XRP7708 Datasheet, PDF (7/27 Pages) Exar Corporation – Quad Channel Digital PWM Step Down Controller

XRP7708
Quad Channel Digital PWM Step Down Controller
Name
DVDD
DGND
AGND
GL1-GL4
GH1-GH4
LX1-LX4
BST1-BST4
GPIO0-GPIO3
GPIO4_SDA,
GPIO5_SCL
VOUT1-VOUT4
LDOOUT
ENABLE
AGND
Pin Number
2
10
11
17,22,30,55
19,24,28,33
34,29,23,18
32,27,20,25
3,4,5,6
7,8
12,13,14,15
40
9
Exposed Pad
Description
Input for powering the internal digital logic. This pin should be connected to AVDD.
Digital Ground. This pin should be connected to the ground plane at the exposed pad
with a separate trace.
Analog Ground. This pin should be connected to the ground plane at the exposed pad
with a separate trace
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.
These pins can be configured as inputs or outputs to implement custom flags, power
good signals and enable/disable controls. A GPIO pin can also be programmed as an
input clock synchronizing IC to external clock. Refer to the “GPIO Pins” Section and the
“External Clock Synchronization” Section for more information.
I²C serial interface communication pins. These pins can be re-programmed to perform
GPIO functions in applications when I²C bus is not used.
Voltage sense.
Connect to the output of the corresponding power stage.
Output of the Standby LDO. It can be configured as a 5V or 3.3V output. A
compensation capacitor should be used on this pin [see Application Note].
If ENABLE is pulled high, the chip powers up (logic reset, registers configuration loaded,
etc.). If pulled low for longer than 100us, the XRP7708 is placed into shutdown.
Analog Ground.
Connect to analog ground (as noted above for pin 11).
ORDERING INFORMATION
Part Number
XRP7708ILB- F
XRP7708ILBTR-F
XRP7708EVB
Temperature Range Marking Package Packing Quantity
Note 1
-40°C≤T_J≤+125°C
XRP7708ILB
YYWW X
40-pin TQFN
-40°C≤T_J≤+125°C
XRP7708ILB
YYWW X
40-pin TQFN
XRP7708 Evaluation Board
Bulk
3K/Tape & Reel
Halogen Free
Halogen Free
“YY” = Year – “WW” = Work Week – “X” = Lot Number
Note 2
© 2010 Exar Corporation
7/27
Rev. 1.0.3