TPS2340A

SLUS528A – MARCH 2002 – REVISED AUGUST 2002

11

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APPLICATION INFORMATION

Figure 1 shows three TPS2340A devices cascaded in a system to control six PCI or PCI–X hot-plug slots. A

hot-plug controller communicates with three TPS2340A devices over a nine-signal serial bus. Three signals are

used to gather status information from the slots, and six signals are used to control the slots. In this bus, seven

of the nine signals are connected in parallel. The remaining signals facilitate a cascaded bus and are comprised

of the signal pair SIDI/SIDO and SODI/SODO. The SIDO signal drives the PCI hot-plug controller serial input

data pin or the SIDI pin of another up–stream TPS2340. The SODI signal is driven by the PCI hot-plug controller

and is cascaded down to the next TPS2340A via the SODO signal.

The SIDO and SODO outputs are dual-function pins that also serve as mode-select pins upon the rising edge

of PGOOD. See Digital Circuits section for more details.

UDG–01015

U1

PCI

HOT–PLUG

CONTROLLER

SERIAL/PARALLEL CONVERTER

SOLC

SOLRC

SOR

SORR

SIC

SIL

ANALOG CONTROL

ANALOG CONTROL

PCIXCAP1A

PCIXCAP2A

OUTPUTS

INPUTS

OUTPUTS

INPUTS

PGOOD

PMEO

TEST

PWR_GOOD PME

SWA

PRTSNT2A

PRTSNT1A

BUTTONA

M66ENA

PWRLEDA

ATTLEDA

BUSENA

CLKENA

RESETA

SLOT A

SWB

PRTSNT2B

PRTSNT1B

BUTTONB

M66ENB

PWRLEDB

ATTLEDB

BUSENB

CLKENB

RESETB

SLOT B

SOD

SID

SIDO/MODE0

SODI

SOD1

SID1

SIDI

SODO/MODE1

FaultA

AuxfltA

PwrenA

FaultB

AuxfltB

PwrenB

PCIXCAP1A

PCIXCAP2A

U2

ANALOG I/O

PMEB PCIXCAPB

PMEA PCIXCAPA

U3

U4

SOD2

SID2

SOD3

SID3

SLOTS C AND D

SLOTS E AND F

Figure 1. Hot-Plug System Block Diagram

analog circuits

power controller

The functional block diagram shows the TPS2340A with detailed information on the analog functions. For clarity,

circuits for only one slot are shown in detail.

3.3-V auxiliary supply (3.3-Vaux) support

In today’s hot-plug systems, a 3.3Vaux rail remains live while the system power is shut down to allow

implementation of the PCI Power Management Specification, version 1.1. The TPS2340A provides a 3.3-Vaux

input pin that is monitored for undervoltage and generates a 3.3-Vaux supply pin for each hot-plug slot that is

monitored for overcurrent. These supply pins are switched by the slot-specific SWx slot switch inputs. When

the slot switch is opened, the slot-specific 3.3-Vaux supply is disabled to allow safe removal of the adapter card.

When the slot switch is closed (SWx grounded), the slot-specific 3.3-Vaux supply is restored.