LED Driver. LT3932 Datasheet

LT3932 Driver. Datasheet pdf. Equivalent

LT3932 Datasheet
Recommendation LT3932 Datasheet
Part LT3932
Description 2A Synchronous Step-Down LED Driver
Feature LT3932; FEATURES nn ±1.5% LED Current Regulation nn ±1.2% Output Voltage Regulation nn 5000:1 PWM Dimming at.
Manufacture Linear Technology
Datasheet
Download LT3932 Datasheet




Linear Technology LT3932
FEATURES
nn ±1.5% LED Current Regulation
nn ±1.2% Output Voltage Regulation
nn 5000:1/10000+:1 PWM Dimming at 100Hz
(LT3932/LT3932-1)
nn 128:1 Internal PWM Dimming
nn Spread-Spectrum Frequency Modulation
nn Silent Switcher® Architecture for Low EMI
nn 3.6V to 36V Input Voltage Range
nn 0V to 36V LED String Voltage
nn 200kHz to 2MHz with SYNC Function
nn 99.9% Maximum Duty Cycle
nn 20:1 Analog or Duty Cycle LED Current Control
nn Open/Short LED Protection and Fault Indication
nn Accurate LED Current Sense with Monitor Output
nn Programmable UVLO
nn Thermally Enhanced 28-Pin (4mm × 5mm) QFN
APPLICATIONS
nn Automotive Lighting
nn Industrial and General Purpose Lighting
nn Machine Vision Systems
LT3932/LT3932-1
36V, 2A Synchronous
Step-Down LED Driver
DESCRIPTION
The LT®3932 , featuring the Silent Switcher®architecture
to minimize EMI/EMC emissions, utilizes fixed-frequency,
peak current control and provides PWM dimming for a
string of LEDs. The LED current is programmed by an ana-
log voltage or the duty cycle of pulses at the CTRL pin. An
output voltage limit can be set with a resistor divider to
the FB pin.
The switching frequency is programmable from 200kHz to
2MHz by an external resistor at the RT pin or by an exter-
nal clock at the SYNC/SPRD pin. With the optional spread
spectrum frequency modulation enabled, the frequency
varies from 100% to 125% to reduce EMI. The LT3932
also includes a driver for an external, high side PMOS for
PWM dimming and an internal PWM signal generator for
analog control of PWM dimming when an external signal is
not available. The LT3932-1 permits higher dimming ratios.
Additional features include an LED current monitor, an
accurate EN/UVLO pin threshold, open-drain fault report-
ing for open-circuit and short-circuit load conditions, and
thermal shutdown.
All registered trademarks and trademarks are the property of their respective owners. Protected
by U.S. Patents including 7199560, 7321203, 9596728, 9642200 and other patents pending.
TYPICAL APPLICATION
2A LED Driver with Internal PWM Dimming
VIN
20V
2.2µF
VIN
274k
10µF 2x1µF
EN/UVLO
30.1k
100k
100k
VREF
CTRL
PWM
INTVCC
BST
SW
VOUT
LT3932
FB
GND
ISP
2.2µF
100k
FAULT
INTVCC
ISN
FAULT
SYNC/SPRD
PWMTG
ISMON
SS RT RP VC
45.3k
2MHz
28.7k
7.8kHz
162k
100nF
10nF
22nF 8.2µH
110k
10k
C10O0UµTF
2A MAX
50mΩ
ISMON
9V
3932 TA01a
Internal PWM Dimming
SW
20V/DIV
PWMTG
10V/DIV
IL
1A/DIV
ILED
1A/DIV
PWM = 1.078V 2µs/DIV
(8% PWM DUTY RATIO)
3932 TA01b
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For more information www.analog.com
Rev B
1



Linear Technology LT3932
LT3932/LT3932-1
ABSOLUTE MAXIMUM RATINGS
(Note 1)
VIN, EN/UVLO.............................................................40V
ISP, ISN, and VOUT.....................................................40V
ISP – ISN................................................................±0.3V
CTRL and FB.............................................................3.3V
PWM, SYNC/SPRD, and FAULT....................................6V
SS and VC.................................................................3.3V
SW, BST, INTVCC, VREF, ISMON, PWMTG, RT,
and RP................................................................ (Note 2)
Operating Junction Temperature Range (Notes 3, 4)
LT3932E/LT3932I............................... –40°C to 125°C
LT3932H............................................. –40°C to 150°C
Storage Temperature Range................... –65°C to 150°C
PIN CONFIGURATION
TOP VIEW
VREF
SS
VC
FB
ISP
ISN
ISMON
FAULT
28 27 26 25 24 23
1 22 GND
2 21 VIN
3 20 VIN
4 29 19 SW
5 GND 18 SW
6 17 VIN
7 16 VIN
8 15 GND
9 10 11 12 13 14
UFD PACKAGE
28-LEAD (4mm × 5mm) PLASTIC QFN
θJA = 25°C/W (MEASURED ON DC2286A)
EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT3932EUFD#PBF
LT3932EUFD#TRPBF
3932
28-Lead (4mm × 5mm) Plastic QFN
–40°C to 125°C
LT3932IUFD#PBF
LT3932IUFD#TRPBF
3932
28-Lead (4mm × 5mm) Plastic QFN
–40°C to 125°C
LT3932HUFD#PBF
LT3932HUFD#TRPBF
3932
28-Lead (4mm × 5mm) Plastic QFN
–40°C to 150°C
LT3932EUFD-1#PBF
LT3932EUFD-1#TRPBF 39321
28-Lead (4mm × 5mm) Plastic QFN
–40°C to 125°C
LT3932IUFD-1#PBF
LT3932IUFD-1#TRPBF 39321
28-Lead (4mm × 5mm) Plastic QFN
–40°C to 125°C
LT3932HUFD-1#PBF
LT3932HUFD-1#TRPBF 39321
28-Lead (4mm × 5mm) Plastic QFN
–40°C to 150°C
Contact the factory for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix.
E LECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VEN/UVLO = 5V unless otherwise noted.
PARAMETER
CONDITIONS
MIN TYP MAX
Input Voltage Range
3.6 36
VIN Pin Quiescent Current
EN/UVLO = 2V, Not Switching
EN/UVLO = 300mV, Shutdown
2.2 2.7
l2
EN/UVLO Threshold (Falling)
1.09 1.15 1.21
EN/UVLO Rising Hysteresis
20
EN/UVLO Pin Hysteresis Current
4
UNITS
V
mA
µA
V
mV
µA
Rev B
2 For more information www.analog.com



Linear Technology LT3932
LT3932/LT3932-1
E LECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, VEN/UVLO = 5V unless otherwise noted.
PARAMETER
CONDITIONS
MIN TYP MAX
Reference
VREF Voltage
VREF Pin Current Limit
LED Current Regulation
IVREF = 0µA
IVREF = 500µA
VREF = 1.9V, Current Out of Pin
l 1.975
1.980
2
1.998
2
2.020
2.016
CTRL-Off Threshold (Falling)
l 200 218 228
CTRL-Off Rising Hysteresis
20
CTRL Pin Current
VCTRL = 2V
−100 100
Sense Voltage
(Analog Input)
(VISP−VISN)
VVCCTTRRLL
=
=
715.50Vm(V10(05%0%),)V, VININ==363V6V, V, VISIPSP==242V4V
VCTRL = 300mV (5%), VIN = 36V, VISP = 24V
l 98.5
l 48.5
l4
100 101.5
50 51.5
56
ISP Pin Current
VIN = 36V, VISP = 24V, VCTRL = 2V, Current Into Pin
50
ISN Pin Current
VIN = 36V, VISN = 23.9V, VCTRL = 2V, Current Into Pin
50
ISP/ISN Common Mode Range
VIN = 36V (Note 5)
0 36
Current Error Amplifier Transconductance
VIN = 36V, VISP = 24V
200
Duty Cycle Control of LED Current
Sense Voltage (VISP−VISN)
(Duty Cycle Input)
CTRL Pulse Input High (VIH)
CTRL Pulse Input Low (VIL)
CTRL Pulse Input Frequency Range
CTRL Duty = 75% (100%), VIN = 36V, VISP = 24V
CTRL Duty = 37.5% (50%), VIN = 36V, VISP = 24V
CTRL Duty = 15% (5%), VIN = 36V, VISP = 24V
99 100 101
49 50 51
456
1.6
0.4
100 1000
Voltage Regulation
FB Regulation Voltage
FB Pin Current
Voltage Error Amplifier Transconductance
VISP = VISN = 6V, VCTRL = 2V
VFB = 1V
l 0.988
−100
1.000
480
1.012
100
Power Stage
Peak Current Limit
3.0 3.6 4.2
Minimum Off-Time
(Note 6)
55
Minimum On-Time
(Note 6)
55
Bottom Switch On-Resistance
90
Top Switch On-Resistance
90
Oscillator
Programmed Switching Frequency (fSW)
Spread Spectrum Frequency Range
RT Pin Current Limit
SYNC/SPRD Threshold (Rising)
RT = 45.3k, VSYNC/SPRD = 0V
RT = 523k, VSYNC/SPRD = 0V
RT = 45.3k, VSYNC/SPRD = 3.3V
RT = 523k, VSYNC/SPRD = 3.3V
VRT = 0V, Current Out of Pin
l 1900 2000 2100
l 180 200 230
1900 2650
180 290
34
1.4 1.5
SYNC/SPRD Falling Hysteresis
220
SYNC/SPRD Pin Current
Soft-Start
VSYNC/SPRD = 3.3V
−100 100
SS Pin Charging Current
VSS = 0V
20
UNITS
V
V
mA
mV
mV
nA
mV
mV
mV
µA
µA
V
µA/V
mV
mV
mV
V
V
kHz
V
nA
µA/V
A
ns
ns
kHz
kHz
kHz
kHz
µA
V
mV
nA
µA
For more information www.analog.com
Rev B
3







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