19-3880; Rev 0; 10/05
Off-Line and DC-DC PWM Controllers for
High-Brightness LED Drivers
General Description
The MAX16801A/B/MAX16802A/B high-brightness (HB)
LED driver-control ICs contain all the circuitry required
for the design of wide-input voltage range LED drivers
for general lighting and display applications. The
MAX16801 is well suited for universal input (rectified
85VAC to 265VAC) LED drivers, while the MAX16802 is
intended for low-input-voltage (10.8VDC to 24VDC) LED
drivers.
When the LED current needs to be tightly regulated, an
additional on-board error amplifier with 1% accurate ref-
erence can be utilized. A wide dimming range can be
implemented by using low-frequency PWM dimming.
The MAX16801/MAX16802 feature an input undervoltage
lockout (UVLO) for programming the input-supply start
voltage, and to ensure proper operation during brownout
conditions. The MAX16801 has an internal-bootstrap
undervoltage lockout circuit with a large hysteresis that
simplifies off-line LED driver designs. The MAX16802
does not have this internal bootstrap circuit and can be
biased directly from a +12V rail.
The 262kHz fixed switching frequency is internally
trimmed, allowing for optimization of the magnetic and fil-
ter components, resulting in a compact, cost-effective
LED driver.The MAX16801A/MAX16802A are offered with
50% maximum duty cycle. The MAX16801B/MAX16802B
are offered with 75% maximum duty cycle. These devices
are available in an 8-pin µMAX
®
package and operate
over the -40°C to +85°C temperature range.
Features
♦
Suitable for Buck, Boost, Flyback, SEPIC, and
Other Topologies
♦
Up to 50W or Higher Output Power
♦
Universal Off-Line Input Voltage Range: Rectified
85VAC to 265VAC (MAX16801)
♦
IN-Pin Directly Driven From 10.8VDC to 24VDC
Input (MAX16802)
♦
Internal Error Amplifier with 1% Accurate
Reference for Precise LED Current Regulation
♦
PWM or Linear Dimming
♦
Fixed Switching Frequency of 262kHz ±12%
♦
Thermal Shutdown
♦
Digital Soft-Start
♦
Programmable Input Startup Voltage
♦
Internal Bootstrap UVLO with Large Hysteresis
(MAX16801)
♦
45µA (typ) Startup Supply Current, 1.4mA (typ)
Operating Supply Current
♦
50% (MAX16801A/MAX16802A) or 75%
(MAX16801B/MAX16802B) Maximum Duty Cycle
♦
Available in a Tiny 8-Pin µMAX Package
MAX16801A/B/MAX16802A/B
Ordering Information
PART
MAX16801AEUA+
MAX16801BEUA+
MAX16802AEUA+*
MAX16802BEUA+
TEMP
RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
8 µMAX
8 µMAX
8 µMAX
8 µMAX
Applications
Off-Line and DC-DC
LED Drivers
RGB Back Light for LCD
TVs and Monitors
Commercial and
Industrial Lighting
Decorative and
Architectural Lighting
+Denotes
lead-free package.
*Future
product–contact factory for availability.
µMAX is a registered trademark of Maxim Integrated Products, Inc.
10.8VDC TO 24VDC
ENABLE
UVLO/EN
DIM/FB
PWM
IN
L1
VCC
D1
C3
Typical Operating Circuit
LEDs
MAX16802B
COMP
CS
U1
NDRV
GND
Q1
C1
GND
C2
R1
Warning:
The MAX16801/MAX16802 are designed to work with high voltages. Exercise caution.
________________________________________________________________
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.
Off-Line and DC-DC PWM Controllers for
High-Brightness LED Drivers
MAX16801A/B/MAX16802A/B
ABSOLUTE MAXIMUM RATINGS
IN to GND
..........................................................................
-0.3V to +30V
VCC to GND
.....................................................................
-0.3V to +13V
DIM/FB, COMP, UVLO, CS to GND..........................-0.3V to +6V
NDRV to GND.............................................-0.3V to (V
CC
+ 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
8-Pin µMAX (derate 4.5mW/°C above +70°C) ..............362mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range ............................-65°C to +150°C
Junction Temperature ......................................................+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
= +12V (MAX16801: V
IN
must first be brought up to +23.6V for startup), 10nF bypass capacitors at IN and VCC, C
NDRV
= 0,
V
UVLO
= +1.4V, V
DIM/FB
= +1.0V, COMP = unconnected, V
CS
= 0V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are
at T
A
= +25°C.) (Note 1)
PARAMETER
Bootstrap UVLO Wake-Up Level
Bootstrap UVLO Shutdown Level
UVLO/EN Wake-Up Threshold
UVLO/EN Shutdown Threshold
UVLO/EN Input Current
UVLO/EN Hysteresis
IN Supply Current In
Undervoltage Lockout
IN Voltage Range
UVLO/EN Propagation Delay
Bootstrap UVLO Propagation
Delay
INTERNAL SUPPLY
VCC Regulator Set Point
IN Supply Current After Startup
Shutdown Supply Current
GATE DRIVER
Driver Output Impedance
Driver Peak Sink Current
Driver Peak Source Current
PWM COMPARATOR
Comparator Offset Voltage
CS Input Bias Current
Comparator Propagation Delay
Minimum On-Time
VO
PWM
I
CS
t
PWM
t
ON(MIN)
V
COMP
- V
CS
V
CS
= 0V
V
CS
= +0.1V
1.15
-2
60
150
1.38
1.70
+2
V
µA
ns
ns
R
ON(LOW)
Measured at NDRV sinking, 100mA
2
4
1
0.65
4
12
R
ON(HIGH)
Measured at NDRV sourcing, 20mA
Ω
A
A
V
CCSP
I
IN
V
IN
= +10.8V to +24V, sinking 1µA to 20mA
from V
CC
V
IN
= +24V
UVLO/EN = low
7
1.4
10.5
2.5
90
V
mA
µA
I
START
V
IN
t
EXTR
t
EXTF
t
BUVR
t
BUVF
UVLO/EN steps up from +1.1V to +1.4V
UVLO/EN steps down from +1.4V to +1.1V
V
IN
steps up from +9V to +24V
V
IN
steps down from +24V to +9V
V
IN
= +19V, for MAX16801 only when in
bootstrap UVLO
10.8
12
1.8
5
1
SYMBOL
V
SUVR
V
SUVF
V
ULR2
V
ULF2
I
UVLO
CONDITIONS
V
IN
rising (MAX16801 only)
V
IN
falling (MAX16801 only)
UVLO/EN rising
UVLO/EN falling
T
J
= +125°C
MIN
19.68
9.05
1.188
1.168
TYP
21.6
9.74
1.28
1.23
25
50
45
90
24
MAX
23.60
10.43
1.371
1.291
UNITS
V
V
V
V
nA
mV
µA
V
µs
µs
UNDERVOLTAGE LOCKOUT/STARTUP
2
_______________________________________________________________________________________
Off-Line and DC-DC PWM Controllers for
High-Brightness LED Drivers
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= +12V (MAX16801: V
IN
must first be brought up to +23.6V for startup), 10nF bypass capacitors at IN and VCC, C
NDRV
= 0,
V
UVLO
= +1.4V, V
DIM/FB
= +1.0V, COMP = unconnected, V
CS
= 0V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are
at T
A
= +25°C.) (Note 1)
PARAMETER
CURRENT-SENSE COMPARATOR
Current-Sense Trip Threshold
CS Input Bias Current
Propagation Delay From
Comparator Input to NDRV
Switching Frequency
Maximum Duty Cycle
IN CLAMP VOLTAGE
IN Clamp Voltage
ERROR AMPLIFIER
Voltage Gain
Unity Gain Bandwidth
Phase Margin
DIM/FB Input Offset Voltage
COMP Pin Clamp Voltage
Source Current
Sink Current
Reference Voltage
Input Bias Current
COMP Short-Circuit Current
THERMAL SHUTDOWN
Thermal-Shutdown Temperature
Thermal Hysteresis
DIGITAL SOFT-START
Soft-Start Duration
Reference Voltage Steps During
Soft-Start
Reference Voltage Step
15,872
31
40
clock
cycles
steps
mV
130
25
°C
°C
8
V
REF
(Note 2)
High
Low
2.2
0.4
0.5
0.5
1.218
1.230
1.242
50
R
LOAD
= 100kΩ
R
LOAD
= 100kΩ, C
LOAD
= 200pF
R
LOAD
= 100kΩ, C
LOAD
= 200pF
80
2
65
3
3.5
1.1
dB
MHz
degrees
mV
V
mA
mA
V
nA
mA
V
INC
2mA sink current, MAX16801 only (Note 3)
24.1
26.1
29.0
V
V
CS
I
CS
t
PWM
f
SW
D
MAX
MAX1680_A
MAX1680_B
V
CS
= 0V
50mV overdrive
230
262
-2
60
262
50
75
290
50.5
76
291
320
+2
mV
µA
ns
kHz
%
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX16801A/B/MAX16802A/B
Note 1:
All devices are 100% tested at T
A
= +85°C. All limits over temperature are guaranteed by characterization.
Note 2:
V
REF
is measured with DIM/FB connected to the COMP pin (see the
Functional Diagram).
Note 3:
The MAX16801 is intended for use in universal input off-line drivers. The internal clamp circuit is used to prevent the boot-
strap capacitor (C1 in Figure 5) from charging to a voltage beyond the absolute maximum rating of the device when
EN/UVLO is low. The maximum current to IN (hence to clamp) when UVLO is low (device in shutdown), must be externally
limited to 2mA (max). Clamp currents higher than 2mA may result in clamp voltage higher than +30V, thus exceeding the
absolute maximum rating for IN. For the MAX16802, do not exceed the +24V maximum operating voltage of the device.
_______________________________________________________________________________________
3
Off-Line and DC-DC PWM Controllers for
High-Brightness LED Drivers
MAX16801A/B/MAX16802A/B
Typical Operating Characteristics
(V
UVLO/EN
= +1.4V, V
FB
= +1V, COMP = unconnected, V
CS
= 0V, T
A
= +25°C, unless otherwise noted.)
BOOTSTRAP UVLO WAKE-UP LEVEL
vs. TEMPERATURE
MAX16801 toc01
BOOTSTRAP UVLO SHUTDOWN LEVEL
vs. TEMPERATURE
MAX16801 toc02
UVLO/EN WAKE-UP THRESHOLD
vs. TEMPERATURE
UVLO/EN RISING
1.275
1.270
1.265
1.260
MAX16801 toc03
MAX16801 toc09
MAX16801 toc06
21.60
MAX16801 V
IN
RISING
21.55
21.50
V
IN
(V)
21.45
21.40
10.1
MAX16801 V
IN
FALLING
10.0
1.280
9.9
9.8
21.35
21.30
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
9.7
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
1.255
1.250
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
UVLO/EN SHUTDOWN THRESHOLD
vs. TEMPERATURE
MAX16801 toc04
UVLO/EN (V)
V
IN
(V)
V
IN
SUPPLY CURRENT IN UNDERVOLTAGE
LOCKOUT vs. TEMPERATURE
MAX16801 toc05
V
IN
SUPPLY CURRENT AFTER STARTUP
vs. TEMPERATURE
1.5
V
IN
= 24V
1.4
I
IN
(mA)
1.30
UVLO/EN FALLING
52
51
50
49
V
IN
= 19V
MAX16801 WHEN IN BOOTSTRAP UVLO
MAX16802 WHEN UVLO/EN IS LOW
1.25
UVLO/EN (V)
I
START
(µA)
48
47
46
45
44
43
1.20
1.3
1.15
1.2
1.10
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
42
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
1.1
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
V
CC
REGULATOR SET POINT
vs. TEMPERATURE
MAX16801 toc07
V
CC
REGULATOR SET POINT
vs. TEMPERATURE
MAX116801 toc08
CURRENT-SENSE THRESHOLD
vs. TEMPERATURE
310
CURRENT-SENSE THRESHOLD (µV)
305
300
295
290
285
280
275
270
-3σ
MEAN
+3σ
TOTAL NUMBER OF
DEVICES = 100
9.8
9.7
9.6
V
CC
(V)
9.5
9.4
9.3
9.2
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
NDRV OUTPUT IS
SWITCHING
V
IN
= 19V
NO LOAD
NDRV OUTPUT IS NOT
SWITCHING, V
FB
= 1.5V
8.9
V
IN
= 10.8V
8.8
8.7
10mA LOAD
8.6
V
CC
(V)
8.5
8.4
20mA LOAD
8.3
8.2
8.1
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
4
_______________________________________________________________________________________
Off-Line and DC-DC PWM Controllers for
High-Brightness LED Drivers
MAX16801A/B/MAX16802A/B
Typical Operating Characteristics (continued)
(V
UVLO/EN
= +1.4V, V
FB
= +1V, COMP = unconnected, V
CS
= 0V, T
A
= +25°C, unless otherwise noted.)
CURRENT-SENSE THRESHOLD
MAX16801 toc10
SWITCHING FREQUENCY
vs. TEMPERATURE
MAX16801 toc11
SWITCHING FREQUENCY
TOTAL NUMBER OF
DEVICES = 200
MAX16801 toc12
MAX16801 toc18
MAX16801 toc15
30
25
PERCENTAGE OF UNITS (%)
20
15
10
5
0
260
270
280
290
280
275
SWITCHING FREQUENCY (kHz)
270
265
260
255
250
245
240
-40
-20
0
20
-3σ
MEAN
+3σ
TOTAL NUMBER OF
DEVICES = 200
TOTAL NUMBER OF
DEVICES = 100
30
25
PERCENTAGE OF UNITS (%)
20
15
10
5
0
300
310
320
40
60
80
230
240
250
260
270
280
290
CURRENT-SENSE THRESHOLD (mV)
TEMPERATURE (°C)
SWITCHING FREQUENCY (kHz)
PROPAGATION DELAY FROM
CURRENT-SENSE COMPARATOR INPUT
TO NDRV vs. TEMPERATURE
MAX16801 toc13
UVLO/EN PROPAGATION DELAY
vs. TEMPERATURE
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
-40
-20
0
20
MAX16801 toc14
REFERENCE VOLTAGE
vs. TEMPERATURE
1.230
V
IN
= 12V
75
t
PWM
(ns)
65
REFERENCE VOLTAGE (V)
UVLO/EN FALLING
70
UNDERVOLTAGE LOCKOUT DELAY (µs)
UVLO/EN RISING
1.229
1.228
60
1.227
55
1.226
50
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
1.225
40
60
80
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
INPUT CURRENT
vs. INPUT CLAMP VOLTAGE
MAX16801 toc16
INPUT CLAMP VOLTAGE
vs. TEMPERATURE
26.8
INPUT CLAMP VOLTAGE (V)
26.6
26.4
R
ON
(Ω)
26.2
26.0
25.8
25.6
25.4
25.2
25.0
I
IN
= 2mA
MAX16801 toc17
NDRV OUTPUT IMPEDANCE
vs. TEMPERATURE
2.2
2.1
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
V
IN
= 24V
SINKING 100mA
10
9
8
INPUT CURRENT (mA)
7
6
5
4
3
2
1
0
27.0
10.0 12.5 15.0 17.5 20.0 22.5 25.0 27.5 30.0
INPUT VOLTAGE (V)
-40
-20
0
20
40
60
80
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
_______________________________________________________________________________________
5
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