SC190 Synchronous Buck Converter with Programmable Output POWER MANAGEMENT Features Description Features The SC190 is a synchronous step-down converter with Less than 1mV Supply Ripple integrated power devices and an integrated front-end Output Voltage Regulated by Either the Switching LDO to minimize input supply ripple. Output voltage is Regulator or Linear Regulator programmable using two control bits, eliminating the need Dynamic Handover Between Linear and Switching for feedback resistors tied to the output. The device is Regulator for Maximum Efciency offered in four distinct variants with each variant providing 2.7V to 5.5V Input Range four xed output voltage options to choose from. 300mA Guaranteed Output Current Fixed Frequency 1MHz Operation or 750kHz to The front-end LDO can be bypassed externally to maximize 1.5MHz Clocked Operation efciency. A second LDO is switched in place of the No Schottky Diode Required switching regulator for low current operation to further Up to 95% Efciency (VIN=BP) improve efciency and reduce noise. Over-current Protection Over-voltage Protection The SC190s exible clocking scheme allows it to be Over-temperature Protection synchronized to an external oscillator or controlled by the Soft Start internal oscillator. The 1MHz switching frequency allows MLP-10, 3 x 3mm Lead-frame, Lead-free Package the use of small inductors and capacitors. Low Output Noise < 100Vrms The internal MOSFET switches provide peak current Applications greater than 500mA to achieve a DC output of at least Cell Phones 300mA. Shutdown current is typically 0.1A. Cordless Phones Notebook and Subnotebook Computers The SC190 has four different variants with four voltage PDAs and Mobile Communicators settings each. It is designed for single-cell Li-ion battery WLAN Peripherals applications, but also performs well in xed 3.3V and 5V 1 Li-Ion or 3 NiMH/NiCd Powered Devices applications. Typical Application Circuit 4.7H VIN VIN VOUT LX SC190 LOUT EN VOUT SYNC/PWM CIN COUT VID0 4.7F BP 4.7F CBP VID1 GND 4.7F MODE June 30, 2005 www.semtech.com 1SC190 POWER MANAGEMENT Absolute Maximum Ratings Exceeding the specications below may result in permanent damage to the device or device malfunction. Operation outside of the parameters specied in the Electrical Characteristics section is not implied. Parameter Symbol Maximum Units VIN Input V -0.3 to 7 V IN Logic Inputs (SYNC/PWM, V -0.3 to 7 V N EN, MODE, VID0, and VID1) LX Voltage V -1 to BP +1 V LX VOUT Voltage V -0.3 to VIN + 0.3 V OUT BP Voltage V VIN -0.3 to VIN + 0.3 V BP Thermal Impedance Junction to Ambient *31 JA C/W VOUT Short Circuit to GND t Continuous s SC BP Current I 0.8 A BP LX Current I +1.2 A LX Storage Temperature T -65 to +150 C S Junction Temperature T +150 C JC Peak IR Reow Temperature T 260 C LEAD * Tied to PCB with 1 square inch, 2 ounce copper. Electrical Characteristics Unless otherwise noted: V = 3.6V, SYNC/PWM = V , MODE = GND, EN = V , T = -40 to 85C. Typical values are at T = +25C. This device is ESD sensitive. IN IN IN A A Use of standard ESD handling precautions is required. Parameter Symbol Conditions Min Typ Max Units V = V 2.7 5.5 V IN BP Input Voltage Range V IN V V 2.9 5.5 V IN BP Input Voltage Ripple V C , C = 10F 1 mV IN PK-PK IN BP 190A, B and D: see note (1) -0.3 0.3 %/V Line Regulation V LINEREG 190C: see note (2) -0.5 0.5 %/V Load Regulation V I = 5mA to 300mA 0.002 %/mA LOADREG OUT P-Channel On Resistance R I = 100mA 0.3 DSP LX N-Channel On Resistance R I = 100mA 0.2 DSN LX Start Up Time T I = 150mA 1.25 ms START OUT 2005 Semtech Corp. 2 www.semtech.com