SE3362 SEAWARD | Alldatasheet
Document overview
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Technical content
Features
¾ Drives individually up to 4 LEDs ¾ Output current up to 30mA per LED ¾ Digital control On/Off of each LED ¾ Compatible with supply voltage of 2.85V to 5.5V ¾ Power efficiency up to 90% ¾ 2 modes of operation 1x and 2x ¾ Automatic short circuit detect/disable ¾ High-frequency Operation at 1MHz ¾ Low value ceramic capacitors ¾ Automatically switch to power save mode if no LED is deteted to be connected to the IC ¾ Thin QFN 16-lead package, 3×3mm ¾ 100% Lead (Pb)-Free Application Diagram Application ¾ Color LCD and keypad Backlighting ¾ Cellular Phones ¾ Handheld Devices ¾ Digital Cameras ¾ PDAs ¾ Portable MP3 players
Preliminary and all contents are subject to change without prior notice Pin Configuration Note: The package exposed pad is electrically connected inside the package to AGND. Functional Pin Description Pin Number Name Function 1 EN Chip Enable (Active High). Note that this pin is high impedance. There should be a pull low 100kΩ resistor connected to GND when the control signal is floating. 2 CTR0 Output Control Bit 0. (See Table 1) 3 CTR1 Output Control Bit 1. (See Table 1)
4 AGND Analog Ground
5 RSET LED current is set by the value of the resistor RSET connected from the RSET pin to
ground. Do not short the RSET pin. VISET is typically 1.1V. All external capacitance at this pin, including board parasitic capacitance, must be less than or equal to 30pF. 6 VOUT Output Voltage Source for connection to the LED anodes.
7 VIN Input Voltage
8 C1+ Positive Terminal of Bucket Capacitor 1
9 C1- Negative Terminal of Bucket Capacitor 1
10 NC No Connection
11 NC No Connection
12 PGND Power Ground. This ground should be connected to Power GND on PCB. 13 to16 LED 4 to 1 Current Sink for LED. (If not in use, pin should be connected to VOUT) Exposed Pad GND Exposed pad should be soldered to PCB board and connected to GND.
Preliminary and all contents are subject to change without prior notice Absolute Maximum Rating (1) Parameter Value Units VIN, VOUT, LEDx voltage -0.3～7V V EN, CTRx,RSET voltage -0.3 to VIN V RSET current ±1 mA Lead Temperature (Soldering, 5 sec.) 260 °C Junction Temperature 0 to +150 °C Storage Temperature -40 to +150 °C Operating Rating (2) Parameter Symbol Value Units Supply Input Voltage Range V IN 5.5 V Junction Temperature Range T J 0 to +125 °C I LED per LED pin 0to 30 mA
Electrical Characteristics
VIN = 3.5V; C1＝1.0μF; TJ = 25°C; unless otherwise noted Parameter Symbol Conditions Min Typ Max Unit Input Supply Voltage V IN 2.85 -- 5.5 V RSET Regulated Voltage V RSET 1.22 1.25 1.28 V Current into LEDs I LED RSET=100K -- 5 -- mA RSET=25.0 K -- 20 -- mA RSET=16.7 K -- 30 -- mA EN=Low, Shutdown Mode -- 1 -- uA 1x Mode , No Load -- 170 -- uA Quiescent Current I Q 2x Mode, No Load -- 2.5 -- mA ILED Accuracy I LED-ERR 2mA<ILED<30mA -- 2 7.5 % Current Matching(3) I LED-LED-ERR 2mA<ILED<30mA -- 1 5 % x1 mode to x2 mode Transition Voltage(VIN falling) VTRANS VLED=3.5V,IOUT=80mA,ILED=20mA -- 3.8 -- V Oscillator Frenquency F OSC VLED=3.5V,IOUT=80mA,ILED=20mA -- 1.0 -- MHz Input High Threshold V IH Input high logic threshold 1.5 -- -- V Input Low Threshold V IL Input low logic threshold -- -- 0.4 V Input Leakage Current IIN -- -- 1 μA Thermal Protection Temperature -- 150 -- TPROTECTION Thermal Protection Protection Hysterisys -- 20 --
Preliminary and all contents are subject to change without prior notice Note 1: Exceeding the absolute maximum rating may damage the device. Note 2: The device is not guaranteed to function outside its operating rating. Note 3: Current Matching refers to the difference in current from on LED to the next. I L E D C u r r e n t M a t c h i n g = ± %100 )()( )()( MINLEDMAXLED MINLEDMAXLED II II Control Inputs Output Status CTRL1 CTRL0 LED4 LED3 LED2 LED1 0 0 OFF OFF ON ON 0 1 OFF ON ON ON 1 0 ON ON ON ON Table1 1 1 OFF OFF OFF OFF Operations The SE3362 is a high efficiency charge pump white LED driver. It provides 4 channels low drop-out voltage current source to regulated 4 white LED’s current. For high efficiency, the SE3362 implements x1/x2 mode charge pump. An external R SET is used to set the current of white LED. Dimming Control CTRL0 and CTRL1 are used to control the on/off of White LED. When an external PWM signal is connected to the control pin, brightness of white LED is adjusted by the duty cycle. The SE3362 supports the dimming control frequency up to 1KHz. LED Current Setting The current of white LED connected to SE3362 can be set by R SET. The channel current that flows through the white LED is 400 times greater than the current of RSET. The white LED can be estimated by following equation: ILED = 400× ⎟⎟ SET RSET R V where V RSET = 1.25V, and R SET is the resistance connected from RSET to GND. Thermal Shutdown The SE3362 provides a high current capability to drive 4 white LEDs. A thermal shutdown circuit is needed to protect the chip from thermal damage. When the chip reaches the shutdown temperature 150 °C, the thermal shutdown circuit turns off the chip to prevent the thermal accumulation in the chip. Short Circuit Protection The SE3362 provides short circuit protection function. When output Voltage is shorted to GND, short circuit protection cell shutdown ChargePump and current source, and consequently the IC and the related LED’s are protected.
low-pass filter as shows in Figure 1. equivalent resister of RSET pin and control signal. Figure 2. The application circuit of setting LED current which using a NMOS to set RSET.
dimming frequency is recommended below 1kHz. Table 4. The common dimming frequency and its enable pin voltage is higher than the threshold voltage. recommended conditions are shown as following.
- The recommended value for R1 and C3 are
- The forward voltage of the Schottky diode shall be
- The output voltage of GPIO should be greater than
- The PWM frequency should be in the range of
- The PWM duty cycle shall be in the range of 30% to
- The driving capability of the GPIO should be greater
- The LED current can be obtained by the equation,
Figure 6. The GPIO PWM dimming application
Preliminary and all contents are subject to change without prior notice Customer Support Seaward Electronics Incorporated – China Section B, 2nd Floor, ShangDi Scientific Office Complex, #22 XinXi Road Haidian District, Beijing 100085, China Tel: 86-10-8289-5700/01/05 Fax: 86-10-8289-5706 Seaward Electronics Corporation – Taiwan 2F, #181, Sec. 3, Minquan East Rd, Taipei, Taiwan R.O.C Tel: 886-2-2712-0307 Fax: 886-2-2712-0191 Seaward Electronics Incorporated – North America 1512 Centre Pointe Dr. Milpitas, CA95035, USA Tel: 1-408-821-6600 Last Updated - 12/4/2008 Outline Drawing for QFN16 3X3