ST735SCD

ST735S ST735T 300kHz, -5V/ADJ INVERTING, NEGATIVE OUTPUT CURRENT-MODE PWM REGULATOR ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ CONVERTS +4.0V TO + 6.2V INPUT TO -5V OUTPUT (735S) OR +3.5V TO + 9.0V TO A NEGATIVE ADJUSTABLE OUTPUT (735T) 1W GUARANTEED OUTPUT POWER 72% TYPICAL EFFICIENCY 0.8mA QUIESCENT CURRENT 1µA SHUTDOWN MODE 300KHZ FIXED FREQUENCY OSCILLATOR CURRENT MODE PWM CONVERTER LOW NOISE AND JITTER SOFT START SIMPLE APPLICATION CIRCUIT UNDERVOLTAGE LOCKOUT (735S) DESCRIPTION The ST735S/ST735T is a Bi-CMOS, inverting switch mode DC-DC regulator with internal Power MOSFET that generates a fixed -5V (S version) or a negative adjustable (T version) output voltage from a 4V (3.5V for the 735T) to 6.2V input voltage (9V for the 735T); is guaranteed an output current of 200mA for inputs greater than 4.5V. The quiescent current for this device is typically of ) s ( ct SCHEMATIC DIAGRAM DIP-8 SO-8 ) s t( 0.8mA and, in shutdown mode it is reduced to 1µA. These power-conserving features, along with high efficiency and applications circuits, thaT lend itself to minaturization, make the ST735S/ST735T excellent in a broad range of on-card, HDD and portable equipment applications. These device employ a high performance current mode pulse with modulation (PWM) control scheme to provide tight output voltage regulation and low noise. The fixed frequency oscillator is factory trimmed to 300KHz, allowing for easy noise filtering. The regulator in production is tested to guarantee an output accuracy within ±5% over all specified conditions. c u d e t le o r P o s b O - u d o r P e t e l o s b O October 2002 1/11 ST735S/ST735T ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit VIN DC Input Voltage (VIN to GND) for ST735S -0.3 to +7 V VIN DC Input Voltage (VIN to GND) for ST735T (Note 1) -0.3 to +11 V SHDN Shutdown Voltage (SHDN to GND) -0.3 to VIN+0.3 V VLX Switch Voltage (Lx to VIN) Feedback Voltage (VOUT to GND) -12.5 to +0.3 V -11 to +0.3 V -11 to +0.3 V -0.3 to V++0.3 V VFB VOUT Output Voltage (VOUT to GND) Other Input Voltage (SS, CC to GND) Peack Switch Current ILX Ptot Power Dissipation at Tj = 70°C DIP-8 SO-8 2 A 725 470 mW Tstg Storage Temperature Range -55 to +150 °C Top Operating Junction Temperature Range -40 to +125 °C ) s t( Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied. Note 1: The input to output differential voltage is limited to VIN+|VOUT|