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LX1686E
TM (R)
Digital Dimming CCFL Controller IC
PRODUCTION DATA
SHEET
DESCRIPTION
KEY FEATURES
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The LX1686E Backlight Controller IC provides all the control functions needed to implement Microsemi's direct drive inverters used to operate cold cathode fluorescent lamps (CCFL's). This IC can be used to control single or multiple-lamp configurations. CCFL's are used for back or edge lighting of liquid crystal flat panel displays (LCD's) and typically find application in notebook computers, web browsers, automotive and industrial instrumentation, and entertainment systems. The LX1686E includes a PWM controlled lamp current burst circuit that can provide a > 100:1 dimming range from a simple zero to 2.5V potentiometer input. The PWM dimming burst rate is easily synchronized to the LCD panel's frame rate to prevent interference from optical beat frequencies.
Safety and reliability features include a new dual feedback control loop that permits regulation of maximum lamp strike voltage as well as lamp current. Regulating maximum lamp voltage permits the designer to provide for ample worst case lamp strike voltage while at the same time conservatively limit maximum open circuit voltage. An innovative new strike voltage generation technique enables the module designer to optimize high voltage transformer design for maximum operating efficiency with no power dissipating overhead to guarantee strike capability Direct drive topology is a nonresonant, oscillator-controlled PWM regulation method. The LX1686E allows a wide choice of fixed operating frequencies to match lamp current frequency to the lamp's most efficient operating point, and to minimize high frequency interference.
RangeMAXTM Wide Range Dimming (>100:1) Synchronizable to Display Video Frequency High Voltage Feedback Loop Directly Controls Maximum Open Lamp Micro-Amp Sleep Mode User Programmable Fixed Frequency Operation Under-Voltage Lockout Feature With Power-Up Reset Built-In Soft-Start Feature Operates With 3.3V or 5V power Supplies 100mA Output Drive Capability APPLICATIONS Notebooks Instrumentation Display Desktop Computer Monitors Low Ambient Light Displays (used in Aircraft, Automobiles, and Hand-Held Equipment) BENEFITS Extremely High Efficiency From 3.3V to 5V Power Supplies Lower Cost Than Conventional Buck / Royer Inverter Topologies Improved Lamp Strike Capability Improved Over-Voltage Control
IMPORTANT: For the most current data, consult MICROSEMI's website: http://www.microsemi.com Protected by U.S. Patents 5,615,093; 5,923,129; 5,930,121; 6,198,234; Patents Pending
PRODUCT HIGHLIGHT
5
4
Standard Analog Dimming Inverter
Power Used (Watts)
3
2
Microsemi's RangeMAX
1
0 0 30 45 60 75 90 105
Light emitted by a CCFL is proportional to the current flowing through it. There are two ways to control the current: by adjusting the amplitude of a continuous AC current; or, as with RangeMAX technology, by varying the amount of time a burst of full current is present. RangeMAX technology frees the backlight inverter module designer to operate in a lower brightness and lower power consumption mode than is possible with conventional amplitude control methods.
LX1686E LX1686E
Light Output (Nits)
PACKAGE ORDER INFO
TA (C) 0 to 85 -40 to 85
Copyright (c) 2004 Rev. 1.1, 2006-02-27
PW
Plastic TSSOP 24-PIN
RoHS compliant / Pb-free
LX1686ECPW LX1686EIPW
Note: Available in Tape & Reel. Append the letters "TR" to the part number. (i.e. LX1686ECPW-TR)
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
LX1686E
TM (R)
Digital Dimming CCFL Controller IC
PRODUCTION DATA
SHEET
ABSOLUTE MAXIMUM RATINGS Supply Voltage (VDD, VDD_P) .................................................................................. 6.5V Digital Inputs ........................................................................................ -0.3 to VDD +0.5V Analog Inputs........................................................................................ -0.3 to VDD +0.5V Digital Outputs...................................................................................... -0.3 to VDD +0.5V Analog Outputs ..................................................................................... -0.3 to VDD +0.5V Maximum Operating Junction Temperature ..............................................................150C Storage Temperature ................................................................................... -65C to 150C RoHS / Pb-free Peak Package Solder Reflow Temperature (40 second maximum exposure)....................................................................260C (+0, -5)
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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AOUT VSS_P VSS AFD_C RAMP_C RAMP_R FVERT PD_CR VCO_C BRT_POS BRITE DIG_DIM
1 2 3 4 5 6 7 8 9 10 11 12
24 23 22 21 20 19 18 17 16 15 14 13
BOUT VDD_P VDD TRI_C OLSNS ISNS ICOMP VSNS VCOMP BRT I_R ENABLE
PW PACKAGE
(Top View)
RoHS / Pb-free 100% Matte Tin lead Finish
THERMAL DATA
PW
PACKAGE 100C/W
THERMAL RESISTANCE-JUNCTION TO AMBIENT, JA
Junction Temperature Calculation: TJ = TA + (PD x JA). The JA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow.
PACKAGE DATA PACKAGE DATA
Copyright (c) 2004 Rev. 1.1, 2006-02-27
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 2
LX1686E
TM (R)
Digital Dimming CCFL Controller IC
PRODUCTION DATA
SHEET
FUNCTIONAL PIN DESCRIPTION PIN NAME AOUT VSS_P VSS AFD_C RAMP_C RAMP_R FVERT PD_CR VCO_C BRT_POS BRITE DIG_DIM ENABLE I_R BRT VCOMP VSNS ICOMP ISNS OLSNS TRI_C VDD VDD_P BOUT DESCRIPTION Output driver A, typical 10K pull down resistor to VSS_P. Power ground for output drivers only. Signal ground. Connects to an external capacitor, CAFD. Forcing to ground or VDD will make the VCO oscillate at approximately 50% of the maximum VCO frequency. Forcing to VDD/2 will make the VCO oscillate at 2x the FVERT frequency. Connects to external capacitor CRAMP for setting Direct Drive PWM operating frequency. Connects to external resistor RRAMP for setting Direct Drive PWM operating frequency. Vertical frequency reference digital input. Has internal pull down. Phase Detector Filter. Part of phase lock loop. Connects to external capacitor and resistor network. Connects to external capacitor CVCO Brightness control polarity. Has internal pull up. Leave open or pull up to VDD for dimming brightness proportional to BRITE voltage, connect to ground for brightness inversely proportional to BRITE voltage. Analog voltage input for brightness control. Digital Dimming Enable internal pull up. Leave open or pull up to VDD for operating in digital dimming mode. Connect to ground for analog dimming mode. Chip Enable internal pull up. High enables the chip. Low disables. Current Reference Resistor. External resistor to ground (Ri) determines internal capacitor CICOMP. Current Error Amplifier non-inverting input Voltage Error Amplifier output. Connects to external frequency compensation capacitor CVCOMP. Controls softstart timing. Voltage Error Amplifier inverting input. Current Error Amplifier output. Connects to external frequency compensation capacitor CICOMP. Current Error Amplifier inverting Input. Open Lamp Sense Input. Connects to external capacitor CTRI for setting strike Frequency ramp slope. VDD Dedicated VDD for output buffers only. Output Driver B typical 10K pull down resistor to VSS_P.
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PACKAGE DATA PACKAGE DATA
Copyright (c) 2004 Rev. 1.1, 2006-02-27
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 3
LX1686E
TM (R)
Digital Dimming CCFL Controller IC
PRODUCTION DATA
SHEET
ELECTRICAL CHARACTERISTICS Unless otherwise specified, the following specifications apply over the operating ambient temperature -0C TA 85C for the LX1686E CPW and -40C TA 85C for the LX1686E IPW except where otherwise noted. Test conditions: VDD = VDD_P = 3.0 to 5.5V, Ri = 40k, CVCO = 0.01F, CAFD = 0.22F, CTRI = 0.83F, CRAMP = 208pF, RRAMP = 15k, CPD = 0.22F, CPDB = 0.047F, RPD = 110k Parameter
Power Supply Voltage Operating Current Power Supply Voltage Output Buffer Operating Current UVLO Threshold UVLO Hysteresis
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Symbol
VDD IDD VDD_P IDD_P VTH_UVLO VH_UVLO
Test Conditions
VDD = VDD_P VDD = VDD_P = 5V VDD = VDD_P Volsns = VDD = VDD_P = 5V, CA = CB = 1000pF
Min
3
LX1686E Typ Max
5 5.5 10 5.5 10 2.9
Units
V mA V mA V mV
3 2 2.7 160
DIRECT DRIVE RAMP BLOCK Triangular Wave Generator Analog VP_TRI Output Peak Voltage Triangular Wave Generator Analog VV_TRI Output Valley Voltage Triangular Wave Generator Oscillation F_TRI Frequency Triangular Wave Generator Oscillation ICHG_TRI Charge Current Triangular Wave Generator Oscillation IDISCHG_TRI Discharge Current Ramp Generator Analog Output Peak VP_RAMP Voltage Ramp Generator Analog Output Valley VV_RAMP Voltage Ramp Frequency Change Threshold Ramp Generator Oscillation Frequency - Nominal Ramp Generator Oscillation Frequency - Maximum OLSNS Threshold Voltage OLSNS Hysteresis OLSNS-to-ICOMP Propagation Delay DIGITAL DIMMER BLOCK FVERT Input Frequency Capture Range FVERT Logic Threshold FVERT Input Resistance VCO Analog Output Peak Voltage VCO Analog Output Valley Voltage VCO Forced Source Current Forced VCO Oscillation Frequency Auto-Frequency Detection Response BRITE Voltage Range Full-Brightness Brite Input Voltage Full-Darkness Brite Input Voltage VTH_RAMP_R FRAMP FRAMP_HI VTH_OLSNS VH_OLSNS TD_OLSNS
2.25 0.75 10 Tri_c = 0V Tri_c = 3V -2.3 2.3 -2.55 2.65 2.25 0.75 VDD = 3V VDD = 5.5V 0 < VTRI_C < 1.35V VTRI_C = 2.25V VDD = 3V VDD = 3V GBD 1.35 1.35 84 170 200 1.6 1.6 100 200 300 45 1 1.65 1.85 116 256 400 -2.9 2.9
V V Hz A A V V V V KHz KHz mV mV S
FR_FVERT VTH_FVERT RFVERT VP_VCO VV_VCO FR_VCO_I_SRC FX_VCO TD_AFD Design Reference Only Design Reference Only
45 VDD/2 50 2.5 0.65 -5.6 250 1000 0 2.25 2.25 0.35 0.35 2.5 2.5 0.5 0.5
200
Hz V k V V A Hz ms V V V V V
VPD_CR = 3V, VDD = 3V AFC_C = 0V, CVCO = 0.01F FVERT Frequency is 200Hz, VDD = 3V
-6.4
-5.1
E ELECTRICALS
VR_BRITE VBRITE_FULL VBRT_POS = VDD or float; BRITE = 2.5V VBRT_POS = 0V, BRITE = 0.5V VBRITE_DARK VBRT_POS = VDD or float, BRITE = 0.5V VBRT_POS = 0V, BRITE = 2.5V
VDD 2.65 2.65 0.65 0.65
Copyright (c) 2004 Rev. 1.1, 2006-02-27
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
LX1686E
TM (R)
Digital Dimming CCFL Controller IC
PRODUCTION DATA
SHEET
ELECTRICAL CHARACTERISTICS Unless otherwise specified, the following specifications apply over the operating ambient temperature -0C TA 85C for the LX1686E CPW and -40C TA 85C for the LX1686E IPW except where otherwise noted. Test conditions: VDD = VDD_P = 3.0 to 5.5V, Ri = 40k, CVCO = 0.01F, CAFD = 0.22F, CTRI = 0.83F, CRAMP = 208pF, RRAMP = 15k, CPD = 0.22F, CPDB = 0.047F, RPD = 110k Parameter Symbol Test Conditions LX1686E Typ Max
300 VDD/2 VDD/2 DIG_DIM = VDD VCOMP = 1.25V VCOMP = 1.5V VCOMP = 1.5V VCOMP = VSNS VCOMP = 0.5V, VDD = 3V BRITE = 0.5 - 2.6V ICOMP = 1.5V, VDD = 3V ICOMP = 1.5V, VDD = 3V VCOMP = 1.25V, VDD = 3V VDD = 3V ICOMP = 0.5 to 2.25V, VDD = 3V BRITE = 1.25V, RAMP_C = 2V, VDD = 3V AOUT, BOUT = 1V, VDD = 3V AOUT, BOUT = VDD = 3V AOUT, BOUT = 0V, VDD = 3V AOUT, BOUT = 2V, VDD = 3V 0 10 15 0 1.12 0.8 70 -15 20 0 -10 -10 400 50 70 1.25 1.5 200 -40 60 3 250 3 1100 2.5 110 120 VDD 1.38 10 700 -80 100 VDD 10 500 10
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Min
Units
DIGITAL DIMMING BLOCK (CONTINUED) BRITE-to-ICOMP Propagation Delay BRITE_POS Logic Threshold DIG-DIM Logic Threshold DIRECT DRIVE PWM BLOCK ISNS Threshold Voltage Range VAMP Transconductance VAMP Output Source Current VAMP Output Sink Current VAMP Output Voltage Range VSNS Threshold Voltage VCOMP Discharge Current IAMP Transconductance IAMP Output Source Current IAMP Output Sink Current IAMP Output Voltage Range VCMP Input Offset Voltage VCOMP-to-Output Propagation Delay ICMP Input Offset Voltage ICOMP-to-Output Propagation Delay OUTPUT BUFFER BLOCK Output Sink Current Output Source Current BIAS CONTROL BLOCK Voltage at Pin I_R Pin I_R Maximum Source Current ENABLE Logic Threshold - 3V ENABLE Logic Threshold - 5.5V ENABLE Threshold Hysteresis - 3V ENABLE Threshold Hysteresis - 5.5V VIR IMAX_IR VEN3V VEN5.5 VH_EN3 VH_EN5.5 .975 Design Reference Only VDD = 3V VDD = 5.5V 0.8 0.8 50 1.4 1.4 20 300 1.02 2.0 2.0 V A V V mV mV ISK_OUTBUF ISOUT_BUF 20 25 -35 -20 200 300 -300 -200 mA mA mA mA VR_ISNS GM_VAMP IS_VAMP ISK_VAMP VR_VAMP VTH_VSNS ID_VCOMP GM_IAMP IS_IAMP ISK_IAMP VR_IAMP VOS_VCMP TD_VCOMP VOS_ICMP TD_ICOMP V mho A A V V mA mho A A V mV ns mV ns TD_BRITE ns V V
ELECTRICALS ELECTRICALS
Copyright (c) 2004 Rev. 1.1, 2006-02-27
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 5
LX1686E
TM (R)
Digital Dimming CCFL Controller IC
PRODUCTION DATA
SHEET
BLOCK DIAGRAM
CVCOMP BRT ISNS VSNS Dimming Control PD_CR Output Drivers CICOMP
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VCOMP
ICOMP PWM Controllers
CPDN
RPD CPD
Phase Detector
Voltage Error Amp VCO + VAMP 1.25V
-
Voltage Comparator
Output Steering Logic Q A
VDD_P
+ VCOMP ICOMP + Current Comparator CLK OUT
AOUT
FVERT Auto Freq. Detect AFD_C +
IAMP
Q
RAMP_DOUT
B
BOUT
Current Error Amp 0.5 - 2.5V +
VSS_P Bias Generator, UVLO, and VREF VDD
CAFD VCO_C
2.5V 0V
ENA PWR_GD 2.50V VDD_SW
CVCO
Burst Comparator
ENABLE
I_R BRITE 50k VSS ENA 1.5V BRT_POS 50k + 0-3V VDD VDD Triangle Wave Gen. Ignite Open Lamp Comparator 300mV 255mV Ri
BLOCK DIAGRAM BLOCK DIAGRAM
DIG_DIM PWM Ramp Generator RAMP_C CRAMP RAMP_R RRAMP2 RRAMP1 TRI_C OLSNS CTRI
VDD
Copyright (c) 2004 Rev. 1.1, 2006-02-27
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 6
LX1686E
TM (R)
Digital Dimming CCFL Controller IC
PRODUCTION DATA
SHEET
PACKAGE DIMENSIONS
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PW
24-Pin Thin Small Shrink Outline (TSSOP)
Dim
321
E
P
F D AH
SEATING PLANE
B
G
L
C
M
A B C D E F G H L M P *LC
Note:
MILLIMETERS MIN MAX 0.85 0.95 0.19 0.30 0.09 0.20 7.70 7.90 4.30 4.50 0.65 BSC 0.05 0.15 - 1.10 0.50 0.75 0 8 6.25 6.55 - 0.10
INCHES MIN MAX 0.033 0.037 0.007 0.012 0.0035 0.008 0.303 0.311 0.169 0.177 0.025 BSC 0.002 0.005 - .0433 0.020 0.030 0 8 0.246 0.256 - 0.004
* Lead Coplanarity
1. Dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm(.006") on any side. Lead dimension shall not include solder coverage.
M MECHANICALS
Copyright (c) 2004 Rev. 1.1, 2006-02-27
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 7
LX1686E
TM (R)
Digital Dimming CCFL Controller IC
PRODUCTION DATA
SHEET
NOTES
WWW .Microsemi .C OM
NOTES NOTES
PRODUCTION DATA - Information contained in this document is proprietary to Microsemi and is current as of publication date. This document may not be modified in any way without the express written consent of Microsemi. Product processing does not necessarily include testing of all parameters. Microsemi reserves the right to change the configuration and performance of the product and to discontinue product at any time.
Copyright (c) 2004 Rev. 1.1, 2006-02-27
Microsemi
Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 8

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