LM3503ITL-25EV National Semiconductor, LM3503ITL-25EV Datasheet - Page 2

• Manufacturer Part Number: LM3503ITL-25EV
• Description: BOARD EVALUATION LM3503ITL-25
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM3503ITL-25EV

• Current - Output / Channel: 9mA
• Outputs And Type: 2, Non-Isolated
• Voltage - Output: 25 V
• Features: Dual Display(s)
• Voltage - Input: 2.7 ~ 5.5V
• Utilized Ic / Part: LM3503
• Core Chip: LM3503
• Topology: Boost
• No. Of Outputs: 1
• Output Voltage: 25V
• Input Voltage: 2.5V To 5.5V
• Development Tool Type: Hardware - Eval/Demo Board
• Lead Free Status / RoHS Status: Not applicable / Not applicable

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Typical Application
PWM Dimming
If PWM dimming is desired to control the brightness of the LED string, care must be taken to balance the tradeoffs between
audible noise and brigthness control. For best PWM duty cycle vs current linearity, the recommended PWM frequency should be
between 200Hz to 500Hz for the LM3502.
Similarly if PWM dimming is desired to control the brightness, a RC filter is necessary at the control pin for the LM3503( see
Figure 3). To select the PWM frequency, use equations below.
F
F
R: Chosen Filter Resistor
C: Chosen Filter Capacitor
PWM
RC
: RC Filter Bandwidth Cutoff Frequency
: PWM Singal Frequency
(Continued)
FIGURE 2. Typical Application Circuit for LM3503
2
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