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ADM1060ARU

Communications System Supervisory/Sequencing Circuit

Analog Devices 

Communications System

Supervisory/Sequencing Circuit

ADM1060

FEATURES

Faults detected on 7 independent supplies

1 high voltage supply (2 V to 14.4 V)

4 positive voltage only supplies (2 V to 6 V)

2 positive/negative voltage supplies

(+2 V to +6 V and –2 V to –6 V)

Watchdog detector input—timeout delay programmable

from 200 ms to 12.8 sec

4 general-purpose logic inputs

Programmable logic block—combinatorial and sequencing

logic control of all inputs and outputs

9 programmable output drivers:

Open collector (external resistor required)

Open collector with internal pull-up to VDD

Fast internal pull-up to VDD

Open collector with internal pull-up to VPn

Fast internal pull-up to VPn

Internally charge-pumped high drive (for use with

external N-channel FETs—PDOs 1 to 4 only)

EEPROM—256 bytes of user EEPROM

Industry-standard 2-wire bus interface (SMBus)

Guaranteed PDO low with VPn, VH = 1 V

APPLICATIONS

Central office systems

Servers

Infrastructure network boards

High density, multivoltage system cards

GENERAL DESCRIPTION

The ADM1060 is a programmable supervisory/sequencing

device that offers a single chip solution for multiple power

supply fault detection and sequencing in communications

systems.

In central offices, servers, and other infrastructure systems, a

common backplane dc supply is reduced to multiple board sup-

plies using dc-to-dc converters. These multiple supplies are used

to power different sections of the board, such as 3.3 V logic

circuits, 5 V logic circuits, DSP core, and DSP I/O circuits. There

is usually a requirement that certain sections power up before

others; for example, a DSP core may need to power up before

the DSP I/O, or vice versa, to avoid damage, miscommunication,

or latch-up. The ADM1060 facilitates this, providing supply

fault detection and sequencing/combinatorial logic for up to

seven independent supplies. The seven supply fault detectors

consist of one high voltage detector (up to +14.4 V), two bipolar

voltage detectors (up to +6 V or down to −6 V), and four posi-

tive low voltage detectors (up to +6 V). All of the detectors can

be programmed to detect undervoltage, overvoltage, or out-of-

window (undervoltage or overvoltage) conditions. The inputs to

these supply fault detectors are via the VH (high voltage) pin,

VBn (positive or negative) pins, and VPn (positive only) pins.

Either the VH supply or one of the VPn supplies is used to

power the ADM1060 (whichever is highest). This ensures that

in the event of a supply failure, the ADM1060 is kept alive for as

long as possible, thus enabling a reliable fault flag to be asserted

and the system to be powered down in an ordered fashion.

Other inputs to the ADM1060 include a watchdog detector

(WDI) and four general-purpose inputs (GPIn). The watchdog

detector can be used to monitor a processor clock. If the clock

does not toggle (transition from low to high or from high to

low) within a programmable timeout period (up to 18 sec.), a

fail flag will assert. The four general-purpose inputs can be con-

figured as logic buffers or to detect positive/negative edges and

to generate a logic pulse or level from those edges. Thus, the

user can input control signals from other parts of the system

(e.g., RESET or POWER_GOOD) to gate the sequencing of the

supplies supervised by the ADM1060.

The ADM1060 features nine programmable driver outputs

(PDOs). All nine outputs can be configured to be logic outputs,

which can provide multiple functions for the end user such as

RESET generation, POWER_GOOD status, enabling of LDOs,

and watchdog timeout assertion. PDOs 1 to 4 have the added

feature of being able to provide an internally charge-pumped

high voltage for use as the gate drive of an external N-channel

FET that could be placed in the path of one of the supplies

being supervised.

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Rev. B

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However, no responsibility is assumed by Analog Devices for its use, nor for any

infringements of patents or other rights of third parties that may result from its use.

Specifications subject to change without notice. No license is granted by implication

or otherwise under any patent or patent rights of Analog Devices. Trademarks and

registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

www.analog.com

Fax: 781.326.8703 © 2003 Analog Devices, Inc. All rights reserved.

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