ZXCT1021 LOW OFFSET HIGH-SIDE CURRENT MONITOR DESCRIPTION APPLICATIONS The ZXCT1021 is a precision high side current sense monitor. Using this type of device eliminates the need to disrupt the ground plane when sensing a load current. • Battery Chargers • Smart Battery Packs • DC Motor control The ZXCT1021 provides a fixed gain of 10 for applications where minimal sense voltage is required. • Over current monitor • Power Management The very low offset voltage enables a typical accuracy of 3% for sense voltages of only 10mV, giving better tolerances for small sense resistors necessary at higher currents. • Level translating • Programmable current source The wide input voltage range of 20V down to as low as 2.5V make it suitable for a range of applications. With a minimum operating current of just 25µA, combined with its SOT23-5 package make it suitable for portable battery equipment too. FEATURES TYPICAL CIRCUIT APPLICATION • Accurate high-side current sensing • Output voltage scaling • 2.5V – 20V supply range • 25A quiescent current • 1% typical accuracy • SOT23-5 package ORDERING INFORMATION DEVICE ZXCT1021E5TA REEL SIZE TAPE WIDTH QUANTITY PER REEL 7” 8mm 3,000 units PARTMARK 1021 ISSUE 2 - MARCH 2004 1 SEMICONDUCTORS ZXCT1021 Absolute Maximum Ratings Voltage on any pin Vsense -0.6V to 20V -0.6V to Vin +0.5V Operating Temperature -40 to 85°C Storage Temperature -55 to 150°C Package Power Dissipation (TA = 25°C) SOT23 450mW ELECTRICAL CHARACTERISTICS Test Conditions TA = 25°C, Vin = 15V SYMBOL PARAMETER CONDITIONS LIMITS Min UNIT Typ Max V in V CC range V out Output voltage V sense = 30mV 291 300 309 mV (ZXCT1021) V sense = 100mV 0.98 1.00 1.02 V V sense = 150mV 1.47 1.50 1.53 V 10 15 20 50 300 25 35 R out Output resistance Tc Output temperature coefficient Ground pin current Iq V sense I sense (2) 2.5 V sense = 0V Sense voltage 20 0 Load pin V K⍀ ppm A 1.5 V 100 nA input current Acc Accuracy V sense = 100mV -2 Gain V out / V sense V sense = 100mV 98 BW Bandwidth V sense = 10mV V sense = 100mV 2 100 102 % mV 300 kHz 2 MHz NOTES (2) Vsense= Vin - Vload ISSUE 2 - MARCH 2004 SEMICONDUCTORS 2 ZXCT1021 TYPICAL CHARACTERISTICS ISSUE 2 - MARCH 2004 3 SEMICONDUCTORS ZXCT1021 TYPICAL CHARACTERISTICS BLOCK DIAGRAM ISSUE 2 - MARCH 2004 SEMICONDUCTORS 4 ZXCT1021 Application Information The devices have fixed dc voltage gains of 10, no external scaling resistors are required for the output. Output voltage is simply defined as: Vout = 10 x Vsense (V) Where Vsense = Vin - VLoad PCB trace shunt resistor for low cost solution The figure below shows a PCB layout suggestion for a low cost solution where a PCB resistive trace in replacement for a conventional shunt resistor, can be used. The resistor section is 25mm x 0.25mm giving approximately 150mΩ using 1 oz copper. Smaller resistances can be used if required. GND Load Total circuit solution: 1 component. Shows area of 150mΩ sense resistor compared to SOT23 package. Practical tolerance of the PCB resistor will be around 5% depending on manufacturing methods. PINOUT N/C 1 5 Load PIN NAME PIN FUNCTION N/C Not internally connected GND Ground V out Voltage output referenced to GND. Intended to drive high impedance loads Load High impedance negative sense voltage input V in Supply and positive sense voltage input GND 2 4 Vin Vout 3 Top view ISSUE 2 - MARCH 2004 5 SEMICONDUCTORS ZXCT1021 PACKAGE DIMENSIONS SOT23-5 PACKAGE DIMENSIONS DIM Millimetres Inches MIN MAX MIN MAX A 0.90 1.45 0.035 0.057 A1 0.00 0.15 0.00 0.006 A2 0.90 1.3 0.035 0.051 b 0.35 0.50 0.014 0.020 C 0.09 0.20 0.0035 0.008 D 2.80 3.00 0.110 0.118 E 2.60 3.00 0.102 0.118 E1 1.50 1.75 0.059 0.069 e 0.95 REF 0.037 REF e1 1.90 REF 0.075 REF L 0.10 0.60 0.004 0.024 © Zetex plc 2004 Europe Americas Asia Pacific Corporate Headquaters Zetex GmbH Streitfeldstraße 19 D-81673 München Germany Zetex Inc 700 Veterans Memorial Hwy Hauppauge, NY 11788 USA Zetex (Asia) Ltd 3701-04 Metroplaza Tower 1 Hing Fong Road, Kwai Fong Hong Kong Zetex plc Fields New Road, Chadderton Oldham, OL9 8NP United Kingdom Telefon: (49) 89 45 49 49 0 Fax: (49) 89 45 49 49 49 [email protected] Telephone: (1) 631 360 2222 Fax: (1) 631 360 8222 [email protected] Telephone: (852) 26100 611 Fax: (852) 24250 494 [email protected] Telephone (44) 161 622 4444 Fax: (44) 161 622 4446 [email protected] These offices are supported by agents and distributors in major countries world-wide. This publication is issued to provide outline information only which (unless agreed by the Company in writing) may not be used, applied or reproduced for any purpose or form part of any order or contract or be regarded as a representation relating to the products or services concerned. The Company reserves the right to alter without notice the specification, design, price or conditions of supply of any product or service. For the latest product information, log on to www.zetex.com ISSUE 2 - MARCH 2004 SEMICONDUCTORS 6