PIN NAME FUNCTION
1, 2 PGND
Power Ground. Internal connection to the source of the internal synchronous-rectifier switch. Connect
both PGND pins together.
3 IC Internally Connected Pin. Connect to PGND.
4V
DD
Supply Input for the Low-Side Gate Drive and REFOUT Buffer. Connect to the system supply voltage,
+3.0V to +3.6V. Bypass to PGND with a 1µF (min) ceramic capacitor. V
DD
supplies power to the
drivers and the REFOUT buffer.
5 REFOUT
REFIN Buffered Output. REFOUT provides a buffered output voltage of REFIN when MODE = V
CC
.
Bypass to GND with a 0.47µF ceramic capacitor. REFOUT is disabled when MODE = GND.
6 SS Soft-Start. Connect a capacitor from SS to GND to limit the inrush current during startup.
7 PGOOD
Power-Good Open-Drain Output. PGOOD is low when the output voltage is more than 10% above or
below the normal regulation point. PGOOD is high impedance when the output is in regulation.
PGOOD is low in shutdown.
8 TOFF Off-Time Select Input. Connect a resistor from TOFF to GND to adjust the off-time.
9FB
Feedback Input.
In DDR mode (MODE = V
CC
), FB regulates to the voltage at REFIN.
In non-DDR mode (MODE = GND), connect directly to the output for preset voltage operation or to a
resistive voltage-divider for adjustable-mode operation.
10 COMP
Integrator Compensation. Connect a 470pF capacitor from COMP to V
CC
for integrator
compensation.
11 V
CC
Analog Supply Input. Connect to the system supply voltage, +3.0V to +3.6V, with a series 10Ω
resistor. Bypass to GND with a 1µF (min) ceramic capacitor.
12 GND Analog Ground. Connect exposed backside pad to GND.
13 REF
+1.1V Reference Voltage Output. Bypass to GND with a 1.0µF bypass capacitor. Can supply 50µA
for external loads. Reference turns off in shutdown.
14 REFIN
External Reference Input. In DDR mode (MODE = V
CC
), REFIN sets the voltage that FB regulates to.
In non-DDR mode (MODE = GND), connect REFIN to REF.
15 SHDN
Shutdown Control. Low disables the switching regulator. SHDN and MODE select the operational
mode of the MAX1515.
SHDN
Low Low Step-down regulator and REFOUT OFF
Low High Step-down regulator OFF, REFOUT active
High Low Step-down regulator ON, non-DDR mode, REFOUT OFF
High High Step-down regulator ON, DDR mode, REFOUT active
16 MODE
Mode-Select Pin. Mode sets the regulator into DDR mode or non-DDR operation mode, and controls
the REFOUT buffer. When MODE = V
CC
, MAX1515 is set in DDR mode and REFOUT is active. When
MODE = GND, MAX1515 is set in non-DDR mode and REFOUT is disabled. See the Modes of
Operation (MODE) section.
17 FBSEL0
Used with FBSEL1 to set the output voltage of the step-down regulator when MODE = GND.
Connect to GND if MODE = V
CC
.
