19-1128; Rev 0; 9/96
KIT
ATION
EVALU
E
BL
AVAILA
Digitally Controlled CCFL Backlight
Power Supplies
____________________________Features
_______________General Description
The MAX1610/MAX1611 are fully integrated, high-
efficiency drivers for cold-cathode fluorescent lamps
(CCFLs). They operate from a 4.5V to 26V power
source. An on-board, high-switching-frequency power
MOSFET reduces external component count and mag-
netics size. The MAX1610/MAX1611 protect against
open or shorted lamps. The CCFL can be driven from
an isolated transformer secondary winding to improve
efficiency and avoid flicker at dim tube settings.
Brightness is adjusted by scaling the lamp current, or
by operating with a fixed lamp current and chopping
the CCFL on and off at a rate faster than the eye can
detect.
The MAX1610’s digital inputs increment, decrement, or
clear an internal, 5-bit up/down counter, which sets
CCFL brightness. The MAX1611 uses a System
Management Bus (SMBus) 2-wire serial interface to
directly set CCFL brightness. Both devices include
micropower shutdown and a linear regulator that elimi-
nates the need for a separate logic supply. The digital
interface remains active in shutdown, preserving the
brightness setting.
MAX1610/MAX1611
®
Direct Digital Control of CCFL Brightness
®
Low Supply Current: 3mA Max Operating
®
Low-Voltage Operation, Down to 4.5V
®
Internal 26V, 0.7
W
Power Switch
®
Protection Against Open or Shorted Lamps
®
Supports Isolated Transformer Secondary
®
SMBus Serial Interface (MAX1611)
®
No Flicker at Low Brightness (internal 280Hz
®
High Power-to-Light Efficiency
®
Selectable 290kHz/145kHz Switching Frequency
®
Oscillator SYNC Input
®
16-Pin Narrow SO Package
______________Ordering Information
PART
MAX1610CSE
MAX1611CSE
TEMP. RANGE
0°C to +70°C
0°C to +70°C
PIN-PACKAGE
16 Narrow SO
16 Narrow SO
20µA Max Shutdown
Winding
current chopping)
________________________Applications
Notebook/Laptop Computers
Point-of-Sale Terminals
Portable Medical Equipment
Instrument Displays
__________________________________________________________Pin Configurations
TOP VIEW
UP 1
DN 2
SHDN 3
SYNC 4
SS 5
CC 6
CSAV 7
MINDAC 8
16 BATT
15 LX
14 BST
SDA 1
SCL 2
SMBSUS 3
SYNC 4
SS 5
CC 6
CSAV 7
MINDAC 8
16 BATT
15 LX
14 BST
MAX1610
13 GND
12 VL
11 CS
10 OTP
9
REF
MAX1611
13 GND
12 VL
11 CS
10 OTP
9
REF
SO
SO
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
Digitally Controlled CCFL Backlight
Power Supplies
MAX1610/MAX1611
ABSOLUTE MAXIMUM RATINGS
BATT to GND ............................................................-0.3V to 28V
BST to GND ..............................................................-0.3V to 30V
BST to LX ....................................................................-0.3V to 6V
LX to GND ................................................-0.6V to (BATT + 0.3V)
VL to GND...................................................................-0.3V to 6V
CS, CSAV, CC, SYNC, REF, MINDAC,
SS, OTP to GND............................................-0.3V to (VL + 0.3V)
SHDN,
UP, DN to GND ...............................................-0.3V to 6V
SMBSUS, SDA, SCL to GND ......................................-0.3V to 6V
BATT, LX Current .....................................................................1A
SDA Current ........................................................................50mA
VL Current ...........................................................................50mA
Continuous Power Dissipation (T
A
= +70°C)
SO (derate 8.70mW/°C above +70°C) .........................696mW
Operating Temperature Range
MAX1610CSE/MAX1611CSE ..............................0°C to +70°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°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.
ELECTRICAL CHARACTERISTICS
(T
A
= 0°C to +70°C, BATT = 8.2V, MINDAC = 0V, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SUPPLY AND REFERENCE
BATT Input Voltage Range
BATT Quiescent Supply Current,
Operate Mode
BATT Quiescent Supply Current,
Shutdown Mode
VL Output Voltage, Operate Mode
VL Output Voltage, Shutdown Mode
REF Output Voltage
REF Load Regulation
SWITCHING REGULATOR
BATT-to-LX Switch On-Resistance
LX Switch Off-Leakage Current
Oscillator Frequency
Oscillator SYNC Pin Synchronization Range
SYNC High Pulse Width
SYNC Low Pulse Width
SYNC Input Current
SYNC Input Low Voltage
SYNC Input High Voltage
Power-Switch Maximum Duty Cycle
SS Source Current
SS Sink Current
SYNC = REF
SS = GND
SS = 0.5V
4.0
89
2.5
2
91
4.0
5.5
SYNC = GND or VL
SYNC = REF
SYNC = GND
250
125
240
200
200
-1
1
0.5
290
145
BST - LX = 4.1V
0.7
1.0
10
330
165
350
Ω
µA
kHz
kHz
ns
ns
µA
V
V
%
µA
mA
No load
I
SOURCE
= 100µA
4.75V < BATT < 26V
4.25
3.0
1.92
BATT = 25V
4.75
1.5
10
4.5
3.6
2.0
6
26
3
20
4.75
4.75
2.08
20
V
mA
µA
V
V
V
mV
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
Digitally Controlled CCFL Backlight
Power Supplies
ELECTRICAL CHARACTERISTICS (continued)
(T
A
= 0°C to +70°C, BATT = 8.2V, MINDAC = 0V, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
DAC AND ERROR AMPLIFIER
DAC Resolution
MINDAC Input Voltage Range
MINDAC Input Bias Current
MINDAC Digital PWM Threshold
CSAV Input Voltage Range
CSAV Regulation Point
CSAV Input Bias Current
CSAV to CC Voltage-to-Current Converter
Transconductance
CC Sink Current
CC Source Current
OPEN AND SHORTED TUBE PROTECTION
OTP Voltage Trip Point
OTP Input Bias Current
CS Overcurrent Cutoff Threshold
MAX1610 LOGIC LEVELS
SHDN,
UP, DN Input Low Voltage
SHDN,
UP, DN Input High Voltage
SHDN,
UP, DN Input Bias Current
MAX1611 LOGIC LEVELS
SMBSUS, SDA, SCL Input Low Voltage
SMBSUS, SDA, SCL Input High Voltage
SMBSUS, SDA, SCL Input Bias Current
SDA Output Low Sink Current
V
SDA
= 0.6V
2.2
-1
6
1
0.8
V
V
µA
mA
2.4
-1
1
0.8
V
V
µA
Referred to REF
GND < OTP < VL
OTP rising
-20
-1
500
20
1
mV
µA
mV
CC = 2V, CSAV = 1V, D/A at 1LSB
CC = 2V, CSAV = 1V, D/A at 1LSB
CC = 2V, CSAV = 0V, D/A at full scale
D/A at full scale
D/A at 1LSB
-5
85
80
20
0
232
247
12
5
Guaranteed monotonic
5
0
-1
3
1.0
260
1
1
Bits
V
µA
V
V
mV
µA
µmho
µA
µA
CONDITIONS
MIN
TYP
MAX
UNITS
MAX1610/MAX1611
_______________________________________________________________________________________
3
Digitally Controlled CCFL Backlight
Power Supplies
MAX1610/MAX1611
TIMING CHARACTERISTICS—MAX1610
(Figure 1, T
A
= +25°C, unless otherwise noted.)
PARAMETER
UP, DN Pulse Width High
UP, DN Pulse Width Low
UP, DN Pulse Separation
Counter Reset Time
SYMBOL
t
1
t
2
t
3
t
4
CONDITIONS
MIN
1
1
1
1
TYP
MAX
UNITS
µs
µs
µs
µs
TIMING CHARACTERISTICS—MAX1611
(Figures 2 and 3, T
A
= +25°C, unless otherwise noted.)
PARAMETER
SCL Serial Clock High Period
SCL Serial Clock Low Period
SCL, SCA Rise Time
SCL, SDA Fall Time
Start Condition Setup Time
Start Condition Hold Time
SDA Valid to SCL Rising Edge
Setup Time, Slave Clocking in Data
SCL Falling Edge to SDA
Transition
SCL Falling Edge to SDA Valid,
Reading Out Data
Note 1:
Guaranteed by design.
SYMBOL
t
HIGH
t
LOW
t
R
t
F
t
SU:STA
t
HD:STA
t
SU:DAT
t
HD:DAT
t
DV
(Note 1)
(Note 1)
(Note 1)
4.7
4
500
0
1
CONDITIONS
MIN
4
4.7
1
0.3
TYP
MAX
UNITS
µs
µs
µs
µs
µs
µs
ns
ns
µs
4
_______________________________________________________________________________________
Digitally Controlled CCFL Backlight
Power Supplies
__________________________________________Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
REF OUTPUT VOLTAGE
vs. REF OUTPUT CURRENT
MAX1610/1611-TOC1
MAX1610/MAX1611
BATT SUPPLY CURRENT
vs. BATT VOLTAGE (SHDN = VL)
MAX1610/1611-TOC2
VL OUTPUT VOLTAGE
vs. VL OUTPUT CURRENT
SHDN = VL, OTP = 3V
4.5
VL VOLTAGE (V)
BATT = 5V
4.0
3.5
3.0
2.5
2.0
BATT = 12V
MAX1610/1611-TOC3
2.2
SHDN = VL, BATT = 5V
2.1
REF OUTPUT VOLTAGE (V)
2.0
1.9
1.8
1.7
1.6
1.5
1
10
100
1000
2.0
SHDN = VL, OTP = 3V
1.8
BATT CURRENT (mA)
5.0
1.6
1.4
1.2
1.0
10000
0
4
8
12
16
20
24
28
REF OUTPUT CURRENT (µA)
BATT (V)
0
10
20
30
40
VL OUTPUT CURRENT (mA)
VL OUTPUT VOLTAGE
vs. VL LOAD CURRENT
MAX1610/1611-TOC4
BATT SUPPLY CURRENT
vs. BATT VOLTAGE (SHDN = OV)
MAX1610/1611-TOC5
VL OUTPUT VOLTAGE
vs. BATT VOLTAGE (SHDN = OV)
NO LOAD ON VL,
SHDN = OV
MAX1610/1611-TOC6
3.70
SHDN = GND
3.65
3.60
VL VOLTAGE (V)
3.55
3.50
3.45
3.40
BATT = 5V
3.35
3.30
0
200
400
600
800
BATT = 12V
10
SHDN = OV
8
BATT CURRENT (µA)
5.0
4.5
4.0
VL (V)
6
3.5
3.0
4
2
0
1000
0
4
8
12
16
20
24
28
2.5
2.0
0
4
8
12
16
20
24
28
BATT (V)
BATT (V)
VL LOAD CURRENT (µA)
VL OUTPUT VOLTAGE
vs. BATT VOLTAGE (SHDN = VL)
MAX1610/1611-TOC7
5.0
4.5
4.0
VL (V)
3.5
3.0
2.5
2.0
0
NO LOAD ON VL,
SHDN = VL
4
8
12
16
20
24
28
BATT (V)
_______________________________________________________________________________________
5
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