CS5451A Six-channel, Delta-sigma Analog-to-digital Converter Features Description The CS5451A is a highly integrated delta-sigma ( an- Synchronous Sampling alog-to-digital converter (ADC) developed for the power On-chip 1.2 V Reference (25 ppm/C typ.) measurement industry. The CS5451A combines six Power Supply Configurations: ADCs, decimation filters, and a serial interface on a sin- gle chip. The CS5451A interfaces directly to a current - VA+ = +3 V VA- = -2 V VD+ = +3 V transformer or shunt to measure current, and to a resis- - Supply Tolerances: 10% tive divider or transformer to measure voltage. The product features a serial interface for communication Power Consumption with a microcontroller or DSP. The product is initialized - 23 mW Typical at VD+ = +3 V and fully functional upon reset, and includes a voltage reference. Simple Four-wire Serial Interface Charge pump driver output generates ORDERING INFORMATION: negative power supply. Ground-referenced Bipolar Inputs See page 13. VA+ GAIN RESET VD+ IIN1+ x1, 20 4th Order Modulator Decimation Filter IIN1- VIN1+ 4th Order Modulator x1 Decimation Filter VIN1- IIN2+ 4th Order Modulator x1, 20 Decimation Filter IIN2- SE VIN2+ OWRS x1 4th Order Modulator Decimation Filter VIN2- Serial SDO Interface FSO x1, 20 4th Order Modulator Decimation Filter IIN3+ IIN3- SCLK VIN3+ x1 4th Order Modulator Decimation Filter VIN3- x1 VREFIN Voltage VREFOUT Pulse Output CPD Reference Clock Regulator AGND XIN VA- DGND Copyright Cirrus Logic, Inc. 2011 APR 11 CS5451A TABLE OF CONTENTS 1. PIN DESCRIPTION .3 2. CHARACTERISTICS AND SPECIFICATIONS .4 3. THEORY OF OPERATION .8 4. FUNCTIONAL DESCRIPTION 9 4.1 Analog Inputs .9 4.2 Digital Filters 9 4.3 Performing Measurements .9 4.4 Serial Interface 9 4.5 System Initialization . 10 4.6 Voltage Reference 10 4.7 Power Supply 10 5. PACKAGE DIMENSIONS . 12 6. ORDERING INFORMATION 13 7. ENVIRONMENTAL, MANUFACTURING, & HANDLING INFORMATION . 13 8. REVISION HISTORY 13 LIST OF FIGURES Figure 1. Serial Port Timing . 6 Figure 2. Typical Connection Diagram 8 Figure 3. One Data Frame 10 Figure 4. Serial Port Data Transfer 10 Figure 5. Generating VA- with a Charge Pump . 11 2 DS635F4