MAX16812ATI/V+ [MAXIM]
LED Driver;
| 型号： | MAX16812ATI/V+ |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | LED Driver 驱动 接口集成电路 |
| 文件： | 总20页 (文件大小：1551K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
EVALUATION KIT AVAILABLE
MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
General Description
Features
● Integrated 76V, 0.2Ω (typ) Power MOSFET
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.
● 5.5V to 76V Wide Input Range
● Adjustable LED Current with 5% Accuracy
● Floating Differential LED Current-Sense Amplifier
● Floating Dimming N-Channel MOSFET Driver
● PWM LED Dimming with:
• PWM Control Signal
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 cur-
rent-sense amplifier and a dimming MOSFET driver are
also included, simplifying the design and reducing the
total component count.
• Analog Control Signal
• Chopped V Input
IN
● Peak-Current-Mode Control
● 125kHz to 500kHz Adjustable Switching Frequency
● Adjustable UVLO and Soft-Start
● Output Overvoltage Protection
● 5µs LED Current Rise/Fall Times During Dimming
The MAX16812 uses peak-current-mode control, adjust-
able slope compensation that allows for additional design
flexibility. The device has two current regulation loops.
The first loop controls the internal switching MOSFET
peak current, while the second current regulation loop
controls the LED current. Switching frequency can be
adjusted from 125kHz to 500kHz.
Minimize EMI
● Overtemperature and Short-Circuit Protection
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
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.
MAX16812ATI+
-40°C to +125°C
28 TQFN-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Simplified Diagram
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.
C
H_REG
DOUT
R
CS
VOUT
C
OUT
R
SRC
Applications
● Architectural and Industrial Lighting
LV
IN
SRC
GT
V
IN
C
IN
EN
RT
RT
DRV
SLP
MAX16812
R
TGRM
L_REG
TGRM
DIM
C
SLP
C
TGRM
COMP
R
R
C
COMP1
OV1
VOUT
OV2
R
COMP1
R
COMP2
Typical Application Circuit and Pin Configuration appear
at end of data sheet.
BUCK-BOOST CONFIGURATION
19-0880; Rev 1; 4/14
MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
Absolute Maximum Ratings
(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,
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 = +70°C)
A
28-Pin TQFN 5mm x 5mm
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
(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
*As per JEDEC51 standard (multilayer board).
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 = V
= 12V, C
= 3.3µF, C
= 1µF, C
= 47nF, V
= 0V, R
= 0.2Ω, T = T = -40°C to +125°C, unless
IN
EN
L_REG
H_REG
REF
TGRM
SRC
A
J
otherwise noted. Typical values are at T = +25°C.)
A
PARAMETER
Input Voltage Range
SYMBOL
CONDITIONS
MIN
5.5
TYP
MAX
76.0
2.5
45
UNITS
V
V
IN
Q
Quiescent Supply
I
V
V
= 1V, V
DIM
= 0V
0.3
mA
µA
Ω
TGRM
Shutdown Supply Current
Internal MOSFET On-Resistance
Output Current Accuracy
Peak Switch Current Limit
Hiccup Switch Current
Switch Leakage Current
UNDERVOLTAGE LOCKOUT
IN Undervoltage Lockout
UVLO Hysteresis
I
≤ 300mV
EN
20
SHDN
R
I
I
= 1A, V > 10V, V
= V = 5V
DRV
0.2
0.4
+5
DSON
LX
IN
GT
I
= 350mA, R = 1Ω
CS
-5
%
LED
LED
I
2.6
3.1
6
3.6
A
LXLIM
A
I
V
V
= 0V, V = 76V, V = 0V
GT
1
10
µA
LXLEAK
UVLO
EN
LX
rising
4.6
1.2
4.9
100
1.38
100
5.3
V
mV
V
IN
EN Threshold Voltage
EN Hysteresis
V
_
V
rising
1.6
EN THUP
EN
mV
REFERENCE (REF) AND LOW-SIDE LINEAR REGULATOR (L_REG)
Startup Response Time
Reference Voltage
t
V
or V rising
EN
50
µs
V
POR
IN
V
I
= 10µA
1.190
25
1.238
1.288
60
REF
REF
Reference Soft-Start Charging
Current
I
_
V
= 0V
REF
40
µA
REF SLEW
L_REG Supply Voltage
L_REG Load Regulation
L_REG Dropout Voltage
V
= 7.5V, I
L_REG
= 1mA
4.9
5.2
5.5
20
V
Ω
IN
I _
L REG
= 20mA
= 25mA
I _
L REG
400
mV
Maxim Integrated
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
Electrical Characteristics (continued)
(V = V
= 12V, CL_REG = 3.3µF, C
= 1µF, C
= 47nF, V
= 0V, R
= 0.2Ω, T = T = -40°C to +125°C, unless
IN
EN
H_REG
REF
TGRM
SRC
A
J
otherwise noted. Typical values are at T = +25°C.)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
PWM COMPARATOR
V
V
= 1V, V
= 0.5V, V
= 0.5V, V
= 1V,
= 0V,
COMP
DIM
SRC
TGRM
COMP Input Leakage Current
SRC Input Leakage Current
I
-0.10
-5
+0.10
+5
µA
µA
LKCOMP
= 0.5V
V
V
= 0V, V
COMP
SRC
TGRM
I
LKSRC
= 0.5V
DIM
Comparator Offset Voltage
Input Voltage Range
Propagation Delay
ERROR AMPLIFIER
FB Input Current
V
(V
- V
) = V
OS
860
100
mV
V
OS(EA)
COMP
SRC
V
V
= V
+ 860mV
0
1.23
SRC
COMP
SRC
t
50mV overdrive
ns
PD
V
V
V
V
= 1V, V
= 1V, V
= 1.2V
= 1V
-100
-100
-23
0
+100
+100
+23
nA
nA
mV
V
FB
FB
FB
FB
REFI
REFI Input Current
Error-Amplifier Offset Voltage
Input Common-Mode Range
Source Current
REFI
V
= V
= 1.2V
OS
COMP
= (V
- 0.9V)
1.5
COMP
I
(V
- V ) ≥ 0.5V
300
80
µA
µA
V
COMP
REFI
FB
Sink Current
(V - V
) ≥ 0.5V
FB
REFI
COMP Clamp Voltage
DC Gain
V
V
= 1.2V, V = 0V
1.20
2.56
COMP
REF
FB
72
dB
MHz
Unity-Gain Bandwidth
0.8
Electrical Characteristics
(V = V
= 12V, C
= 3.3µF, C
= 1µF, C
= 47nF, V
= 0V, R
= 0.2Ω, R
= 1Ω, T = T = -40°C to +125°C,
IN
EN
L_REG
H_REG
REF
TGRM
SRC
CS
A
J
unless otherwise noted. Typical values are at T = +25°C.)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
HIGH-SIDE UNDERVOLTAGE LOCKOUT AND LINEAR REGULATOR (H_REG) ((V
- V ) = 21V)
LV
HV
H_REG Input-Voltage Threshold
H_REG Supply Voltage
H_REG Load Regulation
Dropout Voltage
V _
is rising
= 0
3.60
4.75
3.887
5
4.20
5.40
80
V
V
H REG
I _
H REG
I
I
_
= 0 to 3mA
= 5mA
Ω
H REG
_
820
mV
H REG
HIGH-SIDE CURRENT-SENSE AMPLIFIERS (V
HV
- V ) = 21V
LV
CS- Input Bias Current
CS+ Input Bias Current
Input Voltage Range
I
V
= V , (V
- V
- V
) = -0.1V
) = 0.1V
500
+1
µA
µA
V
CS-
CS-
CS-
CS-
LV
CS+
CS+
CS-
I
V
V
= V , (V
-1
0
CS+
LV
CS-
= V
0.25
LV
Sinking
25
400
0
Minimum Output Current
I
_
µA
CS OUT
Sourcing
Output Voltage Range
DC Voltage Gain
V
_
1.5
1.0
V
V/V
MHz
V
CS OUT
4
Unity-Gain Bandwidth
Maximum REFI Input Voltage
0.8
V
REFI
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│ 3
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
Electrical Characteristics (continued)
(V = V
= 12V, C
= 3.3µF, C
= 1µF, C
= 47nF, V
= 0V, R
= 0.2Ω, R
= 1Ω, T = T = -40°C to +125°C,
IN
EN
L_REG
H_REG
REF
TGRM
SRC
CS
A
J
unless otherwise noted. Typical values are at T = +25°C.)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
HIGH-SIDE DIMMING LINEAR REGULATOR ((V
- V ) = 21V)
LV
HV
V
= V
, (V
- V
DIM
= 1.0V, sinking
) = 0.3V,
= 1V, V
TGRM
LV
CS-
LV
CS+
CS-
(V
- V ) = 1V, V
= 0V,
= 3V,
1.2
1.2
DD
V
= 1V, V
DGT
REFI
Minimum Output Current
I
mA
DGT
V
(V
= V
, (V
- V
) = 0.2V,
= 0V, V
LV
CS-
CS+
CS-
- V ) = 1V, V
DD
LV
TGRM DGT
V
= 1.0V, V
= 1V, sourcing
REFI
DIM
Output Voltage Range
DC Gain
0.2
5.0
V
C
= 1nF to LV
60
dB
µA
DGT
DD Input Bias Current
I
(V
- V -) = 0.5V
CS
-3
+3
DD
DD
V
= 0V, V
LV)
= 1V, V
= 1.2V,
TGRM
DGT
DIM
REFI
DD Input Low Threshold
0.25
0.50
0.75
V
(V
- V
> 1.5V, V
falling
DD
DIMMING ((V
HV
- V ) = 21V)
LV
DIM Input Bias Current
I
V
V
= 1.1V
DIM
-1
+1
µA
V
DIM
TGRM Input High Threshold
1.18
1.23
1
1.27
TGRM Reset High-to-TGRM Low
Pulse Width
µs
Ω
TGRM Reset Switch R
DS(ON)
= 1.3V
20
TGRM
Dimming Rise and Fall LED
Current Times
5
µs
OVERVOLTAGE PROTECTION (OV)
OV Input High Threshold
V
V
rising
1.180
-1
1.230
14
1.292
+1
V
OV
OV
OV Input Threshold Hysteresis
OV Input Bias Current
mV
µA
I
= 1.1V
OV
INTERNAL OSCILLATOR CLOCK
RT = 2MΩ to AGND
RT = 50kΩ to AGND
470
105
525
125
570
155
Internal Clock Frequency
f
kHz
µA
OSC
SLOPE COMPENSATION INPUT (SLP)
SLP Input Current
I
V
= 0V
SLP
150
SLP
LOW-SIDE GATE DRIVE (DRV)
DRV Output Low Impedance
DRV Output High Impedance
INTERNAL POWER MOSFET
GT Input Leakage Current
R
DRV sinking 20mA
DRV sourcing 20mA
3
30
45
Ω
Ω
DRV_LO
R
10
DRV_HI
V
V
= 0 to 5V
= 50V
-1
+1
µA
V
GT
LX
Internal MOSFET Gate-to-
Source Threshold Voltage
V
2.5
8
TH
Internal MOSFET Gate Charge
Q
nC
g
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
Typical Operating Characteristics
(V = V
IN
= 12V, C
= 3.3µF, C
= 1µF, V
= 0V, T = +25°C, unless otherwise noted.)
EN
L_REG
H_REG
TGRM A
SWITCH CURRENT LIMIT
vs. TEMPERATURE
R
vs. I
R
vs. V
DS(ON) GT
DS(ON)
LX
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
3.300
3.250
3.200
3.150
3.100
3.050
3.000
2.950
2.900
T
= +25C
A
T
= +125C
A
T
= +25C
A
T
= -40C
A
1.0
1.5
2.0
(A)
2.5
3.0
2.2 2.8 3.4 4.0 4.6 5.2 5.8 6.4 7.0
(V)
-40 -25 -10
5 20 35 50 65 80 95 110 125
I
V
GT
TEMPERATURE (°C)
LX
IN UVLO THRESHOLD
vs. TEMPERATURE
SHUTDOWN CURRENT
vs. TEMPERATURE
V
REF
vs. TEMPERATURE
5.20
5.15
5.10
5.05
5.00
1.25
1.24
1.23
1.22
1.21
30
25
20
15
10
5
V
RISING
IN
I
= 10µA
REF
0
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -25 -10
5
20 35 50 65 80 95 110 125
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
IN UVLO THRESHOLD
vs. TEMPERATURE
EN UVLO THRESHOLD
vs. TEMPERATURE
5.10
5.09
5.08
5.07
5.06
5.05
5.04
5.03
5.02
5.01
5.00
1.50
V
IN
FALLING
V
EN
RISING
1.45
1.40
1.35
1.30
1.25
1.20
1.15
1.10
1.05
1.00
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -25 -10
5
20 35 50 65 80 95 110 125
TEMPERATURE (°C)
TEMPERATURE (°C)
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
Typical Operating Characteristics (continued)
(V = V
IN
= 12V, C
= 3.3µF, C
= 1µF, V
= 0V, T = +25°C, unless otherwise noted.)
EN
L_REG
H_REG
TGRM A
EN UVLO THRESHOLD
vs. TEMPERATURE
OSCILLATOR FREQUENCY
vs. TEMPERATURE
V
vs. I
L_REG
L_REG
600
500
400
300
200
100
0
5.5
5.4
5.3
5.2
5.1
5.0
4.9
4.8
4.7
4.6
4.5
1.50
1.45
1.40
1.35
1.30
1.25
1.20
1.15
1.10
1.05
1.00
V
EN
FALLING
R
= 2MΩ
T
T
= +125C
A
T
= +25C
A
R
= 180kΩ
= 50kΩ
T
T
= -40C
A
R
T
V
IN
= 7.5V
-40 -25 -10
5
20 35 50 65 80 95 110 125
0
2
4
6
8
10 12 14 16 18 20
(mA)
-40 -25 -10
5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
I
TEMPERATURE (°C)
L_REG
V
THRESHOLD
H_REG
vs. TEMPERATURE
OSCILLATOR FREQUENCY vs. R
T
4.2
4.1
4.0
3.9
3.8
3.7
3.6
3.5
3.4
600
500
400
300
200
100
0
-40 -25 -10
5
20 35 50 65 80 95 110 125
0.01
0.1
1
10
TEMPERATURE (°C)
R
(MΩ)
T
V
vs. I
V
vs. TEMPERATURE
H_REG
H_REG
H_REG
5.00
4.95
4.90
4.85
4.80
4.75
4.70
4.65
4.60
4.55
4.50
5.2
5.1
5.0
4.9
4.8
4.7
4.6
4.5
4.4
4.3
4.2
(V - V ) = 6V
(V - V ) = 21V
HV
LV
HV
LV
V
IN
= 12V
I
= 3mA
LOAD
V
IS MEASURED
H_REG
WITH RESPECT TO V
LV
0
0.5
1.0
1.5
(mA)
2.0
2.5
3.0
-40 -25 -10
5
20 35 50 65 80 95 110 125
I
TEMPERATURE (°C)
H_REG
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
Pin Description
PIN
NAME
FUNCTION
1
FB
Low-Side Error Amplifier’s Inverting Input
2
3
COMP
Low-Side Error Amplifier’s Output. Connect a compensation network from COMP to FB for stable operation.
Reference Input. V
LED current.
provides the reference voltage for the high-side current-sense amplifier to set the
REFI
REFI
REF
4
5
6
+1.23V Reference Output. Connect an appropriate soft-start capacitor from REF to AGND.
is proportional to the current through R
CS_OUT High-Side Current-Sense Amplifier Output. V
_
.
CS
CS OUT
AGND
EN
Analog Ground
Enable Input/Undervoltage Lockout. Connect EN to IN through a resistive voltage-divider to program the
UVLO threshold. Connect EN directly to IN to set up the device for 5V internal threshold. Apply a logic-level
input to EN to enable/disable the device.
7
8
IN
Positive Power-Supply Input. Bypass with a 1µF ceramic capacitor to AGND.
9
L_REG 5V Low-Side Regulator Output. Bypass with a 3.3µF ceramic capacitor to AGND.
10
11
12
SGND
DD
Signal Ground
MOSFET’s Drain Voltage-Sense Input. Connect DD to the drain of the external dimming MOSFET.
External Dimming MOSFET’s Gate Drive
DGT
High-Side Current-Sense Amplifier’s Positive Input. Connect R
referenced to LV.
between CS+ and CS-. CS+ is
CS
13
14
15
16
17
18
CS+
CS-
High-Side Current-Sense Amplifier’s Negative Input. Connect R
referenced to LV.
between CS- and CS+. CS- is
CS
High-Side Reference Voltage Input. A DC voltage at LV sets the lowest reference point for the high-side
current-sense and dimming MOSFET control circuitry.
LV
High-Side Regulator Output. H_REG provides a regulated supply for high-side circuitry. Bypass with a 1µF
ceramic capacitor to LV.
H_REG
HV
High-Side Positive Supply Voltage Input. HV provides power for dimming and LED current-sense circuitry.
HV is referenced to LV.
Internal MOSFET Gate Driver Output. Connect to a resistor between DRV and GT to set the rise and fall
times at LX.
DRV
19
GT
LX
Internal MOSFET GATE. Connect a resistor between GT and DRV to set the rise and fall times at LX.
20, 21
22, 23
Internal MOSFET Drain
SRC
Internal Power MOSFET Source
Slope Compensation Setting. Connect an appropriate external capacitor from SLP to AGND to generate a
ramp signal for stable operation.
24
SLP
25
26
TGRM
DIM
Dimming Comparator’s Reference/Ramp Generator
Dimming Control Input
Resistor-Programmable Internal Oscillator Setting. Connect a resistor from RT to AGND to set the internal
oscillator frequency.
27
28
—
RT
OV
EP
Overvoltage Protection Input. Connect OV to HI through a resistive voltage-divider to AGND to set the
overvoltage limit for the load. When the voltage at OV exceeds the 1.238V (typ) threshold, the gate drive
(DRV) for the switching MOSFET is disabled. Once V
MOSFET turns on again.
goes below 1.238V by 14mV, the switching
OV
Exposed Pad. Connect EP to a large-area ground plane for effective power dissipation. Do not use as the
IC ground connection.
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
DD
DS
0.5V
CMP
HV
DRMP
ADIM
DGT
CS+
LDOH
POR
3.88V
H_REG
DIM
RAMP
REF
1.2X
1.1X
1X
CS-
LX
CMP
IHI
CSA
LX
SRC
LV
IN
t
= 200ns
D
SRC
GT
2.5V
V
= 1.2V
= 0.3V
REFI
PREG
BG
V
RAMP
V
REF
V
DD
UVLO/
POR
LDOL
S
Q
L_REG
EN
G1
DRV
LATCH
1.2V
0.6V
R
SGND
HICCUP
REF
1X
EN
LOGIC
CONTROL
RT
OSC
I
LIM
DIM
SIGNAL
DIM
V
BE
CMP
PWM
1.238V
CMP
X0.2
SLP
TGRM
OV
MAX16812
COMP
FB
ERROR
AMPLIFIER
AND
DIMMING
S/H
2µs PULSE
LOW TO DISCHARGE
X1
CS_OUT
REFI
OVP
1.238V
SGND
AGND
Figure 1. Functional Diagram
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
Current-Mode Control
Detailed Description
The MAX16812 offers a current-mode control opera-
tion feature with leading-edge blanking that blanks the
sensed current signal applied to the input of the PWM
current-mode comparator. In addition, a current-limit com-
parator monitors the same signal at all times and provides
cycle-by-cycle current limit. An additional hiccup com-
parator limits the absolute peak current to two times the
cycle-by-cycle current limit. The leading-edge blanking of
the current-sense signal prevents noise at the PWM com-
parator input from prematurely terminating the on-cycle.
The switch current-sense signal contains a leading-edge
spike that results from the MOSFET gate-charge current,
and the capacitive and diode reverse-recovery current of
the power circuit. The MAX16812’s capacitor-adjustable
slope-compensation feature allows for easy stabilization
of the inner switching MOSFET current-mode loop. Upon
triggering the hiccup current limit, the soft-start capacitor
on REF is discharged and the gate drive to DRV is dis-
abled. Once the inductor current falls below the hiccup
current limit, the soft-start capacitor is released and it
begins to charge after 10µs.
The MAX16812 is a current-mode PWM LED driver with
an integrated 0.2Ω power MOSFET for use in driving HB
LEDs. By using two current regulation loops, 5% LED
current accuracy is achieved. One current regulation
loop controls the internal MOSFET peak current through
a sense resistor (R
) from SRC to ground, while the
SRC
other current regulation loop controls the average LED
current in a single LED string through another sense
resistor (R ) in series with the LEDs.
CS
The MAX16812 includes a cycle-by-cycle current limit
that turns off the gate drive to the internal MOSFET
during an overcurrent condition. The MAX16812 features
a programmable oscillator that simplifies and optimizes
the design of magnetics. The MAX16812 is well suited
for inputs from 5.5V to 76V. An external resistor in series
with the internal MOSFET gate can control the rise and
fall times on the drain of the internal switching MOSFET,
therefore minimizing EMI problems.
The MAX16812 high-frequency, current-mode PWM
HB LED driver integrates all the necessary building blocks
for driving a series LED string in an adjustable constant
current mode with PWM dimming. Current-mode control
with leading-edge blanking simplifies control-loop design,
and an external adjustable slope-compensation control
stabilizes the inner current-mode loop when operating at
duty cycles above 50%.
Slope Compensation
The MAX16812 uses an internal ramp generator for
slope compensation. The internal ramp signal resets at
the beginning of each cycle and slews at the rate pro-
grammed by the external capacitor connected at SLP
and an internal ISLP current source of 150µA. An internal
attenuator attenuates the actual slope compensation
signal by a factor of 0.2. Adjust the MAX16812 slew-rate
capacitor by using the following equation:
An input undervoltage lockout (UVLO) programs the input
supply startup voltage. An external voltage-divider on
EN programs the supply startup voltage. If EN is directly
connected to the input, the UVLO is set at 5V. A single
external resistor from RT to AGND programs the switch-
ing frequency from 125kHz to 500kHz.
SLP
SR
C
= 0.2 ×
SLOPE
Wide contrast (100:1) PWM dimming can be achieved
with the MAX16812. A DC input on DIM controls the
dimming duty cycle. The dimming frequency is set by
the sawtooth ramp frequency on TGRM (see the PWM
Dimming section). In addition, PWM dimming can be
achieved by applying a PWM signal to DIM with TGRM
set to a DC voltage less than 1.238V. A floating high-volt-
age driver drives an external n-channel MOSFET in series
with the LED string. REFI allows analog dimming of the
LED current, further increasing the effective dimming
range over PWM alone. The MAX16812 has a 5µs pre-
programmed LED current rise and fall time.
where I
is the charging current in mA and C
is
SLOPE
SLP
the slope compensation capacitance on the SLP in µF,
and SR is the designed slope in mV/µs.
When using the MAX16812 for internal switching MOSFET
duty cycles greater than 50%, the following conditions
must be met to avoid current-loop subharmonic oscilla-
tions.
0.5 ×R
× V
IND_OFF
SRC
SR ≥
mV / µs
L
where R
is in mΩ, V
is in volts, and L is in
IND_OFF
SRC
A nonlatching overvoltage protection limits the voltage on
the internal switching MOSFET under open-circuit condi-
tions in the LED string. The internal thermal shutdown cir-
cuit protects the device if the junction temperature should
exceed +165°C.
µH. L is the inductor connected to the LX pin of the
internal switching MOSFET and V is the voltage
across the inductor during the off-time of the internal
MOSFET.
IND_OFF
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
minimizing output-voltage overshoot. While the part is in
UVLO, CREF is discharged (Figure 3). Upon coming out
of UVLO, an internal current source starts charging CREF
during the soft-start cycle. Use the following equation to
calculate total soft-start e:
Undervoltage Lockout
The MAX16812 features an adjustable UVLO through the
enable input (EN). Connect EN directly to IN to use the 5V
default UVLO. Connect EN to IN through a resistive divid-
er to ground to set the UVLO threshold. The MAX16812
is enabled when VEN exceeds the 1.38V (typ) threshold.
1.238
Calculate the EN UVLO resistor-divider values as follows
(see Figure 2):
t
= C
×
REF
ST
I
REF
where I
is 40µA, CREF is in µF, and t is in seconds.
ST
V
REF
EN
- V
EN
R
= R
x
UV2
UV1
Operation begins when REF ramps above 0.6V. Once
the soft-start is complete, REF is regulated to 1.238V, the
internal voltage reference.
V
UVLO
where RUV1 is in the 20kΩ range, VEN is the 1.38V
(typ) EN threshold voltage, and V is the desired
input-voltage UVLO threshold in volts. Due to the 100mV
hysteresis of the UVLO threshold, capacitor C is
required to prevent chattering at the UVLO threshold due
to line impedance drops at power-up and during dimming.
If the undervoltage setting is very close to the required
minimum operating voltage, there can be jumps in the
Low-Side Internal
Switching MOSFET Driver Supply (L_REG)
L_REG is the regulated (5.2V) internal supply voltage
capable of delivering 20mA. L_REG provides power to
the gate drive of the internal switching power MOSFET.
UVLO
EN
V
is referenced to AGND. Connect a 3.3µF ceramic
L_REG
capacitor from L_REG to AGND.
voltage at IN while dimming. C
should be large enough
EN
High-Side Regulator (H_REG)
to limit the ripple on EN to less than 100mV (EN hystere-
sis) under these conditions so that it does not turn on and
off due to the ripple on IN.
H_REG is a low-dropout linear regulator referenced
to LV. H_REG provides the gate drive for the external
n-channel dimming MOSFET and also powers up the
MAX16812’s LED current-sense circuitry. Bypass H_REG
to LV with a 1µF ceramic capacitor.
Soft-Start
The soft-start feature of the MAX16812 allows the LED
string current to ramp up in a controlled manner, thus
V
V
IN
IN
IN
IN
R
R
UV2
MAX16812
MAX16812
EN
REF
C
REF
C
UV1
EN
AGND
AGND
Figure 2. UVLO Threshold Setting
Figure 3. Soft-Start Setting
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
is low, COMP is disconnected from the output of the error
amplifier and CS_OUT is simultaneously disconnected
from the buffered LED current-sense output signal (Figure
5). When the internal dimming signal is high, the output
of the op amp is connected to COMP and CS_OUT is
connected to the buffered LED current-sense signal at
the same time (Figure 4). This enables the compensation
capacitor to hold the charge when the DIM signal has
turned off the internal switching MOSFET gate drive.
To maintain the charge on the compensation capacitors
High-Side Current-Sense Output (CS_OUT)
A high-side transconductance amplifier converts the volt-
age across the LED current-sense resistor (RCS) into
an internal current output. This current flows through an
internal resistor connected to AGND. The voltage gain for
the LED current-sense signal is 4. The amplified signal is
then buffered and connected through an internal switch
to CS_OUT.
Internal Error Amplifier
C
and C
, the capacitors should be of the
The MAX16812 includes a built-in voltage-error amplifi-
er, which can be used to close the feedback loop. The
internal LED current-sense output signal is buffered
internally and then connected to CS_OUT through an
internal switch. CS_OUT is connected to the inverting
input (FB) pin of the error amplifier through a resistor.
See Figures 4 and 5. The reference voltage for the out-
put current is connected to REFI, the noninverting input
of the error amplifier. When the internal dimming signal
COMP1
COMP2
low-leakage ceramic type.
When the internal dimming signal is enabled, the volt-
age on the compensation capacitor forces the converter
into steady state almost instantaneously. The voltage on
COMP is subtracted from the internal slope compensation
signal and is then connected to one of the inputs of the
PWM comparator. The PWM comparator input is of the
CMOS type with very low bias currents.
C
COMP2
STATE A
C
COMP1
R
COMP2
R
OUT
COMP1
X1
COMP
EA
REFI
Figure 4. Internal Error Amplifier Connection (Dimming Signal High)
C
COMP2
STATE B
C
COMP1
R
COMP2
R
OUT
COMP1
X1
COMP
EA
REFI
Figure 5. Internal Error Amplifier Connections (Dimming Signal Low)
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
voltage produced by this current (through the cur-
rent-sense resistor) exceeds the current-limit (ILIM) com-
parator threshold, the MOSFET driver (DRV) quickly
terminates the current on-cycle. The 200ns leading-edge
blanking circuit suppresses the leading-edge spike on
the current-sense waveform from appearing at the cur-
rent-limit comparator. There is also a hiccup comparator
(HICCUP) that limits the peak current in the internal
switch set at twice the peak limit setting.
Analog Dimming
The MAX16812 offers analog dimming of the LED current
by allowing the application of an external voltage at REFI.
The output current is proportional to the voltage at REFI.
Use a potentiometer from REF or directly apply an exter-
nal voltage source at REFI.
PWM Comparator
The PWM comparator uses the instantaneous switch
current, the error-amplifier output, and the slope com-
pensation to determine when the gate drive DRV to the
internal n-channel switching MOSFET turns off. In normal
operation, gate drive DRV to the n-channel MOSFET
turns off when:
Internal n-Channel
Switching MOSFET Driver (DRV)
L_REG provides power for the DRV output. Connect a
resistor from DRV to gate GT of the internal switching
MOSFET to control the switching MOSFET rise and fall
times, if necessary.
I
x R
≥ V
- V
- V
SW
SRC
COMP
OFFSET SCOMP
where I
switching MOSFET, R
resistor, V
is the current through the internal n-channel
SW
External Dimming
MOSFET Gate Drive (DGT)
is the switch current-sense
SRC
is the output voltage of the internal ampli-
COMP
DGT is the gate drive to the external dimming MOSFET
referenced to LV. H_REG provides the power to the gate
drive.
fier, V
drop, and V
and slews at the programmed slew rate (SR).
is the internal DC offset, which is a V
OFFSET
BE
is the ramp function that starts at zero
SCOMP
Overvoltage Protection
Internal Switching MOSFET Current Limit
The overvoltage protection (OVP) comparator compares
the voltage at OV with a 1.238V (typ) internal reference.
When the voltage at OV exceeds the internal reference,
the OVP comparator terminates PWM switching and no
further energy is transferred to the load. Connect OV to
HV through a resistive voltage-divider to ground to set the
overvoltage threshold at the output.
The current-sense resistor (RSRC), connected between
the source of the internal MOSFET and ground, sets
the current limit. The SRC input has a voltage trip level
(V
) of 600mV for the cycle-by-cycle current limit. Use
SRC
the following equation to calculate the value RSRC:
V
SRC
R
=
SRC
I
LXLIM
Setting the Overvoltage Threshold
Connect OV to HV or to the high-side of the LEDs through
a resistive voltage-divider to set the overvoltage threshold
at the output (Figure 6).
where I
is the peak current that flows through the
LXLIM
switching MOSFET at full load and low line. When the
V
LED+
V
LED+
HV
OV
MAX16812
MAX16812
R
R
R
R
OV1
OV2
OV1
OV
OV2
AGND
AGND
Figure 6. OVP Setting
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
The overvoltage protection (OVP) comparator compares
the voltage at OV with a 1.238V (typ) internal reference.
Use the following equation to calculate resistorlues:
REF
DIM
L_REG
V
− V
R
R
R
TGRM
DIM1
DIM2
MAX16812
OV_LIM
OV
R
= R
x
OV2
OV1
V
OV
TGRM
where V
is the 1.238V OV threshold. Choose R
C
TGRM
OV
OV1
AGND
and R
to be reasonably high-value resistors to pre-
OV2
vent the discharge of filter capacitors. This prevents
degraded performance during dimming.
Internal Oscillator Switching Frequency
The oscillator switching frequency is programmed by a
resistor connected from RT to AGND. To program the
oscillator frequency above 125kHz, choose the appropri-
ate resistor RT from the curves shown in the Oscillator
Frequency vs. RT graph in the Typical Operating
Characteristics section.
Figure 7. PWM Dimming from REF
PWM dimming can also be achieved by connecting
TGRM to a DC voltage less than VREF and applying the
PWM signal at DIM. The moment the internal dimming
signal goes low, gate drive DRV to the internal switching
MOSFET is turned off. The error amplifier goes to state
B (see the Internal Error Amplifier section and Figures 4
and 5). The peak current in the inductor prior to disabling
PWM Dimming
PWM dimming can be achieved by driving DIM with an
analog voltage less than V
. See Figure 7. An external
REF
DRV is I . Gate drive DGT to the external dimming
LX
resistor on TGRM from L_REG in conjunction with the
ramp capacitor, C , from TGRM to AGND creates a
MOSFET is held high. Then after a switchover period,
TGRM
gate voltage V
on the external dimming MOSFET is
DGT
sawtooth ramp that is compared with the DC voltage on
DIM. The output of the comparator is a pulsating dimming
linearly controlled to reduce the LED current to 0. The fall
time of the LED current is controlled by an internal timing
circuit to 5µs for the MAX16812. During this period, the
gate (DRV) to the internal switching MOSFET is enabled.
After the fall time, the gate drive to the external dimming
MOSFET is turned off and the gate drive to the internal
switching MOSFET is still held high after the switchover
period. The peak current in the inductor is controlled at
signal. The frequency f
TGRM is given by:
of the sawtooth signal on
RAMP
3.67
f
≅
RAMP
C
×R
TGRM
TGRM
Use the following formula to calculate the voltage V
necessary for a given output duty cycle, D:
,
DIM
I
. Then after a time period of 20µs, the gate drive is
LX
disabled. The scope shots in Figures 8–11 show the dim-
ming waveforms.
V
DIM
= D x 1.238V
where V
is the DC voltage applied to DIM in volts.
DIM
The DC voltage for DIM can also be created by connect-
ing DIM to REF through a resistive voltage-divider. Using
the required dimming input voltage, V
, calculate the
DIM
resistor values for the divider string using the following
equation:
R
= [V
/ (V
- V )] x R
DIM DIM1
DIM2
DIM
REF
where V
is the voltage on REF.
REF
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
MAX16812 fig08
MAX16812 fig10
V
OUT
10V/div
10V/div
V
OUT
100mA/div
0A, 0V
100mA/div
0A, 0V
I
LED
I
LED
2V/div
0V
2V/div
0V
V
V
DRV
DRV
10s/div
10s/div
Figure 8. LED Current, Output Voltage, and DRV Waveforms
when DIM Signal Goes Low
Figure 10. LED Current, Output Voltage, and DRV Waveforms
when DIM Signal Goes High
MAX16812 fig11
MAX16812 fig09
I
LED
I
LED
100mA/div
100mA/div
V
DIM
V
DIM
5V/div
5V/div
0A, 0V
0A, 0V
V
DRV
2V/div
V
DRV
2V/div
0V
0V
10s/div
10s/div
Figure 11. LED Current, DIM Signal, and DRV Waveforms
when DIM Signal Goes High
Figure 9. LED Current, DIM Signal, and DRV Waveforms when
DIM Signal Goes Low
When the DIM signal goes high, the LED current is grad-
ually increased to the programmed value. The rise time
of the LED current is controlled to 5µs for the MAX16812
by controlling the voltage on DGT. After the rise time, an
internal sensing circuit monitors the voltage across the
drain to the source of the external dimming MOSFET. The
LED current is now controlled at the programmed value
by a linear current regulating circuit. Once the voltage
across the drain to source of the dimming MOSFET drops
below 0.5V, the reference for the linear current regulating
circuit is increased to 1.1 times the programmed value.
The gate drive (DRV) to the internal switching MOSFET is
enabled and the error amplifier is returned to state A (see
the Internal Error Amplifier section and Figures 4 and 5).
Fault Protection
The MAX16812 features built-in overvoltage protection
and thermal shutdown. Connect a resistive voltage-di-
vider between HV, OV, and AGND to program the over-
voltage protection. In the case of a short circuit across
the LED string, the temperature of the external dimming
MOSFET could exceed the maximum allowable junction
temperature. This is due to excess power dissipation in the
MOSFET. Use the fault protection circuit shown in Figure
12 to protect the external dimming MOSFET.
Internal thermal shutdown in the MAX16812 safely turns
off the IC when the junction temperature exceeds +165°C.
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
V
IN
100k
GND
GND
TO EN PIN OF
MAX16812
TOVER
5.1V
ZENER
MAX6501
TO L_REG PIN
OF MAX16812
V
CC
4.7F
Figure 12. Dimming MOSFET Protection
where V
switching frequency, and V
is the maximum input voltage, f
is the
Inductor Selection
The minimum required inductance is a function of the
operating frequency, the input-to-output voltage differen-
INMAX
SW
is the output voltage.
OUT
Boost Configuration: In the boost converter, the aver-
age inductor current varies with the input voltage and the
maximum average current occurs at the lowest input volt-
age. For the boost converter, the average inductor current
is equal to the input current. In this case, the inductance,
L, is calculated as:
tial and the peak-to-peak inductor current (∆I ). Higher
L
∆I allows for a lower inductor value while a lower ∆I
L
L
requires a higher inductor value. A lower inductor value
minimizes size and cost, improves large-signal transient
response, but reduces efficiency due to higher peak
currents and higher peak-to-peak output ripple voltage
for the same output capacitor. On the other hand, higher
inductance increases efficiency by reducing the ripple
V
x V
− V
OUT INMIN
(
)
INMIN
L =
V
x f
x ∆I
SW L
OUT
current, ∆I . However, resistive losses due to the extra
L
turns can exceed the benefit gained from lower ripple cur-
rent levels, especially when the inductance is increased
without allowing for larger inductor dimensions. A good
where V
output voltage, and f
Figure 14.
is the minimum input voltage, V
is the
INMIN
OUT
is the switching frequency. See
SW
compromise is to choose ∆I equal to 30% of the full
L
load current. The inductor saturating current specification
is also important to avoid runaway current during output
overload and continuous short-circuit conditions.
Buck-Boost Configuration: In a buck-boost converter
(see the Typical Application Circuit), the average inductor
current is equal to the sum of the input current and the
LED current. In this case, the inductance, L, is:
Buck Configuration: In a buck configuration (Figure 13),
the average inductor current does not vary with the input.
The worst-case peak current occurs at the highest input
voltage. In this case, the inductance, L, for continuous
conduction mode given by:
V
x V
OUT
INMIN
x f
L =
V
+ V
x ∆I
SW L
(
)
OUT
INMIN
where V
is the minimum input voltage, V
is the
INMIN
OUT
V
x V
− V
(
)
output voltage, and f
is the switching frequency.
OUT
INMAX OUT
SW
L =
V
x f
x ∆I
SW L
INMAX
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
C
OUT
V
IN
D
R
CS
OUT
C
C
H_REG
IN
IN HV
H_REG
LX
LV DD DGT CS-
CS+
SRC
R
R
EN
SRC
R
RT
GT
RT
C
L_REG
MAX16812
G
L_REG
DRV
SLP
R
TGRM
C
SLP
TGRM
DIM
C
TGRM
COMP
FB
OV SGND AGND
REF
REFI CS_OUT
V
OUT
R
COMP1
C
REF
C
R
R
COMP1
OV1
OV2
R
REF1
R
COMP2
R
REF2
C
COMP2
Figure 13. Buck Configuration
C
H_REG
R
D
OUT
CS
V
OUT
V
IN
C
OUT
R
SRC
CS-
CS+
DGT
DD
H_REG HV
LX
SRC
LV
IN
V
C
IN
GT
R
G
EN
RT
IN1
R
RT
DRV
SLP
C
L_REG
MAX16812
L_REG
C
R
SLP
TGRM
TGRM
DIM
C
TGRM
COMP
OV SGND AGND
REF
REFI CS_OUT
FB
V
OUT
R
COMP1
C
REF
C
R
R
COMP1
OV1
OV2
R
REF1
R
COMP2
R
REF2
C
COMP2
Figure 14. Boost Configuration
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MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
L1
L2
C
S
C
H_REG
D
VOUT
OUT
R
CS
V
IN
C
OUT
R
SRC
V
IN
LV
IN
SRC
GT
C
IN1
EN
RT
RT
R
G
C
L_REG
DRV
SLP
MAX16812
L_REG
C
SLP
R
TGRM
TGRM
DIM
COMP
C
TGRM
VOUT
C
COMP1
R
R
R
OV1
OV2
COMP2
R
REF1
R
COMP1
R
REF2
C
COMP2
Figure 15. SEPIC Configuration
In a buck-boost configuration, the output capacitance,
Output Capacitor
C
is:
OUT
The function of the output capacitor is to reduce the out-
put ripple to acceptable levels. The ESR, ESL, and the
bulk capacitance of the output capacitor contribute to the
output ripple. In most of the applications, the output ESR
and ESL effects can be dramatically reduced by using
low-ESR ceramic capacitors. To reduce the ESL effects,
connect multiple ceramic capacitors in parallel to achieve
the required capacitance.
2 × V
×I
OUT OUT
C
≥
OUT
OUT
∆V × (V
+ V
) × f
R
OUT
INMIN SW
where V
is the voltage across the load and I
is
OUT
the output current.
Input Capacitor
In a buck configuration, the output capacitance, C
calculated using the follow equation:
, is
OUT
An input capacitor connected between IN and ground
must be used when configuring the MAX16812 as a buck
converter. Use a low-ESR input capacitor that can handle
the maximum input RMS ripple current. Calculate the
maximum RMS ripple using the follow equation:
(V
− V
) × V
OUT OUT
INMAX
C
≥
OUT
2
∆V × 2 ×L × V
× f
R
INMAX SW
where ∆VR is the maximum allowable output ripple.
I
× V
×(V
- V
)
OUT
In a boost configuration, the output capacitance, C
is calculated as:
,
OUT
OUT
INMIN
OUT
I
=
IN(RMS)
V
INMIN
(V
− V ) × 2 ×I
INMIN OUT
OUT
∆V × V
C
≥
When using the MAX16812 in a boost or buck-boost con-
figuration, the input capacitor’s RMS current is low and
the input capacitance can be small. However, an addi-
tional electrolytic capacitor may be required to prevent
oscillations due to line impedances.
OUT
× f
SW
R
OUT
where C
is the output capacitor.
OUT
Maxim Integrated
│ 17
www.maximintegrated.com
MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
● Keep the high-current paths short, especially at the
ground terminals. This practice is essential for stable,
jitter-free operation. Keep switching loops short.
Layout Recommendations
Typically, there are two sources of noise emission in a
switching power supply: high di/dt loops and high dv/dt
surfaces. For example, traces that carry the drain current
often form high di/dt loops. Similarly, the drain of the
internal MOSFET connected to the LX pin presents a dv/
dt source. Keep all PCB traces carrying switching cur-
rents as short as possible to minimize current loops. Use
ground planes for best results.
● Connect AGND and SGND to a ground plane.
Ensure a low-impedance connection between all
ground points.
● Keep the power traces and load connections short.
This practice is essential for high efficiency. Use thick
copper PCBs to enhance full-load efficiency.
Careful PCB layout is critical to achieve low switching
losses and clean, stable operation. Use a multilayer board
whenever possible for better noise immunity and power
dissipation. Follow these guidelines for good PCB layout:
● Ensure that the feedback connection to FB is short
and direct.
● Route high-speed switching nodes away from the
sensitive analog areas.
● Use a large copper plane under the MAX16812 pack-
age. Ensure that all heat-dissipating components
have adequate cooling. Connect the exposed pad of
the device to the ground plane.
● To prevent discharge of the compensation capacitors,
C
and C
, during the off-time of the dim-
COMP1
COMP2
ming cycle, ensure that the PCB area close to these
components has extremely low leakage.
● Isolate the power components and high-current paths
from sensitive analog circuitry.
Maxim Integrated
│ 18
www.maximintegrated.com
MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
Typical Application Circuit
BUCK-BOOST CONFIGURATION
C
H_REG
R
D
OUT
CS
V
OUT
C
OUT
R
SRC
CS-
CS+
DGT
DD
H_REG HV
LX
SRC
LV
IN
V
C
IN
GT
R
EN
RT
IN1
G
RT
DRV
SLP
C
L_REG
MAX16812
L_REG
C
R
SLP
TGRM
TGRM
DIM
C
TGRM
COMP
FB
OV SGND AGND
REF
REFI CS_OUT
V
OUT
R
COMP1
C
REF
C
R
R
COMP1
OV1
OV2
R
REF1
R
COMP2
R
REF2
C
COMP2
Pin Configuration
Chip Information
PROCESS: BiCMOS
TOP VIEW
TRANSISTOR COUNT: 8699
21 20 19 18 17 16 15
14
13
12 DGT
SRC 22
SRC 23
CS-
CS+
24
25
26
27
28
SLP
TGRM
DIM
Package Information
DD
11
10
9
MAX16812
For the latest package outline information and land patterns
(footprints), go to www.maximintegrated.com/packages. Note
that a “+”, “#”, or “-” in the package code indicates RoHS status
only. Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
SGND
L_REG
IN
RT
*EP
+
8
OV
1
2
3
4
5
6
7
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
*EP = EXPOSED PAD
TQFN
28 TQFN-EP
T2855+8
21-0140
90-0028
Maxim Integrated
│ 19
www.maximintegrated.com
MAX16812
Integrated High-Voltage LED Driver
with Analog and PWM Dimming Control
Revision History
REVISION REVISION
PAGES
CHANGED
DESCRIPTION
NUMBER
DATE
0
1
7/07
4/14
Initial release
—
1
No /V OPNs; removed Automotive reference from Applications section
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
©
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
2014 Maxim Integrated Products, Inc.
│ 20
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