LM3535 Datasheet, PDF (2/34 Pages) National Semiconductor (TI) – Multi-Display LED Driver with Ambient Light Sensing and Dynamic Backlight Control Compatibility

LM3535
SNVS598A – AUGUST 2010 – REVISED MAY 2013
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These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
DESCRIPTION (CONTINUED)
The LM3535 provides multi-zone Ambient Light Sensing (1 or 2 ALS inputs depending on option) allowing
autonomous backlight intensity control in the event of changing ambient light conditions. A PWM input is also
provided to give the user a means to adjust the backlight intensity dynamically based upon the content of the
display.
The LM3535 provides excellent efficiency without the use of an inductor by operating the charge pump in a gain
of 3/2 or in Pass-Mode. The proper gain for maintaining current regulation is chosen, based on LED forward
voltage, so that efficiency is maximized over the input voltage range.
The LM3535 is available in a tiny 20-bump, 0.4mm pitch, thin DSBGA package.
Connection Diagram
4
4
3
3
2
2
1
1
ABCDE
EDCBA
Top View
Bottom View
Figure 3. 20 Bump DSBGA Package
Package Number YFQ0020
Bump Number
A3
A2
A1, C1, B1, B2
D3, E3, E4, D4
C4, B4
B3
C3
D2
E1
C2
E2
A4
D1
Pin Names
V_IN
V_OUT
C1+, C1-, C2+, C2-
D1A-D4A
D53, D62
D1B / INT
D1C / ALS
PWM
HWEN
SDIO
SCL
GND
(LM3535)
ALSB
(LM3535-2ALS)
GND
PIN DESCRIPTIONS
Pin Descriptions
Input voltage. Input range: 2.7V to 5.5V.
Charge Pump Output Voltage
Flying Capacitor Connections
LED Drivers - GroupA
LED Drivers - Configurable Current Sinks. Can be assigned to GroupA or GroupB
LED Driver/ ALS Interrupt - GroupB Current Sink or ALS Interrupt Pin. In ALS Interrupt
mode, a pull-up resistor is required. A '0’ means a change has occurred, while a ‘1’ means
no ALS adjustment has been made.
LED Driver / ALS Input - Indicator LED current sink or Ambient Light Sensor Input
External PWM Input - Allows the current sinks to be turned on and off at a frequency and
duty cycle externally controlled. Minimum On-Time Pulse Width = 15µsec.
Hardware Enable Pin. High = Normal Operation, Low = RESET
Serial Data Input/Output Pin
Serial Clock Pin
Ground for LM3535 or Ambient Light Sensor B for LM3535-2ALS
Ground
2
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