LT1932ES6#TRMPBF [Linear]
LT1932 - Constant-Current DC/DC LED Driver in ThinSOT; Package: SOT; Pins: 6; Temperature Range: -40°C to 85°C;
| 型号： | LT1932ES6#TRMPBF |
| 厂家： | 
Linear |
| 描述： | LT1932 - Constant-Current DC/DC LED Driver in ThinSOT; Package: SOT; Pins: 6; Temperature Range: -40°C to 85°C 驱动器 稳压器 开关式稳压器或控制器 电源电路 开关式控制器 光电二极管 |
| 文件： | 总16页 (文件大小：237K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Final Electrical Specifications
LT1932
Constant-Current DC/DC
LED Driver in ThinSOT
July 2001
U
FEATURES
DESCRIPTIO
Up to 80% Efficiency
TheLT®1932isafixedfrequencystep-upDC/DCconverter
designed to operate as a constant-current source. Be-
cause it directly regulates output current, the LT1932 is
ideal for driving light emitting diodes (LEDs) whose light
intensity is proportional to the current passing through
them, not the voltage across their terminals.
■
■
Inherently Matched LED Current
■
Drives Five White LEDs from 2V
■
Drives Six White LEDs from 2.7V
■
Drives Eight White LEDs from 3V
■
Precise, Adjustable Control of LED Current
■
Disconnects LEDs In Shutdown
1.2MHz Fixed Frequency Switching
With an input voltage range of 1V to 10V, the device works
from a variety of input sources. The LT1932 accurately
regulates LED current even when the input voltage is
higher than the LED voltage, greatly simplifying battery-
powered designs. A single external resistor sets LED
current between 5mA and 40mA, which can then be easily
adjusted using either a DC voltage or a pulse width
modulated (PWM) signal. When the LT1932 is placed in
shutdown, the LEDs are disconnected from the output,
ensuring a quiescent current of under 1µA for the entire
circuit. The device’s 1.2MHz switching frequency permits
theuseoftiny, lowprofilechipinductorsandcapacitorsto
minimize footprint and cost in space-conscious portable
applications.
■
■
Uses Tiny Ceramic Capacitors
Uses Tiny 1mm-Tall Inductors
■
■
Regulates Current Even When VIN > VOUT
■
Operates with VIN as Low as 1V
Low Profile (1mm) ThinSOTTM Package
■
U
APPLICATIO S
■
Cellular Telephones
■
Handheld Computers
■
Digital Cameras
■
Portable MP3 Players
■
Pagers
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
U
TYPICAL APPLICATIO
Li-Ion Driver for Four White LEDs
Efficiency
85
L1
6.8µH
D1
V
IN
V
V
= 4.2V
= 2.7V
IN
80
2.7V TO 4.2V
IN
75
70
C1
4.7µF
6
1
V
SW
IN
LT1932
SHDN
PWM
DIMMING
CONTROL
5
3
C2
1µF
65
60
55
LED
GND
R
SET
15mA
4
2
R
SET
1.50k
0
5
10
LED CURRENT (mA)
15
20
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN EMK212BJ105
D1:ZETEX ZHCS400
1932 TA01
1932 TA02
L1: SUMIDA CLQ4D106R8 OR PANASONIC ELJEA6R8
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection ofits circuits as described herein willnotinfringe on existing patentrights.
1
LT1932
W W U W
U W
U
ABSOLUTE AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
(Note 1)
ORDER PART
VIN Voltage ............................................................. 10V
SHDN Voltage ......................................................... 10V
SW Voltage ............................................................. 36V
LED Voltage ............................................................. 36V
NUMBER
TOP VIEW
SW 1
GND 2
LED 3
6 V
IN
5 SHDN
4 R
LT1932ES6
SET
R
SET Voltage ............................................................. 1V
S6 PART MARKING
LTST
Junction Temperature.......................................... 125°C
Operating Temperature Range (Note 2) .. –40°C to 85°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
S6 PACKAGE
6-LEAD PLASTIC SOT-23
TJMAX = 125°C, θJA = 250°C/ W
Consult LTC Marketing for parts specified with wider operating temperature
ranges.
ELECTRICAL CHARACTERISTICS
The ● denotes specifications that apply over the full operating temperature
range, otherwise specifications are at TA = 25°C. VIN = 1.2V, VSHDN = 1.2V, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Minimum Input Voltage
Quiescent Current
1
V
V
V
= 0.2V
= 0V
1.2
0.1
1.6
1.0
mA
µA
RSET
SHDN
R
Pin Voltage
R
R
= 1.50k
100
120
mV
mV
SET
SET
SET
LED Pin Voltage
LED Pin Current
= 1.50k, V < V (Figure 1)
180
IN
OUT
R
R
R
R
= 562Ω, V = 1.5V
= 750Ω, V = 1.2V
= 1.50k, V = 1.2V
= 4.53k, V = 1.2V
34
26
12.5
38
30
15
5
42
34
17.5
mA
mA
mA
mA
SET
SET
SET
SET
IN
IN
IN
IN
LED Pin Current Temperature Coefficient
Switching Frequency
I
= 15mA
–0.02
1.2
mA/°C
MHz
%
LED
V
= 1V
0.8
90
1.6
IN
Maximum Switch Duty Cycle
Switch Current Limit
●
95
400
550
150
780
200
mA
Switch V
I
= 300mA
mV
CESAT
SW
SHDN Pin Current
V
V
= 0V
= 2V
0
15
0.1
30
µA
µA
SHDN
SHDN
Start-Up Threshold (SHDN Pin)
Shutdown Threshold (SHDN Pin)
0.85
V
V
0.25
5
Switch Leakage Current
Switch Off, V = 5V
0.01
µA
SW
Note 1: Absolute Maximum Ratings are those values beyond which the life of
a device may be impaired.
Note 2: The LT1932E is guaranteed to meet specifications from 0°C to 70°C.
Specifications over the –40°C to 85°C operating temperature range are
assured by design, characterization and correlation with statistical process
controls.
2
LT1932
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Switch Saturation Voltage (VCESAT
)
Switch Current Limit
Switching Frequency
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
700
600
400
350
300
250
V
IN
= 1.2V
T
= 125°C
J
V
IN
= 10V
500
400
300
200
100
T
= 25°C
J
V
= 10V
IN
V
= 1.2V
IN
200
150
T
= –50°C
J
100
50
0
0
–50
–25
0
25
50
75 100 125
50
100 125
–50 –25
0
25
75
100
200
400
0
500
600
300
TEMPERATURE (°C)
TEMPERATURE (°C)
SWITCH CURRENT (mA)
1932 G03
1932 G02
1932 G01
LED Pin Voltage
LED Current
LED Current
50
45
40
35
30
25
20
15
10
5
50
45
40
35
30
25
20
15
10
5
400
350
300
250
R
R
= 562Ω
= 750Ω
R
R
= 562Ω
= 750Ω
SET
SET
SET
SET
T
= 125°C
J
200
150
T
= 25°C
J
R
R
= 1.50k
= 4.53k
50
R
= 1.50k
= 4.53k
SET
SET
T
= –50°C
J
100
50
0
R
SET
SET
0
0
0
5
10 15 20 25 30 35 40
LED CURRENT (mA)
1932 G04
–50 –25
0
25
75 100 125
0
2
4
6
8
10
TEMPERATURE (°C)
INPUT VOLTAGE (V)
1932 G05
1932 G06
Quiescent Current
SHDN Pin Current
Switching Waveforms
2.00
50
45
40
35
30
25
20
15
10
5
VSW
T
= –50°C
J
10V/DIV
1.75
1.50
IL1
200mA/DIV
VOUT
V
= 10V
IN
T
= 25°C
1.25
1.00
0.75
0.50
0.25
J
20mV/DIV
AC COUPLED
V
IN
= 1.2V
ILED
10mA/DIV
T
= 125°C
J
1093 G09
VIN = 3V
0.5µs/DIV
4 WHITE LEDs
I
LED = 15mA
CIRCUIT ON FIRST PAGE
OF THIS DATA SHEET
0
0
–25
0
50
75 100 125
2
6
–50
25
0
4
8
10
TEMPERATURE (°C)
SHDN PIN VOLTAGE (V)
1932 G07
1932 G08
3
LT1932
U
U
U
PI FU CTIO S
RSET (Pin 4): A resistor between this pin and ground
programs the LED current (that flows into the LED pin).
This pin is also used to provide LED dimming.
SW(Pin1):SwitchPin.Thisisthecollectoroftheinternal
NPN power switch. Minimize the metal trace area con-
nected to this pin to minimize EMI.
SHDN (Pin 5): Shutdown Pin. Tie this pin higher than
0.85VtoturnontheLT1932;tiebelow0.25Vtoturnitoff.
GND (Pin 2): Ground Pin. Tie this pin directly to local
ground plane.
VIN (Pin 6): Input Supply Pin. Bypass this pin with a
capacitor to ground as close to the device as possible.
LED (Pin 3): LED Pin. This is the collector of the internal
NPN LED switch. Connect the cathode of the bottom LED
to this pin.
W
BLOCK DIAGRA
D1
L1
V
OUT
V
IN
V
IN
SW
SHDN
C1
C2
5
6
1
DRIVER
Q1
+
0.04Ω
×5
–
LED
3
+
1.2MHz
OSCILLATOR
Σ
I
LED
+
Q2
DRIVER
S
R
+
Q
A2
–
+
A1
–
LED CURRENT
REFERENCE
1932 F01
2
4
GND
R
SET
I
SET
R
SET
Figure 1. LT1932 Block Diagram
U
OPERATIO
The LT1932 uses a constant frequency, current mode
power switch. In this manner, A1 sets the correct peak
current level to keep the LED current in regulation. If A1’s
output increases, more current is delivered to the output;
if it decreases, less current is delivered. A1 senses the
LED current in switch Q2 and compares it to the current
reference, which is programmed using resistor RSET. The
RSET pin is regulated to 100mV and the output current,
ILED, is regulated to 225 • ISET. Pulling the RSET pin higher
than 100mV will pull down the output of A1, turning off
power switch Q1 and LED switch Q2.
control scheme to regulate the output current, ILED
.
Operation can be best understood by referring to the
block diagram in Figure 1. At the start of each oscillator
cycle, theSRlatchisset, turningonpowerswitchQ1. The
signal at the noninverting input of the PWM comparator
A2 is proportional to the switch current, summed to-
gether with a portion of the oscillator ramp. When this
signalreachesthelevelsetbytheoutputoferroramplifier
A1, comparator A2 resets the latch and turns off the
4
LT1932
W U U
APPLICATIO S I FOR ATIO
U
Inductor Selection
efficiency by up to 12% over the smaller, thinner ones.
Keep this in mind when choosing an inductor.
SeveralinductorsthatworkwellwiththeLT1932arelisted
in Table 1. Many different sizes and shapes are available.
Consult each manufacturer for more detailed information
and for their entire selection of related parts. As core
losses at 1.2MHz are much lower for ferrite cores that for
the cheaper powdered-iron ones, ferrite core inductors
should be used to obtain the best efficiency. Choose an
inductor that can handle at least 0.5A and ensure that the
inductor has a low DCR (copper wire resistance) to mini-
mize I2R power losses. A 4.7µH or 6.8µH inductor will be
a good choice for most LT1932 designs.
The value of inductance also plays an important role in the
overall system efficiency. While a 1µH inductor will have
a lower DCR and a higher current rating than the 6.8µH
version of the same part, lower inductance will result in
higher peak currents in the switch, inductor and diode.
Efficiency will suffer if inductance is too small. Figure 3
showstheefficiencyoftheTypicalApplicationonthefront
page of this data sheet, with several different values of the
same type of inductor (Panasonic ELJEA). The smaller
values give an efficiency 3% to 5% lower than the 6.8µH
value.
Table 1. Recommended Inductors
MAX
DCR
(mΩ)
MAX
HEIGHT
(mm)
85
L
(µH)
PANASONIC
ELJEA6R8
PART
VENDOR
80
SUMIDA
CLQ4D10-6R8
ELJEA4R7
ELJEA6R8
4.7
6.8
180
250
2.2
2.2
Panasonic
(714) 373-7334
www.panasonic.com
75
SUMIDA
CMD4D06-6R8
70
LQH3C4R7M24
LQH3C100M24
4.7
10
260
300
2.2
2.2
Murata
(814) 237-1431
www.murata.com
65
60
55
TAIYO YUDEN
LB2016B6R8
V
IN
= 3.6V
LB2016B4R7
LB2016B100
4.7
6.8
250
350
2.0
2.0
Taiyo Yuden
(408) 573-4150
www.t-yuden.com
4 WHITE LEDs
ALL ARE 10µH
INDUCTORS
TAIYO YUDEN
LB2012B6R8
0
5
10
15
20
CMD4D06-4R7
CMD4D06-6R8
CLQ4D10-4R7
CLQ4D10-6R8
4.7
6.8
4.7
6.8
216
296
162
195
0.8
0.8
1.2
1.2
Sumida
(847) 956-0666
www.sumida.com
LED CURRENT (mA)
1932 F02
Figure 2. Efficiency for Several Different Inductor Types
Inductor Efficiency Considerations
85
Many applications have thickness requirements that re-
strictcomponentheightsto1mmor2mm. Thereare2mm
tall inductors currently available that provide a low DCR
and low core losses that help provide good overall effi-
ciency. Inductors with a height of 1mm (and less) are
becoming more common, and a few companies have
introduced chip inductors that are not only thin, but have
a very small footprint as well. While these smaller induc-
tors will be a necessity in some designs, their smaller size
gives higher DCR and core losses, resulting in lower
efficiencies. Figure 2 shows efficiency for the Typical
Applicationcircuitonthefrontpageofthisdatasheet,with
several different inductors. The larger devices improve
80
6.8µH
75
70
22µH
4.7µH
2.2µH
65
60
55
V
IN
= 3.6V
4 WHITE LEDs
PANASONIC ELJEA
INDUCTORS
0
5
10
15
20
LED CURRENT (mA)
1932 F03
Figure 3. Efficiency for Several Different Inductor Values
5
LT1932
W U U
U
APPLICATIO S I FOR ATIO
Capacitor Selection
turnedoff(typicallylessthanone-thirdthetime),soa0.4A
or 0.5A diode will be sufficient for most designs.
LowESR(equivalentseriesresistance)capacitorsshould
be used at the output to minimize the output ripple
voltage. Because they have an extremely low ESR and are
available in very small packages, multilayer ceramic ca-
pacitors are an excellent choice. X5R and X7R type
capacitors are preferred because they retain their capaci-
tance over wider voltage and temperature ranges than
other types such as Y5V or Z5U. A 1µF or 2.2µF output
capacitor is sufficient for most applications. Always use a
capacitor with a sufficient voltage rating. Ceramic capaci-
torsdonotneedtobederated(donotbuyacapacitorwith
a rating twice what your application needs). A 16V ce-
ramic capacitor is good to more than 16V, unlike a 16V
tantalum, which may be good to only 8V when used in
certain applications. Low profile ceramic capacitors with
a 1mm maximum thickness are available for designs
having strict height requirements.
Table 3. Recommended Schottky Diodes
PART
VENDOR
MBR0520
MBR0530
MBR0540
ON Semiconductor
(800) 282-9855
www.onsemi.com
ZHCS400
ZHCS500
Zetex
(631) 543-7100
www.zetex.com
Programming LED Current
The LED current is programmed with a single resistor
connected to the RSET pin (see Figure 1). The RSET pin is
internally regulated to 100mV, which sets the current
flowing out of this pin, ISET, equal to 100mV/RSET. The
LT1932regulatesthecurrentintotheLEDpin, ILED, to225
times the value of ISET. For the best accuracy, a 1% (or
better) resistor value should be used. Table 4 shows
several typical 1% RSET values. For other LED current
Ceramic capacitors also make a good choice for the input
decoupling capacitor, which should be placed as close as
possible to the LT1932. A 2.2µF or 4.7µF input capacitor
is sufficient for most applications. Table 2 shows a list of
several ceramic capacitor manufacturers. Consult the
manufacturers for detailed information on their entire
selection of ceramic parts.
values, use the following equation to choose RSET
.
0.1V
RSET = 225 •
ILED
Table 4. RSET Resistor Values
I
(mA)
R
VALUE
SET
Table 2. Recommended Ceramic Capacitor Manufacturers
LED
40
562Ω
VENDOR
Taiyo Yuden
Murata
PHONE
URL
30
20
15
10
5
750Ω
1.13k
1.50k
2.26k
4.53k
(408) 573-4150
(814) 237-1431
(408) 986-0424
www.t-yuden.com
www.murata.com
www.kemet.com
Kemet
Diode Selection
Schottky diodes, with their low forward voltage drop and
fast switching speed, are the ideal choice for LT1932
applications. Table 3 shows several different Schottky
diodes that work well with the LT1932. Make sure that the
diode has a voltage rating greater than the output voltage.
The diode conducts current only when the power switch is
MostwhiteLEDsaredrivenatmaximumcurrentsof15mA
to 20mA. Some higher power designs will use two parallel
strings of LEDs for greater light output, resulting in 30mA
to 40mA (two strings of 15mA to 20mA) flowing into the
LED pin.
6
LT1932
W U U
APPLICATIO S I FOR ATIO
U
Open-Circuit Protection
If the RSET pin is used, increasing the duty cycle will
decrease the brightness. Using this method, the LEDs are
dimmed using RSET and turned off completely using
SHDN. If the RSET pin is used to provide PWM dimming,
the approximate value of RPWM should be (where VMAX is
the “high” value of the PWM signal):
For applications where the string of LEDs can be discon-
nectedorcouldpotentiallybecomeanopencircuit,azener
diode can be added across the LEDs to protect the LT1932
(see Figure 4). If the device is turned on without the LEDs
present, no current feedback signal is provided to the LED
pin. The LT1932 will then switch at its maximum duty
cycle, generating an output voltage 10 to 15 times greater
thantheinputvoltage. Withoutthezener, theSWpincould
see more than 36V and exceed its maximum rating. The
zener voltage should be larger than the maximum forward
voltage of the LED string.
VMAX
0.15V
RPWM = RSET
•
– 1
In addition to providing the widest dimming range, PWM
brightness control also ensures the “purest” white LED
color over the entire dimming range. The true color of a
white LED changes with operating current, and is the
“purest” white at a specific forward current, usually 15mA
or 20mA. If the LED current is less than or more than this
value, the emitted light becomes more blue. For color
LCDs, this often results in a noticeable and undesirable
blue tint to the display.
L1
D1
6.8µH
V
IN
24V
6
1
V
SW
IN
LT1932
SHDN
5
3
C1
4.7µF
C2
When a PWM control signal is used to drive the SHDN pin
of the LT1932 (see Figure 6), the LEDs are turned off and
on at the PWM frequency. The current through them
alternates between full current and zero current, so the
average current changes with duty cycle. This ensures
that when the LEDs are on, they can be driven at the
appropriate current to give the purest white light. Figure
5 shows the LED current when a 5kHz PWM dimming
control signal is used with the LT1932. The LED current
waveform cleanly tracks the PWM control signal with no
delays, so the LED brightness varies linearly with the
PWM duty cycle.
LED
GND
1µF
R
SET
4
15mA
2
R
1.50k
SET
1932 F04
Figure 4. LED Driver with Open-Circuit Protection
Dimming Using a PWM Signal
PWM brightness control provides the widest dimming
range (greater than 20:1) by pulsing the LEDs on and off
usingthecontrolsignal. TheLEDsoperateateitherzeroor
full current, but their average current changes with the
PWM signal duty cycle. Typically, a 5kHz to 40kHz PWM
signal is used. PWM dimming with the LT1932 can be
accomplished two different ways (see Figure 6). The
SHDN pin can be driven directly or a resistor can be added
to drive the RSET pin.
VPWM
2V/DIV
ILED
10mA/DIV
If the SHDN pin is used, increasing the duty cycle will
increase the LED brightness. Using this method, the LEDs
can be dimmed and turned off completely using the same
control signal. A 0% duty cycle signal will turn off the
LT1932, reducing the total quiescent current to zero.
50µs/DIV
1932 F05
Figure 5. PWM Dimming Using the SHDN Pin
7
LT1932
W U U
U
APPLICATIO S I FOR ATIO
Dimming Using a Filtered PWM Signal
Dimming Using a DC Voltage
While the direct PWM method provides the widest dim-
ming range and the purest white light output, it causes the
LT1932 to enter into Burst ModeTM operation. This opera-
tion may be undesirable for some systems, as it may
reflect some noise to the input source at the PWM fre-
quency.Thesolutionistofilterthecontrolsignalbyadding
a 10k resistor and a 0.1µF capacitor as shown in Figure 6,
converting the PWM to a DC level before it reaches the
Forsomeapplications,thepreferredmethodofbrightness
control uses a variable DC voltage to adjust the LED
current. As the DC voltage is increased, current flows
through RADJ into RSET, reducing the current flowing out
of the RSET pin, thus reducing the LED current. Choose the
RADJ value as shown below where VMAX is the maximum
DC control voltage, ILED(MAX) is the current programmed
by RSET, and ILED(MIN) is the minimum value of ILED (when
the DC control voltage is at VMAX).
R
SET pin. The 10k resistor minimizes the capacitance seen
by the RSET pin.
V
MAX – 0.1V
R
ADJ = 225 •
Dimming Using a Logic Signal
I
LED(MAX) –ILED(MIN)
For applications that need to adjust the LED brightness in
discrete steps, a logic signal can be used as shown in
Figure 6. RMIN sets the minimum LED current value (when
the NMOS is off):
Regulating LED Current when VIN > VOUT
The LT1932 contains special circuitry that enables it to
regulate the LED current even when the input voltage is
higherthantheoutputvoltage.WhenVIN islessthanVOUT
,
0.1V
ILED(MIN)
RMIN = 225 •
the internal NPN LED switch (transistor Q2 in Figure 1) is
saturated to provide a lower power loss. When VIN is
greater than VOUT, the NPN LED switch comes out of
saturation to keep the LED current in regulation.
RINCR sets how much the LED current is increased when
the NMOS is turned on:
Burst Mode is a trademark of Linear Technology Corporation.
0.1V
ILED(INCREASE)
RINCR = 225 •
LT1932
SHDN
5
LT1932
LT1932
LT1932
LT1932
R
R
R
R
SET
4
SET
4
SET
4
SET
4
R
R
R
INCR
R
PWM
10k
ADJ
PWM
PWM
PWM
PWM
V
DC
LOGIC
SIGNAL
R
R
0.1µF
R
R
MIN
SET
SET
SET
1932 F06
PWM
PWM
FILTERED PWM
DC VOLTAGE
LOGIC
Figure 6. Five Methods of LED Dimming
8
LT1932
W U U
APPLICATIO S I FOR ATIO
U
Board Layout Considerations
L1
As with all switching regulators, careful attention must be
paid to the PCB board layout and component placement.
Tomaximizeefficiency, switchriseandfalltimesaremade
as short as possible. To prevent radiation and high fre-
quency resonance problems, proper layout of the high
frequency switching path is essential. Minimize the length
and area of all traces connected to the SW pin and always
use a ground plane under the switching regulator to
minimize interplane coupling. The signal path including
the switch, output diode D1 and output capacitor C2,
contains nanosecond rise and fall times and should be
kept as short as possible. In addition, the ground connec-
tionfor theRSET resistor should be tieddirectly tothe GND
pinandnotbesharedwithanyothercomponent, ensuring
a clean, noise-free connection. Recommended compo-
nent placement is shown in Figure 7.
C1
D1
V
IN
C2
1
6
5
4
SHDN
2
3
GND
R
SET
DIMMING
CONTROL
1932 F07
Figure 7. Recommended Component Placement
U
TYPICAL APPLICATIO S
5V Driver for 16 White LEDs
Efficiency
80
75
D1
L1
10µH
70
65
V
IN
5V
6
1
60
55
50
V
SW
IN
LT1932
SHDN
5
3
C1
C2
2.2µF
LED
GND
4.7µF
R
SET
4
0
5
10
15
20
25
30
2
5V DC
DIMMING
CONTROL
51.1k
100Ω
100Ω
LED CURRENT (mA)
1932 TA14b
R
750Ω
SET
30mA
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN GMK325BJ225
D1: ZETEX ZHCS400
(408) 573-4150
(408) 573-4150
(631) 543-7100
(814) 237-1431
1932 TA14a
L1: MURATA LQH3C100M24
9
LT1932
U
TYPICAL APPLICATIO S
Efficiency
Single Cell Driver for One White LED
80
75
L1
D1
4.7µH
V
IN
1V TO 1.5V
V
= 1.5V
= 1.1V
IN
6
1
70
65
V
SW
IN
V
IN
LT1932
5
3
C1
C2
4.7µF
SHDN
LED
GND
4.7µF
R
60
55
50
SET
15mA
4
2
2.5V PWM
DIMMING
CONTROL
24.9k
R
SET
1.50k
0
2.5
5
7.5
10
12.5
15
LED CURRENT (mA)
C1, C2: TAIYO YUDEN JMK212BJ475 (408) 573-4150
1932 TA03a
D1: ZETEX ZHCS400
(631) 543-7100
(814) 237-1431
1932 TA03b
L1: MURATA LQH3C4R7M24
Efficiency
Single Cell Driver for Two White LEDs
L1
4.7µH
D1
80
75
70
V
IN
1V TO 1.5V
V
= 1.5V
= 1.1V
IN
6
1
V
SW
V
IN
IN
LT1932
SHDN
5
3
65
60
55
50
C1
C2
2.2µF
LED
GND
4.7µF
R
SET
4
15mA
2
2.5V PWM 24.9k
DIMMING
CONTROL
R
SET
1.50k
0
2.5
5
7.5
10
12.5
15
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN LMK212BJ225
D1: ZETEX ZHCS400
(408) 573-4150
(408) 573-4150
(631) 543-7100
(814) 237-1431
1932 TA04a
LED CURRENT (mA)
1932 TA04b
L1: MURATA LQH3C4R7M24
10
LT1932
U
TYPICAL APPLICATIO S
Efficiency
2-Cell Driver for Two White LEDs
85
80
75
70
65
60
55
L1
D1
4.7µH
V
IN
1.8V TO 3V
V
= 3V
IN
6
1
V
SW
IN
V
= 1.8V
IN
LT1932
SHDN
5
3
C1
C2
2.2µF
LED
GND
4.7µF
R
SET
4
15mA
2
2.5V DC 60.4k
DIMMING
CONTROL
R
SET
1.50k
0
5
10
15
20
LED CURRENT (mA)
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN LMK212BJ225
D1: ZETEX ZHCS400
(408) 573-4150
(408) 573-4150
(631) 543-7100
(814) 237-1431
1932 TA15a
1932 TA15b
L1: MURATA LQH3C4R7M24
2-Cell Driver for Three White LEDs
Efficiency
L1
4.7µH
85
80
D1
V
IN
1.8V TO 3V
V
IN
= 3V
6
1
V
SW
75
70
IN
V
IN
= 1.8V
LT1932
SHDN
5
3
C1
4.7µF
C2
2.2µF
LED
GND
R
SET
4
15mA
65
60
55
2
2.5V DC
DIMMING
CONTROL
60.4k
R
1.50k
SET
0
5
10
LED CURRENT (mA)
15
20
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN EMK316BJ225
D1: ZETEX ZHCS400
(408) 573-4150
(408) 573-4150
(631) 543-7100
(814) 237-1431
1932 TA06a
1932 TA06b
L1: MURATA LQH3C4R7M24
11
LT1932
U
TYPICAL APPLICATIO S
2-Cell Driver for Four White LEDs
Efficiency
L1
4.7µH
85
80
D1
V
IN
1.8V TO 3V
V
IN
= 3V
75
70
6
1
C1
4.7µF
V
IN
= 1.8V
V
SW
IN
LT1932
SHDN
PWM
5
3
C2
1µF
LED
GND
DIMMING
CONTROL
65
60
55
R
SET
4
15mA
2
R
SET
1.50k
0
5
10
15
20
LED CURRENT (mA)
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN EMK212BJ105
D1: ZETEX ZHCS400
(408) 573-4150
(408) 573-4150
(631) 543-7100
(814) 237-1431
1932 TA07a
1932 TA07b
L1: MURATA LQH3C4R7M24
2-Cell Driver for Five White LEDs
Efficiency
L1
4.7µH
85
80
D1
V
IN
2V TO 3V
6
1
C1
75
70
4.7µF
V
IN
= 3V
V
SW
IN
LT1932
SHDN
PWM
5
3
C2
1µF
V
IN
= 2V
LED
GND
DIMMING
CONTROL
65
60
55
R
SET
4
2
R
1.50k
SET
15mA
0
5
10
LED CURRENT (mA)
15
20
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN TMK316BJ105
D1: ZETEX ZHCS400
(408) 573-4150
(408) 573-4150
(631) 543-7100
(814) 237-1431
1932 TA05a
1932 TA05b
L1: MURATA LQH3C4R7M24
12
LT1932
U
TYPICAL APPLICATIO S
Li-Ion Driver for Two White LEDs
Efficiency
L1
6.8µH
85
80
D1
V
IN
2.7V TO 4.2V
V
= 4.2V
= 2.7V
IN
6
1
V
75
70
IN
V
SW
IN
LT1932
SHDN
5
3
C1
C2
LED
GND
4.7µF
2.2µF
R
SET
4
15mA
65
60
55
2
3.3V PWM
DIMMING
CONTROL
31.6k
R
1.50k
SET
0
5
10
15
20
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN LMK212BJ225
D1: ZETEX ZHCS400
(408) 573-4150
(408) 573-4150
(631) 543-7100
(714) 373-7334
1932 TA08a
LED CURRENT (mA)
1932 TA08b
L1: PANASONIC ELJEA6R8
Li-Ion Driver for Three White LEDs
Efficiency
85
80
L1
6.8µH
D1
V
IN
V
IN
= 4.2V
2.7V TO 4.2V
V
= 2.7V
6
1
IN
75
70
V
SW
IN
LT1932
5
3
C1
C2
SHDN
LED
GND
4.7µF
2.2µF
R
65
60
55
SET
15mA
4
2
3.3V PWM
DIMMING
CONTROL
31.6k
R
1.50k
SET
0
5
10
LED CURRENT (mA)
15
20
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN EMK316BJ225
D1: ZETEX ZHCS400
(408) 573-4150
(408) 573-4150
(631) 543-7100
(714) 373-7334
1932 TA09a
1932 TA09b
L1: PANASONIC ELJEA6R8
13
LT1932
U
TYPICAL APPLICATIO S
Li-Ion Driver for Four White LEDs
Efficiency
L1
6.8µH
85
80
D1
V
IN
V
= 4.2V
= 2.7V
IN
2.7V TO 4.2V
V
IN
75
70
C1
4.7µF
6
1
V
SW
IN
LT1932
SHDN
PWM
DIMMING
CONTROL
5
3
C2
1µF
65
60
55
LED
GND
R
SET
4
15mA
2
R
SET
1.50k
0
5
10
15
20
LED CURRENT (mA)
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN EMK212BJ105
D1: ZETEX ZHCS400
(408) 573-4150
(408) 573-4150
(631) 543-7100
(714) 373-7334
1932 TA10a
1932 TA10b
L1: PANASONIC ELJEA6R8
Li-Ion Driver for Five White LEDs
Efficiency
85
80
L1
D1
4.7µH
V
IN
2.7V TO 4.2V
V
= 4.2V
= 2.7V
IN
6
1
75
70
V
IN
C1
V
SW
4.7µF
IN
LT1932
SHDN
PWM
5
3
C2
LED
GND
DIMMING
CONTROL
1µF
65
60
55
R
SET
4
2
R
SET
1.50k
15mA
0
5
10
LED CURRENT (mA)
15
20
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN TMK316BJ105
D1: ZETEX ZHCS400
(408) 573-4150
(408) 573-4150
(631) 543-7100
(814) 237-1431
1932 TA11a
1932 TA11b
L1: MURATA LQH3C4R7M24
14
LT1932
U
TYPICAL APPLICATIO S
Li-Ion Driver for Eight White LEDs
Efficiency
85
80
L1
4.7µH
D1
V
IN
3V TO 4.2V
V
= 4.2V
IN
6
1
75
70
V
SW
IN
LT1932
SHDN
5
3
V
IN
= 3V
C1
C2
LED
GND
4.7µF
1µF
65
60
55
R
SET
4
2
3.3V DC
DIMMING
CONTROL
80.6k
R
1.50k
SET
15mA
0
5
10
LED CURRENT (mA)
15
20
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN GMK316BJ105
D1: ZETEX ZHCS400
(408) 573-4150
(408) 573-4150
(631) 543-7100
(814) 237-1431
1932 TA13a
1932 TA13b
L1: MURATA LQH3C4R7M24
U
PACKAGE DESCRIPTIO
S6 Package
6-Lead Plastic SOT-23
(LTC DWG # 05-08-1634)
(LTC DWG # 05-08-1636)
2.80 – 3.10
(.110 – .118)
(NOTE 3)
.20
(.008)
A2
A
2.60 – 3.00 1.50 – 1.75
(.102 – .118) (.059 – .069)
(NOTE 3)
DATUM ‘A’
PIN ONE ID
1.90
(.074)
REF
L
.09 – .20
A1
(.004 – .008)
NOTE:
(NOTE 2)
1. CONTROLLING DIMENSION: MILLIMETERS
MILLIMETERS
2. DIMENSIONS ARE IN
(INCHES)
SOT-23
SOT-23
(Original)
(ThinSOT)
.90 – 1.45
1.00 MAX
(.039 MAX)
A
A1
A2
L
.95
(.037)
REF
(.035 – .057)
3. DRAWING NOT TO SCALE
4. DIMENSIONS ARE INCLUSIVE OF PLATING
5. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
6. MOLD FLASH SHALL NOT EXCEED .254mm
7. PACKAGE EIAJ REFERENCE IS:
.00 – 0.15
(.00 – .006)
.01 – .10
(.0004 – .004)
.25 – .50
(.010 – .020)
S6 SOT-23 0401
.90 – 1.30
.80 – .90
(.031 – .035)
(6PLCS, NOTE 2)
(.035 – .051)
SC-74A (EIAJ) FOR ORIGINAL
JEDEL MO-193 FOR THIN
.35 – .55
.30 – .50 REF
(.014 – .021)
(.012 – .019 REF)
15
LT1932
U
TYPICAL APPLICATIO
Li-Ion Driver for Ten White LEDs
Efficiency
80
75
L1
10µH
D1
V
IN
= 4.2V
V
IN
2.7V TO 4.2V
V
= 2.7V
IN
6
1
70
65
V
SW
IN
LT1932
SHDN
C2
5
3
C1
4.7µF
LED
GND
4.7µF
60
55
50
R
SET
4
2
100Ω
100Ω
R
750Ω
SET
30mA
0
5
10
15
20
25
30
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN TMK325BJ475
D1: ZETEX ZHCS400
(408) 573-4150
(408) 573-4150
(631) 543-7100
(814) 237-1431
1932 TA16a
TOTAL LED CURRENT (mA)
1932 TA16b
L1: MURATA LQH3C100M24
Li-Ion Driver for Six White LEDs
Efficiency
L1
85
80
D1
4.7µH
V
IN
2.7V TO 4.2V
V
V
= 4.2V
= 2.7V
IN
6
1
75
70
V
SW
IN
IN
LT1932
SHDN
5
3
C1
C2
LED
GND
4.7µF
1µF
65
60
55
R
SET
4
2
3.3V DC
DIMMING
CONTROL
80.6k
R
SET
1.50k
15mA
0
5
10
LED CURRENT (mA)
15
20
C1: TAIYO YUDEN JMK212BJ475
C2: TAIYO YUDEN TMK316BJ105
D1: ZETEX ZHCS400
(408) 573-4150
(408) 573-4150
(631) 543-7100
(814) 237-1431
1932 TA12a
1932 TA12b
L1: MURATA LQH3C4R7M24
RELATED PARTS
PART NUMBER DESCRIPTION
COMMENTS
LT1615
LT1617
LT1618
LTC1682
LT1930
LT1931
LTC3200
Micropower DC/DC Converter in 5-Lead ThinSOT
20V at 12mA from 2.5V Input, ThinSOT Package
–15V at 12mA from 2.5V Input, ThinSOT Package
Drives 20 White LEDs from Li-Ion, MS10 Package
Micropower Inverting DC/DC Converter in 5-Lead ThinSOT
Constant-Current/Constant-Voltage DC/DC Converter
Doubler Charge Pump with Low Noise Linear Regulator
1.4MHz Switching Regulator in 5-Lead ThinSOT
Inverting 1.2MHz Switching Regulator in 5-Lead ThinSOT
Low Noise Regulated Charge Pump
3.3V and 5V Outputs with 60µV
Noise, Up to 80mA Output
RMS
5V at 480mA from 3.3V Input, ThinSOT Package
–5V at 350mA from 5V Input, ThinSOT Package
5V Output with Up to 100mA Output
1932i LT/TP 0701 1.5K • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
16
●
●
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
LINEAR TECHNOLOGY CORPORATION 2001
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