LINER LTC3490

LTC3490
Single Cell 350mA
LED Driver
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FEATURES
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DESCRIPTIO
350mA Constant Current Output
2.8V to 4V Output Compliance
1- or 2-Cell NiMH or Alkaline Input
Synchronous Rectification: Up to 90% Efficiency
Fixed Frequency Operation: 1.3MHz
Low Quiescent Current: <1mA
Very Low Shutdown Current: <50µA
Open LED Output Limited to 4.7V
VIN Range: 1V to 3.2V
Dimming Control
Undervoltage Lockout to Protect Batteries
Low Profile (0.75mm) 3mm × 3mm Thermally
Enhanced 8-Lead DD and S8 Packages
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APPLICATIO S
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Portable Lighting
Rechargeable Flashlights
The LTC®3490 provides a constant current drive for 1W
LED applications. It is a high efficiency boost converter
that operates from 1 or 2 NiMH or alkaline cells and
generates 350mA of constant current with up to 4V of
compliance. It contains a 100mΩ NFET switch and a
130mΩ PFET synchronous rectifier. The fixed switching
frequency is internally set to 1.3MHz.
The LTC3490 limits the output voltage to 4.7V if the output
load is disconnected. It also features an analog dimming
capability that reduces the drive current proportional to
the CTRL/SHDN pin voltage. A low-battery logic output
signals when the battery has dropped below 1V/cell. An
undervoltage lockout circuit shuts down the LTC3490
when the battery voltage drops below 0.85V/cell. The
feedback loop is internally compensated to minimize component count.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
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TYPICAL APPLICATIO
Efficiency vs VIN at VLED = 3.5V
Single Cell Minimum Component LED Driver
100
3.3µH
IOUT = 350mA
90
80
SW
1 NiMH OR
ALKALINE
CELL
LTC3490
+
CTRL/SHDN LED
CELLS
1M
70
CAP
ON/OFF
LOBAT
GND
350mA
4.7µF
HIGH
CURRENT
LED
EFFICIENCY (%)
VIN
60
50
40
30
20
10
3490 TA01
0
1
1.5
2
VIN (V)
2.5
3
3490 TA02
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LTC3490
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ABSOLUTE
RATI GS
(Note 1)
Supply Voltage (VIN) ................................... – 0.3V to 6V
Input Voltages (CTRL/SHDN, CELLS) ......... – 0.3V to 6V
Output Voltages (CAP, LED, SW) ................ – 0.3V to 6V
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 125°C
Lead Temperature (Soldering, 10 sec, S8) .......... 300°C
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PACKAGE/ORDER I FOR ATIO
TOP VIEW
TOP VIEW
CELLS 1
8
CTRL/SHDN
VIN 2
7
LOBAT
6
CAP
5
LED
SW 3
9
GND 4
CELLS 1
8
CTRL/SHDN
VIN 2
7
LOBAT
SW 3
6
CAP
GND 4
5
LED
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 125°C, θJA = 43°C/ W (NOTE 4)
EXPOSED PAD (PIN 9) IS GND
MUST BE SOLDERED TO PCB (NOTE 5)
TJMAX = 125°C, θJA = 150°C/ W (NOTE 4)
ORDER PART NUMBER
DD PART MARKING
ORDER PART NUMBER
S8 PART MARKING
LTC3490EDD
LBRQ
LTC3490ES8
3490
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are TA = 25°C. VIN = 2.5V unless otherwise specified.
SYMBOL
PARAMETER
VIN
Input Supply Range
CONDITIONS
VIN(START)
Minimum Start-Up Voltage
(Note 3)
ILED(MAX)
LED Drive Current
VCTRL/SHDN = VIN, DD Package
25°C to 85°C
– 40°C to <25°C
VCTRL/SHDN = VIN, S8 Package
25°C to 85°C
– 40°C to <25°C
MIN
TYP
1
MAX
UNITS
3.2
V
0.9
1
V
330
310
350
350
370
385
mA
mA
337
325
350
345
363
365
mA
mA
0.1
1
µA
4
V
ILED(SHDN)
LED Drive Current in Shutdown
VLED
Output Compliance Voltage
VCTRL/SHDN = 0V
VLED(OVL)
Output Voltage Overvoltage Limit
Open LED
4.7
V
IIN(SHDN)
Input Current, Shutdown
VCTRL/SHDN = 0V, Excluding Switch Leakage
20
50
µA
IIN(ACTIVE)
Input Current, Active
Excluding Load Power
20
30
mA
fSW
Switching Frequency
1.3
1.6
MHz
IL(NMOS)
Leakage Current, NMOS Switch
0.1
RON(NMOS)
On-Resistance, NMOS Switch
0.1
●
2.8
●
4.2
●
1.0
µA
Ω
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LTC3490
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are TA = 25°C. VIN = 2.5V unless otherwise specified.
SYMBOL
IL(PMOS)
PARAMETER
Leakage Current, PMOS Switch
RON(PMOS)
On-Resistance, PMOS Switch
VIH
Input High (CELLS)
CONDITIONS
MIN
MAX
UNITS
µA
Ω
0.13
VIN – 0.4
Input High (SHDN)
VIL
TYP
0.1
V
VIN • 0.9
Input Low (CELLS)
V
0.4
Input Low (SHDN)
V
VIN • 0.2
V
0.01
µA
500
mA/V
IIN
Input Current (CTRL/SHDN, CELLS)
KCTRL
Control Gain, ILED/VCTRL
RON(LOBAT)
On-Resistance, LOBAT Output
VIN < VIN(LOBAT)
●
300
Ω
VIN(LOBAT1)
Input Voltage, Low Battery, 1 Cell
VCELLS = 0V
●
0.8
1.12
V
VIN(LOBAT2)
Input Voltage, Low Battery, 2 Cells
VCELLS = VIN
●
1.8
2.24
V
VIN(UVLO2)
Input Voltage, Undervoltage Lockout, VCELLS = VIN
2 Cells
●
1.4
1.8
V
VIN(UVLO1)
Input Voltage, Undervoltage Lockout, VCELLS = 0 V
1 Cell
●
0.7
0.9
V
Scales Linearity with VIN, VIN = 1V
Note 4: This device includes overtemperature protection intended to
protect the device during momentary overload conditions. The maximum
junction temperature may be exceeded when overtemperature protection
is active. Continuous operation above the specified maximum operating
junction temperature may result in device degradation or failure.
Note 5: The Exposed Pad of the DFN package must be soldered to a
PCB pad for optimum thermal conductivity. This pad must be connected
to ground.
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC3490 is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C range are
assured by design, characterization and correlation with statistical process
controls.
Note 3: The LTC3490 input voltage may drop below the minimum start-up
voltage once the LED voltage has risen above 2.3V.
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TYPICAL PERFOR A CE CHARACTERISTICS
Oscillator Frequency
vs Temperature
ILED vs VCTRL
1.400
ILED vs VIN
375
400
VLED = 3.5V
350
350
1.360
1.280
250
ILED (mA)
1.320
ILED (mA)
FREQUENCY (MHz)
300
MAXIMUM
200
150
325
300
MINIMUM
100
275
1.240
50
1.200
–50
50
0
TEMPERATURE (°C)
100
3490 G01
0
250
0
0.2
0.4
0.6
VCTRL/VIN (V)
0.8
1
3490 G02
1
1.5
2
VIN (V)
2.5
3
3490 G03
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LTC3490
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TYPICAL PERFOR A CE CHARACTERISTICS
ILED vs VLED
360
Efficiency vs ILED
100
VIN = 2.4V
358
356
80
EFFICIENCY (%)
354
ILED (mA)
VIN = 2.4V
90
352
350
348
50
40
346
30
344
20
342
10
340
VIN = 1.2V
70
60
0
3
2.8
3.2
3.4
3.6
VLED (V)
3.8
4
3490 G04
0
100
200
ILED (mA)
400
300
3490 G05
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PI FU CTIO S
CELLS (Pin 1): A logic input to set the low-battery and
undervoltage shutdown thresholds. A logic low (tied to
GND) will set the thresholds for 1 cell. A logic high (tied to
VIN) will set the thresholds for 2 cells.
VIN (Pin 2): Supply Voltage.
SW (Pin 3): Switch Input. Connect this pin to an external
inductor from VIN.
GND (Pin 4): Circuit Ground.
LED (Pin 5): Output Drive Current to LED.
CAP (Pin 6): Filter Capacitor. A 4.7µF low ESR capacitor
should be tied to this pin.
CTRL/SHDN (Pin 8): Analog Control Voltage and Shutdown. When VIN • 0.2 < VCTRL < VIN • 0.9, the LED drive
current varies according to the formula:
⎛V
⎞
ILED = 500 • ⎜ CTRL – 0.2⎟ mA
⎝ VIN
⎠
When VCTRL > VIN • 0.9, the LED drive current is clamped
at 350mA. When VCTRL < VIN • 0.2, then the part is in low
power shutdown.
Exposed Pad (Pin 9, DD Package): Ground. This pin must
be soldered to the PCB to provide both electrical contact
to ground and good thermal contact to the PCB.
LOBAT (Pin 7): Low active, open-drain logic output indicating a low-battery condition.
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LTC3490
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FU CTIO AL DIAGRA
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3
SW
–
2
P BODY
CONTROL
+
VIN
CAP
6
GATE
CONTROL
AND
DRIVERS
SENSE
AMP
LIMIT
19.2Ω
+
–
OVERVOLTAGE
DETECT
LED
5
250k
–
PWM
LOGIC
0.1Ω
40k
VREF/2
+
OSCILLATOR
START-UP
–
8
CTRL/
SHDN
DIMMING
AMP
+
LOBAT
IREF
1
BATTERY
MONITOR
CELLS
7
SHUTDOWN
GND
4
3490 FD
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LTC3490
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OPERATIO
The LTC3490 is a high efficiency, constant current source
for 1W high intensity white LEDs. These high intensity
LEDs require a fixed current of 350mA with a voltage
compliance of 2.8V to 4V.
The LTC3490 operates with 1 or 2 NiMH or alkaline cells.
It functions as a boost converter with a current sense resistor providing the control feedback. If the battery voltage
is greater than the required LED compliance, it will cycle
off periodically to maintain the correct average current. It
features a low voltage start-up circuit that will start with an
input voltage of only 1V. Once the drive voltage exceeds
2.3V, the circuit operates from the drive voltage.
to the battery voltage. The LED drive current is given by the
formula:
⎛V
⎞
ILED = 500 • ⎜ CTRL – 0.2⎟ mA
⎝ VIN
⎠
When VCTRL > VIN • 0.9, the LED drive current is clamped
at 350mA.
Open-Circuit Protection
All of the loop compensation is internal; only the main filter
capacitor is needed for stable operation.
Since this is a boost converter attempting to drive a current into the load, an open or high impedance load will cause
the regulator loop to increase the output voltage in an effort to achieve regulation. To protect the device, maximum
output voltage is limited to 4.7V under all conditions.
Dimming Function
Undervoltage Sense and Protection
During normal operation with the CTRL/SHDN pin connected to VIN, the LED drive current is controlled at
350mA. The drive current can be reduced by changing the
voltage on the CTRL/SHDN pin.
The undervoltage lockout prevents excessive inductor
peak current and protects the batteries from deep discharging which can damage them. The low-battery indicator allows the end user to be made aware that the batteries
are nearing the end of their useful life.
For VIN • 0.2 < VCTRL < VIN • 0.9, the LED current is
proportional to VCTRL/VIN. This allows a simple potentiometer from VIN to control the current without sensitivity
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LTC3490
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APPLICATIO S I FOR ATIO
The LTC3490 requires only four external components to
operate: an inductor, an output capacitor, a switch and a
pull-down resistor. The inductor is nominally set at 3.3µH
and the capacitor at 4.7µF. Optional components include
an input capacitor and dimming resistors.
where:
VIN = Input Voltage (V)
VOUT = Output Voltage (V)
IOUT = LED Drive Current (A)
IIN = Input Current = VOUT/VIN • IOUT (A)
COMPONENT SELECTION
RP = RDSON of the PFET Switch (Ω)
Inductor Selection
RN = RDSON of the NFET Switch (Ω)
The high frequency operation of the LTC3490 allows the
use of small surface mount inductors. The minimum
inductance value is proportional to the operating frequency and is limited by the following constraints:
3
L≥ H
f
and
L≥
(
VIN(MIN) • VOUT(MAX) – VIN(MIN)
f • Ripple • VOUT(MAX)
)H
where:
f = Operating Frequency (Hz)
Ripple = Inductor Current Ripple (A)
VIN(MIN) = Minimum Input Voltage (V)
VOUT(MAX) = Maximum Output Voltage (V)
The inductor current ripple is typically set to 20% to 40%
of the inductor current.
The peak inductor current is given by:
ILPK = IOUT
For high efficiency, choose an inductor with a high frequency core material, such as ferrite, to reduce core
losses. The inductor should have low ESR (equivalent
series resistance) to reduce the I2R losses and must be
able to handle the peak inductor current at full load without
saturating. In single cell applications, the inductor ESR
must be below 25mΩ to keep the efficiency up and
maintain output current regulation. Dual cell applications
can tolerate significantly higher ESR (up to 75mΩ) with
minimal efficiency degradation. Molded chokes or chip
inductors usually do not have enough core to support the
peak inductor currents in the 1A to 2A region. If radiated
noise is an issue, use a toroid, pot core or shielded bobbin
inductor to minimize radiated noise. See Table 1 for a list
of suggested inductors. Look closely at the manufacturers
data sheets; they specify saturation current differently.
Table 1. Inductor Information
INDUCTOR PART NUMBER
ESR (mΩ)
SATURATION CURRENT (A)
TOKO A918CY-3R3M
47
1.97
TYCO DN4835-3R3M
58
2.15
TDK SLF7045T-3R3M2R5
20
2.5
( VOUT + IOUT • RP ) – RN • IIN
Output Capacitor Selection
VIN – RN • IIN
VIN ( VOUT – VIN )
+
2 • L • f • VOUT
The output capacitor value and equivalent series resistance (ESR) are the primary factors in the output ripple.
The output ripple is not a direct concern for LED drive as
the LED will operate at the average current value. However
the peak pulsed forward current rating of the LED must not
be exceeded to avoid damaging the LED.
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LTC3490
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APPLICATIO S I FOR ATIO
The output ripple voltage has two primary components.
The first is due to the value of the capacitor and is given by:
VRCAP =
ILPK • VIN
C • VOUT • f
The second is due to the capacitor ESR:
VRESR = ILPK • RESR
Component values will be calculated for 1 or 2 NiMH cells
and assumes the end-of-charge voltage to be 0.9V per cell.
The operating frequency is assumed to be 1MHz, the
worst-case low frequency. The allowed inductor ripple
current is 0.31A. Table 3 shows a summary of the key
parameters.
Table 3. Summary of Key Parameters
PARAMETER
The LED current ripple and peak pulsed current are calculated by:
VRCAP • VRESR
R SENSE + RLED
IR
= IOUT + LE D
2
IRLED =
1-CELL
2-CELL
UNITS
LMIN
2.2
3.2
µH
Choose L
3.3
3.3
µH
IIN
1.56
0.78
A
ILPK
1.93
0.96
A
Choose C
4.7
4.7
µF
5
5
mΩ
VRCAP
0.09
0.09
V
VRESR
0.01
0.005
V
IRLED
0.10
0.09
A
RSENSE = Internal Sense Resistor = 0.1Ω
IPPFC
0.40
0.39
A
RLED = Dynamic Impedance of the LED
where:
IPPFC
Cap ESR
where:
Low ESR capacitors should be used to minimize output
ripple. Ceramic X5R or X7R type capacitors are recommended. See Table 2 for a list of component suppliers.
Table 2. Capacitor Information
CAPACITOR PART NUMBER
DESCRIPTION
TDK C2012X5R0J475K
4.7µF, 6.3V, X5R in 0805
AVX 1210ZC475MAT
4.7µF, 10V, X7R in 1210
Taiyo Yuden CELMK316BJ475ML
4.7µF, 10V, X7R in 1206
ILPK is the peak inductor current
VRCAP is the ripple voltage due to the output capacitor
value
VRESR is the ripple voltage due to the output capacitor
ESR
IRLED is the LED current ripple
IPPFC is the LED peak pulsed forward current
PC Board Layout Checklist
Input Capacitor Selection
Most battery-powered applications do not need an input
capacitor. In supply-powered applications or battery applications with long leads to the battery, a low ESR 3.3µF
capacitor reduces switching noise and peak currents.
Design Example
The example will use a Lumileds DS25 white LED. The key
specifications are:
Keep the inductor and output capacitor as close to the IC
as possible. Make traces as short and wide as is feasible.
Parasitic resistance and inductance reduce efficiency and
increase ripple.
Keep resistance in the battery connections as low as
possible. In single cell applications, only 0.1Ω in the
battery connections will have a dramatic effect in efficiency and battery life. I2R losses can exceed 100mW and
the converter operates lower on the efficiency curve.
VF (at IF= 350mA) = 3.4 ±0.6V
RLED = 1Ω
Peak Pulsed Forward Current = 0.5A
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LTC3490
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APPLICATIO S I FOR ATIO
Red Luxeon LEDs
is only 2.31V. The LTC3490 requires an additional 190mV
for proper operation. In non-dimming applications, this can
be accomplished with a 0.6Ω resistor in series with the
LED. The resistor voltage drops too low in dimming applications, so a Schottky diode is recommended to keep
sufficient voltage at the output at lower currents.
The red, red-orange and amber Luxeon LEDs have a lower
forward voltage than the white, blue and green LEDs. Since
the LTC3490 internal circuitry is powered from the output,
it requires a minimum LED voltage of 2.5V for reliable
operation. The minimum forward voltage on the red LEDs
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TYPICAL APPLICATIO S
2-Cell Adjustable Amplitude LED Driver
3.3µH
VIN
SW
ON/OFF
2 NiMH OR
ALKALINE
CELLS
CAP
+
LTC3490
+
4.7µF
CTRL/SHDN LED
LOBAT
CELLS
1M
LUMILEDS
LUXEON
LXHL-BW02
GND
3490 TA03
Soft Turn-Off LED Driver
3.3µH
VIN
SW
CAP
ON/OFF
1 NiMH OR
ALKALINE
CELL
LTC3490
+
CTRL/SHDN LED
CELLS
1µF
1M
LOBAT
GND
350mA
4.7µF
LUMILEDS
LUXEON
LXHL-BW02
3490 TA04
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LTC3490
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TYPICAL APPLICATIO S
Luxeon Red LED Driver Without Dimming
3.3µH
ON/OFF
SW
VIN
CAP
1 NiMH OR
ALKALINE
CELL
LTC3490
+
4.7µF
CTRL/SHDN LED
0.6Ω
LOBAT
CELLS
1M
LUMILEDS
LUXEON
LXHL-BD03
GND
3490 TA06
Luxeon Red LED Driver with Dimming
3.3µH
ON/OFF
SW
VIN
CAP
1 NiMH OR
ALKALINE
CELL
LTC3490
+
4.7µF
CTRL/SHDN LED
1M
MBRM120E
LOBAT
CELLS
LUMILEDS
LUXEON
LXHL-BD03
GND
3490 TA07
Efficiency vs VIN with Red LED
90
RESISTOR
80
SCHOTTKY
EFFICIENCY (%)
70
60
50
40
30
20
10
0
1
1.5
2
2.5
3
VIN (V)
3490 G06
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LTC3490
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PACKAGE DESCRIPTIO
DD Package
8-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1698)
R = 0.115
TYP
5
0.38 ± 0.10
8
0.675 ±0.05
3.5 ±0.05
1.65 ±0.05
2.15 ±0.05 (2 SIDES)
3.00 ±0.10
(4 SIDES)
PACKAGE
OUTLINE
1.65 ± 0.10
(2 SIDES)
PIN 1
TOP MARK
(NOTE 6)
(DD8) DFN 1203
0.25 ± 0.05
4
0.25 ± 0.05
0.75 ±0.05
0.200 REF
0.50
BSC
2.38 ±0.05
(2 SIDES)
1
0.50 BSC
2.38 ±0.10
(2 SIDES)
0.00 – 0.05
BOTTOM VIEW—EXPOSED PAD
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON TOP AND BOTTOM OF PACKAGE
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
.189 – .197
(4.801 – 5.004)
NOTE 3
.045 ±.005
.050 BSC
8
.245
MIN
7
6
5
.160 ±.005
.150 – .157
(3.810 – 3.988)
NOTE 3
.228 – .244
(5.791 – 6.197)
.030 ±.005
TYP
1
RECOMMENDED SOLDER PAD LAYOUT
.010 – .020
× 45°
(0.254 – 0.508)
.008 – .010
(0.203 – 0.254)
3
4
.053 – .069
(1.346 – 1.752)
.004 – .010
(0.101 – 0.254)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
NOTE:
1. DIMENSIONS IN
2
.014 – .019
(0.355 – 0.483)
TYP
INCHES
(MILLIMETERS)
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
.050
(1.270)
BSC
SO8 0303
3490fa
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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LTC3490
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TYPICAL APPLICATIO
LED Driver Drops to 20% Amplitude on Low-Battery Detect
3.3µH
ON/OFF
VIN
SW
CAP
1 NiMH OR
ALKALINE
CELL
+
LTC3490
1M
350mA/70mA
CTRL/SHDN LED
CELLS
1M
432k
LOBAT
GND
4.7µF
LUMILEDS
LUXEON
LXHL-BWO2
3490 TA05
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Constant Current, 1.2MHz, High Efficiency White
LED Boost Regulator
VIN: 2.5V to 10V, VOUT(MAX) = 34V, IQ = 1.9mA, ISD < 1µA, ThinSOTTM/SC70
Packages
LTC3205
High Efficiency, Multi-Display LED Controller
VIN: 2.8V to 4.5V, VOUT(MAX) = 6V, IQ = 50µA, ISD < 1µA, QFN24 Package
LTC3216
1A Low Noise, High Current LED Charge Pump with
Independent Flash/Torch Current Control
VIN: 2.9V to 4.4V, VOUT(MAX) = 5.5V, IQ = 300µA, ISD < 2.5µA, DFN Package
LTC3402
2A, 3MHz Micropower Synchronous Boost Converter VIN: 0.85V to 5V, VOUT(MAX) = 5V, IQ = < 38µA, ISD < 1µA,
MS/EDD Packages
LTC3453
500mA Synchronous Buck-Boost High Current LED
Driver in QFN
VIN: 2.7V to 5.5V, VOUT(MAX) = 5.5V, IQ = 0.6mA, ISD < 6µA, QFN Package
LT3465/LT3465A
Constant Current, 1.2MHz/2.7MHz, High Efficiency
White LED Boost Regulator with Integrated Schottky
Diode
VIN: 2.7V to 16V, VOUT(MAX) = 34V, IQ = 1.9mA, ISD < 1µA, ThinSOT Package
LT3466
Dual Constant Current, 2MHz, High Efficiency
White LED Boost Regulator with Integrated Schottky
Diode
VIN: 2.7V to 24V, VOUT(MAX) = 40V, IQ = 5mA, ISD < 16µA, DFN Package
LT3479
3A, Full-Featured DC/DC Converter with Soft-Start
and Inrush Current Protection
VIN: 2.5V to 24V, VOUT(MAX) = 40V, IQ = 6.5mA, ISD < 1µA, DFN/TSSOP
Packages
®
ThinSOT is a trademark of Linear Technology Corporation.
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Linear Technology Corporation
LT 0606 REV A • PRINTED IN THE USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2005