RICOH RP504x SERIES Data Manual (1) Service Manual

RP504x Series

600m A∗ PWM/VFM Step-down DC/DC Converter with Synchronous Rectifier

The RP504x Series are low supply current CMOS-based PWM/VFM step-down DC/DC converters with synchronous rectifier. RP504K/L can be switched from two control types by inputting signal to the MODE pin - forced PWM control or PWM/VFM auto switching control in which mode automatically switches to high-efficiency VFM mode in low output current. (RP504N Series can be selected from forced PWM control or PWM/VFM auto switching control.) RP504x includes a soft start circuit, an under-voltage lockout circuit (UVLO), and a latch protection circuit. By simply using an inductor and capacitors as external components, a high-efficiency step-down DC/DC converter can be easily configured. The small inductor (2.2μH) and output capacitor (4.7μH) can be used by the switching of 2.25MHz. In addition to SOT-23-5 and DFN1616-6B packages, a 1.2mm × 1.6mm DFN(PLP)1216-6B package is also available.

FEATURES • Supply Current (IDD1)·······················Typ. 400μA (VIN=VCE=5.5V, VOUT=VSET×0.8) • UVLO Detect Voltage (VUVLO) ·············Typ. 2.0V • Supply Current (IDD2)·······················Typ. 25μA (VIN=VCE=VOUT=5.5V) • Soft Start Time (tstart)························Typ. 0.15ms • Standby Current (Istandby)··················Max. 5μA (VIN=5.5V, VCE=0V) • Coil-current Limit Circuit ·················Current limit Typ. 900m A • Input Voltage Range (VIN) ···············2.3V to 5.5V • Latch Protection Circuit ··················Delay time for protection Typ. 1.5ms • Output Voltage Range (VOUT)··········0.8V to 3.3V (internally fixed) • Auto-Discharge Function················D Version • Output Voltage Accuracy ················± 1.5% • MODE pin······································· “H”: PWM/VFM auto switching, • Output Current (IOUT)·······················600m A∗ “L”: forced PWM • Oscillator Frequency (fosc)···············2.25MHz (RP504N does not have MODE pin) • Oscillator Maximum Duty Cycle (Maxduty) ··Min. 100% • Packages········································DFN(PLP)1216-6F,

DFN1616-6B, SOT-23-5

∗) This is an approximate value, because output current depending on conditions and external parts.

BLOCK DIAGRAM TYPICAL APPLICATION

RP504L/K RP504L/K

ffi ci en cy VIN VOUT

VIN LX

VIN 2.2μH

Chip Slope Current CIN CE VOUT COUT

CE Enable Compensation Feedback

OSC Current GND MODE

Protection LX

Vref PWM∗1 Switching

Control Control

Soft Start VOUT

UVLO L : MIPSZ2520D2R2、MIPS2520D2R2 (FDK)、

MLP2520S2R2M、VLS252010T-2R2M (TDK)

CKP2520-2R2M (TAIYO YUDEN)

GND CIN : 2.2μF: C1608JB0J225K (TDK)、

2.2μF×2: C1005JB0J225K (TDK)、JMK105BJ225MV (TAIYO YUDEN) 4.7μF: C1005X5R0J475M (TDK)、JMK105BJ475MV (TAIYO YUDEN)

*1) MODE="H": PWM/VFM auto switching、MODE="L": forced PWM

COUT : C1608JB0J475K (TDK)、GRM155B30J475KE18 (MURATA)

Blue Line : only RP504Kxx1D, RP504Lxx1D

SELECTION GUIDES

.∗ . : Select from (.A.) With MODE pin, without auto-discharge function,

Halogen Free Package Q'ty per Reel Part No.

(.D.) With MODE pin, with auto-discharge function,

DFN(PLP)1216-6F 5,000 pcs RP504L .xx1∗-E2

$ : Select from (.B.) PWM/VFM auto switching, without auto-discharge function,

DFN1616-6B 5,000 pcs RP504K .xx1∗ -TR

(.C.) forced PWM, without auto-discharge function,

SOT-23-5 3,000 pcs RP504N .xx1$ -TR-FE .xx. : Specify the output voltage within the range of 0.8V (.08.) to 3.3V (.33.) in 0.1V steps.

PACKAGES (Top View) TYPICAL CHARACTERISTIC

DFN(PLP)1216-6F DFN1616-6B SOT-23-5 RP504x (VOUT=3.3V) Efficiency vs. Output Current

VIN=5.0V, VMODE=0V

VIN=4.3V, VMODE=0V

1 VIN 1 CE 1 VOUT

VIN=VMODE=4.3V

2 MODE 2 MODE 2 GND 3 CE 3 VIN 3 LX

4 VOUT 4 LX 4 VIN VIN=VMODE=3.6V

5 GND 5 GND 5 CE

6 LX 6 VOUT 0.01 0.1

Output Current IOUT (m A)

∗) The tab is substrate level (GND).

APPLICATIONS • Power source for battery-powered equipment • Power source for hand-held communication equipment, cameras, and VCRs • Power source for compact HDD

No.EK-259-120326 Step-down DC/DC Converter