ZXSC400 LED DRIVER BOOST CONVERTER DESCRIPTION The ZXSC400 is a voltage mode boost converter in the SOT23-6 package. Its low feedback voltage allows the current in a chain of LEDs to be set and accurately monitored with a single resistor giving minimal losses. Its excellent load and line regulation means that for the full supply range from lithium-ion cells, the LED current will typically change by less than 1%. Using high efficiency Zetex switching transistors with ratings of 20V and higher allow many LEDs to be chained in series for the best LED current matching possible. FEATURES 1.8V to 8V supply range Typical output regulation of 1% Over 80% typical efficiency 4.5 A typical shutdown current Series connection for ultimate LED current matching APPLICATIONS White LED backlighting for colour LCD panels General LED backlighting High performance white LED flashlights PINOUT General LED driving from batteries ORDERING INFORMATION V DRIVE CC DEVICE REEL TAPE QUANTITY GND V FB SIZE WIDTH PER REEL STDN SENSE 7 8mm 3000 units ZXSC400E6TA Top View DEVICE MARKING C400 ISSUE 1 - JANUARY 2003 1 SOT23-6ZXSC400 ABSOLUTE MAXIMUM RATINGS V -0.3V to +10V CC DRIVE -0.3V to V + 0.3V CC EOR -0.3V to V + 0.3V CC STDN -0.3V to The lower of (+5.0V) or (V + 0.3V) CC SENSE -0.3V to The lower of (+5.0V) or (V + 0.3V) CC Operating Temp. -40C to +85C Storage Temp. -55C to +125C Power Dissipation 450mW ELECTRICAL CHARACTERISTICS Test Conditions V = 3V, T= -40C to 85C unless otherwise stated. CC Symbol Parameter Conditions Limits Units Min Typ Max Supply parameters V V Range 1.8 8 V IN CC 1 Iq Quiescent Current V = 8V 220 A CC I Shutdown Current 4.5 A STDN 1 Eff Efficiency 30mA > I > 10mA 80 % LED Acc Reference tolerance 1.8V < V < 8V -3.0 3.0 % REF CC TCO Reference Temp Co 0.005 %/ C REF T Discharge pulse width 1.8V < V <8V 1.7 s DRIVE CC F Operating Frequency 200 kHz OSC Input parameters V Sense voltage 22 28 34 mV SENSE I Sense input current V =0V, V = 0V -1 -7 -15 A SENSE FB SENSE V Feedback voltage 291 300 309 mV FB 2 I Feedback input current V =0V, V = 0V -1.2 -4.5 A FB FB SENSE V Shutdown high voltage 1.5 V V IH CC V Shutdown low voltage 0 0.55 V IL dV Line voltage regulation 0.5 %/V LN Output parameters 3 I Output current Vin > 2V, Vout = 10.5V 50 mA OUT I Transistor drive current Vdrive = 0.7V 2 3.5 5 mA DRIVE V Transistor voltage drive 1.8V < V <8V 0 V -0.4 V DRIVE CC CC C Mosfet gate drive cpbty 300 pF DRIVE 4 dILD Load current regulation 0.1 mA/V Note 1 Excluding gate/base drive current. 2 I is typically half these values at 300mV. FB 3 System not device spec, including recommended transistors. 10.5V represents 3 white LEDs. 4 Change in LED current with changing supply voltage (LED V x number of series LEDs). F ISSUE 1 - JANUARY 2003 2