TSC888

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 Pin connections (top view) L SOT23-5 (Plastic package) Applications ■ ■ ■ ■ ■ Desktop computers and servers SMPS Photovoltaic/solar systems Battery chargers Notebook computers DC motor control Gnd 2 Vp 3 4 Vm Out 1 5 Vcc 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 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 (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 Vcc Out Monitoring device Stand-by PWM controller 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. Symbol Out Gnd Vcc Vp Vm Pin description Type Analog output Power supply Power supply Analog input Analog input Function The out voltage is proportional to the magnitude of the sense voltage Vp-Vm. Ground line. Positive power supply line. Connection for the external sense resistor. The measured current enters the shunt on the Vp side. Connection for the external sense resistor. The measured current exits the shunt on the Vm side. 2/7 TSC888 Absolute maximum ratings and operating conditions 2 Absolute maximum ratings and operating conditions Table 2. Symbol Vid Vin VCC Vout Tstg Tj Rthja ESD Machine model (MM) Absolute maximum ratings Parameter Input pins differential voltage (Vp-Vm) Input pin voltages (Vp, Vm) DC supply voltage (1) (1) Value ±2 -0.3 to 30 -0.3 to 25 -0.3 to Vcc -55 to 150 150 250 1 100 Unit V V V V °C °C °C/W kV V DC output pin voltage(1) Storage temperature Maximum junction temperature SOT23-5 thermal resistance junction to ambient Human body model (HBM)(2) (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 VCC Toper Vicm Operating conditions Parameter DC supply voltage from Tmin to Tmax Operational temperature range (Tmin to Tmax) Common mode operating range Value 4.0 to 24 -40 to 85 2.8 to 24 Unit V °C V 3/7 Electrical characteristics TSC888 3 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. Symbol ICC Supply Parameter Total supply current Test conditions Vsense = 0 Min. Typ. Max. 1 Unit mA Table 5. Symbol Input Parameter DC common mode rejection Variation of Vout versus Vicm referred to input Supply voltage rejection Variation of Vout versus Vcc referred to input Input leakage current Input bias current Test conditions 2.8V< Vicm < 24V Vsense= 30mV 4.0V< VCC < 24V Vsense= 30mV Vcc=0V Vsense=0V 5.5 Min. Typ. Max. Unit CMR 95 dB SVR Ilk Iib 95 1 8 dB µA µA Table 6. Symbol Av ΔVout Isc Output Parameter Gain Total output voltage accuracy Short-circuit current Output stage high-state saturation voltage VOH=VCC-Vout Output stage low-state saturation voltage OUT connected to VCC or GND Vsense=1V Iout=1mA Vsense=-1V Iout=1mA 2 Test conditions TSC888A TSC888B TSC888C Min. Typ. 20 50 100 ±6 Max. Unit V/V % mA VOH 0.8 1 V VOL 50 100 mV 4/7 TSC888 Package information 4 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. Min. A A1 A2 b C D E E1 e e1 L 0.35 0.90 0.00 0.90 0.35 0.09 2.80 2.60 1.50 Millimeters Typ. Max. 1.45 0.15 1.30 0.50 0.20 3.00 3.00 1.75 0.95 1.9 0.55 13.7 Min. 35.4 0.00 35.4 13.7 3.5 110.2 102.3 59.0 Mils Typ. Max. 57.1 5.9 51.2 19.7 7.8 118.1 118.1 68.8 37.4 74.8 21.6 5/7 Ordering information TSC888 5 Table 8. Ordering information Order codes Temperature range Package Packaging Marking O111 -40°C, +85°C SOT23-5 Tape & reel O112 O113 Order code TSC888AILT TSC888BILT TSC888CILT Gain 20 50 100 6 Table 9. Date Revision history Document revision history Revision Rev 1 Initial release. Changes 26-Jun-2008 6/7 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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