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MAX1839EEP

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P26
General Description
The MAX1739/MAX1839 fully integrated controllers are
optimized to drive cold-cathode fluorescent lamps
(CCFLs) using the industry-proven Royer oscillator
inverter architecture. The Royer architecture provides
near sinusoidal drive waveforms over the entire input
range to maximize the life of CCFLs. The MAX1739/
MAX1839 optimize this architecture to work over a wide
input voltage range, achieve high efficiency, and maxi-
mize the dimming range.
The MAX1739/MAX1839 monitor and limit the trans-
former center-tap voltage when required. This ensures
minimal voltage stress on the transformer, which
increases the operating life of the transformer and
eases its design requirements. These controllers also
provide protection against many other fault conditions,
including lamp-out and buck short faults.
These controllers achieve 50:1 dimming range by
simultaneously adjusting lamp current and “chopping”
the CCFL on and off using a digitally adjusted pulse-
width modulated (DPWM) method. CCFL brightness is
controlled by an analog voltage or is set with an
SMBus
TM
-compatible two-wire interface (MAX1739).
The MAX1739/MAX1839 drive an external high-side
N-channel power MOSFET and two low-side N-channel
power MOSFETs, all synchronized to the Royer oscilla-
tor. An internal 5.3V linear regulator powers the MOS-
FET drivers and most of the internal circuitry. The
MAX1739/MAX1839 are available in space-saving
20-pin QSOP packages and operate over the -40°C to
+85°C temperature range.
________________________Applications
Notebook/Laptop Computers
Car Navigation Displays
LCD Monitors
Point-of-Sale Terminals
Portable Display Electronics
Features
♦ Fast Response to Input Change
♦ Wide Input Voltage Range (4.6V to 28V)
♦ High Power-to-Light Efficiency
♦ Minimizes Transformer Voltage Stress
♦ Lamp-Out Protection with 2s Timeout
♦ Buck Switch Short and Other Single-Point Fault
Protection
♦ Integrated Royer MOSFET Drivers Reduce
Transformer Pin Count
♦ Buck Operation Synchronized to Royer Oscillator
♦ Synchronizable DPWM Frequency
♦ Pin-Selectable Brightness Control Interface
♦ SMBus Serial Interface (MAX1739)
♦ Analog Interface (MAX1739/MAX1839)
MAX1739/MAX1839
†
Wide Brightness Range
CCFL Backlight Controllers
________________________________________________________________ Maxim Integrated Products 1
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
BATT
DH
LX
BSTCCV
CCI
MINDAC
REF
TOP VIEW
VL
GND
CS
DL1MODE
CTL/SCL
CRF/SDA
SH/SUS
12
11
9
10
DL2
SYNCCTFB
CSAV
MAX1739
QSOP
Pin Configuration
19-1755; Rev 1; 3/01
EVALUATION KIT
AVAILABLE
†
Pg
SMBus is a trademark of Intel Corp.
PART TEMP. RANGE PIN-PACKAGE
MAX1739EEP -40°C to +85°C 20 QSOP
MAX1839EEP -40°C to +85°C 20 QSOP
Ordering Information
Pin Configurations continued at end of data sheet.
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim's website at www.maxim-ic.com.
MAX1739/MAX1839
†
Wide Brightness Range
CCFL Backlight Controllers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V+ = 8.2V, V
SH
/SUS = V
SH
= 5.5V, MINDAC = GND, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
VBATT to GND ...........................................................-0.3V to 30V
V
BST
, V
SYNC
to GND.................................................-0.3V to 34V
V
BST
to V
LX
.................................................................-0.3V to 6V
V
DH
to V
LX
.................................................-0.3V to (V
BST
+ 0.3V)
V
LX
to GND...................................................-6V to (V
BST
+ 0.3V)
VL to GND...................................................................-0.3V to 6V
V
CCV
, V
CCI
, V
REF
, V
DL1
, V
DL2
to GND .........-0.3V to (VL + 0.3V)
V
MINDAC
, V
CTFB
, V
CSAV
to GND ................................-0.3V to 6V
V
CS
to GND...................................................-0.6V to (VL + 0.3V)
V
MODE
to GND.............................................................-6V to 12V
V
CRF/SDA
, V
CRF
, V
CTL/SCL
, V
CTL
, V
SH/SUS
,
V
SH
to GND ............................................................-0.3V to 6V
Continuous Power Dissipation (T
A
= +70°C)
20-Pin QSOP (derate 9.1mW/°C above +70°C)...........727mW
Operating Temperature .......................................-40°C to +85°C
Storage Temperature.........................................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER CONDITIONS
MIN TYP MAX
UNITS
SUPPLY AND REFERENCE
V
L
= V
BATT
4.6 5.5
V
BATT
Input Voltage Range
V
L
= open 6 28
V
V
BATT
= 28V 3.2 6
V
BATT
Quiescent Current, Operation
with Full Duty Cycle on DH
DH = DL1 = DL2 = open
V
BATT
= V
L
= 5V 3.2 6
mA
V
BATT
Quiescent Current, Shutdown SH/SUS = SH = GND 6 20 μA
VL Output Voltage, Normal Operation
6V < V
BATT
< 28V, 0 < I
LOAD
< 15mA
5.0
5.35
5.5 V
VL Output Voltage, Shutdown SH/SUS = SH = GND, no load 3.5 4.5 5.5 V
VL rising (leaving lockout) 4.6
VL Undervoltage Lockout Threshold
VL falling (entering lockout) 4.0 V
VL Undervoltage Lockout Hysteresis 300 mV
REF Output Voltage, Normal
Operation
4.5V < VL < 5.5V, I
REF
= 40μA
1.96 2.00 2.04
V
V
L
POR Threshold 0.9 2.7 V
SWITCHING REGULATOR
DH Driver On-Resistance 18 Ω
DL1, DL2 Driver On-Resistance 18 Ω
Minimum DH Switching Frequency 1/t
DH
, SYNC = CS or GND, not synchronized 49 56 64 kHz
DH Minimum Off-Time 250 375 500 ns
DH Maximum Duty Cycle 98 %
SYNC Synchronization Range Detect falling edges on SYNC 64 200 kHz
SYNC Input Current 0 < V
SYNC
< 30V -2 2 μA
SYNC Input Threshold SYNC falling, referred to CS 400 500 600 mV
SYNC Input Hysteresis Referred to the SYNC input threshold 50 100 150 mV
SYNC Threshold Crossing to DL1,
DL2 Toggle Delay
V
SYNC
= 0 to 5V, C
DL_1
and
C
DL_2
< 100pF,
50% point on SYNC to 50% point on DL1 or DL2
120 ns
CS Overcurrent Threshold 408 450 492 mV
MAX1739/MAX1839
†
Wide Brightness Range
CCFL Backlight Controllers
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 8.2V, V
SH
/SUS = V
SH
= 5.5V, MINDAC = GND, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER CONDITIONS
MIN TYP MAX
UNITS
DAC AND ERROR AMPLIFIER
DAC Resolution Guaranteed monotonic 5 Bits
MINDAC Input Voltage Range 0 2 V
MINDAC Input Bias Current 0 < V
MINDAC
< 2V -1 1 μA
MINDAC Digital PWM Disable
Threshold
MINDAC = VL 2.4 2.9 4 V
CSAV Input Voltage Range 0 0.8 V
V
MINDAC
= 0, DAC code = 11111 binary 188 194 200
V
MINDAC
= 0, DAC code = 00001 binary 2
6.25
16
CSAV Regulation Point
V
MINDAC
= 1V, DAC code = 00000 binary 93 100 110
mV
CSAV Input Bias Current -1 1 μA
CSAV to CCI Transconductance 1V < V
CCI
< 2.7V 100
μmho
CTFB Input Voltage Range 0 2 V
CTFB Input Bias Current -1 1 μA
CTFB Regulation Point 570 600 630 mV
CTFB to CCV Transconductance 1V < V
CCV
< 2.7V 30 40 50
μmho
TIMERS AND FAULT DETECTION
Chopping Oscillator Frequency No AC signal on MODE, not synchronized 24 28 32 kHz
No AC signal on MODE 205 220 235
32kHz AC signal on MODE 250
Digital PWM Chop-Mode Frequency
100kHz AC signal on MODE 781
Hz
MODE to DPWM Sync Ratio F
MODE
/ F
DPWM
128
No AC signal on MODE
2.06 2.33 2.73
32kHz AC signal on MODE
2.05
Lamp-Out Detection Timeout Timer
(Center-Tap Voltage Stuck at
Maximum) (Note 1)
V
CSAV
< CSAV
lamp-out
threshold
100kHz AC signal on MODE 0.66
s
CSAV Lamp-Out Threshold 50 75 100 mV
Fault-Detection Threshold on CCV (Note 2) 0.4 1 V
No AC signal on MODE 332 291 259
32kHz AC signal on MODE 256
Shorted Buck-Switch Detection
Timeout Timer (UL1950 Protection)
(Note 3)
V
CCV
< fault-
detection
threshold on CCV
100kHz AC signal on MODE
82
ms
Lamp Turn-On Delay After SH/SUS or SH forces device on or SH rises 4 ms
MODE Operating Voltage Range -5.5 11 V
MODE = GND Threshold
(min Brightness = 0)
To sync DPWM oscillator, not in shutdown
(Note 4)
0.6 V
MODE = REF Threshold
(max Brightness = 0)
To sync DPWM oscillator, not in shutdown
(Note 4)
1.4 2.6 V
MODE = V
L
Threshold
(MAX1739 SMB Interface Mode)
To sync DPWM oscillator, not in shutdown
(Note 4)
VL - 0.6
V
MODE AC Signal Amplitude Peak to peak (Note 5) 2 V
MODE AC Signal Synchronization
Range
Chopping oscillator synchronized to MODE AC
signal
32 100 kHz
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P26

MAX1839EEP

Mfr. #:
Buy MAX1839EEP
Manufacturer:
Maxim Integrated
Description:
IC CTRLR CCFL BCKLGHT 20-QSOP
Lifecycle:
New from this manufacturer.
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