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November 2004
LP3942 The Dual RGB LED Controller with 1.5x/2x Charge Pump and SPI Interface
LP3942 The Dual RGB LED Controller with 1.5x/2x Charge Pump and SPI Interface
General Description
The LP3942 is an integrated stand-alone RGB LED controller with a high efficiency and low noise programmable 1.5x and 2x charge pump. The RGB LEDs are controlled through the low voltage SPI interface. RGB programmability allows unique color and brightness control with both RGB outputs. The color control has preselected color settings for color blending. The LED current control is done using constant current sinks that can be also used as switches. The nonoverlapping RGB output PWM control minimizes the input noise. See also: LP3931, LP3933 and LP3936 Lighting Management Units
Features
n Pre-regulated 1.5x and 2x charge pump with regulated output (4.5V and 5.0V) n 2 separately controlled PWM RGB LED drivers with programmable color and brightness n Overlapping and non-overlapping RGB mode n Wide input voltage range 3V–5.0V n Output current up to 120 mA n Low voltage SPI interface n Programmable low current Standby mode n Tiny LLP24 package (5mm*4mm*0.8mm)
Applications
n Cellular Phones, PDAs
Typical Application
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© 2004 National Semiconductor Corporation
DS201292
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LP3942
Connection Diagrams and Package Mark Information
24-Lead LLP package (5 mm*4 mm*0.8 mm), Bumped See NS Package Number YQA24A
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Top View
Bottom View
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Package Mark — Top View
Note: The actual physical placement of the package marking will vary from part to part. The package marking “XY” designates the date code. “UZ” and “TT” are NSC internal codes for die manufacturing and assembly traceability. Both will vary considerably.
Ordering Information
Order Number LP3942YQ LP3942YQX Package Marking LP3942YQ LP3942YQX Supplied As 1000 units, Tape-and-Reel 2500 units, Tape-and-Reel
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LP3942
Pin Description
Pin # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Name SS SI SCK R1 G1 B1 GND3 B2 G2 R2 POUT C1P VIN C2N GND1 C1N C2P VDD GND2 IBIAS IR IG IB NRST Power Ground Input Input Input Input Logic Input Ground Power Type Logic Input Logic Input Logic Input Output Output Output Ground Output Output Output Output SPI Slave Select SPI Serial Data SPI Clock Open Drain, Red LED (1) Open Drain, Green LED (1) Open Drain, Blue LED (1) Ground 3 Open Drain, Blue LED (2) Open Drain, Green LED (2) Open Drain, Red LED (2) Charge Pump Output Flying capacitor C1 connection Input voltage from battery Flying capacitor C2 connection Ground 1 Flying capacitor C1 connection Flying capacitor C2 connection LDO/Supply voltage input Ground 2 Bias resistor connection Red LED current set resistor Green LED current set resistor Blue LED current set resistor Low active reset input pin. (Internal pull down 1 MΩ) Description
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LP3942
Absolute .