MIC5400 Micrel MIC5400 Dual, 8-Output, 14-Bit LED Video Display Driver General Description Features The MIC5400 consists of 2 banks of 8 LED driver outputs, 2 banks of 8 outputs each output capable of sinking up to 30mA. Each bank is Output characteristics: intended to drive 8 LED pixels of the same color. Most Current sink: 30mA applications will use the MIC5400 to drive pixel clusters of 4 Programmable brightness control LEDs (RRGB.) Typically two red LEDs are used for every one Coarse: 4-bit resolution DAC green and blue to compensate for red LED brightness. Fine: 10-bit resolution PWM Resistor sets maximum LED current to compensate A single external resistor sets maximum drive current. Use of variation in LEDs an external resistor allows different color LED banks to be Current limit on each output biased to the same intensity. Brightness control is digitally Full protection: programmed through the serial interface. Coarse Brightness Over-temperature shutdown Control is determined by two 4-bit DACs, one for each driver Watchdog disables output under fault condition bank, limiting the full-scale output to a fraction of the maxi- Power-on reset (all LEDs Off) mum value. Additionally, each output has Fine Brightness Soft-start on power up and watchdog recovery Control using 10-bit resolution PWM. Output open fault detection with status register Groups of drivers can be cascaded in Daisy Chain fashion. readback Open circuit output faults are detected and can be read back Output transitions are staggered to minimize supply from the internal Status register. transients Applications Outdoor video screen Large LED display Ordering Information Part Number Junction Temp. Range Package MIC5400BWM 40C to +85C 28-Pin Wide SOIC MIC5400YWM 40C to +85C 28-Pin Wide SOIC Typical Application )*+ ( & )*+ % ( % Micrel, Inc. 1849 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 944-0970 MIC5400 Micrel Pin Configuration A4 1 28 A5 A3 2 27 A6 A2 3 26 A7 A1 4 25 A8 LOAD 5 24 VDDA SHFTCLK 6 23 BD A VDD 7 22 GND GND 8 21 IREF SHIFTIN 9 20 BD B SHIFTOUT 10 19 VDDB B1 11 18 B8 B2 12 17 B7 B3 13 16 B6 B4 14 15 B5 28-Lead SOIC Pin Description Pin Number Pin Name Pin Function Pin Name Function 1,2,3,4 A4,A3,A2,A1 Current Sink pins to be connected to LED cathodes 5 LOAD If this pin is Low, the device acts as a shift register. When this pin is High, only the first falling edge of the clock transfers data from the Shift-Register to the Parallel Register. The next rising edge transfers data from the Status Register to the Shift Register 6 SHFTCLK Shift-register Clock Input 7 VDD Positive Supply Voltage 8,22 GND Ground 9 SHIFTIN Shift-register Data Input 10 SHIFTOUT Shift-register Data Output 11,12,13,14 B1,B2,B3,B4 Current Sink pins to be connected to LED cathodes 15,16,17,18 B5,B6,B7,B8 Current Sink pins to be connected to LED cathodes 19 VDDB Analog Power source pins which provide current sense points for Channel A and Channel B PNP emitter currents, independently. 20 BD B Base Drive Outputs for external PNP transistors. Feedback Loop compensa- tion requires one external capacitor at each PNP transistor collector. 21 REF Reference current output. Must be connected to an external resistor to set the maximum current for the current sink outputs. 23 BD A Base Drive Outputs for external PNP transistors. Feedback Loop compensa- tion requires one external capacitor at each PNP transistor collector. 24 VDDA Analog Power source pins which provide current sense points for Channel A and Channel B PNP emitter currents, independently. 25,26,27,28 A8,A7,A6,A5 Current Sink pins to be connected to LED cathodes MIC5400 2 January 2005