PWM/VFM STEP-DOWN DC/DC CONVERTER
WITH SYNCHRONOUS RECTIFIER
R1230D SERIES
NO. EA-085-0305
OUTLINE
The R1230D Series are CMOS-based PWM step-down DC/DC Converters with synchronous rectifier, low supply
current.
Each of these ICs 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/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
R1230D001G/H types, divider resistors are also necessary.) In terms of Output Voltage, it is fixed internally in the
R1230Dxx1E/F types. While in the R1230D001G/H types, Output Voltage is adjustable with external divider resistors.
PWM/VFM alternative circuit is active with Mode Pin of the R1230D Series. Thus, when the load current is small,
the operation can be switching into the VFM operation from PWM operation by the logic of MODE pin and the effi-
ciency 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.
FEATURES
•
Built-in Driver ON Resistance ....................................P-channel 0.35Ω, N-channel 0.45Ω (at V
IN
=3V)
•
Built-in Soft-start Function (Typ. 1.5ms), and Latch-type Protection Function (Delay Time; Typ. 1.5ms)
•
Two choices of Oscillator Frequency...........................500kHz, 800kHz
•
PWM/VFM alternative with MODE pin .....................PWM operation; MODE pin at "L",
VFM operation; MODE pin at "H"
•
High Efficiency .............................................................Typ. 90%
•
Output Voltage..............................................................Stepwise Setting with a step of 0.1V in the range of 1.2V ~
3.3V (xx1E/F Type) or adjustable in the range of 0.8V to V
IN
(001G/H Type)
•
High Accuracy Output Voltage ....................................±2.0% (xx1E/F Type)
•
Package .........................................................................SON8 (Max height 0.9mm, thin type)
1
R1230D
SELECTION GUIDE
In the R1230D Series, the output voltage, the oscillator frequency, and the taping type for the ICs can be selected at
the user's request.
The selection can be made by designating the part number as shown below;
R1230Dxxxx-xx
↑ ↑↑ ↑
a bc d
Code
Setting Output Voltage(V
OUT
):
a
b
Stepwise setting with a step of 0.1V in the range of 1.2V to 3.3V is possible for E/F version.
"00" is for Output Voltage Adjustable G/H version (0.8V ~ )
1 : fixed
Designation of Optional Function
E : 500kHz, Fixed Output Voltage
c
F : 800kHz, Fixed Output Voltage
G : 500kHz, Adjustable Output Voltage
H : 800kHz, Adjustable Output Voltage
d
Designation of Taping Type; (Refer to Taping Specification)
"TR" is prescribed as a standard.
Contents
←
Part Number
PIN CONFIGURATION
SON-8
8 7 6 5
1
2
3
4
3
MEMS sensors
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