RT4805BWSC Richtek

RT4805B 2.5MHz, Synchronous Boost Regulator with Bypass Mode Features General Description 4 Few External Components : 0.47H Inductor The RT4805B allows systems to take advantage of and 0603 Case Size Input and Output Capacitors new battery chemistries that can supply significant Input Voltage Range : 1.8V to 5V energy when the battery voltage is lower than the Output Range from 2.85V to 4.4V required voltage for system power ICs. By combining VSEL = L 3.15V built-in power transistors, synchronous rectification, VSEL = H 3.6V and low supply current this IC provides a compact Maximum Continuous Load Current : 2A at V > IN solution for systems using advanced Li-Ion battery 2.65V Boosting V to 3.35V OUT chemistries. Up to 96% Efficient The RT4805B is a boost regulator designed to provide True Bypass Operation when V > Target V IN OUT a minimum output voltage from a single-cell Li-Ion Internal Synchronous Rectifier battery, even when the battery voltage is below system True Load Disconnect when Shut Down minimum. In boost mode, output voltage regulation is Forced Bypass Mode guaranteed to a maximum load current of 2A. V Control to Optimize Target V SEL OUT Quiescent current in Shutdown Mode is less than 1 A, Short-Circuit Protection which maximizes battery life. The regulator transitions 2 I C Controlled Interface smoothly between Bypass and normal Boost Mode. Ultra Low Operating Quiescent Current The device can be forced into Bypass Mode to reduce Small WL-CSP 16B Package quiescent current. The RT4805B is available in the WL-CSP-16B Applications 1.67x1.67 (BSC) package. 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 To pull high voltage VSEL EN nBYP PGOOD SDA SCL AGND PGND Copyright 2017 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS4805B-01 April 2017 www.richtek.com 1 RT4805B Ordering Information Pin Configuration (TOP VIEW) RT4805B Package Type A1 A2 A3 A4 WSC : WL-CSP-16B 1.67x1.67 (BSC) EN PGOOD VIN VIN B1 B2 B3 B4 Note : VSEL SCL VOUT VOUT Richtek products are : C1 C2 C3 C4 nBYP SDA LX LX RoHS compliant and compatible with the current D1 D2 D3 D4 requirements of IPC/JEDEC J-STD-020. AGND PGND PGND PGND Suitable for use in SnPb or Pb-free soldering processes. WL-CSP-16B 1.67x1.67 (BSC) Marking Information 4M : Product Code W : Date Code 4MW Functional Pin Description Pin No. Pin Name Pin Function A1 EN Enable. When this pin is HIGH, the circuit is enabled. Power good. It is a open-drain output. PGOOD pin pulls low automatically if A2 PGOOD the overload or OTP event occurs. A3, A4 VIN Input voltage. Connect to Li-Ion battery input power source. Output voltage select. When boost is running, this pin can be used to select B1 VSEL output voltage 2 B2 SCL Serial interface clock. (Pull down if I C is non-used). B3, B4 VOUT Output voltage. Place C as close as possible to the device. OUT Bypass. This pin can be used to activate forced bypass mode. When this pin C1 nBYP is LOW, the bypass switches are turned on and the IC is otherwise inactive. 2 C2 SDA Serial interface date line. (Pull down if I C is non-used). C3, C4 LX Switching node. Connect to inductor. Analog ground. This is the signal ground reference for the IC. All voltage D1 AGND levels are measured with respect to this pin. Power ground. This is the power return for the IC. The C bypass OUT D2, D3, D4 PGND capacitor should be returned with the shortest path possible to these pins. Copyright 2017 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS4805B-01 April 2017 2