TSC888 Low cost high-side current sense amplifier Features Independent supply and input common-mode voltages Wide common-mode operating range: 2.8 V to 24 V Wide supply voltage range: 4 to 24 V L Low current consumption: I max = 1 mA CC SOT23-5 Internally fixed gain: 20 V/V, 50 V/V or 100 V/V (Plastic package) Buffered output Pin connections Applications (top view) Desktop computers and servers SMPS Photovoltaic/solar systems Out 1 5 Vcc Battery chargers Gnd 2 Notebook computers DC motor control Vp 3 4 Vm Description The TSC888 measures a small differential voltage on a high-side shunt resistor and translates it into a ground-referenced output voltage. The gain is internally fixed. Wide input common-mode voltage range, low quiescent current, and tiny SOT23-5 packaging make the TSC888 ideal for use in a wide variety of applications. Input common-mode and power supply voltages are independent. Common-mode voltage can range from 2.8 V to 24 V in operating conditions. Current consumption lower than 1 mA and wide supply voltage range allow to connect the power supply to either side of the current measurement shunt with minimal error. June 2008 Rev 1 1/7 www.st.com 7Application schematics and pin description TSC888 1 Application schematics and pin description The TSC888 high-side current-sense amplifier features a 2.8 V to 24 V input common-mode range that is independent of supply voltage. The main advantage of this feature is to allow high-side current sensing at voltages much greater than the supply voltage (V ). The CC TSC888 can therefore be supplied by a 5 Vsb line and monitor a 3.3 V, 5 V or 12 V power line. Considering the wide supply voltage operating range (4 V to 24 V) another option available in most cases is to connect the V pin to the V pin. CC p Figure 1. Application schematics V sense I load 12V, 5V or 3.3V line Main PWM controller TSC888 Vp Vm 5Vsb Monitoring device Vcc Out Stand-by Gnd PWM controller V =V .A out sense v Table 1 describes the function of each pin. Their position is shown in the illustration on the cover page and in Figure 1 above. Table 1. Pin description Symbol Type Function The out voltage is proportional to the magnitude of the sense Out Analog output voltage V -V . p m Gnd Power supply Ground line. Vcc Power supply Positive power supply line. Connection for the external sense resistor. The measured current Vp Analog input enters the shunt on the V side. p Connection for the external sense resistor. The measured current Vm Analog input exits the shunt on the V side. m 2/7