19-0625; Rev 1; 1/07
IT
TION K
VALUA
E
BLE
AVAILA
EEPROM-Programmable, High-Voltage,
350mA LED Drivers with LED Current Foldback
General Description
The MAX16805/MAX16806 LED drivers eliminate the
need for microcontrollers or switch-mode converters for
automotive interior dome, map, and courtesy light
applications. An EEPROM-programmable LED current-
sense reference simplifies production by using one
sense resistor to set the LED current for all LED bins. A
dual-mode DIM pin and an on-board 200Hz ramp gen-
erator allow for PWM dimming with an analog or PWM
control signal. The analog control signal at dimming
input DIM allows for the “theater dimming” effect to be
implemented. Fast turn-on/-off times ensure a wide-
range PWM operation, while waveshaping circuitry min-
imizes EMI. EEPROM-programmable LED current
foldback makes it possible to operate at a high input
voltage, while saving the cost and space associated
with having a large heatsink. The MAX16806 works with
an external thermal sensor to maintain maximum LED
junction temperature by folding back the LED current.
The thermal foldback temperature knee and slope are
EEPROM programmable. The MAX16806 SW pin sup-
plies necessary wetting current to a momentary switch.
Features
♦
EEPROM or I
2
C Dynamically Programmable:
LED Current Foldback for High Input Voltage
LED Current Reference
LED Current Thermal Foldback (MAX16806)
♦
On-Board 200Hz Ramp Generator Eliminates the
Need for µC PWM Signal
♦
Flexible Analog or PWM Control for PWM or
Theater Dimming
♦
Wetting Current and Debounce for Momentary
Switch (MAX16806)
♦
5.5V to 40V Input with Up to 39V Output Capability
♦
35mA to 350mA Adjustable LED Current
♦
Waveshaping Minimizes EMI During Dimming
♦
Output Short-Circuit and Overtemperature
Protection
♦
-40°C to +125°C Operating Temperature Range
MAX16805/MAX16806
Ordering Information
PART
TEMP RANGE
PIN
PACKAGE
PKG
CODE
Applications
Automotive Interior: Map, Dome, and Courtesy
Lighting
Automotive Exterior:
Rear Combination Light (RCL)
Daytime Running Light (DRL)
Adaptive Front Light
Emergency Vehicle Warning Lights
Navigation and Marine Indicators
MAX16805ATP+
-40°C to +125°C 20 TQFN-EP** T2055M-5
MAX16806ATP+
-40°C to +125°C 20 TQFN-EP** T2055M-5
+Denotes
lead-free package.
**EP
= Exposed pad.
Pin Configurations appear at end of data sheet.
Typical Operating Circuits
+5.5V TO +40V
IN
0.1μF
EN
SERIAL CLOCK
SERIAL DATA
V5
CS-
DIM
PWM DIMMING
GND
DIM
GND
SW
SCL
SDA
V5
0.1μF
LEDs
V
CC
OUT
+5V REG
V5
0.1μF
EN
V5
0.1μF
LEDs
I
LED
+5.5V TO +40V
IN
OUT
+5V REG
I
LED
MAX16805
CS+
R
SENSE
MAX16806
MAX6613
†
OUT
GND
TFP/SCL
CS+
R
SENSE
TFN/SDA
CS-
ANALOG CONTROL PWM DIMMING
†
MAX6613 THERMAL SENSOR IS OPTIONAL.
PWM CONTROL DIMMING
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
EEPROM-Programmable, High-Voltage, 350mA
LED Drivers with LED Current Foldback
MAX16805/MAX16806
ABSOLUTE MAXIMUM RATINGS
IN to GND ...............................................................-0.3V to +45V
DIM, OUT, EN to GND ................................-0.3V to (V
IN
+ 0.3V)
IN Slew Rate (20V < V
IN
< 45V) ...................................250mV/µs
SDA, SCL (MAX16805), TFN/SDA,
TFP/SCL (MAX16806) to GND...............................-0.3V to +6V
CFD, CS+, V5 to GND ..............................................-0.3V to +6V
DGND and CS- to GND.........................................-0.3V to +0.3V
OUT Short Circuited to GND Duration (V
IN
< +16V)..........1 hour
Maximum Current Into Any Pin (except IN and OUT) ......±20mA
Continuous Power Dissipation (T
A
= +70°C)
20-Pin Thin QFN (derate 34.5mW/°C above +70°C)....2758.6mW
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+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
(V
IN
= V
EN
= 12V, C
V5
= 0.1µF, I
V5
= 0, CS- = GND, R
SENSE
= 0.56Ω, V
DIM
= 4V, DGND = GND, TFP/SCL = 5V, TFN/SDA = 0V,
SW = CFD = Open, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Supply Voltage Range
Ground Current
Shutdown Supply Current
Guaranteed Output Current
Output Current Accuracy
Dropout Voltage (Note 3)
Output Current Slew Rate
(External PWM Signal at DIM)
Short-Circuit Current
ENABLE INPUT
EN Input Current
EN Input-Voltage High
EN Input-Voltage Low
Enable Turn-On Time
5V REGULATOR
Output Voltage Regulation
(MAX16806)
0 < I
V5
< 0.5mA,
SW = GND
V5
6.5V < V
IN
< 40V
0 < I
V5
< 2mA,
SW = open
4.9
4.9
4.9
5.1
5.1
5.1
5.3
V
5.3
5.3
V
I
EN
V
IH
V
IL
t
ON
EN rising edge to 90% of OUT
225
2.8
0.6
100
nA
V
V
µs
ΔV
DO
SYMBOL
V
IN
I
G
I
SHDN
I
OUT
(Note 2)
I
LOAD
= 350mA
V
EN
≤
0.3V
R
SENSE
= 0.55Ω
35mA < I
OUT
< 350mA, R
SENSE
tolerance
not included
I
OUT
= 350mA, 12V < V
IN
< 40V
I
OUT
= 350mA, 6.5V < V
IN
< 12V
Current rising, DIM rising to 4V
Current falling, DIM falling to 0.6V
V
OUT
= 0V
0.4
0.5
17
17
600
350
3.0
1.2
1.5
CONDITIONS
MIN
5.5
2.5
12
TYP
MAX
40
4.5
40
UNITS
V
mA
µA
mA
%
V
mA/µs
mA
Output Voltage Regulation
(MAX16805)
CURRENT SENSE
Regulated R
SENSE
Voltage
Input Current (CS+)
Input Current (CS-)
V5
0 < I
V5
< 2mA, 6.5V < V
IN
< 40V
V
RSNS
V
SENSE
= [V
CS+
- V
CS-
], Binning
Adjustment register at factory default
(0x0F)
V
CS+
= 210mV
V
CS+
= 210mV
192
12
198
204
mV
µA
-75
µA
2
_______________________________________________________________________________________
EEPROM-Programmable, High-Voltage, 350mA
LED Drivers with LED Current Foldback
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
EN
= 12V, C
V5
= 0.1µF, I
V5
= 0, CS- = GND, R
SENSE
= 0.56Ω, V
DIM
= 4V, DGND = GND, TFP/SCL = 5V, TFN/SDA = 0V,
SW = CFD = Open, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Minimum Regulated V
SENSE
Programming Range
Maximum Regulated V
SENSE
Programming Range
Regulated V
SENSE
Default
Voltage
EXTERNAL PWM DIMMING INPUT
DIM Input Current
Turn-On Time
Turn-Off Time
Maximum Thermal Foldback
Knee Point Programming Range
Minimum Thermal Foldback Knee
Point Programming Range
Minimum Thermal Foldback
Temperature Programming Range
Maximum Thermal Foldback
Temperature Programming Range
Thermal Foldback Default
Threshold Temperature
Thermal Foldback Default
Threshold Voltage
Minimum Thermal Foldback Slope
Maximum Thermal Foldback Slope
Thermal Foldback Default Slope
TFP/SCL (SCL for MAX16805)
Voltage Compliance Range
TFN/SDA (SDA for MAX16805)
Voltage Compliance Range
Minimum Thermal Foldback
Clamp Current Reduction Range
V
TFP
V
TFN
TF
C(MIN)
+25
o
C
≤
T
A
≤
+125
o
C
t
ON
t
OFF
After DIM rising to 4V (Note 4)
After DIM falling to 0.6V (Note 4)
28
19
0.5
52
38
µA
µs
µs
SYMBOL
V
SENSE(MIN)
V
SENSE(MAX)
V
SENSE(DEF)
Binning Adjustment register at factory
default (0x0F)
CONDITIONS
MIN
99.4
192
TYP
103
198
198
MAX
106.6
mV
204
mV
UNITS
MAX16805/MAX16806
THERMAL FOLDBACK (MAX16806 with MAX6613)
TF
KNEE(MAX)
TF
KNEE(MIN)
TF
(MIN)
TF
(MAX)
V
TH
TF
VTH
TF
SL(MIN)
TF
SL(MAX)
Thermal Foldback Slope Gain register at
factory default (0x03)
I
2
C interface active
Remote thermal sensor active
-0.3
+0.3
-0.3
40
3.88
15.52
Thermal Foldback Knee Point register at
factory default (0x00)
326
1143
335
1174
+60
°C
+135
+60
1.174
4
16
4
V5
V5
V5
4.12
16.48
°C
V
V/V
V/V
V/V
V
V
%
354
mV
1213
_______________________________________________________________________________________
3
EEPROM-Programmable, High-Voltage, 350mA
LED Drivers with LED Current Foldback
MAX16805/MAX16806
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
EN
= 12V, C
V5
= 0.1µF, I
V5
= 0, CS- = GND, R
SENSE
= 0.56Ω, V
DIM
= 4V, DGND = GND, TFP/SCL = 5V, TFN/SDA = 0V,
SW = CFD = Open, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Maximum Thermal Foldback
Clamp Current Reduction Range
Default Thermal Foldback Clamp
Current Reduction Range
THERMAL PROTECTION
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
LED CURRENT FOLDBACK
Minimum Input LED Current
Foldback Range
Maximum Input LED Current
Foldback Range
LED Current Foldback Default
Level
LED Current Foldback Voltage
Step Size
INTERNAL RAMP GENERATOR
Internal RAMP Frequency
External Sync Frequency Range
External Sync Voltage Low
External Sync Voltage High
V
DIM
= 0V
Output Current Duty Cycle
Minimum Ramp Peak
Programming Range
Maximum Ramp Peak
Programming Range
Ramp Peak Default Voltage
Ramp Offset Voltage
MOMENTARY SWITCH INTERFACE (SW) (MAX16806)
SW Pullup Current
SW Input-Voltage High
SW Input-Voltage Low
Minimum Pulse Width
Minimum Debounce Time
I
SW
V
IH
V
IL
120
40
V
SW
= 0V
I
SW
= 100µA
1
4
0.4
3
mA
V
V
ms
ms
I
DC
V
DIM
> (V
RAMP
+ 0.4V) (MAX16806),
V
DIM
> +3.3V (MAX16805)
1.49
2.77
Ramp Peak register at factory default
(0x07)
2.8
0
100
1.55
2.88
2.88
210
1.60
3.00
%
f
RAMP
f
DIM
176
80
200
224
2000
0.4
Hz
Hz
V
V
V
CFD(MIN)
V
CFD(MAX)
V
CFD
LED Current Foldback Threshold register
at factory default (0x00)
V
IN
> 11V, CFD register bit 3 = 0
V
IN
> 11V, CFD register bit 3 = 1
11.4
16.4
16.4
0.71
0.355
V
V
V
V/step
T
J(SHDN)
+155
+23
°C
°C
SYMBOL
TF
C(MAX)
CONDITIONS
+25
o
C
≤
T
A
≤
+125
o
C
Thermal Foldback Clamp register at
factory default (0x07),
+25
o
C
≤
T
A
≤
+125
o
C
MIN
TYP
100
MAX
UNITS
%
TF
DEF
40
%
V
RAMP(MIN)
V
RAMP(MAX)
V
V
V
mV
4
_______________________________________________________________________________________
EEPROM-Programmable, High-Voltage, 350mA
LED Drivers with LED Current Foldback
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
EN
= 12V, C
V5
= 0.1µF, I
V5
= 0, CS- = GND, R
SENSE
= 0.56Ω, V
DIM
= 4V, DGND = GND, TFP/SCL = 5V, TFN/SDA = 0V,
SW = CFD = Open, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
EEPROM
V
IN
Voltage for EEPROM
Programming
EEPROM Data-Retention Time
I
2
C DIGITAL INPUTS (TFP/SCL, TFN/SDA) (Note 5)
Logic Input-Voltage High
Logic Input-Voltage Low
Input Capacitance
SDA Output Voltage Low
I
2
C INTERFACE TIMING (Figure 1)
Serial Clock Frequency
Bus Free Time Between STOP
and START Condition
START Condition Hold Time
Clock Low Period
Clock High Period
Repeat START Condition Setup
Time
f
SCL
t
BUF
t
HD:STA
t
LOW
t
HIGH
t
SU:STA
A master device must provide a hold time
of at least 300ns for the SDA signal
(referred to V
IL
of the SCL signal) in order
to bridge the undefined region of SCL’s
falling edge
1.3
0.6
1.3
0.6
0.6
400
kHz
µs
µs
µs
µs
µs
V
OL
I
SINK
= 3mA
V
IH
V
IL
5
0.4
2.8
0.8
V
V
pF
V
20
10
22
24
V
Years
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX16805/MAX16806
Data Hold Time
t
HD:DAT
0
0.9
µs
Data Setup Time
Receive SCL/SDA Rise Time
Receive SCL/SDA Fall Time
STOP Condition Setup Time
Pulse Width of Spike Suppressed
Transmit SDA Fall Time
t
SU:DAT
t
R
t
F
t
SU:STO
t
SP
I
SINK
< 6mA, C
B
≤
400pF (Note 6)
100
300
250
0.6
50
250
ns
ns
ns
µs
ns
ns
Note 1:
All devices 100% production tested at T
J
= +25°C. Limits over the operating temperature range are guaranteed by design.
Note 2:
Resistors were added from OUT to CS+ to aid with the power dissipation during testing.
Note 3:
Dropout is measured as follows: Connect a resistor from OUT to CS+. Connect R
SENSE
= 0.56Ω from CS+ to CS-. Set V
IN
=
V
OUT
+3V (record V
OUT
as V
OUT1
). Reduce V
IN
until V
OUT
= 0.97 x V
OUT1
(record as V
IN2
and V
OUT2
).
ΔV
DO
= V
IN2
- V
OUT2
.
Note 4:
t
ON
time includes the delay and the rise time needed for I
OUT
to reach 90% of its final value. t
OFF
time is the time needed for
I
OUT
to drop below 10%. See the
Typical Operating Characteristics.
t
ON
and t
OFF
are tested with 13Ω from OUT to CS+.
Note 5:
TPF/SCL (SCL for MAX16805) and TPN/SDA (SDA for the MAX16805) are I
2
C interface compatible only when the
MAX16805/MAX16806 are the only parts on the bus for production programming.
Note 6:
C
B
is the total bus capacitance.
_______________________________________________________________________________________
5
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