Kontron AT8902M - Manual (Page 49)

AT8902M Hardware Description
Page 3 - 16 AT8902M User Guide
3.1.8.2 Power Distribution
The 48 Volts are supplied by the backplane via two independent rails, primary (A) and second-
ary (B). The rails are mixed using power Schottky rectifiers. A 7A fuse protects each -48V line
and a 10A fuse protects each RTN line. A hot swap controller enables the 48V power to the
board.
A quarter brick DC/DC converter transforms the 48 Volts to secondary 12 Volts, which are dis-
tributed on the board. The converter allows a maximum of 14A output current.
Two different management voltages (3.3V and 5V) and five payload voltages (3.3V, 2.5V, 1.8V,
1.25V and 1.2V) are generated by point of load converters. These are either switches or linear
regulators.
The management (or suspend) power is present once the board is connected to the backplane.
It supplies the IPMI part which in turn controls the payload power. The various payload voltages
are sequenced. The initial power up sequence is as follows (20ms delay between steps):
1. 3.3V, 1.8V and fabric mezzanine
2. 2.5V, 1.25V and 1.2V
The Power Down Sequence is performed in reversed order with a 1ms delay.
3.1.8.3 Power Supply AMCs
Each AMC has its own power supply. The 12V payload power is generated by a hot swap con-
troller and for the 3V3 management power a current limit switch is used. The maximum power
dissipation for an AMC is 60W. Both AMCs together must not consume more than 75W.
For further details please refer the AMC Specification.
3.1.8.4 Power Supply RTM
The RTM has its own power supply. The 12V payload power is generated by a hot swap con-
troller and for the management power a current limit switch is used. The maximum power dis-
sipation for an RTM is 10W.
For further details please refer the PICMG 3.0 standard.