DEMO MANUAL DC1698A LT1999: High Voltage, Bidirectional Current Sense Amplifier DESCRIPTION Demonstration circuit 1698A features the LT1999, a high voltage, bi-directional current sense amplifier. The demo board amplifies the voltage drop across an on board current sense resistor. The output voltage is a bidirectional signal that is centered on the VREF voltage and is proportional to the current through the sense resistor. The output is scaled by one of three fixed gain options. The gain options are: 10V/V (DC1698A-A), 20V/V (DC1698A-B) and 50V/V (DC1698A-C). The input voltage range is from –5V to 80V (independent of the device supply voltage) allowing the part to be used for high or low side current sensing. The LT1999 requires a separate 5V supply voltage. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. PERFORMANCE SUMMARY Table 1. Performance Summary (TA = 25°C) SYMBOL PARAMETER VS Supply Range 4.5 5.5 V VCM CM Input Voltage Range –5 80 V CMRR Common Mode Rejection Ratio VCM = 0V , 7VP-P, f = 100kHz VOUT Swing Output High (with Respect to V+) Swing Output Low (with Respect to V–) RLOAD = Open RLOAD = Open VOSI Input Referred Offset Voltage TA = 25°C, VCM > 5.5V 550 μV IQ V+ Quiescent Current VCM > 5.5V 1.55 mA VREF Open Circuit Voltage VS = 5V VREFIN CONDITIONS REF Pin Input Range MIN 80 TYP 100 5 150 2.44 1.25 MAX 2.5 UNITS dB 125 225 mV mV 2.55 V V+ – 1.5 V OPERATING PRINCIPLES The LT1999 operates by amplifying the voltage drop across a user selected sense resistor. The voltage across the resistor is amplified by a fixed gain of 10V/V, 20V/V or 50V/V(LT1999-10,LT1999-20,LT1999-50) and is level shifted to the OUT pin of the device. The voltage difference and polarity with respect to the VREF pin voltage indicates the magnitude and direction of the current in the sense resistor. dc1698afa 1 DEMO MANUAL DC1698A BLOCK DIAGRAM V+ 2μA V+ 4.5k SHDN 1 V(G+IN) R +IN 2 +IN V(G–IN) 2k 2k CF 4pF 3 –IN 2k 2k 0.8k R +S 0.8k R –S R –IN RG + GIN – V+ D1 8 – + AO OUT 7 V+ 300Ω 160k REF 6 160k V+ GND 4 5 LT1999 1999 BD QUICK START PROCEDURE Demonstration circuit 1698 is easy to set up and evaluate the performance of the LT1999. Refer to Figure 1 for proper measurement equipment setup and follow the procedure: 3. Connect a voltmeter to the VOUT terminal, with the common connected to the VREF terminal. An oscilloscope can also be used to monitor Vout with respect to ground. 1. With power off, connect a power supply to V+ and the common to GND. This supply should be between 4.5V and 5.5V. Connect a second supply’s positive terminal to the VSENSE+ and connect its common to the circuit ground. The second supply’s (load supply) output voltage can range from –5V to 80V. 4. Turn on the power supply to the device and the load supply. 5. Measure the output voltage with respect to VREF. The output voltage will be proportional to the load and with the factory set sense resistor will equal 0.5V per 1A. 2. With power off, connect the load to the VSENSE–. If the load power source does not have accurate current readout a DMM may be connected in series with the load as shown in Figure 1. dc1698afa 2 DEMO MANUAL DC1698A QUICK START PROCEDURE LOAD SUPPLY (–5V TO 80V) 20V 5.00V DEVICE SUPPLY (4.5V TO 5.5V) 1.00V VOUT 2.00A LOAD 10Ω Figure 1. Proper Measurement Equipment Setup dc1698afa 3 DEMO MANUAL DC1698A PARTS LIST ITEM QUANTITY REFERENCE DESCRIPTION MANUFACTURER’S PART NUMBER 1 2 C1, C2 Capacitor, 0.1μF 10% 25V X7R 0603 AVX, 06033C104KAT2A 2 1 C3 Capacitor, 100pF 10% 16V X7R 0402 AVX, 0402YC101KAT2A 3 1 R2 Resistor, 0Ω 0603 1% 1/16W YAGEO, RC0603FR-070RL 1 1 DC1698A 2 1 R1 Resistor, 0.05Ω 1% 2512 2W SEI, CSRN2512FT50L0 3 1 U1 IC, LT1999IMS8-10 Linear Technology, LT1999IMS8-10#PBF 1 1 DC1698A 2 1 R1 Resistor, 0.025Ω 1% 2512 1W Vishay, WSL2512R0250FEA 3 1 U1 IC, LT1999IMS8-20 Linear Technology, LT1999IMS8-20#PBF 1 1 DC1698A 2 1 R1 Resistor, 0.01Ω 1W 1% 2512 SMD Vishay, WSL2512R0100FEA 3 1 U1 IC, LT1999IMS8-50 Linear Technology, LT1999IMS8-50#PBF General BOM DC1698A-A General BOM DC1698A-B General BOM DC1698A-C General BOM dc1698afa 4 V+ E1 E2 1 * 2512 R1 E6 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 1. ALL RESISTORS ARE IN OHMS, 0603 2. ALL CAPACTORS ARE IN MICROFARADS, 0603 NOTES: UNLESS OTHERWISE SPECIFIED VSENSE - -5V - +80V VSENSE + 4.5V - 5.5V 1 1 VSUPPLY IN- IN+ VSUPPLY CUSTOMER NOTICE 0.1uF C2 4 3 2 1 LT1999IMS8* U1 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. R2 0.1uF C1 0 Ohm CUYLER L. APP ENG. SCALE = NONE CL APPROVALS 5 6 7 8 PCB DES. GND VREF VOUT VSHDN\ LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMERSUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. V+ V+ E5 E4 E3 E7 GND VREF 2V AT 4A VOUT /SHDN * -C -B -A ASSY DATE 10/01/2010 0.01 ohm 0.025 ohm LTC CONFIDENTIAL FORCUSTOMER USE ONLY WWW.LINEAR.COM R1 CUYLER L. APPR 0.05 ohm 1630 McCarthy Blvd. Milpitas, CA 95035 PH: (408) 432-1900 LT1999IMS8-50 LT1999IMS8-20 LT1999IMS8-10 U1 PRODUCTION DESCRIPTION SIZE HIGH VOLTAGE BI-DIRECTIONAL CURRENT SENSE REV IC NO. LT1999IMS8-10/-20/-50 1 N/A DEMO CIRCUIT 1698A 10/2010 DATE: SH 1 of 1 TITLE: SCHEMATIC 1 1 1 0402 100pF C3 1 1 ECO REV DEMO MANUAL DC1698A SCHEMATIC DIAGRAM dc1698afa 5 DEMO MANUAL DC1698A DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive. Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and observe good laboratory practice standards. Common sense is encouraged. This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer. Mailing Address: Linear Technology 1630 McCarthy Blvd. Milpitas, CA 95035 Copyright © 2004, Linear Technology Corporation dc1698afa 6 Linear Technology Corporation LT 0911 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2011