LP3958TL/NOPB National Semiconductor, LP3958TL/NOPB Datasheet - Page 15

• Manufacturer Part Number: LP3958TL/NOPB
• Description: IC LED DRVR WT/CLR BCKLT 25-USMD
• Manufacturer: National Semiconductor
• Series: PowerWise®r
• Type: Backlight, White LED, Color LEDr

Specifications of LP3958TL/NOPB

• Constant Current: Yes
• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 5
• Internal Driver: Yes
• Type - Primary: Backlight, Light Management Unit (LMU)
• Type - Secondary: White LED
• Frequency: 1MHz
• Voltage - Supply: 3 V ~ 5.5 V
• Voltage - Output: 18V
• Mounting Type: Surface Mount
• Package / Case: 25-MicroSMD
• Operating Temperature: -30°C ~ 85°C
• Internal Switch(s): Yes
• Efficiency: 90%
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output / Channel: -
• Other names: LP3958TLTR

Backlight Drivers
LP3958 has 2 independent backlight drivers. Both drivers are regulated constant current sinks. LED current for both LED strings
are controlled by the 8-bit current mode DACs with 0.1 mA step. MAIN and SUB LEDs can be also controlled with one DAC
(MAIN) for better matching allowing the use of larger displays having up to 8 white LEDs by setting DISPL bit to 1.
20175590
SUB output for 2 LEDs (DISPL = 0)
20175589
MAIN output for 4 LEDs (DISPL = 0)
20175591
MAIN and SUB outputs for 8 LEDs (DISPL = 1)
PWM CONTROL
External PWM control is enabled by writing 1 to EN_MAIN_PWM and/or EN_SUB_PWM bits in register address 2BH. GPIO[0]
pin is used as external PWM input when EN_PWM_PIN is set high. PWM input is active high, i.e. LED is activated when in high
state.
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