SMH4811A(2000) Ver la hoja de datos (PDF) - Summit Microelectronics

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Fabricante

SMH4811A
(Rev.:2000)

Distributed Power Hot-Swap Controller

Summit Microelectronics 

SMH4811A

PROGRAMMABLE FEATURES

Because the SMH4811A is electrically programmable it

can be fine-tuned for a wide variety of applications prior to

shipment to the customer. Because of this a manufacturer

can use a common part type across a wide range of boards

that are used on a common host but have different

electrical loads, power-on timing requirements, host volt-

age monitoring needs, etc.

This ability to use a common solution across many plat-

forms shifts the focus of design away from designing a new

power interface for each board to concentrating on the

value added back-end logic.

Because the programming of the features is done at final

test all combinations (all 128 possibilities) are readily

available as off the shelf stock items.

Quick-Trip Circuit Breaker Threshold

The Quick-Trip circuit breaker threshold can be set to

200mV, 100mV, 60mv or Off. This is the threshold voltage

drop across RS that is placed between VSS and CB-

SENSE.

Circuit Breaker Delay

The circuit breaker delay defines the period of time the

voltage drop across RS is greater than 50mV but less than

VQCB before the VGATE output will be shut down. This is

effectively a filter to prevent spurious shutdowns of

VGATE. The delays that can be programmed are 5µs,

50µs, 150µs and 400µs.

Pin Detect

The Pin Detect function can be enabled or disabled.

Power Good Delay

The PG delay timer that controls the delay from VGATE to

PG# being asserted can be set to typical values of 5ms,

20ms, 80ms or 160ms.

50mV

CBSENSE

tCBD

tCBD

VGATE

VQCB

50mV

CBSENSE

VGATE

6

tCYC

Figure 2. Circuit Breaker Timing

< tCBD

tFSTSHTDN

Figure 3. Circuit Breaker Timing — Quick Trip

2044 4.1 8/1/00

SUMMIT MICROELECTRONICS, Inc.

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