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19-2877; Rev 0; 5/03
MAX1582 Evaluation Kit
General Description
The MAX1582 evaluation kit (EV kit) is a fully assembled and tested circuit board that evaluates the MAX1582 white LED step-up converter. The circuit operates from 2.6V to 5.5V and delivers 0 to 20mA to light a series of up to six white LEDs. The evaluation kit has two groups of white LEDs--a main group with four LEDs, and a subgroup with two LEDs. These two groups of LEDs have independent shutdown/enable control through jumpers provided on the board. A flexible dimming feature allows the LED brightness to be controlled with either an analog voltage or a PWM signal.
Features
o Constant Current Regulation for Uniform Illumination o Up to 84% Efficiency o Flexible Analog or PWM Dimming Control o Low 15mVP-P Input Ripple o 0.9W Output Power with Internal 30V MOSFET Switch o Output Overvoltage Protection Eliminates Zener Diode o Small, Low-Profile Components o 2.6V to 5.5V Input Range o 0.01A Shutdown Current o Thin QFN 4mm x 4mm IC Package o Fully Assembled and Tested
Evaluates: MAX1582
Component Suppliers
SUPPLIER Central Semiconductor Kamaya Murata Nichia Panasonic Sumida Taiyo Yuden TDK TOKO PHONE 631-435-1110 260-489-1533 814-237-1431 248-352-6575 714-373-7939 847-956-0666 408-573-4150 847-803-6100 847-297-0070 WEBSITE www.centralsemi.com www.kamaya.com www.murata.com www.nichia.com www.panasonic.com www.sumida.com www.t-yuden.com www.component.tdk.com www.toko.com
Ordering Information
PART MAX1582EVKIT TEMP RANGE -30C to +85C IC PACKAGE 12 Thin QFN
Note: When contacting these suppliers, please specify you are using the MAX1582.
Component List
DESIGNATION QTY DESCRIPTION 2.2F, 6.3V X5R capacitor (0603) Taiyo Yuden JMK107BJ225KA, or Panasonic ECJ1VB0J225M, or equivalent 0.1F, 50V X7R capacitor (0603) TDK C1608X7R1H104KT or equivalent 0.022F X7R capacitor (0603) Taiyo Yuden TMK107BJ223KA or equivalent 30V, 200mA Schottky diode (SOD323) Central CMDSH2-3 White LEDs Nichia NSCW215T DESIGNATION QTY DESCRIPTION JU1, JU2 JU3 2 1 3-pin headers 2-pin header 22H inductor (1210) 250mA, 710m, 2.5 mm x 2.2 mm x 2.0mm Murata LQH32CN220K 7.5 1% resistor (0603) 100k 5% resistor (0603) MAX1582ETC (12-pin thin QFN 4 x 4) MAX1582EBE (UCSP 4 x 4) Shunts MAX1582 EV kit PC board
C1
1
L1 C2 1
1
R1 R2 U1 U2 None None
1 1 1 1 3 1
C3
1
D1
1
D2-D7
6
________________________________________________________________ Maxim Integrated Products
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For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
MAX1582 Evaluation Kit Evaluates: MAX1582
Quick Start
Follow the steps below to verify board operation. Do not turn on the power supply until all connections are completed: 1) Verify the shunts on JU1 and JU2 are across pins 2 and 3. Verify that a shunt is across the pins of jumper JU3. Preset the power supply to between 2.6V and 5.5V. Turn off the power supply. Connect the power-supply positive terminal to the V+ pad on the EV kit. 6) Connect the power-supply ground terminal to the GND pad on the EV kit. 7) Turn on the power supply and verify that the LEDs are lit. 2) 3) 4) 5) and 3 of JU2 to enable the subgroup, or connect pins 1 and 2 to disable the subgroup (Table 1). If both LED groups are disabled, then the IC enters low-power shutdown mode.
Controlling LED Intensity
LED intensity is controlled using the CTRL input. CTRL is used either as an analog input or a digital PWM input. When using CTRL as an analog input, connect a 0 to 1.62V voltage source to CTRL, where 0V corresponds to the dimmest setting, and 1.62V is full brightness. Exceeding 1.62V does not increase brightness. For digital dimming, connect a PWM signal (200Hz to 200kHz) directly to CTRL. In this case, the duty cycle controls the brightness of the LEDs, where 0% duty cycle corresponds to zero current and 100% duty cycle corresponds to full current. PWM signal VIL should equal 0V and VIH should exceed 1.62V. A pullup resistor and jumper (R2 and JU3) are provided so the evaluation kit can be used without an external connection to CTRL. With JU3 shorted and no other connection to CTRL, the LEDs are set to full brightness. If CTRL is being driven, the shunt across JU3 can be removed. Remove the shunt across JU3 when measuring quiescent current with the circuit in shutdown mode; otherwise excessive current is measured.
Detailed Description
Enable/Shutdown
The LEDs on the MAX1582 EV kit are divided into two groups--a main group consisting of D2-D5 and a subgroup consisting of D6 and D7. Connect pins 2 and 3 of JU1 to enable the main LED group, or connect pins 1 and 2 to disable the main LED group. Connect pins 2
Table 1. Jumper Functions
JUMPER JU1 JU2 JU3 JU4 JU5 JU6 POSITION 1, 2 2, 3 1, 2 2, 3 Short Open Short Open Short Open Short Open FUNCTION Disable Enable Disable Enable CTRL open--must be driven externally. Shorts D2 so only D3, D4, and D5 are used in the LED main group. All four LEDs (D2-D5) are used. LED main group connected. LED main group disconnected; connect external LEDs from OUT1 to OUT2. LED subgroup connected. LED subgroup disconnected; connect external LEDs from OUT2 to CS. LEDs AFFECTED D2-D5 (main group) D6, D7 (subgroup)
100k pullup resistor connected from CTRL to V+.
2
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MAX1582 Evaluation Kit Evaluates: MAX1582
V+ V+ C1 2.2F JU3 1 V+ R2 100k CTRL 2 3 6 EN1 V+ V+ 7 4 JU2 C3 0.022F VP CTRL EN1 EN2 COMP EP U1 MAX1582ETC LX OUT1 PGND OUT2 CS GND 11 10 12 9 8 5 JU6 SHORT D4 C2 0.1F D3 OUT1
L1 22H D1 D2
JU5 SHORT
JU4 OPEN
1 2 3 12 16 4
V+ VP CTRL EN1 EN2 COMP
U2
LX
9
MAX1582EBE OUT1 13 PGND OUT2 CS GND 5 14 15 8
3 2 1 JU1
3 2 1
D6 D5
EN2
D7
OUT2
GND
CS
R1 7.5
Figure 1. MAX1582 EV Kit Schematic
Changing the Number of LEDs
The MAX1582 can be used to drive a total of up to six LEDs, and the MAX1582 EV kit comes configured for driving six LEDs. To evaluate the MAX1582 driving fewer than six LEDs, short out the pads of the unused LEDs. To prevent excessive leakage in shutdown, there must be at least two white LEDs in the circuit. For accurate dimming control, there must be at least two white LEDs in each group. If dimming is not required, this can be reduced to one LED per group. For convenience, JU4 can be used to short D2, reducing the number of main LEDs to three.
Connecting External LEDs
Although the MAX1582 EV kit comes with surfacemount LEDs installed, it can also be used to drive external LEDs. For the main group, cut the PC board trace shorting JU5, and connect a series string of two to six white LEDs from OUT1 to OUT2. Connect the anode to OUT1 and the cathode to OUT2. For the subgroup, cut the PC board trace shorting JU6 and connect a series string of two to three white LEDs from OUT2 to CS. Connect the anode to OUT2 and the cathode to CS. Ensure the total number of subgroup LEDs does not exceed three.
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MAX1582 Evaluation Kit Evaluates: MAX1582
Figure 2. MAX1582 EV Kit Component Placement Guide-- Component Side
Figure 3. MAX1582 EV Kit PC Board Layout--Component Side
Figure 4. MAX1582 EV Kit PC Board Layout--Solder Side
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
4 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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