1. Board Design > Power Management
11
Tsi382 (BGA) Evaluation Board User Manual
60E2010_MA001_03
Integrated Device Technology
www.idt.com
1.4.2
Power Requirements
The power requirements and implementation for the Tsi382 is as follows.
The target power draw of the Tsi382 is a maximum of 1W, all supplies combined. The supplies to the
Tsi382 are controlled during ramp up using enable pins on regulators and switches.
1.4.2.1
PCIe
The
PCIe CEM Specification 1.1
defines power limits on PCIe slots according to the number of lanes
available on a card. Power rules regarding x1 PCIe slots are a maximum of 25W slot. Current limits are
included in
Table 4
.
The usage of the 12V supply provides access to the full 25W available from the system to the board.
The PCIe pinout design includes more 12V power pins as it allows more power-per-pin capability. The
evaluation board regulates all power from the 12V system rail; however, 3.3V from the system remains
unused.
Table 3: Tsi382 Power Requirements
Supply Name
Symbol
Supplied Source
Device Core
1.2V_384
DC/DC switching regulator w/Enable pin
PCIe 1.2V Core
1.2V_A_384
Passive Filter
PCI 3.3V supply
3.3V_384
Power switch w optional Ferrite filter to reduce
EMI/noise from PCI environment
PCIe 3.3V supply
3.3V_A_384
Passive Filter
Table 4: PCIe Connector Current Limits
Rail
Current
3.3V
3A
12V
2.1A
