voltage vs. Sense Voltage 0.6% 3 TA = 25°C VSENSE = 50mV 2.5 VS+ =3.6V w.r.t. VOUT at 25°C VSENSE = 10mV, 30mV, 50mV 0.4% 10mV 2 0.2% VSENSE = 30mV 1.5 1 ΔVOUT %Error VOUT (V) Vs+ = 3.6v Relative to gain = 50 30mV 0.0% 50mV 50mV 30mV -0.2% VSENSE = 10mV 0.5 -0.4% 0 2 4 6 8 10 12 14 16 18 20 -0.6% -40 VS+ (V) Output Voltage vs. Input voltage ZXCT1023 Document number: DS31997 Rev. 3 - 2 -15 10 35 Temperature (°C) 60 85 Relative Output Voltage Change vs. Temperature 4 of 8 www.diodes.com June 2011 © Diodes Incorporated ZXCT1023 MICROPOWER FIXED GAIN OF 50 CURRENT MONITOR Typical AC Characteristics 70 40 VSENSE = 50mV 30 VS+=3.6V TA =25°C 50 PSRR (dB) VSENSE = 10mV 10 0 40 VS+ = 10V 30 VS+ = 20 -10 10 100E+0 1E+3 10E+3 100E+3 frequency (Hz) 1E+6 0 0.01 10E+ Small Signal Frequency Response VS+=3.6V, TA = 25°C VSENSE = 50mV 1 50 2.5 0.8 40 2.0 0.6 Output 0.4 5 30 3.0 1.5 Input 20 1.0 Output 10 0.5 0 0.0 0.2 0 0 50 100 -5 150 200 0 300 250 -10 0 -0.2 Time (µs) 50 Large Signal Pulse Response 20mV 2.75 50 2.50 49 2.45 2.65 52 2.60 2.55 Output 50 49 0 50 100 time (µs) 150 Document number: DS31997 Rev. 3 - 2 2.55 48 2.40 Input 47 2.35 46 2.50 45 2.45 200 44 Small Signal Positive Pulse Response ZXCT1023 VSENSE (mV) 53 VS+=3.6V, TA =25°C VSENSE = 50mV(DC) - 5mV pulse 51 2.70 Input 51 -0.5 200 150 2.80 Output voltage (V) 55 54 100 Time (µs) Large Signal Pulse Response 50mV VS+=3.6V, TA =25°C VSENSE = 50mV(DC) + 5mV 56 Sense voltage (mV) 1000 60 Input (mV) Input (mV) 15 10 100 1.2 Output (V) 20 Input 1 10 Frequency (kHz) Power Supply Rejection Ratio VS+=3.6V, TA = 25°C VSENSE = 20mV 25 0.1 Output (V) -20 10E+0 Output VOUT (V) Gain (dB) 20 TA = 25°C VSENSE = 50mV 60 2.30 2.25 0 25 50 75 time (µs) 100 125 2.20 150 Small Signal Negative Pulse Response 5 of 8 www.diodes.com June 2011 © Diodes Incorporated ZXCT1023 MICROPOWER FIXED GAIN OF 50 CURRENT MONITOR Application Information The ZXCT1023 is line powered (derives its power from the rail being sensed) this reduces the number of pins used and PCB trace routing. The fixed gain of 50 reduces the PCB area by reducing the number of external components. The only external component required is the sense resistor. This coupled with the 1.2mm x 1.8mm TDFN package makes the solution size very small. The ZXCT1023 has its gain setting resistor, RG, set at 15kΩ which further reduces power consumption at larger VSENSE. Application Examples Please refer to Zetex AN39 for sample applications. The fixed gain of 50 has been chosen to meet the normal requirements of most applications. S+ RS S- RGT – + VOUT RG GND Ordering Information Order Reference Package Device Marking Status Reel Size (inches) Quantity Per Reel Tape Width (mm) ZXCT1023DFGTA TDFN1218 23 Active 7 3000 8 ZXCT1023 Document number: DS31997 Rev. 3 - 2 6 of 8 www.diodes.com June 2011 © Diodes Incorporated ZXCT1023 MICROPOWER FIXED GAIN OF 50 CURRENT MONITOR Package Outline Dimensions (All Dimensions in mm) TDFN1218-4 Recommended PCB Land Pattern ZXCT1023 Document number: DS31997 Rev. 3 - 2 7 of 8 www.diodes.com June 2011 © Diodes Incorporated ZXCT1023 MICROPOWER FIXED GAIN OF 50 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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