RT4805B Datasheet, PDF (1/23 Pages) Richtek Technology Corporation – Synchronous Boost Regulator

RT4805B
2.5MHz, Synchronous Boost Regulator with Bypass Mode
General Description
The RT4805B allows systems to take advantage of
new battery chemistries that can supply significant
energy when the battery voltage is lower than the
required voltage for system power ICs. By combining
built-in power transistors, synchronous rectification,
and low supply current; this IC provides a compact
solution for systems using advanced Li-Ion battery
chemistries.
The RT4805B is a boost regulator designed to provide
a minimum output voltage from a single-cell Li-Ion
battery, even when the battery voltage is below system
minimum. In boost mode, output voltage regulation is
guaranteed to a maximum load current of 2A.
Quiescent current in Shutdown Mode is less than 1A,
which maximizes battery life. The regulator transitions
smoothly between Bypass and normal Boost Mode.
The device can be forced into Bypass Mode to reduce
quiescent current.
The RT4805B is available in the WL-CSP-16B
1.67x1.67 (BSC) package.
Features
 4 Few External Components : 0.47H Inductor
and 0603 Case Size Input and Output Capacitors
 Input Voltage Range : 1.8V to 5V
 Output Range from 2.85V to 4.4V
 VSEL = L 3.15V
 VSEL = H 3.6V
 Maximum Continuous Load Current : 2A at V_IN >
2.65V Boosting V_OUT to 3.35V
 Up to 96% Efficient
 True Bypass Operation when V_IN > Target V_OUT
 Internal Synchronous Rectifier
 True Load Disconnect when Shut Down
 Forced Bypass Mode
 V_SEL Control to Optimize Target V_OUT
 Short-Circuit Protection
 I²C Controlled Interface
 Ultra Low Operating Quiescent Current
 Small WL-CSP 16B Package
Applications
 Single-Cell Li-Ion, LiFePO4 Smart-Phones or Tablet
 2.5G/3G/4G Mini-Module Data Cards
Simplified Application Circuit
RT4805B
VIN
VOUT
+
C_IN
-
C_OUT
L1
LX
VSEL
To pull high voltage
EN
nBYP
SDA
PGOOD
SCL
AGND PGND
Copyright © 2017 Richtek Technology Corporation. All rights reserved.
DS4805B-01 April 2017
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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