SC1175 Low Power Dual Synchronous DC/DC Controller With Current Sharing Circuitry POWER MANAGEMENT Features Description The SC1175 is a versatile 2 phase, synchronous, volt- ‹ 300kHz fixed frequency operation age mode PWM controller that may be used in two dis- ‹ Soft Start and Enable function tinct ways. First, the SC1175 is ideal for applications ‹ Power Good output provided where point of use output power exceeds any single in- ‹ Over current protection with 50% fold-back put power budget. Alternatively, the SC1175 can be used ‹ Phase-shifted switchers minimize ripple as a dual switcher. The SC1175 features a temperature ‹ High efficiency operation, >90% compensated voltage reference, over current protection ‹ Programmable output(s) as low as 1.25V with 50% fold-back and internal level-shifted, high-side ‹ Industrial temperature range drive circuitry. ‹ 20 pin SOIC or TSSOP package Two Phase, Current Sharing Controller In current sharing configuration, the SC1175 can pro- duce a single output voltage from two separate voltage ‹ Flexible, same or separate V sources (which can be different voltage levels) while IN ‹ Programmable current sharing maintaining current sharing between the channels. Cur- rent sharing is programmable to allow loading each input ‹ Combined current limit with fold-back supply as required by the application. ‹ 2 phases operating opposed for ripple reduction ‹ Thermal distribution via multi-phase output In dual switcher configuration, two feedback paths are Two Independent PWM Controllers provided for independent control of the separate out- puts. The device will provide a regulated output from ‹ Flexible, same or separate V flexibly configured inputs (3.3V, 5V, 12V), provided 5V is IN ‹ Independent control for each channel present for V . The two switchers are 180° out of phase CC ‹ Independent and separate current limit to minimize input and output ripple. ‹ 2 phases operating opposed for ripple reduction (if same V used) IN Applications ‹ Graphics cards ‹ DDR Memory ‹ Peripheral add-in card ‹ SSTL Termination ‹ Dual-Phase power supply ‹ Power supplies requiring two outputs Revision: September 22, 2004 1 www.semtech.com SC1175 POWER MANAGEMENT Typical Application Circuit 2 Channels with Current Sharing www.semtech.com  2004 Semtech Corp. 2 SC1175 POWER MANAGEMENT Absolute Maximum Rating Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied. Pl arameter Ss ymbo Ls imit Unit VtV o GND -V 0.3 to 15 CC IN PGND to GND ±V 1 BST to GND -V 0.3 to 26 Thermal Resistance Junction to Case θ 3W 0 °C/ JC Thermal Resistance Junction to Ambient 9C 0 °W / θ JA Oe peratingAT mbient Temperature Rang 0C to 85 ° A Oe peratingJT unction Temperature Rang 0C to 125 ° J ST torage Temperature Range -C 65 to +150 ° STG LT ead Temperature (Soldering) 10 sec 3C 00 ° LEAD Electrical Characteristics Unless Specified: V = 4.75 to 5.25V, GND = PGND = 0V, FB = V , 0mV < (CS(+) - CS(-)) < 60mV , T = 25°C CC O J PS ARAMETER CN ONDITION MP I TX YMS A UNIT (1) OI utput Voltage = 2A , Vs5 et to 2.75V 25 .6 25 .7 2V .8 O OUT SV upply Voltage 45 .2 1V CC SV upply Current =0 5.0 1A m CC Reference 15 .237515 .21V .262 (1) LI oad Regulation = 0.3A to 15A 1% O RV eference Line Regulation 5