RICOH R1210N Series 8V Input PWM Step-up DC DC Converter User's Guide

R1210N Series

8V Input PWM Step-up DC/DC Converter

The R1210N Series are low supply current, CMOS-based PWM step-up DC/DC converters. By simply using an inductor, a diode, and a capacitor as external components, a high-efficiency step-up DC/DC converter can be easily configured. The xx1 version with an internal output transistor and the xx2 version with an external transistor are available. The oscillator frequency can be selected from 100k Hz or 180k Hz. The xx1A version is also available, which contains a basic frequency changeover circuit that switches the oscillator frequency from 100k Hz to 35k Hz when output load is reduced. R1210N also has a function that detects drastic changes in output voltage and reduces the amount of overshoot/undershoot by switching control mode.

FEATURES • Supply Current (IDD1)·············· Typ. 35μA (R1210N301, 100k Hz), Typ. 60μA (R1210N301, 180k Hz) • Oscillator Frequency (fosc) ·············· 100k Hz (xx1A/xx1C/xx2C Version),

(VOUT=SET VOUT × 0.96) Typ. 20μA (R1210N302, 100k Hz), Typ. 25μA (R1210N302, 180k Hz) 180k Hz (xx1D/xx2D Version)

• Supply Current (IDD2)·············· Typ. 10μA (VOUT=SET VOUT+0.5V, 100k Hz) • Basic Frequency Change-over Circuit ···· 100k Hz → 35k Hz Typ. 15μA (Same as the above, 180k Hz) (only xx1A Version) • Standby Current (Istandby) ········ Max. 0.5μA (In standby) • Oscillator Maximum Duty Cycle (Maxduty)····· Typ. 85% • Input Voltage Range (VIN) ······ Max. 8.0V • Efficiency········································ Typ. 88% (R1210N301, • Start-up Voltage (Vstart) ··········· Max. 0.9V (xx1 Version), 0.8V(xx2 Version) VIN=1.8V, IOUT=10m A)

ff ic ie

• Output Voltage Range (VOUT) ··· 2.2V to 6.0V (internally fixed) (2.2V to 3.5V for xx1A) • Package ········································· SOT-23-5 • Output Voltage Accuracy ······· ± 2.5%

BLOCK DIAGRAMS R1210Nxx1x R1210Nxx2x (Internal output transistor type) (External transistor type)

Vref Vref

VOUT VOUT

Phase Comp. Phase Comp.

LX VLX limiter EXT Buffer

Buffer PWM Controller

PWM Controller OSC

fosc Control

GND Chip Enable GND

Chip Enable ff ic ie

CE CE

SELECTION GUIDE TYPICAL APPLICATIONS

Halogen Free Package Q'ty per Reel Part No. R1210Nxx1x R1210Nxx2x

SD SD

SOT-23-5 3,000 pcs R1210N.xx∗$ -TR-FE

.xx. : Specify the output voltage within the range of

2.2V (.22.) to 6.0V (.60.) in 0.1V steps. Tr EXT VOUT

LX VOUT CL CL

(up to 3.5V (.35.) for xx1A)

VIN VIN

.∗. : Select from (.1.) internal output transistor type or

GND CE GND CE

(.2.) external transistor type. .$. : Select from (.A.) oscillator frequency 100k Hz, built-in basic frequency change-over circuit, (.C.) 100k Hz or

L : 100μH, SD : MA721, CL : 22μF×2 L : 27μH, SD : RB491D, Tr : 2SD1628G,

(.D.) 180k Hz.

CL : 47μF×2, Rb : 300Ω, Cb : 0.01μF

(R1210Nxx2A-TR-F is not available.)

PACKAGE (Top View) TYPICAL CHARACTERISTICS

SOT-23-5 R1210N301C R1210N302C

Efficiency vs. Output Current Efficiency vs. Output Current

2 VOUT VIN=2.5V

VIN=2.5V

VIN=2.0V

VIN=2.0V

3 NC VIN=1.5V

VIN=1.5V

VIN=0.9V

4 GND VIN=0.9V 5 LX or EXT

Output Current IOUT (m A) Output Current IOUT (m A)

APPLICATIONS • Power source for battery-powered equipment • Power source for hand-held communication equipment, cameras, and VCRs • Power source for equipment that requires the voltage greater than the battery voltage

No.EK-067-111001 Step-up DC/DC Converter