ADM1066 Analog Devices, ADM1066 Datasheet - Page 14

• Manufacturer Part Number: ADM1066
• Manufacturer: Analog Devices

Specifications of ADM1066

• # Supplies Monitored: 12
• Volt Monitoring Accuracy: 1%
• # Output Drivers: 10
• Fet Drive/enable Output: Both
• Voltage Readback: 12-bit ADC
• Supply Adj/margining: 12-bit ADC+6 DACs
• Package: 40 ld LFCSP ,48 ld TQFP

ADM1066
POWERING THE ADM1066
The ADM1066 is powered from the highest voltage input on
either the positive-only supply inputs (VPx) or the high voltage
supply input (VH). This technique offers improved redundancy
because the device is not dependent on any particular voltage rail
to keep it operational. The same pins are used for supply fault
detection (see the Supply Supervision section). A V
on the device chooses which supply to use. The arbitrator can
be considered an OR’ing of five low dropout regulators (LDOs)
together. A supply comparator chooses the highest input to provide
the on-chip supply. There is minimal switching loss with this
architecture (~0.2 V), resulting in the ability to power the
ADM1066 from a supply as low as 3.0 V. Note that the supply on
the VXx pins cannot be used to power the device.
An external capacitor to GND is required to decouple the on-chip
supply from noise. This capacitor should be connected to the
VDDCAP pin, as shown in Figure 21. The capacitor has another
use during brownouts (momentary loss of power). Under these
conditions, when the input supply (VPx or VH) dips transiently
below V
off so that it does not pull V
then act as a reservoir to keep the device active until the next
highest supply takes over the powering of the device. A 10 μF
capacitor is recommended for this reservoir/decoupling function.
The VH input pin can accommodate supplies up to 14.4 V, which
allows the ADM1066 to be powered using a 12 V backplane supply.
In cases where this 12 V supply is hot swapped it is recommended
that the ADM1066 not be connected directly to the supply. Suitable
precautions, such as the use of a hot swap controller, should be
taken to protect the device from transients that could cause
damage during hot swap events.
DD
, the synchronous rectifier switch immediately turns
DD
down. The V
DD
capacitor can
DD
arbitrator
Rev. E | Page 14 of 32
When two or more supplies are within 100 mV of each other,
the supply that first takes control of V
example, if VP1 is connected to a 3.3 V supply, V
to approximately 3.1 V through VP1. If VP2 is then connected to
another 3.3 V supply, VP1 still powers the device, unless VP2
goes 100 mV higher than VP1.
VP1
VP2
VP3
VP4
VH
Figure 21. V
COMPARATOR
SUPPLY
DD
Arbitrator Operation
DD
IN
EN
IN
EN
IN
EN
IN
EN
IN
EN
keeps control. For
4.75V
4.75V
4.75V
4.75V
4.75V
LDO
LDO
LDO
LDO
LDO
OUT
OUT
OUT
OUT
OUT
DD
VDDCAP
powers up
INTERNAL
DEVICE
SUPPLY