EVALUATION KIT AVAILABLE
MAX16818
1.5MHz, 30A High-Efficiency, LED Driver
with Rapid LED Current Pulsing
Benefits and Features
•
•
•
•
General Description
The MAX16818 pulse-width modulation (PWM)
LED driver controller provides high-output-current
capability in a compact package with a minimum number
of external components. The MAX16818 is suitable for
use in synchronous and nonsynchronous step-down
(buck) topologies, as well as in boost, buck-boost, SEPIC,
and Cuk LED drivers. The MAX16818 is the first LED
driver controller that enables Maxim’s technology for
fast LED current transients of up to 20A/µs and 30kHz
dimming frequency.
This device utilizes average-current-mode control that
enables optimal use of MOSFETs with optimal charge and
on-resistance characteristics. This results in the minimized
need for external heatsinking even when delivering up
to 30A of LED current. True differential sensing enables
accurate control of the LED current. A wide dimming range
is easily implemented to accommodate an external PWM
signal. An internal regulator enables operation over a wide
input voltage range: 4.75V to 5.5V or 7V to 28V and above
with a simple external biasing device. The wide switching
frequency range, up to 1.5MHz, allows for the use of small
inductors and capacitors.
The MAX16818 features a clock output with 180° phase
delay to control a second out-of-phase LED driver to
reduce input and output filter capacitors size or to mini-
mize ripple currents. The MAX16818 offers programmable
hiccup, overvoltage, and overtemperature protection.
The MAX16818ETI+ is rated for the extended tempera-
ture range (-40°C to +85°C) and the MAX16818ATI+ is
rated for the automotive temperature range (-40°C to
+125°C). This LED driver controller is available in a lead-
free, 0.8mm high, 5mm x 5mm 28-pin TQFN package with
an exposed pad.
●
Flexible Architecture Supports a Range of LED
LIghting Applications with Minimal Component Count
Up to 30A Output Current
4.75V to 5.5V or 7V to 28V Input Voltage Range
Average-Current-Mode Control
True-Differential Remote-Sense Input
●
Frequency Management Reduces EMI and
Interference with Other System Clocks
• Programmable Switching Frequency or External
Synchronization from 125kHz to 1.5MHz
• Clock Output for 180° Out-of-Phase Operation
●
Integrated Protection Features and Thermally
Enhanced Package Improve System Reliability
• Output Overvoltage and Hiccup-Mode Overcurrent
Protection
• Thermal Shutdown
• Thermally Enhanced 28-Pin TQFN Package
Ordering Information
PART
MAX16818ATI+
MAX16818ETI+
TEMP RANGE
-40°C to +125°C
-40°C to +85°C
PIN-PACKAGE
28 TQFN-EP*
28 TQFN-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Simplified Diagram
7V TO 28V
C1
DH
Q1
L1
V
LED
EN
ILIM
IN
Applications
MAX16818
DL
Q2
C2
Q3
OVI
CLP
CSP
PGND
R1
●
Front Projectors/Rear Projection TVs
●
Portable and Pocket Projectors
●
LCD TVs and Display Backlight
Package Information
appears at end of data sheet.
HIGH-FREQUENCY
PULSE TRAIN
NOTE:
MAXIM TOPOLOGY
19-0666; Rev 4; 5/15
MAX16818
1.5MHz, 30A High-Efficiency, LED Driver
with Rapid LED Current Pulsing
Absolute Maximum Ratings
IN to SGND ...........................................................-0.3V to +30V
BST to SGND ........................................................-0.3V to +35V
BST to LX ................................................................-0.3V to +6V
DH to LX .................................... -0.3V to [(V
BST
- V
LX_
) + 0.3V]
DL to PGND ............................................. -0.3V to (V
DD
+ 0.3V)
V
CC
to SGND ..........................................................-0.3V to +6V
V
CC
, V
DD
to PGND .................................................-0.3V to +6V
SGND to PGND....................................................-0.3V to +0.3V
All Other Pins to SGND ............................ -0.3V to (V
CC
+ 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
28-Pin TQFN (derate 34.5mW/°C above +70°C) ......2758mW
Operating Temperature Range
MAX16818ATI+ ........................................... .-40°C to +125°C
MAX16818ETI+ .............................................. -40°C to +85°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range ............................ -60°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
CC
= 5V, V
DD
= V
CC
, T
A
= T
J
= T
MIN
to T
MAX
, unless otherwise noted. Typical specifications are at T
A
= +25°C.) (Note 1)
PARAMETER
SYSTEM SPECIFICATIONS
Input Voltage Range
Quiescent Supply Current
LED CURRENT REGULATOR
SENSE+ to SENSE- Accuracy
(Note 2)
Soft-Start Time
STARTUP/INTERNAL REGULATOR
V
CC
Undervoltage Lockout
V
CC
Output Voltage
UVLO
V
CC
Undervoltage Hysteresis
MOSFET DRIVERS
Output Driver Impedance
Output Driver Source/Sink Current
Nonoverlap Time
OSCILLATOR
Switching Frequency Range
Switching Frequency
Switching Frequency
Switching Frequency
Switching Frequency Accuracy
f
SW
R
T
= 500kW
R
T
= 120kW
R
T
= 39.9kW
125
121
495
1515
-5
-8
125
521
1620
1500
129
547
1725
+5
+8
%
kHz
kHz
I
DH
,I
DL
t
NO
R
ON
Low or high output, I
SOURCE/SINK
= 20mA
C
DH/DL
= 5nF
1.1
4
35
3.0
W
A
ns
V
CC
rising
V
IN
= 7V to 28V, I
SOURCE
= 0 to 60mA
4.1
4.85
4.3
200
5.1
5.30
4.5
V
mV
V
t
SS
No load, V
IN
= 4.75V to 5.5V, fSW = 500kHz
No load, V
IN
= 7V to 28V, fSW = 500kHz
0.594
0.594
0.6
0.6
1024
0.606
0.606
V
Clock
Cycles
V
IN
I
Q
7
Short IN and V
CC
together for 5V input
operation
EN = V
CC
or SGND, not switching
4.75
2.7
28
5.50
5.5
V
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
120kW
≤ R
T
≤ 500kW
40kW
≤ R
T
≤ 120kW
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Maxim Integrated
│
2
MAX16818
1.5MHz, 30A High-Efficiency, LED Driver
with Rapid LED Current Pulsing
Electrical Characteristics (continued)
(V
CC
= 5V, V
DD
= V
CC
, T
A
= T
J
= T
MIN
to T
MAX
, unless otherwise noted. Typical specifications are at T
A
= +25°C.) (Note 1)
PARAMETER
CLKOUT Phase Shift
CLKOUT Output Low Level
CLKOUT Output High Level
SYNC Input-High Pulse Width
SYNC Input Clock High Threshold
SYNC Input Clock Low Threshold
SYNC Pullup Current
SYNC Power-Off Level
INDUCTOR CURRENT LIMIT
Average Current-Limit Threshold
Reverse Current-Limit Threshold
Cycle-by-Cycle Current Limit
Cycle-by-Cycle Overload
Response Time
Hiccup Divider Ratio
Hiccup Reset Delay
LIM Input Impedance
CURRENT-SENSE AMPLIFIER
CSP or CSN Input Resistance
Common-Mode Range
Input Offset Voltage
Amplifier Gain
3dB Bandwidth
Transconductance
Open-Loop Gain
Common-Mode Voltage Range
DIFF Output Voltage
Input Offset Voltage
Amplifier Gain
3dB Bandwidth
Minimum Output-Current Drive
SENSE+ to SENSE- Input
Resistance
V_IOUT AMPLIFIER
Gain-Bandwidth Product
3dB Bandwidth
Output Sink Current
Output Source Current
V
V_IOUT
= 2.0V
V
V_IOUT
= 2.0V
30
90
4
1
MHz
MHz
µA
µA
V
CMR(CS)
V
OS(CS)
A
V(CS)
f
3dB
gm
A
VOL(CE)
V
CMR(DIFF)
V
OS(DIFF)
A
V(DIFF)
f
3dB
V
CM
No load
0
V
SENSE+
= V
SENSE-
= 0V
0.6
-1
0.994
C
DIFF
= 20pF
V
SENSE-
= 0V
4
50
100
1
3
+1
1.006
R
CS
4
V
IN
= 7V to 28V
0
0.1
34.5
4
550
50
+1.0
5.5
kW
V
mV
V/V
MHz
µS
dB
V
V
mV
V/V
MHz
mA
kW
SYMBOL
q
_CLKOUT
V
CLKOUTH
V
SYNCH
I
SYNC_OUT
V
SYNCL
V
RT/SYNC
= 0V
t
SYNC
V
CLKOUTL
I
SINK
= 2mA
CONDITIONS
With respect to DH, f
SW
= 125kHz
I
SOURCE
= 2mA
4.5
200
2.0
0.4
250
750
0.4
24.0
-3.2
26.9
-2.3
60
260
0.547
0.558
200
55.9
0.565
28.2
-0.1
MIN
TYP
180
0.4
MAX
UNITS
Degrees
V
V
ns
V
V
µA
V
mV
mV
mV
ns
V/V
ms
kW
V
SYNC_OFF
V
CL
CSP to CSN
CSP to CSN
CSP to CSN
V
CSP
to V
CSN
= 75mV
LIM to V
CM
, no switching
LIM to SGND
V
CLR
CURRENT-ERROR AMPLIFIER (TRANSCONDUCTANCE AMPLIFIER)
DIFFERENTIAL VOLTAGE AMPLIFIER FOR LED CURRENT (DIFF)
I
OUT(DIFF)
R
VS
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Maxim Integrated
│
3
MAX16818
1.5MHz, 30A High-Efficiency, LED Driver
with Rapid LED Current Pulsing
Electrical Characteristics (continued)
(V
CC
= 5V, V
DD
= V
CC
, T
A
= T
J
= T
MIN
to T
MAX
, unless otherwise noted. Typical specifications are at T
A
= +25°C.) (Note 1)
PARAMETER
Maximum Load Capacitance
V_IOUT Output to I
OUT
Transfer
Function
Offset Voltage
VOLTAGE-ERROR AMPLIFIER (EAOUT)
Open-Loop Gain
Unity-Gain Bandwidth
EAN Input Bias Current
Error Amplifier Output Clamping
Voltage
A
VOLEA
f
GBW
I
B(EA)
V
EAN
= 2.0V
-0.2
883
70
3
+0.03
930
+0.2
976
dB
MHz
µA
mV
R
SENSE
= 1mW,
100mV ≤ V
_IOUT
≤ 5.5V
132.3
SYMBOL
CONDITIONS
MIN
TYP
50
135
1
137.7
MAX
UNITS
pF
mV/A
mV
V
CLAMP(EA)
With respect to V
CM
POWER-GOOD AND OVERVOLTAGE PROTECTION
PGOOD Trip Level
PGOOD Output Low Level
PGOOD Output Leakage Current
OVI Trip Threshold
OVI Input Bias Current
ENABLE INPUT
EN Input High Voltage
EN Input Hysteresis
EN Pullup Current
THERMAL SHUTDOWN
Thermal Shutdown
Thermal Shutdown Hysteresis
Temperature rising
150
30
°C
°C
I
EN
13.5
V
EN
EN rising
2.437
2.5
0.28
15
16.5
2.562
V
V
µA
V
UV
V
PGLO
I
PG
OVP
TH
I
OVI
PGOOD goes low when V
OUT
is below this
threshold
I
SINK
= 4mA
PGOOD = V
CC
With respect to SGND
1.244
1.276
0.2
87.5
90
92.5
0.4
1
1.308
%V
OUT
V
µA
V
µA
Note 1:
Specifications at T
A
= +25°C are 100% tested. Specifications over the temperature range are guaranteed by design.
Note 2:
Does not include an error due to finite error amplifier gain. See the
Voltage-Error Amplifier (EAOUT)
section.
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Maxim Integrated
│
4
MAX16818
1.5MHz, 30A High-Efficiency, LED Driver
with Rapid LED Current Pulsing
Typical Operating Characteristics
(T
A
= +25°C, using Figure 5, unless otherwise noted.)
MAX16818 toc01
50
SUPPLY CURRENT (mA)
40
30
20
10
0
EXTERNAL CLOCK
NO DRIVER LOAD
V
IN
= 24V
V
IN
= 12V
MAX16818 toc02
SUPPLY CURRENT (mA)
68
66
64
62
60
V
IN
= 12V
f
SW
= 250kHz
C
DL
/C
DH
= 22nF
-40
-15
10
35
60
28.5
(V
CSP
- V
CSN
) (mV)
28.0
27.5
27.0
26.5
26.0
V
IN
= 12V
f
SW
= 250kHz
0
1
2
3
4
V
IN
= 5V
100
300
500
700
900 1100 1300 1500
85
5
FREQUENCY (kHz)
TEMPERATURE (°C)
V
OUT
(V)
MAX16818 toc05
MAX16818 toc04
25.5
CURRENT LIMIT (A)
25.0
5.15
5.05
4.95
4.85
4.75
V
IN
= 24V
V
IN
= 12V
80
60
40
20
0
V
IN
= 12V
f
SW
= 250kHz
V
CC
(V)
24.5
24.0
23.5
23.0
t
R
(ns)
DL
DH
V
IN
= 5V
V
IN
= 12V
f
SW
= 250kHz
R1 = 1mΩ
V
OUT
= 1.5V
0
4
8
12
16
20
R
EXT
(MΩ)
0
25
50
75
100
125
150
1
6
11
16
21
V
CC
LOAD CURRENT (mA)
CAPACITANCE (nF)
DRIVER FALL TIME
vs. DRIVER LOAD CAPACITANCE
V
IN
= 12V
f
SW
= 250kHz
MAX16818 toc07
HIGH-SIDE DRIVER (DH) SINK
AND SOURCE CURRENT
100
80
60
40
20
0
MAX16818 toc08
LOW-SIDE DRIVER (DL) SINK
AND SOURCE CURRENT
C
LOAD
= 22nF
V
IN
= 12V
MAX16818 toc09
C
LOAD
= 22nF
V
IN
= 12V
t
F
(ns)
DL
DH
2A/div
1
6
11
16
21
100ns/div
100ns/div
CAPACITANCE (nF)
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Maxim Integrated
│
5
MAX16818 toc06
26.0
HICCUP CURRENT LIMIT vs. R
EXT
V
CC
LOAD REGULATION
vs. INPUT VOLTAGE
5.25
100
DRIVER RISE TIME
vs. DRIVER LOAD CAPACITANCE
MAX16818 toc03
60
SUPPLY CURRENT (I
Q
) vs. FREQUENCY
70
SUPPLY CURRENT vs. TEMPERATURE
29.0
CURRENT-SENSE THRESHOLD
vs. OUTPUT VOLTAGE
3A/div
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