19-0706; Rev 1; 3/07
KIT
ATION
EVALU
E
BL
AVAILA
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
General Description
The MAX16819/MAX16820, step-down constant-current
high-brightness LED (HB LED) drivers provide a cost-
effective solution for automotive interior/exterior lighting,
architectural and ambient lighting, LED bulbs such as
MR16 and other LED illumination applications.
The MAX16819/MAX16820 operate from a 4.5V to 28V
input voltage range and feature a 5V/10mA on-board
regulator. A high-side current-sense resistor adjusts the
output current and a dedicated PWM input (DIM)
enables a wide range of pulsed dimming.
The MAX16819/MAX16820 are well suited for applica-
tions requiring a wide input voltage range. The high-side
current-sensing and an integrated current-setting circuit-
ry minimize the number of external components while
delivering an LED current with ±5% accuracy. A hys-
teretic control algorithm ensures excellent input-supply
rejection and fast response during load transients and
PWM dimming. The MAX16819 features a 30% inductor
current ripple and the MAX16820 features a 10% current
ripple. These devices operate up to 2MHz switching fre-
quency, thus allowing for small component size.
The MAX16819/MAX16820 operate over the -40°C to
+125°C automotive temperature range and are avail-
able in 3mm x 3mm x 0.8mm, 6-pin TDFN packages.
o
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Features
High-Side Current Sense
Dedicated Dimming Control Input
20kHz Maximum Dimming Frequency
Hysteretic Control: No Compensation
Up to 2MHz Switching Frequency
±5% LED Current Accuracy
Adjustable Constant LED Current
4.5V to 28V Input Voltage Range
Over 25W Output Power
5V, 10mA On-Board Regulator
-40°C to +125°C Operating Temperature Range
MAX16819/MAX16820
Ordering Information
PART
MAX16819ATT+T
MAX16820ATT+T
PIN-PACKAGE
6 TDFN–EP*
6 TDFN-EP*
PKG CODE
T633-2
T633-2
TOP
MARK
+ATB
+ATC
Note:
All devices are specified over the -40°C to +125°C oper-
ating temperature range.
+Denotes
lead-free package.
*EP
= Exposed paddle.
Applications
Architectural, Industrial, and Ambient Lighting
Automotive RCL, DRL, and Fog Lights
MR16 and Other LED Bulbs
Indicators and Emergency Lighting
Typical Operating Circuit
V
IN
R
SENSE
C
IN
L
Pin Configuration
GND
4
DRV
5
TOP VIEW
V
CC
6
C
VCC
MAX16819
MAX16820
+
1
IN
2
CSN
3
DIM
IN
V
CC
CSN
MAX16819
MAX16820
DRV
DIM
GND
TDFN
________________________________________________________________
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.
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
MAX16819/MAX16820
ABSOLUTE MAXIMUM RATINGS
IN, CSN, DIM to GND .............................................-0.3V to +30V
V
CC
, DRV to GND ....................................................-0.3V to +6V
CSN to IN...............................................................-0.3V to +0.3V
Maximum Current into Any Pin
(except IN, V
CC
, and DRV)............................................±20mA
Continuous Power Dissipation (T
A
= +70°C)
6-Pin TDFN (derate 18.17mW/
o
C
*
above +70°C).......1454mW
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
Pin-to-Pin ESD Ratings (HB Model).....................................2.5kV
*As per JEDEC51 Standard (Single-Layer 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
IN
= 12V, V
DIM
= V
IN
, C
VCC
= 1µF, R
SENSE
= 0.5Ω, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at
T
A
= +25°C.) (Note 1)
PARAMETER
Input Voltage Range
Maximum Current Regulator
Switching Frequency
Ground Current
Supply Current
SYMBOL
V
IN
f
SW
I
GND
I
IN
DRV open
V
DIM
< 0.6V
V
IN
= V
CSN
= V
DIM
, V
IN
rising from 4V until
V
DRV
> V
CC
- 0.5V
V
IN
= V
CSN
= V
DIM
, V
IN
falling from 6V,
V
DRV
< 0.5V
Undervoltage Lockout Hysteresis
SENSE COMPARATOR
(V
IN
- V
CSN
) rising from 0V until V
DRV
<
0.5V (MAX16820)
Sense Voltage Threshold High
V
SNSHI
(V
IN
- V
CSN
) rising from 0V until V
DRV
<
0.5V (MAX16819)
(V
IN
- V
CSN
) falling from 0.26V until V
DRV
>
(V
CC
- 0.5V) (MAX16820)
(V
IN
- V
CSN
) falling from 0.26V until V
DRV
>
(V
CC
- 0.5V) (MAX16819)
Falling edge of (V
IN
- V
CSN
) from 0.26V to
0V to DRV high, C
DRV
= 1nF
Rising edge of (V
IN
- V
CSN
) from 0V to
0.26V to DRV low, C
DRV
= 1nF
(V
IN
- V
CSN
) = 200mV
MAX16819
MAX16820
56
17
195
213
176
158
210
230
190
170
82
82
1
70
35
225
mV
246
204
mV
182
ns
ns
µA
mV
mV
0.5
4.7
CONDITIONS
MIN
4.5
TYP
MAX
28.0
2
1.5
425
5.0
V
4.5
V
UNITS
V
MHz
mA
µA
Undervoltage Lockout
UVLO
Sense Voltage Threshold Low
V
SNSLO
Propagation Delay to Output
High
Propagation Delay to Output Low
Current-Sense Input Current
Current-Sense Threshold
Hysteresis
t
DPDH
t
DPDL
I
CSN
CS
HYS
2
_______________________________________________________________________________________
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 12V, V
DIM
= V
IN
, C
VCC
= 1µF, R
SENSE
= 0.5Ω, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at
T
A
= +25°C.) (Note 1)
PARAMETER
GATE DRIVER
Gate Driver Source Current
Gate Driver Sink Current
Gate Driver Output-Voltage High
Gate Driver Output-Voltage Low
DIM INPUT
Maximum DIM Frequency
DIM Input-Voltage High
DIM Input-Voltage Low
DIM Hysteresis
DIM Turn-On Time
DIM Turn-Off Time
DIM Input Leakage High
DIM Input Leakage Low
V
CC
REGULATOR
Regulator Output Voltage
Load Regulation
Line Regulation
Power-Supply Rejection Ratio
Current Limit
Regulator Startup Time
PSRR
I
LIM
t
STRAT
V
CC
I
VCC
= 0.1mA to 10mA, V
IN
= 5.5V to 28V
I
VCC
= 0.1mA to 10mA, V
IN
= 4.5V to 28V
I
VCC
= 0.1mA to 10mA, V
IN
= 12V
V
IN
= 6V to 28V, I
VCC
= 10mA
V
IN
= 12V, I
VCC
= 5mA, f
IN
= 10kHz
V
IN
= 4.5V, V
CC
= 0V
V
IN
= 4.5V, V
CC
= 4V
V
CC
= 0 to 4.5V
4.5
4.0
4
11
-35
45
18
350
5.5
5.5
V
V
Ω
mV
dB
mA
mA
µs
f
DIM
V
IH
V
IL
DIM
HYS
t
DIMON
t
DIMOFF
DIM rising edge to V
DRV
= 0.5 x V
CC
,
C
DRV
= 1nF
DIM falling edge to V
DRV
= 0.5 x V
CC
,
C
DRV
= 1nF
V
DIM
= V
IN
V
DIM
= 0V
-1
V
CSN
= V
IN
, increase DIM until V
DRV
>
(V
CC
- 0.5V)
V
CSN
= V
IN
, decrease DIM until
V
DRV
< 0.5V
200
100
100
10
+1
2.8
0.6
20
kHz
V
V
mV
ns
ns
µA
µA
V
OH
V
OL
V
CSN
= V
IN
, V
DRV
= 0.5 x V
CC
V
CSN
= V
IN
- 250mV, V
DRV
= 0.5 x V
CC
I
DRV
= 10mA
I
DRV
= -10mA
V
CC
- 0.5
0.5
0.5
1
A
A
V
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX16819/MAX16820
Note 1:
All devices are 100% production tested at T
J
= +25°C and +125°C. Limits to -40°C are guaranteed by design.
_______________________________________________________________________________________
3
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
MAX16819/MAX16820
Typical Operating Characteristics
(V
IN
= V
DIM
= 12V, C
VCC
= 1µF, R
SENSE
= 0.5Ω connected between IN and CSN. Typical values at T
A
= +25°C, unless otherwise
noted.)
EFFICIENCY vs. V
IN
MAX16819 toc01
DRV SWITCHING FREQUENCY
vs. V
IN
L = 47µH
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
0
4
LED CURRENT VARIATION FROM SET CURRENT (%)
MAX16819 toc02
LED CURRENT VARIATION vs. V
IN
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
-2.0
5
10
15
V
IN
(V)
20
25
30
LED 3
LED 4
LED 5
LED 1
I
LED(NOMINAL)
= 400mA
L = 47µH
LED 2
MAX16819 toc03
MAX16819 toc06
100
2.0
LED 5
95
90
EFFICIENCY (%)
85
80
75
70
65
60
5
10
15
V
IN
(V)
20
LED 4
LED 5
LED 4
LED 3
LED 2
LED 1
DRV SWITCHING FREQUENCY (kHz)
L = 47µH
8
12
16
V
IN
(V)
20
24
28
25
30
V
CC
vs. V
IN
MAX16819 toc04
V
CC
vs. TEMPERATURE
5.39
5.38
5.37
V
CC
(V)
5.36
5.35
5.34
5.33
5.32
I
LED
= 0
5.31
5.30
V
DIM
= 0V
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
V
IN
= 12V
V
IN
= 24V
MAX16819 toc05
SUPPLY CURRENT vs. V
IN
300
250
SUPPLY CURRENT (µA)
200
150
100
50
V
DIM
= 0V
0
4.5
8.5
12.5
16.5
V
IN
(V)
20.5
24.5
28.5
5.5
5.4
5.3
5.2
V
CC
(V)
5.1
5.0
4.9
4.8
4.7
4.6
4.5
5.40
5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 27.5
V
IN
(V)
PWM DIMMING AT 200Hz
(10% DUTY CYCLE)
MAX16819 toc07
PWM DIMMING AT 200Hz
(90% DUTY CYCLE)
MAX16819 toc08
V
IN
= 12V, L = 47µH,
1 LED MAX16819
V
DIM
2V/div
V
IN
= 12V, L = 47µH,
1 LED MAX16819
V
DIM
2V/div
0V
I
LED
200mA/div
0A
0V
I
LED
200mA/div
0A
1ms/div
1ms/div
4
_______________________________________________________________________________________
2MHz High-Brightness LED Drivers with
High-Side Current Sense and 5000:1 Dimming
Typical Operating Characteristics (continued)
(V
IN
= V
DIM
= 12V, C
VCC
= 1µF, R
SENSE
= 0.5Ω connected between IN and CSN. Typical values at T
A
= +25°C, unless otherwise
noted.)
MAX16819/MAX16820
PWM DIMMING AT 200Hz
(1% DUTY CYCLE)
MAX16819 toc09
PWM DIMMING EXPANDED
(50% DUTY CYCLE)
MAX16819 toc10
PWM DIMMING EXPANDED
(50% DUTY CYCLE)
MAX16819 toc11
V
IN
= 12V, L = 47µH,
1 LED MAX16819
V
DIM
2V/div
V
IN
= 24V, L = 33µH,
4 LEDS MAX16820
V
DIM
2V/div
V
IN
= 12V, L = 47µH,
1 LED MAX16819
V
DIM
2V/div
0V
I
LED
200mA/div
0A
0V
I
LED
200mA/div
0A
0V
I
LED
200mA/div
0A
10µs/div
1µs/div
4µs/div
PWM DIMMING AT 20kHz
(10% DUTY CYCLE)
MAX16819 toc12
PWM DIMMING AT 20kHz
(90% DUTY CYCLE)
MAX16819 toc13
I
LED
VARIATION vs. TEMPERATURE
LED CURRENT VARIATION FROM SET CURRENT (%)
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
I
LED(NOMINAL)
= 400mA
L = 47µH
MAX16819 toc14
V
IN
= 24V, L = 47µH,
4 LEDS MAX16820
V
DIM
2V/div
0V
I
LED
200mA/div
0A
V
IN
= 24V, L = 33µH,
4 LEDS MAX16820
V
DIM
2V/div
0V
I
LED
200mA/div
2.0
V
IN
= 24V
V
IN
= 12V
0A
V
DIM
= 0V
-2.0
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
10µs/div
10µs/div
_______________________________________________________________________________________
5
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