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 ■ Low current consumption: ICC max = 1 mA ■ Internally fixed gain: 20 V/V, 50 V/V or 100 V/V ■ Buffered output L SOT23-5 (Plastic package) Pin connections (top view) Applications ■ Desktop computers and servers SMPS ■ Photovoltaic/solar systems ■ Battery chargers ■ Notebook computers ■ DC motor control Out 1 5 Vcc Gnd 2 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 7 Application schematics and pin description 1 TSC888 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 (VCC). The 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 VCC pin to the Vp pin. Figure 1. Application schematics Vsense Iload 12V, 5V or 3.3V line Main PWM controller 5Vsb Vp Vm TSC888 Out Vcc Stand-by PWM controller Monitoring device Gnd Vout=Vsense.Av 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. 2/7 Pin description Symbol Type Function Out Analog output The out voltage is proportional to the magnitude of the sense voltage Vp-Vm. Gnd Power supply Ground line. Vcc Power supply Positive power supply line. Vp Analog input Connection for the external sense resistor. The measured current enters the shunt on the Vp side. Vm Analog input Connection for the external sense resistor. The measured current exits the shunt on the Vm side. TSC888 2 Absolute maximum ratings and operating conditions Absolute maximum ratings and operating conditions Table 2. Absolute maximum ratings Symbol Vid Vin Parameter Input pins differential voltage (Vp-Vm) Input pin voltages (Vp, Vm) (1) (1) Value Unit ±2 V -0.3 to 30 V -0.3 to 25 V VCC DC supply voltage Vout DC output pin voltage(1) -0.3 to Vcc V Tstg Storage temperature -55 to 150 °C Maximum junction temperature 150 °C SOT23-5 thermal resistance junction to ambient 250 °C/W 1 kV 100 V Tj Rthja Human body model (HBM)(2) ESD Machine model (MM) (3) 1. Voltage values are measured with respect to the Gnd pin. 2. Human body model: 100 pF discharged through a 1.5kΩ resistor between two pins of the device, done for all couples of pin combinations with other pins floating. 3. Machine model: a 200 pF cap is charged to the specified voltage, then discharged directly between two pins of the device with no external series resistor (internal resistor < 5 Ω), done for all couples of pin combinations with other pins floating. Table 3. Symbol Operating conditions Parameter Value Unit VCC DC supply voltage from Tmin to Tmax 4.0 to 24 V Toper Operational temperature range (Tmin to Tmax) -40 to 85 °C Vicm Common mode operating range 2.8 to 24 V 3/7 Electrical characteristics 3 TSC888 Electrical characteristics The electrical characteristics given in the following tables are measured under the following test conditions unless otherwise specified: Tamb=25°C, Vcc=5V, Vsense=Vp-Vm=50mV, Vm=12V, no load on Out Table 4. Supply Symbol ICC Table 5. Parameter Total supply current Min. Typ. Vsense = 0 Max. Unit 1 mA Max. Unit Input Symbol Parameter Test conditions Min. Typ. CMR DC common mode rejection Variation of Vout versus Vicm referred to input 2.8V< Vicm < 24V Vsense= 30mV 95 dB SVR Supply voltage rejection Variation of Vout versus Vcc referred to input 4.0V< VCC < 24V Vsense= 30mV 95 dB Ilk Input leakage current Vcc=0V Iib Input bias current Vsense=0V Table 6. Av ΔVout 5.5 1 µA 8 µA Output Symbol Parameter Gain Test conditions Min. TSC888A TSC888B TSC888C Typ. Max. 20 50 100 Total output voltage accuracy Unit V/V ±6 % Short-circuit current OUT connected to VCC or GND VOH Output stage high-state saturation voltage VOH=VCC-Vout Vsense=1V Iout=1mA 0.8 1 V VOL Output stage low-state saturation voltage Vsense=-1V Iout=1mA 50 100 mV Isc 4/7 Test conditions 2 mA TSC888 4 Package information Package information In order to meet environmental requirements, STMicroelectronics offers these devices in ECOPACK® packages. These packages have a lead-free second level interconnect. The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an STMicroelectronics trademark. ECOPACK specifications are available at: www.st.com. Figure 2. SOT23-5 package mechanical drawing Table 7. SOT23-5 package mechanical data Dimensions Ref. Millimeters Min. Typ. Mils Max. Min. Typ. Max. A 0.90 1.45 35.4 57.1 A1 0.00 0.15 0.00 5.9 A2 0.90 1.30 35.4 51.2 b 0.35 0.50 13.7 19.7 C 0.09 0.20 3.5 7.8 D 2.80 3.00 110.2 118.1 E 2.60 3.00 102.3 118.1 E1 1.50 1.75 59.0 68.8 e 0.95 37.4 e1 1.9 74.8 L 0.35 0.55 13.7 21.6 5/7 Ordering information TSC888 5 Ordering information Table 8. Order codes Order code Temperature range Package Packaging TSC888AILT TSC888BILT -40°C, +85°C SOT23-5 Tape & reel TSC888CILT 6 Revision history Table 9. Document revision history Date Revision 26-Jun-2008 Rev 1 6/7 Changes Initial release. Marking Gain O111 20 O112 50 O113 100 TSC888 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. 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