L6997S STEP DOWN CONTROLLER FOR LOW VOLTAGE OPERATIONS Figure 1. Package 1 Features FROM 3V TO 5.5V V RANGE CC MINIMUM OUTPUT VOLTAGE AS LOW AS 0.6V 1V TO 35V INPUT VOLTAGE RANGE TSSOP20 CONSTANT ON TIME TOPOLOGY Table 1. Order Codes VERY FAST LOAD TRANSIENTS 0.6V, 1% VREF Part Number Package SELECTABLE SINKING MODE L6997S TSSOP20 LOSSLESS CURRENT LIMIT, AVAILABLE L6997STR Tape & Reel ALSO IN SINKING MODE REMOTE SENSING 3 Description OVP,UVP LATCHED PROTECTIONS The device is a high efficient solution for networking 600 A TYP QUIESCENT CURRENT dc/dc modules and mobile applications compatible with 3.3V bus and 5V bus. POWER GOOD AND OVP SIGNALS It s able to regulate an output voltage as low as 0.6V. PULSE SKIPPING AT LIGTH LOADS The constant on time topology assures fast load tran- 94% EFFICIENCY FROM 3.3V TO 2.5V sient response. The embedded voltage feed-forward provides nearly constant switching frequency opera- tion in spite of a wide input voltage range. 2 Applications An integrator can be introduced in the control loop to NETWORKING reduce the static output voltage error. DC/DC MODULES The remote sensing improves the static and dynamic DISTRIBUTED POWER regulation, recovering the wires voltage drop. MOBILE APPLICATIONS Pulse skipping technique reduces power consump- CHIP SET, CPU, DSP AND MEMORIES tion at light loads. Drivers current capability allows SUPPLY output currents in excess of 20A. Figure 2. Minimum Component Count Application 3.3V Rin2 Rin1 Cin OSC Dboot BOOT HGATE HS Cboot L 0.6V PHASE PGOOD Ro1 LGATE OVP LS DS Cout L6997S Ro2 PGND ILIM GND GNDSENSE Rilim VSENSE SS Css INT VFB Vref SHDN Cvref REV. 1 June 2004 1/30 VCC VDRL6997S Table 2. Absolute Maximum Ratings Symbol Parameter Value Unit V V to GND -0.3 to 6 V CC CC V V to GND -0.3 to 6 V DR DR HGATE and BOOT, to PHASE -0.3 to 6 V HGATE and BOOT, to PGND -0.3 to 42 V V PHASE -0.3-to 36 V PHASE LGATE to PGND -0.3 to V +0.3 V DR ILIM, VFB, VSENSE, NOSKIP, SHDN, PGOOD, OVP, VREF, -0.3 to V +0.3 V CC INT, GND to GND SENSE BOOT, HGATE Maximum Withstanding Voltage Range 750 V and PHASE Test Condition:CDF-AEC-Q100-002 Human Body Model PINS Accepatance Criteria: Normal Performance OTHER PINS 2000 V P Power dissipation at T = 25C 1 W tot amb T Storage temperature range -40 to 150 C stg Table 3. Thermal Data Symbol Parameter Value Unit R Thermal Resistance Junction to Ambient 125 C/W th j-amb T Junction operating temperature range -40 to 125 C j Figure 3. Pin Connection (Top View) NOSKIP 1 20 BOOT GNDSENSE 2 19 HGATE ININTT 3 18 PHASE VSENSE 4 17 VDR VCC 5 16 LGATE GND 6 15 PGND VREF 7 14 PGOOD VFB 8 13 OVP OSC 9 12 SHDN SS 10 11 ILIM TSSOP20 Table 4. Pin Function N Name Description 1 NOSKIP Connect to V to force continuous conduction mode and sink mode. CC 2 GNDSENSE Remote ground sensing pin 3 INT Integrator output. Short this pin to VFB pin and connect it via a capacitor to V to insert the OUT integrator in the control loop. If the integrator is not used, short this pin to VREF. 4 VSENSE This pin must be connected to the remote output voltage to detect overvoltage and undervoltage conditions and to provide integrator feedback input. 2/30