Datasheet AD8451 (Analog Devices) - 3

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AD8451 Data Sheet TABLE OF CONTENTS
Features .. 1 MODE Pin, Charge and Discharge Control ... 21 Applications ... 1 Applications Information .. 22 General Description ... 1 Functional Description .. 22 Functional Block Diagram .. 1 Power Supply Connections ... 23 Revision History ... 2 Current Sense IA Connections ... 23 Specifications ... 3 Voltage Sense DA Connections .. 23 Absolute Maximum Ratings .. 6 Battery Current and Voltage Control Inputs (ISET and VSET) Thermal Resistance .. 6 ... 23 ESD Caution .. 6 Loop Filter Amplifiers ... 24 Pin Configuration and Function Descriptions ... 7 Connecting to a PWM Controller (VCTRL Pin) .. 24 Typical Performance Characteristics ... 9 Step-by-Step Design Example... 24 IA Characteristics ... 9 Evaluation Board .. 26 DA Characteristics ... 11 Introduction .. 26 CC and CV Loop Filter Amplifiers, and VSET Buffer .. 13 Features and Tests ... 26 VINT Buffer .. 15 Evaluating the AD8451 .. 27 Reference Characteristics .. 16 Schematic and Artwork ... 28 Theory of Operation .. 17 Outline Dimensions ... 32 Overview .. 17 Ordering Guide .. 32 Instrumentation Amplifier (IA) ... 18 Difference Amplifier (DA) .. 19 CC and CV Loop Filter Amplifiers .. 19
REVISION HISTORY 3/14—Revision 0: Initial Version
Rev. 0 | Page 2 of 32 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS IA CHARACTERISTICS DA CHARACTERISTICS CC AND CV LOOP FILTER AMPLIFIERS, AND VSET BUFFER VINT BUFFER REFERENCE CHARACTERISTICS THEORY OF OPERATION OVERVIEW INSTRUMENTATION AMPLIFIER (IA) Reversing Polarity When Charging and Discharging IA Offset Option Battery Reversal and Overvoltage Protection DIFFERENCE AMPLIFIER (DA) CC AND CV LOOP FILTER AMPLIFIERS Compensation VINT Buffer MODE PIN, CHARGE AND DISCHARGE CONTROL APPLICATIONS INFORMATION FUNCTIONAL DESCRIPTION POWER SUPPLY CONNECTIONS CURRENT SENSE IA CONNECTIONS Current Sensors Optional Low-Pass Filter VOLTAGE SENSE DA CONNECTIONS Reverse Battery Conditions BATTERY CURRENT AND VOLTAGE CONTROL INPUTS (ISET AND VSET) LOOP FILTER AMPLIFIERS CONNECTING TO A PWM CONTROLLER (VCTRL PIN) STEP-BY-STEP DESIGN EXAMPLE Step 1: Design the Switching Power Converter Step 2: Identify the Control Voltage Range of the ADP1972 Step 3: Determine the Control Voltage for the CV Loop Step 4: Determine the Control Voltage for the CC Loop and the Shunt Resistor Step 5: Choose the Control Voltage Sources Step 6: Select the Compensation Devices EVALUATION BOARD INTRODUCTION FEATURES AND TESTS EVALUATING THE AD8451 Test the Instrumentation Amplifier 20 mV Offset at IMEAS Output Test the Difference Amplifier 5 mV Offset at BVMEAS Output CC and CV Integrator Tests Loop Compensation SCHEMATIC AND ARTWORK OUTLINE DIMENSIONS ORDERING GUIDE