Document
LX1689
I N T E G R A T E D P R O D U C T S
Third Generation CCFL Controller
P RODUCTION D ATA S HEET
DESCRIPTION
KEY FEATURES
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The LX1689 is the latest generation Direct Drive CCFL (Cold Cathode Fluorescent Lamp) Controller. It uses new circuit design techniques (patents pending) and combines digital and linear circuits with an advanced BiCMOS process to create a more complete controller in a small package. When compared to the original LX1686 design, identical module applications use from 12 to 30 less components. New functions and enhancements have been added to make the LX1689 even easier to use. The on-chip PLL circuit used to synchronize the digital dimming burst frequency to the video frame rate, as used in the LX1686, is replaced with a programmable counter. This counter can divide the video controller horizontal sync pulse, other external clock source or the internal chip clock source to generate the burst frequency.
The brightness control input allows the use of either a DC voltage or a PWM input to simplify design. Programmable polarity brightness control is retained, except in the case of externally clocked digital dimming. Two onboard LDO regulators extend the input voltage range of the IC up to 28 Volts without using external circuitry as was required with our previous controllers. The LX1689 includes a new lamp strike detection scheme that saves a package pin and three external components. Internal circuits monitor lamp current pulses at the I_SNS input to determine if the lamp strikes and if it stays ignited once operational. Integrating full wave rectifiers for each of three lamp inputs has significantly reduced the lamp feedback component count. In addition the controller features include auto shutdown for open or broken lamps, and a lamp fault detection with a status reporting output.
3 to 28 Volt Single Fixed (±20%) Supply Operating Range Selectable Analog/Digital Dimming Modes Digital Dimming Can Synch to External Or Internal Clocks User Programmable Digital Dimming Burst Frequency 252 mS Power On Delay Flexible Lamp Current Compensation Input Open Lamp Shutdown and Fault Output Indicator “On Chip” Full Wave Lamp Current & Voltage Rectifiers 20 Pin TSSOP Package
BENEFITS
Low Component Count / Module Cost / Size High “Nits/Watt” Efficiency Operates Directly From 1 to 6 Li_Ion Cells Lamp Current Compensation Input Makes Indoor/Outdoor And Wide Temperature Range Applications Easy to Design
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
PRODUCT HIGHLIGHT
LX1689 CCFL Inverter Layouts Examples*
2.64in. (67mm) .397 in.
(10mm) Actual Inverter Size
OR
1.38in. (35mm) .870 in.
(22mm)
Actual Inverter Size *As Shown in Figure 1 (Typical Application)
Bill of Materials 1 LX1689CPW 1 Transformer 1 Dual FET 2 Connectors 7 Resistors 9 Capacitors 21 Total Count
LX1689
PACKAGE ORDER INFO
TJ (°C) 0 to 70 -40 to 85
MIN VDD 3V 3V
MAX VDD 28V 28V
PW
Plastic TSSOP 20-PIN LX1689CPW LX1689IPW
Note: Available in Tape & Reel. Append the letter “T” to the part number. (i.e. LX1689CPWT)
Copyright 2000 Rev. 1.0b, 2003-03-31
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
LX1689
I N T E G R A T E D P R O D U C T S
Third Generation CCFL Controller
P RODUCTION D ATA S HEET
ABSOLUTE MAXIMUM RATINGS Supply Voltage (V_BATT)................................................................................................. 30V Digital Input (ENABLE).....................................................................................-0.3V to 7V Analog Inputs Transient Peak (I_SNS, OC_SNS, OV_SNS)..............................-25V to +25V Analog Inputs (BRITE_IN, EA_IN).................................................................. -0.3V to 5.5V Digital Inputs (DIM_CLK,DIM_MODE, DIV_248) ......................................... -0.3V to 5.5V Digital Output (AOUT, BOUT) .................................................................-0.3V to VDD_P +0.5V Analog Outputs (BRITE_C, I_R, BRITE_OUT, BRITE_R, EA_OUT) ...-0.3V to VDD_A_ +0.5V Operating Temperature Range ..................................................................... -45°C – 100°C Maximum Junction Temperature ...............................................................................125°C
Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground. Currents are positive into, negative out of specified terminal.
PACKAGE PIN OUT
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GND AOUT BOUT DIM_CLK DIM_MODE DIV_248 BRITE_C BRITE_R BRITE_IN ENABLE
1 2 3 4 5 6 7 8 9 10
20 19 18 17 16 15 14 13 12 11
VDD_P VDD_A V_BATT OC_SNS OV_SNS I_SNS BRITE_OUT EA_OUT EA_IN I_R
PW PACKAGE
(Top View)
THERMAL DATA
PW
Plastic TSSOP 20-Pin 144°C/W
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA
Junction Temperature Calculation: TJ = TA + (PD x θJA). The θJA numbers are.