19-5666; Rev 2; 12/10
Dual-Channel Automotive CCFL Controller
General Description
The DS3882 is a dual-channel cold-cathode fluorescent
lamp (CCFL) controller for automotive applications that
provides up to 300:1 dimming. It is ideal for driving
CCFLs used to backlight liquid crystal displays (LCDs)
in navigation and infotainment applications and for dri-
ving CCFLs used to backlight instrument clusters. The
DS3882 is also appropriate for use in marine and avia-
tion applications.
The DS3882 features EMI suppression functionality and
provides a lamp current overdrive mode for rapid lamp
heating in cold weather conditions. The DS3882 sup-
ports configurations of 1 or 2 lamps with fully indepen-
dent lamp control and minimal external components.
Multiple DS3882 controllers can be cascaded to sup-
port applications requiring more than 2 lamps. Control of
the DS3882, after initial programming setup, can be
completely achieved through I
2
C software communica-
tion. Many DS3882 functions are also pin-controllable if
software control is not desired.
Features
♦
Dual-Channel CCFL Controllers for Backlighting
LCD Panels and Instrument Clusters in
Automotive Navigation/Infotainment Applications
♦
Minimal External Components Required
♦
I
2
C Interface
♦
Per-Channel Lamp-Fault Monitoring for Lamp-
Open, Lamp-Overcurrent, Failure to Strike, and
Overvoltage Conditions
♦
Status Register Reports Fault Conditions
♦
Accurate (±5%) Independent On-Board Oscillators
for Lamp Frequency (40kHz to 100kHz) and DPWM
Burst-Dimming Frequency (22.5Hz to 440Hz)
♦
Lamp and DPWM Frequencies can be
Synchronized with External Sources to Reduce
Visual LCD Artifacts in Video Applications
♦
Optional Spread-Spectrum Lamp Clock Reduces
EMI
♦
Lamp Frequency can be Stepped Up or Down to
Move EMI Spurs Out of Band
♦
Lamp Current Overdrive Mode with Automatic
Turn-Off Quickly Warms Lamp in Cold
Temperatures
♦
Analog and Digital Brightness Control
♦
300:1 Dimming Range Possible Using the Digital
Brightness Control Option
♦
Programmable Soft-Start Minimizes Audible
Transformer Noise
♦
On-Board Nonvolatile (NV) Memory Allows Device
Customization
♦
8-Byte NV User Memory for Storage of Serial
Numbers and Date Codes
♦
Low-Power Standby Mode
♦
4.75V to 5.25V Single-Supply Operation
♦
Temperature Range: -40°C to +105°C
♦
28-Pin TSSOP Package
DS3882
Applications
Automotive LCDs
Instrument Clusters
Marine and Aviation LCDs
Pin Configuration
TOP VIEW
FAULT 1
A0 2
SDA 3
SCL 4
LSYNC 5
LOSC 6
BRIGHT 7
PSYNC 8
POSC 9
A1 10
GND_S 11
SVML 12
SVMH 13
V
CC
14
+
28 OVD2
27 LCM2
26 GB2
25 GA2
DS3882
24 V
CC
23 PDN
22 LCO
21 GND
20 STEP
19 N.C.
18 OVD1
17 LCM1
16 GB1
15 GA1
Ordering Information
PART
DS3882E+C
DS3882E+T&R/C
TEMP RANGE
-40°C to +105°C
-40°C to +105°C
PIN-PACKAGE
28 TSSOP
28 TSSOP
TSSOP
+Denotes
a lead(Pb)-free/RoHS-compliant package.
T&R = Tape and reel.
Typical Operating Circuit appears at end of data sheet.
______________________________________________
Maxim Integrated Products
1
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.
Dual-Channel Automotive CCFL Controller
DS3882
ABSOLUTE MAXIMUM RATINGS
Voltage Range on V
CC
, SDA, and
SCL Relative to Ground.....................................-0.5V to +6.0V
Voltage Range on Leads Other than V
CC
, SDA, and
SCL ......................-0.5V to (V
CC
+ 0.5V), not to exceed +6.0V
Continuous Power Dissipation (T
A
= +70°C)
TSSOP (derate 12.8mW/°C above +70°C) .............1025.6mW
Operating Temperature Range .........................-40°C to +105°C
EEPROM Programming Temperature Range .........0°C to +85°C
Storage Temperature Range .............................-55°C to +125°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°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.
RECOMMENDED OPERATING CONDITIONS
(T
A
= -40°C to +105°C)
PARAMETER
Supply Voltage
Input Logic 1
Input Logic 0
SVML/H Voltage Range
BRIGHT Voltage Range
LCM Voltage Range
OVD Voltage Range
Gate-Driver Output Charge
Loading
SYMBOL
V
CC
V
IH
V
IL
V
SVM
V
BRIGHT
V
LCM
V
OVD
Q
G
(Note 2)
(Note 2)
(Note 1)
CONDITIONS
MIN
4.75
2.0
-0.3
-0.3
-0.3
-0.3
-0.3
TYP
MAX
5.25
V
CC
+ 0.3
1.0
V
CC
+
0.3
V
CC
+
0.3
V
CC
+
0.3
V
CC
+
0.3
20
UNITS
V
V
V
V
V
V
V
nC
ELECTRICAL CHARACTERISTICS
(V
CC
= +4.75V to +5.25V, T
A
= -40°C to +105°C.)
PARAMETER
Supply Current
Input Leakage (Digital Pins)
Power-Down Current
Output Leakage (SDA,
FAULT)
Low-Level Output Voltage
(LSYNC, PSYNC)
Low-Level Output Voltage
(SDA,
FAULT)
Low-Level Output Voltage
(GA, GB)
High-Level Output Voltage
(LSYNC, PSYNC)
SYMBOL
I
CC
I
L
I
PDN
I
LO
V
OL
V
OL1
V
OL2
V
OL3
V
OH
High impedance
I
OL
= 4mA
I
OL1
= 3mA
I
OL2
= 6mA
I
OL3
= 4mA
I
OH
= -1mA
2.4
-1.0
CONDITIONS
G
A
, G
B
loaded with 600pF, 2 channels active
-1.0
MIN
TYP
12
+1.0
2
+1.0
0.4
0.4
0.6
0.4
MAX
UNITS
mA
µA
mA
µA
V
V
V
V
2
_____________________________________________________________________
Dual-Channel Automotive CCFL Controller
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +4.75V to +5.25V, T
A
= -40°C to +105°C.)
PARAMETER
High-Level Output Voltage
(GA, GB)
UVLO Threshold: V
CC
Rising
UVLO Threshold: V
CC
Falling
UVLO Hysteresis
SVML/H Threshold: Rising
SVML/H Threshold: Falling
LCM and OVD DC Bias Voltage
LCM and OVD Input Resistance
Lamp Off Threshold
Lamp Over Current
Lamp Regulation Threshold
OVD Threshold
Lamp Frequency Source
Frequency Range
Lamp Frequency Source
Frequency Tolerance
Lamp Frequency Receiver
Frequency Range
Lamp Frequency Receiver
Duty Cycle
DPWM Source (Resistor)
Frequency Range
DPWM Source (Resistor)
Frequency Tolerance
DPWM Source (Ext. Clk)
Frequency Range
DPWM Source (Ext. Clk)
Duty Cycle
DPWM Receiver
Min Pulse Width
BRIGHT Voltage: Minimum
Brightness
BRIGHT Voltage: Maximum
Brightness
Gate Driver Output Rise/Fall Time
GAn and GBn Duty Cycle
SYMBOL
V
OH1
V
UVLOR
V
UVLOF
V
UVLOH
V
SVMR
V
SVMF
V
DCB
R
DCB
V
LOT
V
LOC
V
LRT
V
OVDT
f
LFS:OSC
f
LFS:TOL
f
LFR:OSC
f
LFR:DUTY
f
DSR:OSC
f
DSR:TOL
f
DSE:OSC
f
DFE:DUTY
t
DR:MIN
V
BMIN
V
BMAX
t
R
/ t
F
C
L
= 600pF
(Note 6)
2.0
100
44
(Note 5)
POSC resistor ±2% over temperature
LOSC resistor ±2% over temperature
(Note 3)
(Note 3)
(Notes 3, 4)
(Note 3)
0.22
2.2
0.9
0.9
40
-5
40
40
22.5
-5
22.5
40
25
0.5
2.03
1.95
3.7
200
2.08
2.02
1.1
50
0.25
2.5
1.0
1.0
0.28
2.8
1.1
1.1
100
+5
100
60
440.0
+5
440.0
60
2.15
2.07
I
OH1
= -1mA
CONDITIONS
MIN
V
CC
-
0.4
4.3
TYP
MAX
UNITS
V
V
V
mV
V
V
V
kΩ
V
V
V
V
kHz
%
kHz
%
Hz
%
Hz
%
µs
V
V
ns
%
DS3882
_____________________________________________________________________
3
Dual-Channel Automotive CCFL Controller
DS3882
I
2
C AC ELECTRICAL CHARACTERISTICS (See Figure 9)
(V
CC
= +4.75V to +5.25V, T
A
= -40°C to +105°C, timing referenced to V
IL(MAX)
and V
IH(MIN)
.)
PARAMETER
SCL Clock Frequency
Bus Free Time Between Stop and
Start Conditions
Hold Time (Repeated) Start
Condition
Low Period of SCL
High Period of SCL
Data Hold Time
Data Setup Time
Start Setup Time
SDA and SCL Rise Time
SDA and SCL Fall Time
Stop Setup Time
SDA and SCL Capacitive
Loading
EEPROM Write Time
SYMBOL
f
SCL
t
BUF
t
HD:STA
t
LOW
t
HIGH
t
HD:DAT
t
SU:DAT
t
SU:STA
t
R
t
F
t
SU:STO
C
B
t
W
(Note 9)
(Note 10)
20
(Note 9)
(Note 9)
(Note 8)
(Note 7)
CONDITIONS
MIN
0
1.3
0.6
1.3
0.6
0
100
0.6
20+
0.1C
B
20+
0.1C
B
0.6
400
30
300
300
0.9
TYP
MAX
400
UNITS
kHz
µs
µs
µs
µs
µs
ns
µs
ns
ns
µs
pF
ms
NONVOLATILE MEMORY CHARACTERISTICS
(V
CC
= +4.75V to 5.25V)
PARAMETER
EEPROM Write Cycles
SYMBOL
CONDITIONS
+85°C (Note 11)
MIN
30,000
TYP
MAX
UNITS
Note 1:
All voltages are referenced to ground unless otherwise noted. Currents into the IC are positive, out of the IC negative.
Note 2:
During fault conditions, the AC-coupled feedback values are allowed to be below the absolute max rating of the LCM or
OVD pin for up to 1 second.
Note 3:
Voltage with respect to V
DCB
.
Note 4:
Lamp overdrive and analog dimming (based on reduction of lamp current) are disabled.
Note 5:
This is the minimum pulse width guaranteed to generate an output burst, which generates the DS3882’s minimum burst
duty cycle. This duty cycle may be greater than the duty cycle of the PSYNC input. Once the duty cycle of the PSYNC
input is greater than the DS3882’s minimum duty cycle, the output’s duty cycle tracks the PSYNC’s duty cycle. Leaving
PSYNC low (0% duty cycle) disables the GAn and GBn outputs in DPWM receiver mode.
Note 6:
This is the maximum lamp frequency duty cycle that is generated at any of the GAn or GBn outputs with spread-spectrum
modulation disabled.
Note 7:
I
2
C interface timing shown is for fast-mode (400kHz) operation. This device is also backward compatible with I
2
C stan-
dard-mode timing.
Note 8:
After this period, the first clock pulse can be generated.
Note 9:
C
B
—total capacitance allowed on one bus line in picofarads.
Note 10:
EEPROM write time applies to all the EEPROM memory. EEPROM write begins after a stop condition occurs.
Note 11:
Guaranteed by design.
4
_____________________________________________________________________
Dual-Channel Automotive CCFL Controller
Typical Operating Characteristics
(V
CC
= 5.0V, T
A
= +25°C, unless otherwise noted.)
ACTIVE SUPPLY CURRENT
vs. SUPPLY VOLTAGE
DS3882 toc01
DS3882
ACTIVE SUPPLY CURRENT
vs. TEMPERATURE
7.3
7.1
SUPPLY CURRENT (mA)
6.9
6.7
6.5
6.3
6.1
5.9
f
LF:OSC
= 64kHz
GATE Q
C
= 3.5nC
-40.0
DPWM = 100%
32.5
TEMPERATURE (°C)
105
V
CC
= 5.25V
V
CC
= 4.75V V
CC
= 5.0V
DS3882 toc02
INTERNAL FREQUENCY CHANGE
vs. TEMPERATURE
0.8
FREQUENCY CHANGE (%)
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
-40.0
32.5
TEMPERATURE (°C)
105
LAMP FREQUENCY
DPWM FREQUENCY
DS3882 toc03
8.0
7.5
SUPPLY CURRENT (mA)
7.0
6.5
6.0
5.5
5.0
4.5
4.0
GATE Q
C
= 3.5nC
f
LF:OSC
= 64kHz
SVML< 2V
DPWM = 100%
DPWM = 10%
DPWM = 50%
7.5
1.0
5.7
5.5
4.75 4.80 4.85 4.90 4.95 5.00 5.05 5.10 5.15 5.20 5.25
SUPPLY VOLTAGE (V)
TYPICAL OPERATION AT 11V
DS3882 toc04
TYPICAL OPERATION AT 13V
DS3882 toc05
TYPICAL OPERATION AT 16V
DS3882 toc06
10μs
5.0V
G
A
10μs
5.0V
G
B
10μs
2.00V LCM
10μs
2.00V OVD
10μs
5.0V
G
A
10μs
5.0V
G
B
10μs
5.0V
G
A
10μs
5.0V
G
B
10μs
2.00V LCM
10μs
2.00V OVD
10μs
2.00V LCM
10μs
2.00V OVD
TYPICAL STARTUP WITH SVM
DS3882 toc07
BURST DIMMING AT 150Hz AND 10%
DS3882 toc08
BURST DIMMING AT 150Hz AND 50%
DS3882 toc09
2ms
5.0V SVML
2ms
5.0V
G
B
1ms
5.0V
G
A
1ms
5.0V
G
B
1ms
5.0V
G
A
1ms
5.0V
G
B
1ms
2.00V LCM
1ms
2.00V OVD
2ms
2.00V LCM
2ms
2.00V OVD
1ms
2.00V LCM
1ms
2.00V OVD
_____________________________________________________________________
5
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