E
NGINEERING
D
EPARTMENT
706679 Rev 09-26-18
1 of 9
User’s Guide
XL270 PMBus Interface
This document and the PMBus™ firmware described within are subject to change without notice. PMBus is a
trademark of System Management Interface Forum, Inc.
The N2Power XL270 Series of power supplies optionally supports the industry standard PMBus. This document
lists the commands that are currently supported in Version 1.2 of the XL270 PMBus implementation. Refer to
the complete XL270 Product Specification (Document 706601) for details about the power supply’s operational
characteristics.
Refer to the PMBus Power System Management Protocol Specification Parts I and II
Part I: General Requirements, Transport and Electrical Interface
Part II: Command Language
The PMBus documents can be downloaded at the following URLs:
http://pmbus.org/developers.php
http://pmbus.org/media/PMBus_Specification_Part_I_Rev_1_%200_20050324.pdf
http://pmbus.org/media/PMBus_Specification_Part_II_Rev_1_0_20050328.pdf
The PMBus is a logical protocol based on the SMBus that was originally conceived by Intel Corporation. They
both utilize the 5-volt I
2
C hardware bus. The 3.3-volt integrated circuits of XL270 can tolerate the 5-volt I
2
C
Bus. Electrical and timing requirements must comply with the I
2
C Bus specifications. These physical
requirements are generally fulfilled by an integrated circuit. External pullup resistors on the I
2
C clock and data
lines are required. The XL270 I
2
C inputs provide weak pullups to 3.3V to keep the clock and data input signals
in their high state when not used.
Option Connector (J3)
The J3 connector is a Molex Pico-Blade header (a.k.a. a jack) with 1.25mm pin spacing. The Molex part
numbers for the mating housing and crimp-style snap-in terminals are listed in Table 1. There may be
equivalent connector components available from other manufacturers.
J3
Molex P/N
Number of Circuits (pins)
15
Mating Housing (white)
51021-1500
Crimp Terminal
50212-8100
Rated Contact Current
2 A
Rated Wire Size
AWG 30 thru 24
Table 1 J3 Mating Connectors
