STEVAL-ISQ014V1 Low-side current sensing evaluation board based on the TSZ121 op amp Data brief Description The STEVAL-ISQ014V1 product evaluation board implements low-side current sensing which consists in placing a sense resistor between the load and the circuit ground. The resulting voltage drop is amplified using a TSZ121 op amp. The common mode voltage is close to ground, whatever the voltage of the power source, so the current sense voltage can be amplified by this low voltage op amp without restriction. The circuit offers very stable electrical characteristics over the entire supply voltage range and is particularly suited for automotive and industrial applications. Features • Very high accuracy: offset voltage 5 µV max at 25 °C, 8 µV over full temperature range (-40 °C to 125 °C) • Rail-to-rail input and output Thanks to the highly accurate TSZ121 op amp, precise current measurements can be made through your application without the added cost of high-precision resistors. • Low supply voltage: 1.8 - 5.5 V • Low power consumption: 40 µA max. at 5 V • Gain bandwidth product: 400 kHz • High tolerance to ESD: 4 kV HBM • Extended temperature range: -40 to +125 °C • Micro-packages: SC70-5 (TSZ121), DFN8 2x2 (TSZ122), and QFN16 3x3 (TSZ124) • RoHS compliant May 2014 DocID026324 Rev 1 For further information contact your local STMicroelectronics sales office. 1/4 www.st.com Schematic diagram 1 STEVAL-ISQ014V1 Schematic diagram Figure 1. STEVAL-ISQ014V1 circuit schematic Rf2 47k In Vccp C1 Vccp Rg2 100 22nF Out 3 V+ 4 Rg1 100 Rf1 47k Cf 33nF 2/4 DocID026324 Rev 1 TSZ121ILT 1 V- 2 Rsh 30m GND Vccn 6 Vcc Vccn Vout STEVAL-ISQ014V1 2 Revision history Revision history Table 1. Document revision history Date Revision 08-May-2014 1 Changes Initial release. DocID026324 Rev 1 3/4 4 STEVAL-ISQ014V1 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. All ST products are sold pursuant to ST’s terms and conditions of sale. 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