LTC3532_15 Datasheet, PDF (5/16 Pages) Linear Technology – Micropower Synchronous Buck-Boost DC/DC Converter

LTC3532
TYPICAL PERFOR A CE CHARACTERISTICS T_A = 25°C, unless otherwise specified.
Switch Pins Before Entering
Buck Mode
Output Ripple at 100mA Load
Burst Mode, Boost
SW1
2VDIV
SW2
2VDIV
V_IN = 4V
VOUT = 3.3V
I_LOAD = 100mA
40ns/DIV
V_OUT
50mV/DIV
V_OUT
50mV/DIV
V_OUT
50mV/DIV
V_IN = 2.4V
V_IN = 3.6V
V_IN = 4.5V
3535 G13
V_OUT = 3.6V
I_OUT = 100mA
C_OUT = 10μF
400ns/DIV
SW1
5V/DIV
SW2
5V/DIV
V_OUT
100mV/DIV
3535 G14
INDUCTOR
CURRENT
500mA/DIV
V_IN = 2.4V
V_OUT = 3.3V
I_LOAD = 20mA
C_OUT = 22μF
4μs/DIV
Burst Mode, Buck-Boost
SW1
5V/DIV
SW2
5V/DIV
V_OUT
100mV/DIV
INDUCTOR
CURRENT
500mA/DIV
V_IN = 3.75V
V_OUT = 3.3V
I_LOAD = 20mA
C_OUT = 22μF
4μs/DIV
340612 G16
Burst Mode, Buck
SW1
5V/DIV
SW2
5V/DIV
V_OUT
100mV/DIV
INDUCTOR
CURRENT
500mA/DIV
V_IN = 4.2V
V_OUT = 3.3V
I_LOAD = 20mA
C_OUT = 22μF
4μs/DIV
3535 G17
3535 G15
PI FU CTIO S
RT (Pin 1): Timing Resistor to Program the Oscillator
Frequency. The programming range is 300kHz to 2MHz.
48,000
f(kHz) =
R_T (kΩ)
BURST (Pin 2): Used to Set the Automatic Burst Mode Op-
eration Threshold. Place a resistor and capacitor in parallel
from this pin to ground. See the Applications Information
section for component value selection. For manual control,
ground the pin to force Burst Mode operation, connect to
V_OUT to force fixed frequency mode.
SW1 (Pin 3): Switch Pin Where the Internal Switches A
and B are Connected. Connect inductor from SW1 to SW2.
An optional Schottky diode can be connected from SW1
to ground. Minimize trace length to minimize EMI.
SW2 (Pin 4): Switch Pin Where the Internal Switches C
and D are Connected. For applications with output voltages
over 4.3V, a Schottky diode is required from SW2 to V_OUT
to ensure SW2 does not exhibit excess voltage.
GND (Pin 5): Signal and Power Ground for the IC.
V_OUT (Pin 6): Output of the Synchronous Rectifier. A filter
capacitor is placed from V_OUT to GND.
V_IN (Pin 7): Input Supply Pin. Supplies current to the
inductor through SW1 and supplies internal V_CC for the
IC. A ceramic bypass capacitor as close to the V_IN pin and
GND (Pin 5) is required.
3532fc
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