Evaluates: MAX16823 19-0772 Rev 0 3/07 MAX16823 Evaluation Kit General Description Features The MAX16823 evaluation kit (EV kit) circuit demon- 6.5V to 16V Supply Voltage Range strates a current-controlled LED driver that uses the Open LED Detection Output MAX16823 current regulator. The EV kit is configured to supply 50mA to each of the three output channels and On-Board or External LED Connections the circuit features 3 series LEDs per channel. Output 50mA Load Current pads are provided at two channels to evaluate external LEDs rated up to 70mA. Additional output pads are Configurable 550mA Output Current at OUT 3 available to evaluate LEDs rated up to 550mA (typ) on Separate PWM Dimming Control for Each Channel one of the channels. The MAX16823 EV kit requires a 6.5V to 16V, 1A power supply for proper operation. Fully Assembled and Tested However, the MAX16823 IC can accept input voltages from 5.5V to 40V. Ordering Information The MAX16823 EV kit features pulse-width modulation PART TEMP RANGE IC PACKAGE (PWM) dimming-control inputs and an open LED detec- tion output. The MAX16823 EV kit is a fully assembled MAX16823EVKIT+ 0C to +70C* 16 TQFN-EP and tested printed circuit board (PCB). +Denotes a lead-free and RoHS-compliant EV kit. *This limited temperature range applies to the EV kit PCB only. Component List The MAX16823 IC temperature range is -40C to +125C. DESIGNATION QTY DESCRIPTION EP = Exposed paddle. C1 0 Not ins tall ed, cer am i c capac itor ( 1206) Component Suppliers 0.1F 10%, 50V X7R ceramic C2, C3 2 capacitors (0603) SUPPLIER PHONE WEBSITE Murata GRM188R71H104K Fairchild 888-522-5372 www.fairchildsemi.com Semiconductor 0.015F 10%, 50V X7R ceramic C4 1 capacitor (0603) IRC/TT Electronics 361-992-7900 www.irctt.com Murata GRM188R71H153K M ur ata Mfg . C o., Ltd . 770-436-1300 www.murata.com Red LEDs (4-PLCC) OSRAM Opto D1D9 9 888-446-7726 www.osram-os.com OSRAM LR E6SF-AABB-1-1 Semiconductors JU1JU4 4 3-pin headers Note: Indicate that you are using the MAX16823 when contact- ing these component suppliers. JU5, JU6, JU7 3 2-pin headers 80V, 3A npn transistor (D-PAK) Q1 1 Quick Start Fairchild Semiconductor MJD31CTF R1 0 Not installed, resistor (0805) Recommended Equipment R2, R3, R4 3 4.02 1% resistors (0805) 16V adjustable, 1A power supply Two digital voltmeters 0.4 1%, 500mW sense resist or ( 1206) R5 1 IRC/TT Electronics LRC-LRF- Procedure 1206LF-01-R400-F The MAX16823 EV kit is fully assembled and tested. R6 1 10k 5% resistor (0603) Follow the steps below to verify operation. Caution: Do not turn on the power supply until all connections R7 1 0 5% resistor (1206) are completed. TP1 1 PC mini red test point 1) Connect the power supplys positive terminal to the MAX16823ATE+ (16-pin TQFN, U1 1 IN PCB pad on the EV kit. Connect the power sup- 5mm x 5mm x 0.8mm) plys ground terminal to the GND PC pad located 7 Shunts (JU1JU7) directly above the IN pad. 1 PCB: MAX16823 Evaluation Kit+ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.MAX16823 Evaluation Kit 2) Connect a digital voltmeter across the IN and GND Output Current Setting pads and the other voltmeter across the LEDGOOD The output current for the on-board LEDs is set to and GND pads. 50mA (typ) with resistors R2, R3, or R4. 3) Verify that shunts are installed across pins 1-2 of Use the following equation to adjust the respective jumpers JU1, JU2, and JU3 (LEDs at full intensity). channels output current at OUT1, OUT2, OUT3, or OUT 3: 4) Verify that a shunt is installed across pins 2-3 of jumper JU4 (on-board LEDs selected at OUT3), 203mV()typ and that a shunt is not installed on jumper JU5 R = (LEDs current set to 50mA). I LED 5) Verify that the shunts are installed on jumpers JU6 where R is the external current-sense resistor at CS1, and JU7 (on-board LEDs selected at OUT1 and CS2, CS3, or CS 3, and I is the desired output cur- LED OUT2). rent in milliamperes. 6) Turn on the power supply and increase the input The output current for the LEDs, with the exception of voltage to 12V. The LEDs should illuminate with full external LEDs at OUT 3, can be adjusted to a maxi- brightness. mum 70mA by replacing the respective resistor. 7) Verify that the voltmeter at LEDGOOD measures When a shunt is installed across pins 1-2 of jumper approximately 3.4V. JU4, and a shunt is installed at jumper JU5, the output Detailed Description current for the external LEDs at OUT 3 is set to 550mA (typ) by the parallel resistors combination R2 and R5, The MAX16823 EV kit demonstrates the MAX16823 IC connected at CS 3. LED driver. The MAX16823 outputs (OUT1, OUT2, and OUT3) are configured to supply 50mA to the on-board PWM Dimming LEDs. The MAX16823 EV kit operates over the input- The MAX16823 EV kit features PWM input PCB pads voltage range of 6.5V to 16V and requires a 1A power (DIM1, DIM2, and DIM3) that can be used to control supply. The MAX16823 IC can operate from 5.5V to LED brightness at each output using external logic sig- 40V. Refer to the MAX16823 data sheet for proper con- nals. Jumpers JU1, JU2, and JU3 control the on and off figuration. condition of the EV kit LEDs. Install shunts across pins The MAX16823 EV kit outputs are current controlled by 1-2 to turn on the LEDs current. Install shunts across monitoring the voltage across the respective outputs pins 2-3 to turn off the LEDs current. See Table 1 for external low-side sense resistors (R2, R3, and R4). The EV PWM configuration. kit features 3 series-connected LEDs at each channels Table 1. PWM Configuration (JU1, JU2, output. All outputs provide pads to evaluate external LEDs by bypassing the on-board LEDs after configur- and JU3) ing the appropriate jumpers. Two of the outputs can be SHUNT DIM1, DIM2, DIM3 EV KIT used to evaluate LEDs with current rated up to 70mA. A POSITION PINS FUNCTION third output (OUT 3) provides 550mA (typ) to the exter- nal user-supplied LEDs using transistor Q1 and cur- 1-2 REG LEDs on rent-sense resistor R5. 2-3 GND LEDs off The MAX16823 EV kit features PC pads to control the Driven by external Not installed PWM operation PWM dimming function of each output channel. The source MAX16823 EV kit also features a PCB pad to monitor the status of the LEDGOOD output, which is pulled up To operate the MAX16823 EV kit in PWM operation, to REG by resistors R6 and R7. remove the shunts at jumpers JU1, JU2, or JU3 for indi- vidual PWM control of the respective channels. Typically, capacitor C1 is not required if the power sup- Connect digital PWM signals at the DIM1, DIM2, and ply is relatively close to the EV kit. If long wires are DIM3 pads with a 2.8V to V logic level and square- IN used to connect the power supply to the EV kit, sur- wave frequencies from DC to 3kHz. Vary the duty cycle face-mount 1206 PC pads are provided for adding to adjust the LED brightness. LED brightness increases additional bulk capacitance at C1. when the duty cycle increases and vice versa. When the PWM signal duty cycle at DIM is 100%, the LEDs are fully on. 2 Evaluates: MAX16823