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 V
DD
Fast internal pull-up to V
DD
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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