ZL2004

FN6846 Rev. 3.00

Page 2 of 42

February 15, 2011

Table of Contents

1. Electrical Characteristics.................................................................................................................................................................3

2. Pin Descriptions ..............................................................................................................................................................................6

3. Typical Application Circuit.............................................................................................................................................................8

4. ZL2004 Overview ...........................................................................................................................................................................9

4.1 Digital-DC Architecture.........................................................................................................................................................9

4.2 Power Conversion Overview ...............................................................................................................................................10

4.3 Power Management Overview.............................................................................................................................................11

4.4 Multi-mode Pins ..................................................................................................................................................................11

5. Power Conversion Functional Description....................................................................................................................................12

5.1 Internal Bias Regulators and Input Supply Connections......................................................................................................12

5.2 Output Voltage Selection .....................................................................................................................................................12

5.3 Start-up Procedure ...............................................................................................................................................................15

5.4 Soft Start Delay and Ramp Times........................................................................................................................................15

5.5 Power Good .........................................................................................................................................................................16

5.6 Switching Frequency and PLL.............................................................................................................................................17

5.7 Power Train Component Selection ......................................................................................................................................18

5.8 Current Limit Threshold Selection.......................................................................................................................................22

5.9 Loop Compensation .............................................................................................................................................................25

5.10 Adaptive Loop Compensation ...........................................................................................................................................25

5.11 Non-linear Response (NLR) Settings.................................................................................................................................26

5.12 Efficiency Optimized Driver Dead-time Control...............................................................................................................26

5.13 Adaptive Diode Emulation.................................................................................................................................................27

5.14 Adaptive Frequency Control ..............................................................................................................................................27

6. Power Management Functional Description .................................................................................................................................28

6.1 Input Undervoltage Lockout ................................................................................................................................................28

6.2 Output Overvoltage Protection ............................................................................................................................................28

6.3 Output Pre-Bias Protection ..................................................................................................................................................28

6.4 Output Overcurrent Protection.............................................................................................................................................29

6.5 Thermal Overload Protection...............................................................................................................................................30

6.6 Voltage Tracking .................................................................................................................................................................30

6.7 Voltage Margining ...............................................................................................................................................................31

6.8 External Voltage Monitoring ...............................................................................................................................................31

6.9 I2C/SMBus Communications ...............................................................................................................................................32

6.10 I2C/SMBus Device Address Selection ...............................................................................................................................32

6.11 Digital-DC Bus ..................................................................................................................................................................33

6.12 Phase Spreading .................................................................................................................................................................33

6.13 Output Sequencing.............................................................................................................................................................34

6.14 Fault Spreading ..................................................................................................................................................................35

6.15 Active Current Sharing ......................................................................................................................................................35

6.16 Phase Adding/Dropping.....................................................................................................................................................36

6.17 Monitoring via I2C/SMBus ................................................................................................................................................36

6.18 Temperature Monitoring Using the XTEMP Pin ...............................................................................................................37

6.19 Snapshot™ Parameter Capture ..........................................................................................................................................37

6.20 Non-Volatile Memory and Device Security Features ........................................................................................................38

7. Package Dimensions .....................................................................................................................................................................39

8. Ordering Information ....................................................................................................................................................................40

9. Related Tools and Documentation ................................................................................................................................................40

10. Revision History .........................................................................................................................................................................41