AD8450

Data Sheet

Rev. B | Page 2 of 41

TABLE OF CONTENTS

Features .............................................................................................. 1

Applications....................................................................................... 1

General Description ......................................................................... 1

Functional Block Diagram .............................................................. 1

Revision History ............................................................................... 2

Specifications..................................................................................... 3

Absolute Maximum Ratings............................................................ 8

Thermal Resistance ...................................................................... 8

ESD Caution.................................................................................. 8

Pin Configuration and Function Descriptions............................. 9

Typical Performance Characteristics ........................................... 11

PGIA Characteristics ................................................................. 11

PGDA Characteristics................................................................ 13

CC and CV Loop Filter Amplifiers, Uncommitted Op Amp,

and VSET Buffer......................................................................... 15

VINT Buffer ................................................................................ 17

Current Sharing Amplifier ........................................................ 18

Comparators................................................................................ 19

Reference Characteristics .......................................................... 20

Theory of Operation ...................................................................... 21

Introduction ................................................................................ 21

Programmable Gain Instrumentation Amplifier (PGIA)..... 23

Programmable Gain Difference Amplifier (PGDA).............. 24

CC and CV Loop Filter Amplifiers.......................................... 24

Compensation............................................................................. 26

VINT Buffer ................................................................................ 26

MODE Pin, Charge and Discharge Control ........................... 26

Overcurrent and Overvoltage Comparators........................... 27

Current Sharing Bus and IMAX Output................................. 28

Applications Information .............................................................. 29

Functional Description.............................................................. 29

Power Supply Connections ....................................................... 29

Power Supply Sequencing ......................................................... 29

Power-On Sequence................................................................... 29

Power-Off Sequence................................................................... 30

PGIA Connections ..................................................................... 30

PGDA Connections ................................................................... 31

Battery Current and Voltage Control Inputs (ISET and VSET)

....................................................................................................... 31

Loop Filter Amplifiers ............................................................... 32

Connecting to a PWM Controller (VCTRL Pin) ...................... 32

Overvoltage and Overcurrent Comparators........................... 32

Step by Step Design Example.................................................... 32

Additional Information ............................................................. 33

Evaluation Board ............................................................................ 34

Introduction................................................................................ 34

Features and Tests....................................................................... 34

Testing the AD8450-EVALZ..................................................... 34

Using the AD8450...................................................................... 36

Schematic and Artwork............................................................. 37

Outline Dimensions....................................................................... 41

Ordering Guide .......................................................................... 41

REVISION HISTORY

8/15—Rev. A to Rev. B

Changes to Table 2............................................................................ 8

Added Power Supply Sequencing Section and Power-On

Sequence Section ............................................................................ 29

Added Power-Off Sequence .......................................................... 30

Added Additional Information Section....................................... 33

Changes to Step 4: Determine the Control Voltage for the CC

Loop, the Shunt Resistor, and the PGIA Gain Section .............. 33

7/14—Rev. 0 to Rev. A

Changes to General Description .....................................................1

Changes to Pin 39 and Pin 80 Descriptions................................ 10

Changes to Introduction Section and Figure 50 ........................ 22

Changes to Figure 52...................................................................... 24

Changes to Figure 55...................................................................... 26

Changes to Current Sharing Bus and IMAX Output Section .. 27

Changes to Figure 58...................................................................... 28

Changes to Figure 59...................................................................... 30

Changes to Evaluation Board Section.......................................... 33

1/14—Revision 0: Initial Version