ZXCT1050E5TA

ZXCT1050 Precision wide input range current monitor Description The ZXCT1050 is a wide input range current monitor, which operates over a range of input voltages from ground up to VCC-2V. As a result the ZXCT1050 can be used on the high or low side of the load. The very low offset voltage enables a typical accuracy of 1% for sense voltages of only 30mV, giving better tolerances for small sense resistors necessary at higher currents. The ZXCT1050 provides variable gain by using two external resistors. The first of which sets the transconductance and the second setting the overall gain. Features Applications • Accurate down to end current sensing • Power supply • Output voltage scaling x10 • DC motor and solenoid control • 0 to VCC-2V sense input range • Battery management • 2.7 to 20V supply range • Over current monitor • 50µA quiescent current • Power management • SOT23-5 package • Short circuit detection Pin connections VCC 1 Typical application circuit 5 RSENSE IN SENSE- RSHUNT GND 2 SENSE+ OUT 3 4 SENSE+ VCC SENSE- ZXCT1050 Load OUT OUT RGAIN Ordering information Order code ZXCT1050E5TA Pack Part mark Reel size (inches) Tape width (mm) Quantity per reel SOT23-5 1050 7 8 3000 Issue 1 - June 2007 © Zetex Semiconductors plc 2007 1 www.zetex.com ZXCT1050 Absolute maximum ratings VCC max. 20V Voltage on SENSE- and SENSE+ -0.6 to VCC Voltage on all other pins -0.6V and VCC +0.6V VSENSE = ‘(VSENSE+) - (VSENSE-)’ 500mV Operating temperature -40 to 125°C Storage temperature -55 to 150°C Maximum junction temperature 150°C Package power dissipation 300mW* at TA = 25°C (De-rate to zero for TJ = 150°C) Operation above the absolute maximum rating may cause device failure. Operation at the absolute maximum ratings, for extended periods, may reduce device reliability. Recommended operating conditions VSENSE+ Parameter Common-mode sense input range Min. 0 Max. VCC-2 VCC Supply voltage range 2.7 20 Units V V VSENSE Differential sense input voltage range 10 300 mV VOUT Output voltage range 0 VCC-2 V TA Ambient temperature range -40 125 °C Recommended resistor gain setting combinations Gain RSH RG 10 20 50 100 20 50 100 7.5k⍀ 7.5k⍀ 7.5k⍀ 7.5k⍀ 3.75k⍀ 1.5k⍀ 750⍀ 3.75k⍀ 7.5k⍀ 18.7k⍀ 37.5k⍀ 3.75k⍀ 3.75k⍀ 3.75k⍀ Pin function table PIN 1 Name VCC Description This is the analog supply and provides power to internal circuitry. 2 3 GND OUT 4 SENSE+ Ground pin. Output pin. A resistor, RGAIN, connected from this pin pin down to ground develops an output voltage. This is the positive input of the current monitor and has an input range from 0V up to VCC – 2V. 5 SENSE- This is the negative input of the current monitor and has an input range from 0V up to VCC – 2V. The current through this pin varies with differential sense voltage. A resistor, RSHUNT, from this pin to the rail being sensed set the transconductance of the current monitor. Issue 1 - June 2007 © Zetex Semiconductors plc 2007 2 www.zetex.com ZXCT1050 Electrical characteristics Test conditions TA = 25°C, VSENSE+ = 10V, VCC = 12V, VSENSE = 100mV, RSH = 7.5k⍀, RG = 3.75k⍀. Symbol Parameter Conditions Min. Typ. Max. IQ VCC pin current VSENSE = 0V VOUT Output voltage VSENSE = 0V =30mV =100mV =150mV 45 70 µA 3 300 1.00 1.50 15 315 1.03 1.55 mV mV V V ISENSE+ VSENSE+ input current VSENSE = 0V 60 150 nA ISENSE- VSENSE- input current VSENSE = 0V 15 150 nA VOUT TC VOUT variation with temperature 300 ppm/°C Gain VOUT/VSENSE Accuracy Total output error BW Bandwidth 0 285 0.97 1.45 See note (*) Units 10 -3 VSENSE(DC) = 10mV VSENSE(AC) = 10mVPP CL = 5pF, VSENSE(DC) = 100mV 3 % 300 kHz 0.8 MHz PSRR Power supply rejection ratio VCC = 2.7V to 20V VSENSE+ = 0.7V 60 dB CMRR Common mode rejection ratio VCC = 20V VSENSE+ = 0 to 18V 70 dB NOTES: (*) Temperature dependent measurements are extracted from characterisation and simulation results. Issue 1 - June 2007 © Zetex Semiconductors plc 2007 3 www.zetex.com ZXCT1050 Typical characteristics ICC Supply Current (A) ICC Supply Current (A) RG = 3.75k⍀, RSH = 7.5k⍀ unless otherwise stated. Supply Current v Input Voltage IS- Sense Current (A) ICC Supply Current (A) Supply Current v Supply Voltage Sense- Current v Supply Voltage IS- Sense Current (A) Percentage Change IS- (%) Supply Current v Sense Voltage Sense- Current v Temperature Issue 1 - June 2007 © Zetex Semiconductors plc 2007 Sense- Current v Sense Voltage 4 www.zetex.com ZXCT1050 Typical characteristics 10 1 ΔVOUT Output Voltage (mV) VOUT - Output Voltage (V) RG = 3.75k⍀, RSH = 7.5k⍀ unless otherwise stated. 100m 10m 1E-3 0.01 0.1 5 0 -5 -40 -20 0 20 40 60 80 100 120 Temperature Characteristic 10.1 Incremental Gain VOUT - Output Voltage (mV) 1100 1050 1000 950 900 -20 -15 -10 -5 0 5 10 μ 15 10.0 9.9 20 18 16 14 12 10 8 6 4 2 0 -2 -4 -6 -8 0 2 4 6 8 10 12 14 16 18 20 Common Mode Characteristic Issue 1 - June 2007 © Zetex Semiconductors plc 2007 50m 100m 150m Incremental Gain v Sense Voltage ΔVOUT - Output Voltage (mV) ΔVOUT - Output Voltage (mV) VOUT v Load Current 0 12 8 4 0 -4 -8 -12 0 5 10 15 20 Supply Characteristic 5 www.zetex.com ZXCT1050 Typical characteristics RG = 3.75k⍀, RSH = 7.5k⍀ unless otherwise stated. Referred to 1V Issue 1 - June 2007 © Zetex Semiconductors plc 2007 6 www.zetex.com ZXCT1050 Applications information The ZXCT1050 is a current output version of the ZXCT1051 and as such uses a separate power supply pin. All biasing for the internal amplifiers comes from its separate VCC input and is not ‘line powered’, unlike the ZXCT1021. This means that at very small sense voltages the ZXCT1050 draws very little current (