Signal Description
Pin Description
Table 3: Pin Descriptions
Pin #
Pin Name
Pin Type
Pin Description
6
SDI/ENSEQ
I
Multi-purpose logic input.
Logic high (> 2.0V) enables soft start and sequence. Buck 1 starts followed by
Buck 2, once V is within a specified tolerance. The soft start rise time is
OUT1
typically 5 ms and is dependent on output, but independent of capacitance and
load current. If a short circuit is detected on Buck1, then Buck 2 will be
disabled.
Logic low (< 0.8V) disables the start up sequence. Buck 1 and Buck 2 will start
up together without any soft start.
Serial Data Input.
The input data into this pin is used to program the output voltage (See “Output
Voltage Settings” on page 22). The power-good signal has to be high before
the serial data interface can be used. To implement soft start a 10K pull-up
resistor must be connected to SVIN.
This pin is internally pulled down by a 10 μA current source.
7, 9
8
SW1
O
Switch Node for regulator 1.
Internal power MOSFET drain. Connects to an external inductor.
PGND1
GND
Power Ground.
The power ground must be connected to the negative terminal of the input and
output capacitors.
10
11
PVIN1
POR1
S
Power Input Voltage.
Internal power MOSFET source. Connect the 10µF decoupling capacitor
between PVIN and PGND and position it as close as possible to the IC.
NOTE: PVIN and PVIN2 must be connected together and should not be
separated.
O
Power-On Reset 1.
This pin is an open drain output to indicate the status of the output voltage. The
output pin goes high 40 ms after the output voltage is within the specified
tolerance.
POR2 and POR1 can be connected to the same external pull-up resistor to
indicate “both outputs good”.
12
PSET1
I
Percent Set for Regulator 1.
1. Resistor Programming: Connect an external resistor to ground to set the
output voltage of the switching regulator. See the “Electrical
Characteristics” for resistor values and Output Voltage Settings. Use
resistor values with a tolerance of 5% or better. The total capacitance
across this pin and GND should be equal to 25 pF or less. If the pin is not
used, it must be connected to GND.
2. Logic Programming: Four output voltage levels (1.8V, 2.5V, 3.0V, 3.3V) can
be set by connecting the VSET and PSET pins to either GND or SVIN.
13
VSET1
I
Voltage Set for Regulator 1.
1. Resistor Programming: Connect an external resistor to ground to set the
output voltage of the switching regulator. See the “Electrical
Characteristics” for resistor values and Output Voltage Settings. Use
resistor values with a tolerance of 5% or better. The total capacitance
across this pin and GND should be equal to 25 pF or less.
2. Logic Programming: Four output voltage levels (1.8V, 2.5V, 3.0V, 3.3V) can
be set by connecting the VSET and PSET pins to either GND or SVIN.
Copyright © 2008 Marvell
April 23, 2008, 2.00
Doc. No. MV-S103563-00 Rev. C
Document Classification: Proprietary Information
Page 13
MARVELL [ MARVELL TECHNOLOGY GROUP LTD. ]
