RICOH R1286K Series PWM Step-up Inverting DC-DC Converter for AMOLED LCD with Synchronous Rectifier User's Manual Data Sheet

R1286K Series

PWM Step-up/Inverting DC/DC Converter for AMOLED/LCD with synchronous rectifier

The R1286K Series are CMOS-based PWM step-up/inverting DC/DC converters featuring 250m A×2 output current with synchronous rectifier. R1286K includes a soft start circuit, an under-voltage lockout circuit (UVLO), a latch protection circuit, a thermal shutdown circuit, and a shutdown circuit. By simply using two inductors and three capacitors as external components, a high-efficiency step-up/inverting DC/DC converter can be easily configured. R1286K is available in two types: R1286K001B is the type to which the output voltage (VOUTP and VOUTN) can be adjusted by external resistors. R1286Kxxx A/C~M are the type to which the step-up output voltage (VOUTP) is internally fixed and the inverting output voltage (VOUTN) can be adjusted dynamically by the single wire interface. The R1286K has a sequenced start up. After the CE pin is enabled, the step-up output is starting up followed by the inverting output after a delay time. As for shutdown, both outputs will be turned off by the auto-discharge function. R1286K is used for applications such as LCD and AMOLED displays.

FEATURES • Supply Current (ICC) ·······················Typ. 1.2m A (VCC=4.8V, In non-switching) • Output Current (IOUT) ······················ Step-up:250m A, Inverting:250m A • Standby Current (Istandby) ················Max. 5μA (VCC=VLXP=4.8V, CE="L") • Oscillator Frequency (fosc) ················ 1.75MHz • Input Voltage Range (VIN) ··············2.3V to 4.8V • Maximum Duty Cycle (Maxduty) ··········· Step-up: Typ. 85% , Inverting: Typ. 90% • Step-up Output Voltage (VOUTP) ·····4.6V to 5.8V (internally fixed), • UVLO Detect Voltage (VUVLO)··········· Typ. 2.05V

Externally adjustable (VFB: 1V) (001B) • Soft Start Time (t SSP) ························ Step-up: Typ. 2.4ms, Inverting: Typ. 2.8ms(B)

• Inverting Output Voltage (VOUTN)····-2.0V to -6.0V (internally fixed), • Coil-current Limit Circuit ························ Step-up: Typ. 1A, Inverting: Typ. 1.5A

Externally adjustable (VFB: 0V) (001B) , • Latch Protection Circuit···················· Delay time for protection Typ. 16ms

Dynamically adjustable output voltage with single wire interface. • Auto-Discharge function

• Feedback Voltage Accuracy ··········Step-up: ± 9m V (Except B), ± 15m V (B) • Thermal Shutdown Circuit ·············· Stops at 150°C

Ef fic ie nc y[ • Package···········································

Inverting: ± 70m V (Except B) , ± 25m V (B) DFN(PLP)2730-12

BLOCK DIAGRAM TYPICAL APPLICATION

R1286Kxxx A/C~M

R1286Kxxx A/C~M R1286K001B

VOUTN

C2 VOUTNS TST

EN control

VOUTN CE

L2 S-Wire

LXN VOUTPS

VOUTP

VOUTP PVCC

C1 VCC LXP

GND PGND

Ef fic ie nc y[ R4

VOUTN EN control

VFBN VREF

VOUTN CE

LXN VFBP C5

R3 R2 VOUTP

VOUTP PVCC

C1 VCC LXP

SELECTION GUIDES

xxx :Serial number to specify a combination of the VOUTP voltage and VOUTN preset

Halogen Free Package Q'ty per Reel Part No.

value. The externally adjustable output voltage type is (001).

R1286Kxxx.$ -TR

DFN(PLP)2730-12 5,000 pcs $ :Specify designation method of VOUTP and VOUTN settings..

R1286K001$ -TR

(A/C to M*) VOUTP voltage and VOUTN preset value are internally fixed. VOUTN voltage can be adjusted dynamically by the single wire interface.

*) R1286Kxxx I does not exist. For information about the versions, Please contact us.

(B) VOUTP and VOUTN are externally adjusted.

PACKAGE TYPICAL CHARACTERISTICS

DFN(PLP)2730-12 R1286Kxxxx Efficiency vs. Output Current Bottom View Top View

(VOUTP=4.6V, VOUTN= -4.9V) (VOUTP=5.4V, VOUTN= -5.4V)

xx A/C～M 001B xx A/C～M 001B

Vin= 4.2 V Vin= 4.2 V

1 VOUTNS VFBN 7 PGND Vin= 3.7 V Vin= 3.7 V

Vin= 2.9 V Vin= 2.9 V

2 VOUTN 8 LXP 3 LXN 9 VOUTP

IOUT P [m A] IOUT N [m A]

4 PVCC 10 VOUTPS VFBP 5 VCC 11 CE 6 GND 12 TST VREF ∗) The tab is substrate level (GND).

APPLICATIONS • Power source for AMOLED and LCD • Power source for hand-held equipment No.EK-283-120531 Step-up/Inverting DC/DC Converter