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Parameter Conditions Min. Typ. Max. Units Input Voltage Range 7.0 12 16.0 VDC Maximum Input Voltage 0.5 Sec 20.0 VDC Input Filter Internal Capacitor Output Parameter Conditions Min. Typ. Max. Units Output Voltage Range VIN = 16V 2 14 VDC Output Current See Model Selection Guide Output Current Accuracy See Model Selection Guide Output Power See Model Selection Guide Effi ciency See Model Selection Guide Capacitive Load 47 µF Operating Frequency 60 400 kHz Ripple & Noise (20 MHz) See Model Selection Guide Temperature Coeffi cient ±0.03 %/ ºC Thermal Impedance Natural Convection +35 ºC/W Output Short Circuit Regulated At Rated Output Current Environmental Parameter Conditions Min. Typ. Max. Units Operating Temperature Range Ambient -40 +25 +85 ºCCase +105 Storage Temperature Range -40 +125 ºC Cooling Free Air Convection Humidity RH, Non-condensing 95 % Lead Temperature (Solder) 1.5 mm From Case For 10 Sec 260 ºC Physical Case Material Non-Conductive Black Plastic (UL94-V0) Weight 0.064 Oz (1.8g) Remote On/Off Control Parameter Conditions Min. Typ. Max. Units DC/DC On Open or 0.3V < VADJ <1.25V DC/DC Off VADJ <0.15V Remote Pin Drive Current V ADJ = 1.25V 1 mA Quiescent Input Current (Shutdown Mode) VIN = 16V 25 µA PWM Dimming Parameter Conditions Min. Typ. Max. Units Operation Frequency Recommended Maximum 1.0 kHz Switch On Time 200 nS Switch Off Time 200 nS Analog Dimming Parameter Conditions Min. Typ. Max. Units Input Voltage Range At VADJ Input (Pin 7) 0.0 1.25 VDC Output Current Adjustment 25 100 % Control Voltage Range Limits On 0.30 1.25 VDCOff 0.0 0.15 Drive Current VADJ = 1.25V 1.0 mA EMC Compliance EMI/RFI Radiated/Conducted EN 55015 (CISPR22) Electrostatic Discharge (ESD) Class A IEC/EN 61000-4-2, -6, -8 RF Field Susceptibility Class A IEC/EN 61000-4-3 Electrical Fast Transients/Bursts On Mains Class A IEC/EN 61000-4-4 EMS Immunity EN61547 Reliability Specifi cations Parameter Conditions Min. Typ. Max. Units MTBF MIL HDBK 217F , 25 ºC, Gnd Benign 3.3 MHours MicroPower Direct

292 Page Street

Stoughton, MA 02072 USA T: (781) 344-8226 F: (781) 344-8481 E: sales@micropowerdirect.com W: www.micropowerdirect.com www.micropowerdirect.com Electrical Specifi cations Specifi cations typical @ +25°C, nominal input voltage & rated output current, unless otherwise noted. Specifi cations subject to change without notice. LDM12-xx-xxx Miniature, Wide Input Constant Current DC/DC LED Drivers Key Features:

  • Constant Current Output
  • Wide 7V to 16V Input Range
  • 93% Effi ciency
  • Miniature MiniDIP Case
  • 300 mA to 1A Output
  • Meets EN 60950
  • 3.3 MHrs MTBF
  • Digital & Analog Dimming!

292 Page Street Ste D Stoughton, MA 02072 • TEL: (781) 344-8226 • FAX: (781) 344-8481 • E-Mail: sales@micropowerdirect.com www.micropowerdirect.com Typical Connection: DC/DC Input Model Number Input Output Maximum Power (W) Ripple & Noise (mV P-P, Max) Effi ciency (%, Typ) PackageVoltage (VDC) Voltage (VDC) Current Range Range Max (mA) Accuracy (%) Notes: 1. A reversed power source could damage the unit. 4. The VADJ input should be left open if not used. Grounding VADJ will shut the unit down. Connecting VADJ to VIN may damage the unit.2. No connection should be made between input ground and the output. 3. These are step-down devices, the maximum output open voltage is equal to the input voltage. 5. Exceeding the specifi ed maximum output power could cause damage to the unit. Typical Connection: AC/DC Input Connection Notes: To comply with EN61000-4-5, a TVS should be installed before the input fi lter components. A 3.0SMCJ15A or SMCJ16A is recommended. The TVS max clamping voltage (@max peak pulse current V C) must be /H1101720V . This will prevent any surge from exceeding the maximum input of the driver (20 VDC). Exceeding the maximum input rating could damage the driver. The fi lter shown (C1, C2, C3 and L1) will help to meet conducted emission requirements. With the addition of the fi lter, the unit should meet the levels of EN 55015. Connection Notes: This is a distributed (or two-stage) AC connection. In this confi guration, the AC line in (85 to 264 VAC) is connected to the MPM-20S-15EPB, a compact 20W AC/DC power supply. The MPM-20S-15EPB provides a tightly regulated 15 VDC output at 1,330 mA. The 15 VDC output powers the LED driver. The two stage approach can simplify the safety approval process (most AC/DC power supplies on the market are approved to EN 60950) and may increase design fl ex- ibility. Besides the output voltage/current ratings, other specifi cations to consider when selecting the input AC/DC supply might include input range, case size, effi ciency, EMI ratings and operating temperature range. Note: The output current adjustment circuit shown in both connection diagrams is discussed on page 4.

MicroPower Direct • 292 Page Street Ste D Stoughton, MA 02072 • TEL: (781) 344-8226 • FAX: (781) 344-8481 • E-Mail: sales@micropowerdirect.com www.micropowerdirect.com PWM Output Current Control An LED operates at its maximum effi ciency when operated at the rated drive current specifi ed by the manufacturer. Operating an LED at lower than its rated forward current not only decreases the system effi ciency; but may cause color (or wave- length) shifting. In illumination applications, this could cause visible changes to lighting. A preferred method is using pulse width modula- tion (PWM). As shown at left, the output current is adjusted by applying a PWM signal to the V ADJ input. By varying the signal duty cycle the average output current is adjusted up or down. To avoid visible fl icker, the PWM signal should be greater than 200 Hz. For duty cycles (DPWM) between 0.1 and 1, the output current is derived by the formula: II X DNOM MAX PWM= The VADJ input may be driven via an open collec- tor transistor (as shown). The diode and resistor suppress high amplitude negative spikes that may be caused by the drain-source capacitance of the transistor. Negative spikes on the control input of the unit could cause errors in output current or erratic operation. The V ADJ input can also be driven by the open drain output of a microcontroller. Again, any high amplitude negative spikes that may be caused by the drain- source capacitance of the FET must be supressed. PWM Control Signals PWM Dimming Application A simple method of achieving digital (or PWM) dimming is by using a 555 timer to apply a series of pulses to the VADJ input, as illustrated above. The 555 oper- ates over a supply voltage range of 4.5 VDC to 18VDC. Here it is connected to the 15 VDC output of the SR7805 switching regulator (this is also the V IN of the LED driver). Care should be taken to minimize ripple at the VCC input. Excess ripple could cause timing errors. The timer is connected for astable (free run) operation. The frequency is set by R1, R2 and C4. The timing capacitor (C4) charges through R1 and D2. When it reaches the level of 2/3 VCC, the discharge pin (pin 7) goes low and C4 will discharge through D1 and R2 to the internal discharge transistor. When the C4 voltage drops to 1/3 VCC, the discharge pin goes high and C4 begins to charge again. The formulas for calculating the frequency and duty cycle are included in the MPD application note “Driving LEDs”. The diodes (D1 and D 2) allow duty cycles below 50% to be set. Diode D 1 bypasses R2 while C4 is charging. Diode D2 is optional (but recommended), essentially blocking R2 during the charge period. Theoretically, this circuit will allow for duty cycles over a range of approximately 5% to 95%. If manual adjustment is desired, a potentiometer may be substituted for R2 (with some adjustment of the circuit). The size of C4 is generally not critical, but it should be as low leakage as pos- sible. In order to avoid excessive current fl ow through the internal discharge transistor, it is recommended that R1 be at least 5 k/H9024.

We Power Your Success - For Less! 292 Page Street Ste D Stoughton, MA 02072 • TEL: (781) 344-8226 • FAX: (781) 344-8481 • E-Mail: sales@micropowerdirect.com www.micropowerdirect.com Notes:

  • All dimensions are typical in inches (mm)
  • Tolerance x.xx = ±0.02 (±0.50)
  • Pin 1 is marked by a “dot” or indentation on the top of the unit Mechanical Dimensions Analog Output Current Control (VCNT = 5V) In the second circuit, the 5 VDC regulator (SR2) is replaced by the shunt regulator (D1) circuit connected in parallel with the resis- tor network. The regulator will maintain the voltage across R 2 and R3 at 2.5 VDC, insuring that the 1.25 VDC limit on the VADJ pin will not be exceeded. When using the analog control input, the nominal output current is equal to: .II x V 12 5 NOM MAX ADJ The VADJ input should be left open if not used. Grounding V ADJ will shut the unit down. Connecting VADJ to directly to +VIN may damage the unit. Analog Output Current Control (5 - 16 VDC IN) Pin Connections Pin Function 1+ V IN +DC Supply 4 +LED LED Anode Conn. 5 -LED LED Cathode Conn. ADJ PWM, On/Off 8- V IN -DC Supply The output current of the unit can also be set by adjusting the voltage level on the V ADJ input to a value between 0.3V to 1.25V (IOUT will vary from 25% to 100% of rated output current). Care must be taken not to exceed 1.25V on this input, or the driver may be damaged. A simple analog circuit using two low cost, switching regulators is shown at left. Working from inputs that can range from 20 to 32 VDC,the top regulator (SR 1) keeps the input to the LED driver at 15 VDC. The other regulator (SR2), driven off the same input line maintains the control voltage (for the V ADJ input) at 5 VDC. The resister network of R1 and R2 can now be used to set the output current level of the LED driver. This level is equal to: V RR R XV ADJ CTRL= + Get a full explanation of the circuits in this datasheet and more in “Driving LEDs”. Available free at the MPD website