MAX1515 Datasheet, PDF (11/24 Pages) Maxim Integrated Products – Low-Voltage, Internal Switch, Step-Down/DDR Regulator

Low-Voltage, Internal Switch,
Step-Down/DDR Regulator
Pin Description
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.
Supply Input for the Low-Side Gate Drive and REFOUT Buffer. Connect to the system supply voltage,
4
V_DD
+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 = VCC.}
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.
Power-Good Open-Drain Output. PGOOD is low when the output voltage is more than 10% above or
7
PGOOD 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.
Feedback Input.
9
FB
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.
Shutdown Control. Low disables the switching regulator. SHDN and MODE select the operational
mode of the MAX1515.
SHDN
MODE Description
15
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
Mode-Select Pin. Mode sets the regulator into DDR mode or non-DDR operation mode, and controls
16
MODE
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.
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