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MAX16812ATI/V+T

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21
General Description
The MAX16812 is a peak-current-mode LED driver with
an integrated 0.2Ω power MOSFET designed to control
the current in a single string of high-brightness LEDs
(HB LEDs). The MAX16812 can be used in multiple
converter topologies such as buck, boost, or buck-
boost. The MAX16812 operates over a 5.5V to 76V wide
supply voltage range.
The MAX16812 features a low-frequency, wide-range
brightness adjustment (100:1), analog and PWM dim-
ming control input, as well as a resistor-programmable
EMI suppression circuitry to control the rise and fall
times of the internal switching MOSFET. A high-side
LED current-sense amplifier and a dimming MOSFET
driver are also included, simplifying the design and
reducing the total component count.
The MAX16812 uses peak-current-mode control,
adjustable slope compensation that allows for addition-
al design flexibility. The device has two current regula-
tion loops. The first loop controls the internal switching
MOSFET peak current, while the second current regula-
tion loop controls the LED current. Switching frequency
can be adjusted from 125kHz to 500kHz.
Additional features include adjustable UVLO, soft-start,
external enable/disable input, thermal shutdown, a
1.238V 1% accurate buffered reference, and an on-
chip oscillator. An internal 5.2V linear regulator supplies
up to 20mA to power external devices.
The MAX16812 is available in a thermally enhanced
5mm x 5mm, 28-pin TQFN-EP package and is specified
over the automotive -40°C to +125°C temperature range.
Applications
Automotive Lighting:
DRL, Fog Lights
Rear Combination Lights
Front and Rear Signal Lights
Interior Lighting
Warning and Emergency Lighting
Architectural and Industrial Lighting
Features
o Integrated 76V, 0.2Ω (typ) Power MOSFET
o 5.5V to 76V Wide Input Range
o Adjustable LED Current with 5% Accuracy
o Floating Differential LED Current-Sense Amplifier
o Floating Dimming N-Channel MOSFET Driver
o PWM LED Dimming with:
PWM Control Signal
Analog Control Signal
Chopped V
IN
Input
o Peak-Current-Mode Control
o 125kHz to 500kHz Adjustable Switching Frequency
o Adjustable UVLO and Soft-Start
o Output Overvoltage Protection
o 5µs LED Current Rise/Fall Times During Dimming
Minimize EMI
o Overtemperature and Short-Circuit Protection
MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
________________________________________________________________
Maxim Integrated Products
1
V
IN
C
IN
R
TGRM
C
H_REG
R
OV1
R
OV2
C
TGRM
RT
DIM
TGRM
VOUT
L_REG
RT
EN
IN
LV
R
CS
DOUT
VOUT
SRC
GT
DRV
SLP
COMP
R
COMP1
BUCK-BOOST CONFIGURATION
C
COMP1
C
SLP
R
SRC
C
OUT
R
COMP2
CS-
CS+
DGT
DD
H_REG
HV
LX
OV
SGND
AGND
REFI
REF
CS_OUT
FB
MAX16812
Simplified Diagram
19-0880; Rev 0; 7/07
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.
EVALUATION KIT
AVAILABLE
Typical Application Circuit and Pin Configuration appear at
end of data sheet.
Ordering Information
+
Denotes a lead-free package.
*
EP = Exposed pad.
PART TEMP RANGE
PIN-
PACKAGE
PKG
CODE
MAX16812ATI+ -40°C to +125°C 28 TQFN-EP* T2855-8
MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= V
EN
= 12V, C
L_REG
= 3.3µF, C
H_REG
= 1µF, C
REF
= 47nF, V
TGRM
= 0V, R
SRC
= 0.2Ω, T
A
= T
J
= -40°C to +125°C, unless oth-
erwise 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.
(All voltages are referenced to AGND, unless otherwise noted.)
SGND ....................................................................-0.3V to +0.3V
IN, EN, LX, DIM ......................................................-0.3V to +80V
L_REG, GT, DRV ......................................................-0.3V to +6V
RT, REF, REFI, CS_OUT, FB, COMP, SRC,
SLP, TGRM, OV ....................................................-0.3V to +6V
LV, HV, CS-, CS+, DGT, DD, H_REG ....................-0.3V to +80V
CS+, DGT, H_REG to LV ........................................-0.3V to +12V
CS- to LV ...............................................................-0.3V to +0.3V
CS+ to CS- .............................................................-0.3V to +12V
DD to LV ....................................................................-1V to +80V
Maximum Current into Any Pin (except LX, SRC) ............±20mA
Maximum Current into LX and SRC.......................................+2A
Continuous Power Dissipation (T
A
= +70°C)
28-Pin TQFN 5mm x 5mm
(derate 34.65mW/°C* above +70°C) .........................2759mW
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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Input Voltage Range V
IN
5.5 76.0 V
Quiescent Supply I
Q
V
TGRM
= 1V, V
DIM
= 0V 0.3 2.5 mA
Shutdown Supply Current I
SHDN
V
EN
≤ 300mV 20 45 µA
Internal MOSFET On-Resistance R
DSON
I
LX
= 1A, V
IN
> 10V, V
GT
= V
DRV
= 5V 0.2 0.4 Ω
Output Current Accuracy I
LED
I
LED
= 350mA, R
CS
= 1Ω -5 +5 %
Peak Switch Current Limit I
LXLIM
2.6 3.1 3.6 A
Hiccup Switch Current 6A
Switch Leakage Current I
LXLEAK
V
EN
= 0V, V
LX
= 76V, V
GT
= 0V 1 10 µA
UNDERVOLTAGE LOCKOUT
IN Undervoltage Lockout UVLO V
IN
rising 4.6 4.9 5.3 V
UVLO Hysteresis 100 mV
EN Threshold Voltage V
EN_THUP
V
EN
rising 1.2 1.38 1.6 V
EN Hysteresis 100 mV
REFERENCE (REF) AND LOW-SIDE LINEAR REGULATOR (L_REG)
Startup Response Time t
POR
V
IN
or V
EN
rising 50 µs
Reference Voltage V
REF
I
REF
= 10µA 1.190 1.238 1.288 V
Reference Soft-Start Charging
Current
I
REF_SLEW
V
REF
= 0V 25 40 60 µA
L_REG Supply Voltage V
IN
= 7.5V, I
L_REG
= 1mA 4.9 5.2 5.5 V
L_REG Load Regulation I
L_REG
= 20mA 20 Ω
L_REG Dropout Voltage I
L_REG
= 25mA 400 mV
*As per JEDEC51 standard (multilayer board).
MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
EN
= 12V, C
L_REG
= 3.3µF, C
H_REG
= 1µF, C
REF
= 47nF, V
TGRM
= 0V, R
SRC
= 0.2Ω, T
A
= T
J
= -40°C to +125°C, unless oth-
erwise noted. Typical values are at T
A
= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
PWM COMPARATOR
COMP Input Leakage Current I
LKCOMP
V
COMP
= 1V, V
SRC
= 0.5V, V
TGRM
= 1V,
V
DIM
= 0.5V
-0.10 +0.10 µA
SRC Input Leakage Current I
LKSRC
V
COMP
= 0V, V
SRC
= 0.5V, V
TGRM
= 0V,
V
DIM
= 0.5V
-5 +5 µA
Comparator Offset Voltage V
OS
(
EA
)
(V
COMP
- V
SRC
)
= V
OS
860 mV
Input Voltage Range V
SRC
V
COMP
= V
SRC
+ 860mV 0 1.23 V
Propagation Delay t
PD
50mV overdrive 100 ns
ERROR AMPLIFIER
FB Input Current V
FB
= 1V, V
REFI
= 1.2V -100 +100 nA
REFI Input Current V
FB
= 1V, V
REFI
= 1V -100 +100 nA
Error-Amplifier Offset Voltage V
OS
V
FB
= V
COMP
= 1.2V -23 +23 mV
Input Common-Mode Range V
FB
= (V
COMP
- 0.9V) 0 1.5 V
Source Current I
COMP
(V
REFI
- V
FB
) ≥ 0.5V 300 µA
Sink Current (V
FB
- V
REFI
) ≥ 0.5V 80 µA
COMP Clamp Voltage V
COMP
V
REF
= 1.2V, V
FB
= 0V 1.20 2.56 V
DC Gain 72 dB
Unity-Gain Bandwidth 0.8 MHz
ELECTRICAL CHARACTERISTICS
(V
IN
= V
EN
= 12V, C
L_REG
= 3.3µF, C
H_REG
= 1µF, C
REF
= 47nF, V
TGRM
= 0V, R
SRC
= 0.2Ω, R
CS
= 1Ω, T
A
= T
J
= -40°C to +125°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
HIGH-SIDE UNDERVOLTAGE LOCKOUT AND LINEAR REGULATOR (H_REG) ((V
HV
- V
LV
) = 21V)
H_REG Input-Voltage Threshold V
H_REG
is rising 3.60 3.887 4.20 V
H_REG Supply Voltage I
H_REG
= 0 4.75 5 5.40 V
H_REG Load Regulation I
H_REG
= 0 to 3mA 80 Ω
Dropout Voltage I
H_REG
= 5mA 820 mV
HIGH-SIDE CURRENT-SENSE AMPLIFIERS (V
HV
- V
LV
) = 21V
CS- Input Bias Current I
CS-
V
CS-
= V
LV
, (V
CS+
- V
CS-
) = -0.1V 500 µA
CS+ Input Bias Current I
CS+
V
CS-
= V
LV
, (V
CS+
- V
CS-
) = 0.1V -1 +1 µA
Input Voltage Range V
CS-
= V
LV
0 0.25 V
Sinking 25
Minimum Output Current I
CS_OUT
Sourcing 400
µA
Output Voltage Range V
CS_OUT
0 1.5 V
DC Voltage Gain 4 V/V
Unity-Gain Bandwidth 0.8 MHz
Maximum REFI Input Voltage V
REFI
1.0 V
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21

MAX16812ATI/V+T

Mfr. #:
Buy MAX16812ATI/V+T
Manufacturer:
Maxim Integrated
Description:
LED Lighting Drivers w/Analog & PWM Dimming Control
Lifecycle:
New from this manufacturer.
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