S39421 datasheet(7/28 Pages) SUMMIT

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S39421

2024 9.0 8/8/00

PIN DESCRIPTIONS

PIN NAME [

CompactPCI name] (pin #)

VCC12 (Pin 1): Supplies the 12 volts required for power-

ing the high-side drivers.

DRVREN (Pin 2): Open drain, active low output indicates

the status of the 3 volt and 5 volt high side driver outputs

(VGATE5 and VGATE3). This signal may also be used as

a switching signal for the 12 volt supply.

ISLEW (Pin 3): Diode-connected NFET input may be

used to adjust the 250V/s default slew rate of the high-side

driver outputs. One quarter of the current injected into this

pin will be mirrored into each of the high-side driver

outputs.

VSEL (Pin 4): TTL level input used to determine which of

the Host power supply inputs will be monitored for valid

voltage and reset generation.

VSEL-Voltage

Host Voltage

Select

Monitored

Low

5 Volt or Mixed-Mode

High

3.3 Volt Only

DD (Pin 5): A high going edge on this input will place the

embedded memory into Data Download mode. This

mode allows the entire contents of the E2PROM array to

be read out of the device by selecting the device (CS high)

and providing clock cycles on the SK input. Data Down-

load mode is exited when Chip Select is brought low.

CS (Pin 6): E2PROM memory chip select, active high.

SK (Pin 7): E2PROM memory serial clock input.

DI (Pin 8): E2PROM memory data input.

DO (Pin 9): E2PROM memory data output.

PND2 [BD_SEL2#] (Pin 10): Active low TTL level input

with internal pull-up to VCC5. In conjunction with PND1,

this signal indicates proper card insertion. This pin must

be connected to ground on the host side of the connector.

PND1 and PND2 must be placed on opposite corners of

the connector and will preferably be staggered shorter

than the power connector pins. Board insertion is as-

sumed when PND1 and PND2 are low.

PND1 [BD_SEL1#] (Pin 11): Active low TTL level input

with internal pull-up to VCC5. In conjunction with PND2,

this signal indicates proper card insertion.

GND (Pin 12): Ground.

CARD_V_VLD (pin13): CARD_V_VLD is an open drain

output, indicating the card side voltages are at or above

VTRIP.

SGNL_VLD (Pin 14): Signals valid (SGNL_VLD) is an

open drain active low signal indicating the card side power

is valid and that the reset signals have been released.

This signal can be used by the host as an indication that

the bus interface is active and all signals are valid.

HST_PWR (pin15): The host power (HST_PWR) input is

an active high input. It provides the host system active

control over the sequencing of the power up operation.

When low, the S39421 will hold the add-in card in reset

and block all power to the backend logic. When

HST_PWR is high the power sequencing will begin imme-

diately and the reset outputs will be driven active after

tPURST.

HST_RST [PCI_RST#] (Pin 16): TTL level input used as

a reset input signal from the host interface. An active low

level longer than 40 nsec will cause a reset sequence to

be performed on the card. The power switching logic will

not be affected.

RESET (Pin 17): RESET is an active low open-drain

output. It should be tied high through a pull-up resistor

connected to VCC.

RESET (Pin 18): RESET is an active high open drain

(PFET) output. It should be tied low through a pull-down

resistor connected to ground.

CARD_3V (Pin 19): 3.3 volt card side supply input. This

input is monitored for power integrity. If it falls below the

3.3V sense threshold, the PWR_VLD signal is de-as-

serted and a RESET sequence initiates.

VGATE3 (Pin 20): Slew rate limited high side driver

output for the 3.3V external Power FET gate.

VCC3 (Pin 21): 3.3 volt host side supply input. This input

is monitored for power integrity. If it falls below the 3.3V

sense threshold, the SGNL_VLD signal is de-asserted

and the high side drivers disabled.

CARD_5V (Pin 22): 5 volt card side supply input. This

input is monitored for power integrity. If it falls below the

5V sense threshold and the VSEL input is low, the

PWR_VLD signal is de-asserted and a RESET sequence

initiates.

VGATE5 (Pin 23): Slew rate limited high side driver

output for the 5V external Power FET gate.

VCC5 (Pin 24): Power to the S39421 and 5 volt host side

supply input. This input is monitored for power integrity. If

it falls below the 5V sense threshold and the VSEL input

is low, the SGNL_VLD signal is de-asserted and the high

side drivers disabled.

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