EVAL-ADM1064TQEB Analog Devices Inc, EVAL-ADM1064TQEB Datasheet - Page 13

• Manufacturer Part Number: EVAL-ADM1064TQEB
• Description: BOARD EVALUATION FOR ADM1064TQ
• Manufacturer: Analog Devices Inc

Specifications of EVAL-ADM1064TQEB

• Main Purpose: Power Management, Power Supply Supervisor/Tracker/Sequencer
• Embedded: No
• Utilized Ic / Part: ADM1064
• Primary Attributes: 10 Channel Supervisor / Sequencer, 6 Voltage Output DACs
• Secondary Attributes: GUI Programmable via SMBus (via USB)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

POWERING THE ADM1064
The ADM1064 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 VDD arbitrator 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
ADM1064 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 18. The capacitor has another
use during brownouts (momentary loss of power). Under these
conditions, when the input supply (VPx or VH) dips transiently
below VDD, the synchronous rectifier switch immediately turns
off so that it does not pull VDD down. The VDD capacitor can
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 ADM1064 to be powered using a 12 V backplane
supply. In cases where this 12 V supply is hot swapped, it is
recommended that the ADM1064 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.
Rev. C | Page 13 of 32
When two or more supplies are within 100 mV of each other,
the supply that first takes control of VDD keeps control. For
example, if VP1 is connected to a 3.3 V supply, VDD powers up
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 18. VDD Arbitrator Operation
COMPARATOR
SUPPLY
IN
EN
IN
EN
IN
EN
IN
EN
IN
EN
4.75V
4.75V
4.75V
4.75V
4.75V
LDO
LDO
LDO
LDO
LDO
OUT
OUT
OUT
OUT
OUT
ADM1064
VDDCAP
INTERNAL
DEVICE
SUPPLY