RICOH RP400x Series Current Mode PWM VFM Step-up DC DC Converter User Guide and Data Sheet

RP400x Series

Current Mode PWM/VFM Step-up DC/DC Converter

The RP400x Series are CMOS-based automatic switch PWM- or VFM-controlled step-up DC/DC converters. RP400x includes a soft start circuit. By simply using an inductor, a capacitor, a diode, and (resistors) as external components, a high-efficiency step-up DC/DC converter can be easily configured. Due to current mode PWM control, the RP400x provides a fast response and high efficiency. Ceramic output capacitors can be used. The output voltage can be selected from the internally fixed or the externally adjustment. The RP400x has an anti-ringing switch that prevents inductor current from ringing in PWM discontinuous mode. RP400x switches automatically to VFM control in low output current, keeping high efficiency. In addition to SOT-23-5 package, a 1.8mm × 2.0mm square DFN(PLP)1820-6 package is also available.

FEATURES • Supply Current (IDD1)·······················Typ. 300μA (RP400x301, VIN= SET VOUT × 0.5, • Output Voltage Accuracy·················± 2% VOUT = SET VOUT × 0.95) • Oscillator Frequency (fosc) ···············700k Hz • Supply Current (IDD2)·······················Typ. 160μA (VIN=5V, In non-switching) • Oscillator Maximum Duty Cycle (Maxduty) ···Typ. 88% • Standby Current (Istandby)··················Max. 3μA (In standby, only A Version) • Coil-current Limit Circuit ·················Current Limit Typ. 600m A • Input Voltage Range (VIN) ···············Max. 5.5V • Soft Start Time (tstart)························Typ. 0.7ms • Start-up Voltage (Vstart) ····················Max. 0.9V • Anti-ringing Switch ··························Internal EMI Suppression • Output Voltage Range (VOUT)··········1.8V to 5.0 V (internally fixed) (xx1) • Packages ········································DFN(PLP)1820-6, Externally adjustable (Feedback voltage : 0.6V) (001) SOT-23-5

BLOCK DIAGRAMS RP400xxx1x RP400K001x (Internally fixed output voltage type) (Externally adjustable output voltage type)

LX LX

Startup Control Buffer Startup Control Buffer

VIN Circuit Logic VIN Circuit Logic

Current Current VOUT

PWM PWM

Control Sense Control Sense

ff ic ie

Error Amp Error Amp

fosc VOUT fosc VFB

CE OSC CE Chip OSC

Chip Enable Enable

Vref Vref

VFM Control VFM Control

only A Version only A Version

GND GND

SELECTION GUIDES TYPICAL APPLICATIONS

Halogen Free Package Q'ty per Reel Part No. RP400xxx1A RP400x001A

(Internally fixed output Voltage type) (Externally adjustable output voltage type)

DFN(PLP)1820-6 5,000 pcs RP400K .xx.1.∗ -TR

SOT-23-5 3,000 pcs RP400N .yy.1.∗ -TR-FE SD SD

VIN LX VIN LX

.xx. : Specify the output voltage within the range of VIN CIN CIN RP400x001A

1.8V to 5.0VVIN

10μF RP400x 10μF

1.8V (.18.) to 5.0V (.50.) in 0.1V steps. OUT

CE VOUT R2

For the externally adjustable output voltage type (.00.). "H"active 10μF

"H"active VFB

.yy. : Specify the output voltage within the range of COUT 10μF R1

GND GND

1.8V (.18.) to 5.0V (.50.) in 0.1V steps. (The externally adjustable output voltage type is not available.) .∗ : Select from (.A.) With CE pin or (.B.) Without CE pin.

PACKAGES TYPICAL CHARACTERISTIC

DFN(PLP)1820-6 SOT-23-5 RP400x001A Efficiency vs. Output Current

Top View Bottom View

6 5 4 4 5 6 5 4 SET VOUT=3.0V

xx1A 001A xx1B 001B xx1A xx1B 1 VIN VIN VIN VIN 1 CE NC 2 CE CE NC NC 2 GND GND

VIN=2.5V

3 GND GND GND GND 3 VIN VIN

VIN=1.8V

4 LX LX LX LX 4 VOUT VOUT

VIN=1.5V 5 NC VFB NC VFB 5 LX LX VIN=0.8V

6 VOUT VOUT VOUT VOUT

Output Current IOUT(m A)

∗) The tab is substrate level (GND).

APPLICATIONS • MP3 players and PDA • LCD bias power supply • Wireless Handset • Digital cameras • Personal medical equipment • GPS No.EK-193-111001 Step-up DC/DC Converter