R5220X Datasheet, PDF (1/25 Pages) RICOH electronics devices division – PWM Step-down DC/DC Converter with switch function

R5220x SERIES
PWM Step-down DC/DC Converter with switch function
NO.EA-121-070824
OUTLINE
The R5220x Series are CMOS-based PWM step-down DC/DC Converters with synchronous rectifier, low
supply current and LDO mode.
DC/DC converter of the R5220x consists of an oscillator, a PWM control circuit, a reference voltage unit, an
error amplifier, a soft-start circuit, protection circuits, a protection against miss operation under low voltage
(UVLO), PWM-DC to DC converter / LDO alternative circuit, a chip enable circuit, and a driver transistor. A high
efficiency step-down DC/DC converter can be easily composed of this IC with only a few kinds of external
components, or an inductor and capacitors.
LDO of the R5220x consists of a vortage reference unit, an error amplifier, resistors for voltage setting, output
current limit circuit, a driver transistor, and so on. The output voltage is fixed internally in the R5220x. The output
voltage of the DC/DC converter and the LDO can be set independently.
PWM step-down DC/DC converter / LDO alternative circuit is active with Mode Pin of the R5220x Series. Thus,
when the load current is small, the operation can be switching into the LDO operation from PWM operation by
the logic of MODE pin and the consumption current of the IC itself will be small at light load current. As protection
circuits, the current limit circuit which limits peak current of Lx at each clock cycle, and the latch type protection
circuit which works if the term of the over-current condition keeps on a certain time in PWM mode. Latch-type
protection circuit works to latch an internal driver with keeping it disable. To release the protection, after disable
this IC with a chip enable circuit, enable it again, or restart this IC with power-on or make the supply voltage at
UVLO detector threshold level or lower than UVLO.
FEATURES
• Supply Current ................................................................ Typ. 350µA (DC/DC), Typ. 5µA (VR)
• Standby Current .............................................................. Typ. 0.1µA
• Built-in Driver ON Resistance ......................................... P-channel 0.5Ω, N-channel 0.5Ω (at VIN=3.6V)
• Output Current ................................................................ Min. 400mA (DC/DC), Min. 50mA (VR)
• Input Voltage ................................................................... 2.8V to 5.5V (Absolute Input Maximum: 6.5V)
• Output Voltage ................................................................ 1.0V to 3.3V
• Output Voltage Accuracy................................................. ±2.0% (VOUT ^>= 1.5), ±30mV (VOUT <1.5V)
• Oscillator Frequency (DC/DC) ........................................ Typ. 1.2MHz
• Package .......................................................................... SON-6, PLP2514-6
• Built-in Soft-start Function............................................... Typ. 0.2ms
• Latch-type Protection Function (Delay Time).................. Typ. 3.0ms
• Built-in fold-back protection circuit (DC/DC, VR)
• Ceramic Capacitor is recommended.
APPLICATIONS
• Power source for portable equipment such as DSC, DVC, and communication equipment.
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