XRP7704 Datasheet, PDF (7/31 Pages) Exar Corporation – Quad-Output Digital PWM Buck Controller

REV 1.1.0
XRP7704
Quad-Output Digital PWM Buck Controller
PIN DESCRIPTION
QFN
PIN #
39
38
37
26
36,31,
16,21
PIN NAME
VIN1
VIN2
VCCA
VCCD
PGND1-
PGND4
DESCRIPTION
Power source for the internal linear regulators to generate VCCA, VDD and the
Standby LDO (LDOOUT). Place a decoupling capacitor close to the controller IC.
Also used in UVLO1 fault generation – if VIN1 falls below the user programmed
limit, all channels are shut down. The VIN1 pin needs to be tied to VIN2 on the
board with a short trace.
If the Vin2 pin voltage falls below the user programmed UVLO VIN2 level all
channels are shut down. The VIN2 pin needs to be tied to VIN1 on the board with
a short trace.
Output of the internal 5V LDO. This voltage is internally used to power analog
blocks.
Note that a compensation capacitor should be used on this pin [see Application
Note].
Gate Drive input voltage. This is not an output voltage. This pin can be connected
to VCCA to provide power for the Gate Drive.
VCCD should be connected to VCCA with the shortest possible trace and
decouple with a minimum 1uF capacitor.
Alternatively, VCCD could be connected to an external supply (not greater than
5V).
Power Ground. Ground connection for the low side gate driver.
1
AVDD
Output of the internal 1.8V LDO. A decoupling capacitor should be placed between
AVDD and AGND close to the chip (with short traces).
2
DVDD
Input for powering the internal digital logic. This pin should be connected to
AVDD.
10
11
17,22,
30,55
19,24,
28,33
34,29,
23,18
32,27,
20,25
DGND
Digital Ground. This pin should be connected to the ground plane at the exposed
pad with a separate trace.
AGND
Analog Ground. This pin should be connected to the ground plane at the exposed
pad with a separate trace.
GL1-GL4
GH1-GH4
LX1-LX4
BST1-BST4
Output pin of the low side gate driver. Connect directly to the respective gate of an
external N-channel MOSFET.
Output pin of the high side gate driver. Connect directly to the respective gate of
an external N-channel MOSFET.
Lower supply rail for the high-side gate driver (GHx). Connect this pin to the
switching node at the junction between the two external power MOSFETs and the
inductor. These pins are also used to measure voltage drop across bottom
MOSFETs in order to provide output current information to the control engine.
High side driver supply pin(s). Connect BST to an external boost diode and a
capacitor as shown in the front page diagram.
The high side driver is connected between the BST pin and LX pin.
EXAR CONFIDENTIAL. PROPRIETARY. DO NOT DISTRIBUTE OR COPY.
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