R1230D251B-TL RICOH [RICOH electronics devices division], R1230D251B-TL Datasheet

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R1230D251B-TL

Manufacturer Part Number
R1230D251B-TL
Description
PWM/VFM Step-down DC/DC Converter with Synchronous Rectifier
Manufacturer
RICOH [RICOH electronics devices division]
Datasheet
process.
soft-start circuit, protection circuits, a protection against miss operation under low voltage (UVLO), PWM/VFM
alternative circuit, a chip enable circuit, and a driver transistor. A low ripple, 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. (As for R1230D001C/D types, divider resistors are also necessary.) In terms of Output Voltage, it is fixed
internally in the R1230DXX1A/B types. While in the R1230D001C/D types, Output Voltage is adjustable with external
divider resistors.
the operation can be switching into the VFM operation from PWM operation by the logic of MODE pin and the
efficiency at small load current can be improved. As protection circuits, Current Limit circuit which limits peak current
of Lx at each clock cycle, and Latch type protection circuit which works if the term of Over-current condition keeps on
a certain time in PWM mode exist. Latch-type protection circuit works to latch an internal driver with keeping it disable.
To release the condition of 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.
Rev. 1.12
The R1230D Series are PWM step-down DC/DC Converters with synchronous rectifier, low supply current by CMOS
Each of these ICs consists of an oscillator, a PWM control circuit, a reference voltage unit, an error amplifier, a
PWM/VFM alternative circuit is active with Mode Pin of the R1230D Series. Thus, when the load current is small,
OUTLINE
FEATURES
APPLICATIONS
Power source for portable equipment.
High Accuracy Output Voltage
Package
Built-in Driver ON Resistance
Built-in Soft-start Function (TYP. 1.5ms), and Latch-type Protection Function (Delay Time; TYP. 1.5ms)
Two choices of Oscillator Frequency
PWM/VFM alternative with MODE pin
High Efficiency
Output Voltage
SON8 (Max height 0.9mm, thin type)
or adjustable in the range of 0.8V to V
Stepwise Setting with a step of 0.1V in the range of 1.2V
- 1 -
TYP. 90%
±2.0%(XX1A/B Type)
500kHz, 800kHz
VFM operation; MODE pin at “H”
PWM operation; MODE pin at “L”,
PWM/VFM step-down DC/DC converter with Synchronous
Rectifier
R1230D Series
P-channel 0.35 , N-channel 0.45 (at V
IN
(001C/D Type)
2001. Sep. 8
4.0V(XX1A/B Type)
IN
=3V)

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