SGM3736
PWM Dimming, 38V Step-Up LED Driver
GENERAL DESCRIPTION
The SGM3736 is a versatile constant current LED
driver with a high efficiency step-up converter
architecture.
The
low-side
power
MOSFET
is
integrated in the device, significantly shrinking the
overall PCB layout area and minimizing the total
number of external components. Unique technology
and high 1.35A current limit allow SGM3736 to drive up
to 38V output (10 LEDs in series). Alternatively,
SGM3736 can deliver 260mA total current with 3 series
LEDs per string. It can also maximize the current
capability while achieving high conversion efficiency.
The optimized 1MHz switching frequency results in
reduced conduction loss and small external component
size. Digital PWM dimming interface is integrated to
adjust LED current. The PWM frequency is in the range
from 2kHz to 60kHz.
Various protection features are built into the SGM3736,
including cycle-by-cycle input current limit protection,
open LED (output over-voltage) protection and thermal
shutdown protection. The leakage current in shutdown
mode is less than 1µA.
The SGM3736 is available in Green TDFN-2×2-8L
package. It operates over an ambient temperature
range of -40℃ to +85℃.
FEATURES
●
Wide Output Range: Up to 10 Series LEDs
●
Integrated 40V High Current Switch (1.35A Limit)
●
2.7V to 5.5V Input Voltage Range
●
High Efficiency PWM Converter
●
Low 200mV Feedback Voltage
●
500kΩ Pull-Low Resistor on EN/PWM Pin
●
2kHz to 60kHz PWM Dimming Frequency
●
38V Open LED Protection
●
1MHz Switching Frequency
●
Integrated Soft-Start Function
●
Less than 1µA Shutdown Current
●
Simple, Small Solution Size
●
Available in Green TDFN-2×2-8L Package
●
-40℃ to +85℃ Temperature Range
APPLICATIONS
LED Backlighting
Mobile Phones
Handheld Devices
Digital Photo Frames
Automotive Navigation
SG Micro Corp
www.sg-micro.com
REV. A. 1
SGM3736
SPECIFIED
TEMPERATURE
RANGE
-40℃ to +85℃
PWM Dimming, 38V Step-Up LED Driver
PACKAGE/ORDERING INFORMATION
MODEL
SGM3736
PACKAGE
DESCRIPTION
TDFN-2×2-8L
ORDER NUMBER
SGM3736YTDE8G/TR
MARKING
INFORMATION
3736
XXXX
PACKAGE
OPTION
Tape and Reel, 3000
NOTE:
XXXX
= Date Code.
ABSOLUTE MAXIMUM RATINGS
Input Voltage, V
IN
…………………….........….……….-0.3V to 6V
High Voltage Nodes, SW, VOUT……………….…...-0.3V to 40V
Other Pins, FB, EN/PWM…….……………....-0.3V to V
IN
+ 0.3V
Package Thermal Resistance
TDFN-2×2-8L,
θ
JA
…………..…………….…………….….75℃/W
Storage Temperature Range...….……….……...-65℃ to +150℃
Junction Temperature…………………………………….….150℃
Operating Temperature Range...………………....-40℃ to +85℃
Lead Temperature (Soldering 10 sec)
……………………………………………………………...…. 260℃
ESD Susceptibility
HBM..................................................................................3000V
MM......................................................................................200V
CAUTION
This integrated circuit can be damaged by ESD if you don’t pay
attention to ESD protection. SGMICRO recommends that all
integrated circuits be handled with appropriate precautions.
Failure to observe proper handling and installation procedures
can cause damage. ESD damage can range from subtle
performance degradation to complete device failure. Precision
integrated circuits may be more susceptible to damage because
very small parametric changes could cause the device not to
meet its published specifications.
SGMICRO reserves the right to make any change in circuit
design, specification or other related things if necessary without
notice at any time. Please contact SGMICRO sales office to get
the latest datasheet.
NOTE:
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.
SG Micro Corp
www.sg-micro.com
2
SGM3736
PIN CONFIGURATION
(TOP VIEW)
PWM Dimming, 38V Step-Up LED Driver
SGM3736
PGND
VIN
EN/PWM
GND
1
2
3
4
8
7
6
5
SW
VOUT
FB
RSET
TDFN-2×2-8L
GND
PIN DESCRIPTION
PIN
1
2
3
4
5
6
7
8
Exposed
Pad
NAME
PGND
VIN
EN/PWM
GND
RSET
FB
VOUT
SW
GND
Power Ground.
Supply Input.
Enable Control and PWM Dimming Input. It is a multi-functional pin which can be used for
enable control and digital PWM dimming.
Ground.
RSET Pin. Connect one resistor from RSET pin to GND to program the maximum white
LED current.
Feedback Input. Connect this pin to the cathode of the white LED.
Output and Over-Voltage Protection Pin.
Switch Output. Connect this pin to the inductor and the Schottky diode.
Exposed pad should be soldered to PCB board and connected to GND.
FUNCTION
TYPICAL APPLICATION
Input Range
2.7V~5.5V
C
IN
2
VIN
Up to 38V Output
L
8
SW
VOUT
7
6
5
R
SET
D1
C
OUT
White LEDs
Up to 10 in series
Or up to 10S4P
SGM3736
PWM Dimming
3
1kΩ
EN/PWM
GND
4
PGND
1
FB
RSET
SG Micro Corp
www.sg-micro.com
3
SGM3736
PWM Dimming, 38V Step-Up LED Driver
ELECTRICAL CHARACTERISTICS
(1)
(V
IN
= 3.6V, L = 10μH, C
IN
= 10μF, C
OUT
= 0.47μF, Full = -40℃ to +85℃, typical values are at T
A
= +25℃, unless otherwise noted.)
PARAMETER
IC SUPPLY
Input Voltage Range
Input Under-Voltage Lockout
UVLO Hysteresis
Quiescent Current (Non Switching)
Operating Current (Switching)
VIN Pin Shutdown Current
STEP-UP CONVERTER
Voltage Feedback Regulation Voltage
V
REF
Filter 3dB Frequency
NMOS On-Resistance
SW Pin Leakage Current
Peak NMOS Current Limit
Oscillator Frequency
Maximum Duty Cycle
Over-Voltage Threshold
Start-Up Time
CONTROL
Logic Low Threshold
Logic High Threshold
Minimum Shutdown Pulse Width Timing
Junction Thermal Shutdown Threshold
Junction Thermal Shutdown Hysteresis
V
IL
V
IH
t
OFF
Full
Full
+25℃
1.5
3
150
15
0.35
V
V
ms
℃
℃
V
REF
f
REF(3dB)
R
DS(ON)
I
SW
I
LIM
f
S
D
MAX
V
OVP
t
S
Measured at VOUT pin
Full
+25℃
+25℃
+25℃
+25℃
Full
+25℃
Full
+25℃
1.0
0.8
92
35.5
192
200
500
0.36
0.01
1.35
1.0
95
38
800
40.5
0.55
1
1.7
1.22
212.5
mV
Hz
Ω
μA
A
MHz
%
V
μs
V
IN
UVLO
V
HYS
I
Q
I
SHDN
V
FB
= 0.4V
V
FB
= 0V
V
EN
= 0V
Rising edge
Full
+25℃
+25℃
+25℃
+25℃
+25℃
2.7
2.5
0.15
0.20
0.72
0.1
0.35
1.20
1
5.5
2.6
V
V
V
mA
mA
μA
SYMBOL
CONDITIONS
TEMP
MIN
TYP
MAX
UNITS
NOTE:
1. The SGM3736 is guaranteed to meet performance specifications over the -40℃ to +85℃ operating temperature range by design,
characterization and correlation with statistical process controls.
SG Micro Corp
www.sg-micro.com
4
SGM3736
PWM Dimming, 38V Step-Up LED Driver
TYPICAL PERFORMANCE CHARACTERISTICS
T
A
= +25℃, L = 10μH, C
IN
= 10μF, C
OUT
= 0.47μF, unless otherwise noted.
Feedback Voltage vs. Temperature
215
V
IN
= 3.6V
Feedback Voltage (mV)
Feedback Voltage vs. Input Voltage
215
Feedback Voltage (mV)
210
205
200
195
190
185
210
205
200
195
190
185
-50
-25
0
25
50
Temperature (℃)
75
100
2.5
3
3.5
4
4.5
Input Voltage (V)
5
5.5
Efficiency vs. Input Voltage
90
I
LED
= 20mA, L = 10μH
88
Efficiency (%)
Efficiency vs. Input Voltage
90
I
LED
= 20mA, L = 22μH
88
Efficiency (%)
86
84
82
80
86
84
82
80
2.5
3
3.5
4
4.5
Input Voltage (V)
5
5.5
10LEDs (32V)
10LEDs (32V)
2.5
3
3.5
4
4.5
Input Voltage (V)
5
5.5
Efficiency vs. Output Current
100
V
IN
= 3.6V, L = 10μH
90
LED Current vs. Duty Cycle
25
V
IN
= 3.6V, I
LED
= 20mA, L = 10μH, 6 LEDs
20
LED Current (mA)
f
PWM
= 20kHz
15
10
5
0
Efficiency (%)
80
70
60
50
0
5
10
15
20
Output Current (mA)
25
30
10LEDs (32V)
f
PWM
= 2kHz
0
20
40
60
Duty Cycle (%)
80
100
SG Micro Corp
www.sg-micro.com
5
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