ANALOG DEVICES MAX20810 Integrated Step Down Switching Regulator User Guide

: May 15, 2024
: Analog Devices

Table of Contents

ANALOG DEVICES MAX20810 Integrated Step Down Switching Regulator
Product Information
Product Usage Instructions
Introduction
PMBus Communication Protocol
PMBus Timing Diagram
MAX20810 List of PMBus Commands
Output Voltage Related Commands
Status Commands
Telemetry Commands
Security Commands
References
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ANALOG DEVICES MAX20810 Integrated Step Down Switching Regulator

ANALOG-DEVICES-MAX20810-Integrated-Step-Down-Switching-Regulator-
product

Specifications

Product Name: MAX20810 PMBus Command Set User Guide
Model Number: UG2157
Revision: 0
Date: 10/23

Product Information

This user guide lists and describes the Power Management Bus (PMBus) commands implemented in the MAX20810 integrated step-down switching regulator. The MAX20810 implements a subset of PMBus Application Profile commands for DC-DC point of loads. Standard commands from the PMBus specification are not described in detail unless there are deviations from the PMBus specification functionality. Analog Devices manufacturer-specific commands are fully described in this document.
The MAX20810’s command functionality is based on the Revision 1.3 PMBus specifications, which are referenced throughout this document.

For more information, visit the PMBus and SMBus organization websites: PMBus Specifications SMBus Specifications

Product Usage Instructions

PMBus Communication Protocol
This section describes the protocol and command packet formats required for executing PMBus transactions on the MAX20810. It is implemented in compliance with Revision 1.3 of the PMBus Specification (Part II).

Bit and Byte Symbols Legend

Symbol	Description
Gray-colored symbol	The host is asserting the SDA signal and therefore the

bit or
byte is sent from the host to the MAX20810 device.
Blue-colored symbol| The MAX20810 device is asserting the SDA signal and therefore
the bit or byte is sent from the device to the host.

FAQ

Q: Where can I find the complete list of commands for MAX20810?
A: The complete list of commands can be found in this user guide. Please refer to the specific sections for detailed descriptions.

Q: Is there a specific website for PMBus and SMBus specifications?
A: Yes, you can visit the following links for more information: PMBus Specifications, SMBus Specifications.

Abstract
This user guide lists and describes the Power Management Bus (PMBus) commands implemented in the MAX20810 integrated step-down switching regulator. Standard commands from the PMBus specification are not described in detail unless there are deviations from the PMBus specification functionality. Analog Devices, Inc.’s manufacturer-specific commands are fully described in this document.

Introduction

This document lists and describes the PMBus™ commands implemented in the MAX20810 integrated step-down switching regulator. The MAX20810 implements a subset of PMBus Application Profile commands for DC-DC point of loads. Standard commands from the PMBus specification are not described in detail unless there are deviations from the PMBus specification functionality. Analog Devices manufacturer-specific commands are fully described in this document.
The MAX20810’s command functionality is based on the Revision 1.3 PMBus specifications, which are therefore referenced throughout this document. The PMBus specifications can be found on the PMBus and SMBus™ organization websites.
https://pmbus.org/current-specifications/
http://smbus.org/specs/

The commands in this document are presented in the following format:

---

PMBus Communication Protocol

This section describes the protocol and command packet formats required for executing PMBus transactions on the MAX20810. This has been implemented in compliance with Revision 1.3 of the PMBus Specification (Part II).

Bit and Byte Symbols Legend

$ANALOG-DEVICES-MAX20810-Integrated-Step-Down-Switching-Regulator-fig- $1$$ $ANALOG-DEVICES-MAX20810 -Integrated-Step-Down-Switching-Regulator-fig- $2$$

Read Transaction Protocol
Three main types of read transactions are used by this part: Read Byte, Read Word and Read Block. The command packet format for a read transaction is dependent on the specific transaction type, which varies with respect to each PMBus command. The appropriate read transaction type for each command is specified in its designated section within this document.

The following command packet format should be used for a Read Byte operation: $ANALOG-DEVICES-MAX20810-Integrated-Step-Down-Switching-Regulator- fig- $3$$

The following command packet format should be used for a Read Word operation: $ANALOG-DEVICES-MAX20810-Integrated-Step-Down-Switching-Regulator- fig- $4$$

The following command packet format should be used for a Read Block operation: $ANALOG-DEVICES-MAX20810-Integrated-Step-Down-Switching-Regulator- fig- $5$$

Write Transaction Protocol

Two main types of write transactions are used by this part: Write Byte and Write Word. The command packet format for a write transaction is dependent on the specific transaction type, which varies with respect to each PMBus command. The appropriate write transaction type for each command is specified in its designated section within this document.
The following command packet format should be used for a Write Byte operation $ANALOG-DEVICES-MAX20810-Integrated-Step-Down-Switching-Regulator-fig- $6$$

The following command packet format should be used for a Write Word operation $ANALOG-DEVICES-MAX20810-Integrated-Step-Down-Switching-Regulator-fig- $7$$

Send Byte Transaction Protocol
The following command packet format should be used for a Send Byte operation $ANALOG-DEVICES-MAX20810-Integrated-Step-Down-Switching-Regulator-fig- $8$$

PMBus Timing Diagram

The timing diagrams below illustrate the transaction protocol for the two parts of a Read Byte transaction as an example—starting from the STOP condition of the previous transaction and leading up to the STOP condition of the Read Byte transaction itself. $ANALOG-DEVICES-MAX20810-Integrated-Step- Down-Switching-Regulator-fig- $9$$

MAX20810 List of PMBus Commands

The table lists and summarizes the PMBus commands that are supported by the MAX20810, providing a brief description of each command as well as its command code, transaction type, data format, and factory value, where applicable.

COMMAND CODE| COMMAND NAME| DESCRIPTION| TYPE| DATA FORMAT| FACTORY VALUE
---|---|---|---|---|---
0x01| OPERATION| Output enable/disable.| R/W Byte| Bit field| 0x80
0x02| ON_OFF_CONFIG| EN pin and PMBus OPERATION command setting.| R/W Byte| Bit field| 0x1F
0x03| CLEAR_FAULTS| Clears any fault bits that have been

set.

0x19

|

CAPABILITY

| Summary of PMBus optional communication protocols supported

by this device.

|

R Byte

|

Bit field

|

0xA0

operating configurations.

| R/W Byte| Bit field| PGM0/1

Dependent

Dependent

0xD2| MFR_SCENARIO_1| Manufactures specific device

operating configurations.

| R/W Byte| Bit field| PGM1

Dependent

Dependent

---|---|---|---|---|---

On, Off, and Margin Testing Related Commands

OPERATION

This device supports two settings for the OPERATION command. Invalid data bytes trigger an “Invalid or Unsupported Data” response per Section 10.9.3 of the PMBus specification.

Supported values for the OPERATION command:

DATA BYTE VALUE	MEANING
0x00	Immediate-off, no sequencing
0x80	Output enabled, if allowed by ON_OFF_CONFIG setting

ON_OFF_CONFIG

This device supports three settings for the ON_OFF_CONFIG command. Invalid data bytes trigger an “Invalid or Unsupported Data” response per Section 10.9.3 of the PMBus specification.

Supported Values for the ON_OFF_CONFIG command:

DATA BYTE VALUE	MEANING

0x17

| Ignore OPERATION setting; require EN high for regulation; immediate-off on

loss of EN

0x1B

| Require OPERATION = 0x80 for regulation; ignore EN; immediate-off if OPERATION = 0x00

0x1F

| Require both OPERATION = 0x80 and EN high for regulation; immediate-off on

loss of EN or OPERATION = 0x00

VOUT_MODE

This device supports the PMBus ULINEAR16 format for the values of output voltage related commands. These commands return and receive two-byte data which serve as the integer mantissa in the ULINEAR16 format.

The read-only VOUT_MODE command has a value of 0x17, which indicates a ULINEAR16 exponent of N = -9.

VOUT_COMMAND

The device can receive PMBus ULINEAR16 values. VOUT_COMMAND data sent to and from the device is divided by 512 to determine the actual output voltage value, with an LSB size of 1.95mV.

VOUT_COMMAND accepts values from 0x0CD (+400.4mV) to 0x19A (+800.8mV), provided that the VOUT_MAX value is not being exceeded. Output voltages higher than +800.8mV must be adjusted by means of an external resistive voltage divider.

VOUT_MAX

Switching Frequency and Configuration Commands

MFR_PINSTRAP

The default values of switching frequency and POCP are selected by pin-strap resistors connected to the PGM0 and PGM1 pins of the IC.

MFR_PINSTRAP [7:5] SWITCHING FREQUENCY

0x0 500kHz

0x1 600kHz

0x2 750kHz

0x3 1000kHz

0x4 1200kHz

0x5 1500kHz

0x6 2000kHz

MFR_PINSTRAP [4] DCM OPTION

0x0 Device is always in CCM operation (default) 0x1 Enable DCM operation at light load

MFR_PINSTRAP **[3:2] ****POCP THRESHOLD (INDUCTOR PEAK**

CURRENT)

0x0 15A

0x1 13A

0x2 11A

0x3 9A

MFR_ PINSTRAP [1:0] RESERVED/NOT USED

0x0 –

MFR_SCENARIO_0

The default settings for AMS and the slope compensation are selected by pin- strap resistors connected to the PGM1 pin of the IC.

MFR_SCENARIO_0 [7:4] ADVANCED MODULATION SCHEME OPTION

0x0 AMS is disabled

0x9 AMS is enabled

MFR_SCENARIO_0 [0] MFR_SCENARIO_0 [3:2] SLOPE COMPENSATION

0x0 0x0 420nA

0x0 0x1 630nA

0x0 0x2 840nA

0x0 0x3 1050nA

0x1 0x0 1260nA

0x1 0x1 1470nA

0x1 0x2 1680nA

0x1 0x3 1890nA

MFR_SCENARIO_0 [1] DCM THRESHOLD

0x0 DCM threshold is default, as in data sheet EC table 0x1 DCM threshold is reduced by 20%

MFR_SCENARIO_1

The default value of RVGA is selected by pin-strap resistors connected to the PGM1 pin of the IC.

MFR_ SCENARIO_1 [7:4] VOLTAGE LOOP GAIN (RVGA)

0x0 10.1kΩ

0x1 11.1kΩ

0x2 15.7kΩ

0x3 22.7kΩ

0x4 26.8kΩ

0x5 31.3kΩ

0x6 37.3kΩ

0x7 44.8kΩ

0x8 52.9kΩ

0x9 62.3kΩ

0xA 75.0kΩ

0xE 105.1kΩ

MFR_ SCENARIO_1 [3] SOFT-STARTUP TIME

0x0 3ms

0x1 1ms (default)

MFR_ SCENARIO_1 [2] VDDH OVLO OPTION

0x0 VHDD OVLO is enabled with a rising threshold of 17.8V (typical)

0x1 VHDD OVLO is disabled (default)

MFR_ SCENARIO_1 [1:0] RESERVED/NOT USED

0x0 –

MFR_SCENARIO_2

The default value of the voltage loop zero is selected by pin-strap resistors connected to the PGM1 pin of the IC.

MFR_ SCENARIO_2 [7:5] VOLTAGE LOOP ZERO

0x0 3.22kHz

0x1 5kHz

0x2 7.6kHz

0x3 8.85kHz

0x4 10.6kHz

0x5 12.5kHz

0x6 15.2kHz

0x7 17.7kHz

MFR_ SCENARIO_2 [4:0] RESERVED/NOT USED

0x00 –

Status Commands

CLEAR_FAULTS

When received, the CLEAR_FAULTS command clears any fault bits that have been set and resets all STATUS registers.

STATUS_BYTE

BIT MEANING

7 **** Busy

6 **** Off

5 **** VOUT OV Fault

4 **** IOUT OC Fault

3 **** VIN UV Fault

2 **** TEMPERATURE Faults

1 **** CML Faults

0 **** NONE OF THE ABOVE: A fault or warning not listed in bits [7:1] of STATUS_BYTE has occurred.

STATUS_WORD

BIT MEANING

High **15 ** VOUT Fault

Byte

14 **** IOUT Fault

13 **** VIN Fault

12 **** Manufacturer-specific faults and warnings

11 **** POWER_GOOD# (Power-Good signal not asserted)

10 **** —

9 **** —

8 **** —

Low **7 ** Busy

Byte

6 **** Off

5 **** VOUT OV Fault

4 **** IOUT OC Fault

3 **** VIN UV Fault

2 **** TEMPERATURE Faults

1 **** CML Faults

0 **** NONE OF THE ABOVE: A fault or warning not listed in bits [7:1] of STATUS_BYTE has occurred.

STATUS_VOUT

Reference:| Standard Command| |
Command Code:| 0x7A| Format:| Bit field
Data Bytes:| 1| Units:| N/A
Transfer:| Read Byte| Factory Value:| N/A
| | |
Description/Notes:| See Section 17.3 of the PMBus Specification Part II.
| BIT MEANING
| 7 VOUT OV Fault
| 6 —
| 5 —
| 4 VOUT UV Fault
| 3 VOUT MAX Warnings
| 2 —
| 1 —
| 0 —
STATUS_IOUT

Reference:| Standard Command| |
Command Code:| 0x7B| Format:| Bit field
Data Bytes:| 1| Units:| N/A
Transfer:| Read Byte| Factory Value:| N/A
| | |
Description/Notes:| See Section 17.4 of the PMBus Specification Part II.
| BIT MEANING
| 7 IOUT OC Fault
| 6 —
| 5 —
| 4 —
| 3 —
| 2 —
| 1 —
| 0 —
STATUS_INPUT

Reference:| Standard Command| |
Command Code:| 0x7C| Format:| Bit field
Data Bytes:| 1| Units:| N/A
Transfer:| Read Byte| Factory Value:| N/A
| | |
Description/Notes:| See Section 17.5 of the PMBus Specification Part II.
| BIT MEANING
| 7 VIN OV Fault
| 6 —
| 5 —
| 4 VIN UV Fault
| 3 Unit Off due to Low Input Voltage
| 2 —
| 1 —
| 0 —
STATUS_TEMPERATURE

Reference:| Standard Command| |
Command Code:| 0x7D| Format:| Bit field
Data Bytes:| 1| Units:| N/A
Transfer:| Read Byte| Factory Value:| N/A
| | |
Description/Notes:| See Section 17.6 of the PMBus Specification Part II.
| BIT MEANING
| 7 OT Fault
| 6 —
| 5 —
| 4 —
| 3 —
| 2 —
| 1 —
| 0 —
STATUS_CML

BIT MEANING

7 **** Invalid or Unsupported Command Received

6 **** Invalid or Unsupported Data Received

5 **** Packet Error Check Failed

4 **** —

3 **** —

2 **** — (Reserved, per PMBus specification)

1 **** A communication fault other than the ones listed in this table has occurred

0 **** —

STATUS_MFR_SPECIFIC

BIT MEANING

7 **** Fast POCP Fault. Once triggered, cannot be cleared until power cycle.

6 **** Seal ring fault. Once triggered, cannot be cleared until power cycle.

5 **** —

4 **** AVDD undervoltage

3 **** BST undervoltage

2 **** LX short fault. Once triggered, cannot be cleared until power cycle.

1 **** —

0 **** —

Telemetry Commands

READ_VIN

Reference:| Standard Command| |
Command Code:| 0x88| Format:| LINEAR11
Data Bytes:| 2| Units:| V
Transfer:| Read Word| Factory Value:| N/A
| | |
Description/Notes:| See Section 18.1 of the PMBus Specification Part II.
READ_VOUT

The READ_VOUT command returns the voltage at the feedback pin; the value is not adjusted for any external divider that might be present.

READ_IOUT

Reference:| Standard Command| |
Command Code:| 0x8C| Format:| LINEAR11
Data Bytes:| 2| Units:| A
Transfer:| Read Word| Factory Value:| N/A
| | |
Description/Notes:| See Section 18.5 of the PMBus Specification Part II.
READ_TEMPERATURE_1

Inventory Information and Device Identification Commands

CAPABILITY

The following features are supported:

· Packet error checking

· 1000kHz bus speed

· LINEAR11 numeric format

IC_DEVICE_ID

The IC_DEVICE_ID is a 9-character ASCII string used to represent the part number of the IC. For this part, this command reads: “MAX20810”.

IC_DEVICE_REV

The IC_DEVICE_REV is a 2-character ASCII string, representing a five-bit device revision code from 00-31.

Security Commands

WRITE_PROTECT

Only the following values of WRITE_PROTECT are supported:

DATA BYTE VALUE	MEANING
0x80	Disable all writes except to the WRITE_PROTECT command

0x40

| Disable all writes except to the WRITE_PROTECT and

OPERATION commands

0x20

| Disable all writes except to the WRITE_PROTECT, OPERATION, ON_OFF_CONFIG, and

VOUT_COMMAND commands

0x00| Enable writes to all commands

Note that despite the CLEAR_FAULTS command being a Send Byte command, this command too is protected by WRITE_PROTECT. Therefore, WRITE_PROTECT needs to be set to 0x00 in order to send a CLEAR_FAULTS command.

Trademarks

SMBus is a trademark of SMIF, Inc.
PMBus is a trademark of SMIF, Inc.

Revision History

REVISION NUMBER| REVISION DATE| DESCRIPTION| PAGES CHANGED
---|---|---|---
0| 10/23| Initial release| —

©2023 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners.