LINER LT1930ES5 1a, 1.2mhz/2.2mhz, step-up dc/dc converter Datasheet

LT1930/LT1930A
1A, 1.2MHz/2.2MHz,
Step-Up DC/DC Converters
in ThinSOT
DESCRIPTIO
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FEATURES
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The LT®1930 and LT1930A are the industry’s highest
power SOT-23 switching regulators. Both include an
internal 1A, 36V switch allowing high current outputs to be
generated in a small footprint. The LT1930 switches at
1.2MHz, allowing the use of tiny, low cost and low height
capacitors and inductors. The faster LT1930A switches at
2.2MHz, enabling further reductions in inductor size.
Complete regulator solutions approaching one tenth of a
square inch in area are achievable with these devices.
Multiple output power supplies can now use a separate
regulator for each output voltage, replacing cumbersome
quasi-regulated approaches using a single regulator and
custom transformers.
1.2MHz Switching Frequency (LT1930)
2.2MHz Switching Frequency (LT1930A)
Low VCESAT Switch: 400mV at 1A
High Output Voltage: Up to 34V
5V at 480mA from 3.3V Input (LT1930)
12V at 250mA from 5V Input (LT1930A)
Wide Input Range: 2.6V to 16V
Uses Small Surface Mount Components
Low Shutdown Current: < 1µA
Low Profile (1mm) ThinSOTTM Package
Pin-for-Pin Compatible with the LT1613
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APPLICATIO S
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A constant frequency internally compensated current mode
PWM architecture results in low, predictable output noise
that is easy to filter. Low ESR ceramic capacitors can be
used at the output, further reducing noise to the millivolt
level. The high voltage switch on the LT1930/LT1930A is
rated at 36V, making the device ideal for boost converters
up to 34V as well as for single-ended primary inductance
converter (SEPIC) and flyback designs. The LT1930 can
generate 5V at up to 480mA from a 3.3V supply or 5V at
300mA from four alkaline cells in a SEPIC design.
TFT-LCD Bias Supply
Digital Cameras
Cordless Phones
Battery Backup
Medical Diagnostic Equipment
Local 5V or 12V Supply
External Modems
PC Cards
xDSL Power Supply
, LTC and LT are registered trademarks of Linear Technology Corporation
ThinSOT is a trademark of Linear Technology Corporation.
The LT1930/LT1930A are available in the 5-lead ThinSOT
package.
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TYPICAL APPLICATIO
VIN
5V
C1
2.2µF
SHDN
Efficiency
90
D1
5
1
VIN
SW
R1
113k
LT1930
4
SHDN
FB
3
GND
2
VOUT
12V
300mA
VIN = 5V
85
VIN = 3.3V
80
C3*
10pF
C2
4.7µF
R2
13.3k
EFFICIENCY (%)
L1
10µH
75
70
65
60
C1: TAIYO-YUDEN X5R LMK212BJ225MG
C2: TAIYO-YUDEN X5R EMK316BJ475ML
D1: ON SEMICONDUCTOR MBR0520
L1: SUMIDA CR43-100
*OPTIONAL
1930/A F01
Figure 1. 5V to 12V, 300mA Step-Up DC/DC Converter
55
50
0
200
100
300
LOAD CURRENT (mA)
400
1930 TA01
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LT1930/LT1930A
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PACKAGE/ORDER I FOR ATIO
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ABSOLUTE
RATI GS
(Note 1)
VIN Voltage .............................................................. 16V
SW Voltage ................................................– 0.4V to 36V
FB Voltage .............................................................. 2.5V
Current Into FB Pin .............................................. ±1mA
SHDN Voltage ......................................................... 10V
Maximum 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
ORDER PART
NUMBER
TOP VIEW
SW 1
LT1930ES5
LT1930AES5
5 VIN
GND 2
4 SHDN
FB 3
S5 PART MARKING
S5 PACKAGE
5-LEAD PLASTIC SOT-23
LTKS
LTSQ
TJMAX = 125°C, θJA = 256°C/ W
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 = 3V, VSHDN = VIN unless otherwise noted. (Note 2)
PARAMETER
CONDITIONS
MIN
Minimum Operating Voltage
LT1930
TYP
MAX
2.45
2.6
Maximum Operating Voltage
MIN
LT1930A
TYP
MAX
UNITS
2.45
2.6
V
16
V
1.255
1.270
1.280
V
V
16
Feedback Voltage
●
FB Pin Bias Current
VFB = 1.255V
Quiescent Current
VSHDN = 2.4V, Not Switching
1.240
1.230
●
1.255
1.270
1.280
1.240
1.230
120
360
240
720
nA
4.2
6
5.5
8
mA
Quiescent Current in Shutdown
VSHDN = 0V, VIN = 3V
0.01
1
0.01
1
µA
Reference Line Regulation
2.6V ≤ VIN ≤ 16V
0.01
0.05
0.01
0.05
%/V
1.4
1.6
1.8
1.6
2.2
2.6
2.9
MHz
MHz
75
90
1
1.2
2.5
A
Switching Frequency
Maximum Duty Cycle
1
0.85
1.2
●
●
84
90
1
1.2
2
%
Switch Current Limit
(Note 3)
Switch VCESAT
ISW = 1A
400
600
400
600
mV
Switch Leakage Current
VSW = 5V
0.01
1
0.01
1
µA
SHDN Input Voltage High
2.4
2.4
SHDN Input Voltage Low
SHDN Pin Bias Current
0.5
VSHDN = 3V
VSHDN = 0V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LT1930E/LT1930AE are guaranteed to meet performance
specifications from 0°C to 70°C. Specifications over the – 40°C to 85°C
2
V
16
0
32
0.1
35
0
0.5
V
70
0.1
µA
µA
operating temperature range are assured by design, characterization and
correlation with statistical process controls.
Note 3: Current limit guaranteed by design and/or correlation to static test.
LT1930/LT1930A
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TYPICAL PERFOR A CE CHARACTERISTICS
Quiescent Current
FB Pin Voltage
7.0
SHDN Pin Current
1.28
90
NOT SWITCHING
80
SHDN PIN CURRENT (µA)
1.27
6.0
FB VOLTAGE (V)
QUIESCENT CURRENT (mA)
6.5
LT1930A
5.5
5.0
4.5
LT1930
1.26
1.25
1.24
4.0
50
40
30
LT1930
20
0
3.0
–50
0
25
50
TEMPERATURE (°C)
–25
1.22
–50
100
75
–25
0
25
50
TEMPERATURE (°C)
75
–10
100
Current Limit
1.4
0.40
2.3
0.35
2.1
1.2
FREQUENCY (MHz)
2.5
0.30
VCESAT (V)
0.6
0.25
0.20
0.15
0.4
0.10
0.2
0.05
0
0
10
20
30
40 50 60 70
DUTY CYCLE (%)
80
90
2
4
3
SHDN PIN VOLTAGE (V)
5
6
Oscillator Frequency
Switch Saturation Voltage
0.45
0.8
1
1930/A G03
1.6
1.0
0
1930/A G02
1930/A G01
CURRENT LI MIT (A)
60
10
1.23
3.5
LT1930A
70
LT1930A
1.9
1.7
1.5
1.3
LT1930
1.1
0.9
0.7
0
0.2
0.4
0.6
0.8
SWITCH CURRENT (A)
1930/A G04
1.0
1.2
1930/A G05
0.5
–50
–25
25
50
0
TEMPERATURE (°C)
75
100
1930/A G06
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PI FU CTIO S
SW (Pin 1): Switch Pin. Connect inductor/diode here.
Minimize trace area at this pin to reduce EMI.
SHDN (Pin 4): Shutdown Pin. Tie to 2.4V or more to enable
device. Ground to shut down.
GND (Pin 2): Ground. Tie directly to local ground plane.
VIN (Pin 5): Input Supply Pin. Must be locally bypassed.
FB (Pin 3): Feedback Pin. Reference voltage is 1.255V.
Connect resistive divider tap here. Minimize trace area at
FB. Set VOUT according to VOUT = 1.255V(1 + R1/R2).
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LT1930/LT1930A
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BLOCK DIAGRA
1.255V
REFERENCE
VIN 5
1 SW
+
–
A1
–
DRIVER
RC
VOUT
COMPARATOR
+
A2
R
CC
R1 (EXTERNAL)
S
Q1
Q
+
Σ
FB
0.01Ω
–
R2 (EXTERNAL)
RAMP
GENERATOR
SHUTDOWN
4 SHDN
3
FB
2 GND
1930/A BD
1.2MHz
OSCILLATOR*
*2.2MHz FOR LT1930A
Figure 2. Block Diagram
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OPERATIO
The LT1930 uses a constant frequency, current-mode
control scheme to provide excellent line and load regulation. Operation can be best understood by referring to the
block diagram in Figure 2. At the start of each oscillator
cycle, the SR latch is set, which turns on the power switch
Q1. A voltage proportional to the switch current is added
to a stabilizing ramp and the resulting sum is fed into the
positive terminal of the PWM comparator A2. When this
voltage exceeds the level at the negative input of A2, the SR
latch is reset turning off the power switch. The level at the
negative input of A2 is set by the error amplifier A1, and is
simply an amplified version of the difference between the
feedback voltage and the reference voltage of 1.255V. In
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this manner, the error amplifier sets the correct peak
current level to keep the output in regulation. If the error
amplifier’s output increases, more current is delivered to
the output; if it decreases, less current is delivered. The
LT1930 has a current limit circuit not shown in Figure 2.
The switch current is constantly monitored and not allowed to exceed the maximum switch current (typically
1.2A). If the switch current reaches this value, the SR latch
is reset regardless of the state of comparator A2. This
current limit helps protect the power switch as well as the
external components connected to the LT1930.
The block diagram for the LT1930A (not shown) is identical except that the oscillator frequency is 2.2MHz.
LT1930/LT1930A
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APPLICATIONS INFORMATION
LT1930 AND LT1930A DIFFERENCES
Switching Frequency
The key difference between the LT1930 and LT1930A is
the faster switching frequency of the LT1930A. At 2.2MHz,
the LT1930A switches at nearly twice the rate of the
LT1930. Care must be taken in deciding which part to use.
The high switching frequency of the LT1930A allows
smaller cheaper inductors and capacitors to be used in a
given application, but with a slight decrease in efficiency
and maximum output current when compared to the
LT1930. Generally, if efficiency and maximum output
current are critical, the LT1930 should be used. If application size and cost are more important, the LT1930A will be
the better choice. In many applications, tiny inexpensive
chip inductors can be used with the LT1930A, reducing
solution cost.
iron types. Choose an inductor that can handle at least 1A
without saturating, and ensure that the inductor has a low
DCR (copper-wire resistance) to minimize I2R power losses.
A 4.7µH or 10µH inductor will be the best choice for most
LT1930 designs. For LT1930A designs, a 2.2µH to 4.7µH
inductor will usually suffice. Note that in some applications, the current handling requirements of the inductor
can be lower, such as in the SEPIC topology where each
inductor only carries one-half of the total switch current.
Table 1. Recommended Inductors – LT1930
PART
L
(µH)
MAX
DCR
mΩ
SIZE
L×W×H
(mm)
CDRH5D18-4R1
CDRH5D18-100
CR43-4R7
CR43-100
4.1
10
4.7
10
57
124
109
182
4.5 × 4.7 × 2.0
DS1608-472
DS1608-103
4.7
10
60
75
4.5 × 6.6 × 2.9
Coilcraft
(847) 639-6400
www.coilcraft.com
ELT5KT4R7M
ELT5KT6R8M
4.7
6.8
240
360
5.2 × 5.2 × 1.1
Panasonic
(408) 945-5660
www.panasonic.com
3.2 × 2.5 × 2.0
Duty Cycle
The maximum duty cycle (DC) of the LT1930A is 75%
compared to 84% for the LT1930. The duty cycle for a
given application using the boost topology is given by:
VENDOR
Sumida
(847) 956-0666
www.sumida.com
Table 2. Recommended Inductors – LT1930A
|V
| – | VIN |
DC = OUT
| VOUT |
MAX
DCR
mΩ
SIZE
L×W×H
(mm)
PART
L
(µH)
For a 5V to 12V application, the DC is 58.3% indicating that
the LT1930A could be used. A 5V to 24V application has
a DC of 79.2% making the LT1930 the right choice. The
LT1930A can still be used in applications where the DC, as
calculated above, is above 75%. However, the part must
be operated in the discontinuous conduction mode so that
the actual duty cycle is reduced.
LQH3C2R2M24
LQH3C4R7M24
2.2
4.7
126
195
3.2 × 2.5 × 2.0
Murata
(404) 573-4150
www.murata.com
CR43-2R2
CR43-3R3
2.2
3.3
71
86
4.5 × 4.0 × 3.0
Sumida
(847) 956-0666
www.sumida.com
1008PS-272
1008PS-332
2.7
3.3
100
110
3.7 × 3.7 × 2.6
Coilcraft
(800) 322-2645
www.coilcraft.com
INDUCTOR SELECTION
ELT5KT3R3M
3.3
204
5.2 × 5.2 × 1.1
Panasonic
(408) 945-5660
www.panasonic.com
Several inductors that work well with the LT1930 are listed
in Table 1 and those for the LT1930A are listed in Table 2.
These tables are not complete, and there are many other
manufacturers and devices that can be used. Consult each
manufacturer for more detailed information and for their
entire selection of related parts, as many different sizes and
shapes are available. Ferrite core inductors should be used
to obtain the best efficiency, as core losses at 1.2MHz are
much lower for ferrite cores than for cheaper powdered-
VENDOR
The inductors shown in Table 2 for use with the LT1930A
were chosen for small size. For better efficiency, use
similar valued inductors with a larger volume. For
example, the Sumida CR43 series in values ranging from
2.2µH to 4.7µH will give an LT1930A application a few
percentage points increase in efficiency, compared to the
smaller Murata LQH3C Series.
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LT1930/LT1930A
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APPLICATIONS INFORMATION
CAPACITOR SELECTION
Low ESR (equivalent series resistance) capacitors should
be used at the output to minimize the output ripple voltage.
Multi-layer ceramic capacitors are an excellent choice, as
they have extremely low ESR and are available in very
small packages. X5R dielectrics are preferred, followed by
X7R, as these materials retain the capacitance over wide
voltage and temperature ranges. A 4.7µF to 10µF output
capacitor is sufficient for most applications, but systems
with very low output currents may need only a 1µF or 2.2µF
output capacitor. Solid tantalum or OSCON capacitors can
be used, but they will occupy more board area than a
ceramic and will have a higher ESR. Always use a capacitor
with a sufficient voltage rating.
Ceramic capacitors also make a good choice for the input
decoupling capacitor, which should be placed as close as
possible to the LT1930/LT1930A. A 1µF to 4.7µF input
capacitor is sufficient for most applications. Table 3 shows
a list of several ceramic capacitor manufacturers. Consult
the manufacturers for detailed information on their entire
selection of ceramic parts.
Table 3. Ceramic Capacitor Manufacturers
Taiyo Yuden
(408) 573-4150
www.t-yuden.com
AVX
(803) 448-9411
www.avxcorp.com
Murata
(714) 852-2001
www.murata.com
The decision to use either low ESR (ceramic) capacitors or
the higher ESR (tantalum or OSCON) capacitors can affect
the stability of the overall system. The ESR of any capacitor, along with the capacitance itself, contributes a zero to
the system. For the tantalum and OSCON capacitors, this
zero is located at a lower frequency due to the higher value
of the ESR, while the zero of a ceramic capacitor is at a
much higher frequency and can generally be ignored.
A phase lead zero can be intentionally introduced by
placing a capacitor (C3) in parallel with the resistor (R1)
between VOUT and VFB as shown in Figure 1. The frequency
of the zero is determined by the following equation.
ƒZ =
6
1
2π • R1• C 3
By choosing the appropriate values for the resistor and
capacitor, the zero frequency can be designed to improve
the phase margin of the overall converter. The typical
target value for the zero frequency is between 35kHz to
55kHz. Figure 3 shows the transient response of the stepup converter from Figure 1 without the phase lead capacitor C3. The phase margin is reduced as evidenced by more
ringing in both the output voltage and inductor current. A
10pF capacitor for C3 results in better phase margin,
which is revealed in Figure 4 as a more damped response
and less overshoot. Figure 5 shows the transient response
when a 33µF tantalum capacitor with no phase lead
capacitor is used on the output. The higher output voltage
ripple is revealed in the upper waveform as a set of double
lines. The transient response is not greatly improved
which implies that the ESR zero frequency is too high to
increase the phase margin.
VOUT
0.2V/DIV
AC COUPLED
ILI
0.5A/DIV
AC COUPLED
LOAD 250mA
CURRENT 150mA
50µs/DIV
1930 F03
Figure 3. Transient Response of Figure 1's Step-Up
Converter without Phase Lead Capacitor
VOUT
0.2V/DIV
AC COUPLED
ILI
0.5A/DIV
AC COUPLED
LOAD 250mA
CURRENT
150mA
50µs/DIV
1930 F04
Figure 4. Transient Response of Figure 1's Step-Up
Converter with 10pF Phase Lead Capacitor
LT1930/LT1930A
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APPLICATIONS INFORMATION
LAYOUT HINTS
VOUT
0.2V/DIV
AC COUPLED
The high speed operation of the LT1930/LT1930A
demands careful attention to board layout. You will not get
advertised performance with careless layout. Figure 6
shows the recommended component placement.
ILI
0.5A/DIV
AC COUPLED
LOAD 250mA
CURRENT 150mA
200µs/DIV
1930 F04
Figure 5. Transient Response of Step-Up Converter with 33µF
Tantalum Output Capacitor and No Phase Lead Capacitor
L1
D1
C1
+
VIN
VOUT
DIODE SELECTION
+
C2
A Schottky diode is recommended for use with the LT1930/
LT1930A. The Motorola MBR0520 is a very good choice.
Where the switch voltage exceeds 20V, use the MBR0530
(a 30V diode). Where the switch voltage exceeds 30V, use
the MBR0540 (a 40V diode). These diodes are rated to
handle an average forward current of 0.5A. In applications
where the average forward current of the diode exceeds
0.5A, a Microsemi UPS5817 rated at 1A is recommended.
SHUTDOWN
R2
R1
GND
C3
1930 F06
Figure 6. Suggested Layout
Driving SHDN Above 10V
The maximum voltage allowed on the SHDN pin is 10V. If
you wish to use a higher voltage, you must place a resistor
in series with SHDN. A good value is 121k. Figure 7 shows
a circuit where VIN = 16V and SHDN is obtained from VIN.
The voltage on the SHDN pin is kept below 10V.
SETTING OUTPUT VOLTAGE
To set the output voltage, select the values of R1 and R2
(see Figure 1) according to the following equation.
 V

R1 = R2  OUT – 1
 1.255V 
A good value for R2 is 13.3k which sets the current in the
resistor divider chain to 1.255V/13.3k = 94.7µA.
C1
D1
L1
VIN
16V
VOUT
121k
5
1
VIN
SW
R1
LT1930
4
SHDN
FB
GND
C2
3
R2
2
1930 F07
Figure 7. Keeping SHDN Below 10V
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LT1930/LT1930A
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TYPICAL APPLICATIO S
Efficiency
4-Cell to 5V SEPIC Converter
SHDN
5
1
VIN
SW
D1
VIN = 4V
VOUT
5V
300mA
70
243k
LT1930
4
SHDN
FB
3
L2
10µH
GND
VIN = 6.5V
75
EFFICIENCY (%)
C1
2.2µF
4-CELL
BATTERY
C3
1µF
L1
10µH
4V TO 6.5V
80
C2
10µF
65
60
55
50
82.5k
2
45
C1: TAIYO-YUDEN X5R LMK212BJ225MG
C2: TAIYO-YUDEN X5R JMK316BJ106ML D1: ON SEMICONDUCTOR MBR0520
C3: TAIYO-YUDEN X5R LMK212BJ105MG L1, L2: MURATA LQH3C100K24
1930 TA02a
40
0
100
200
400
300
LOAD CURRENT (mA)
500
1930 TA02b
4-Cell to 5V SEPIC Converter with Coupled Inductors
L1A
10µH
4V TO 6.5V
C1
2.2µF
4-CELL
BATTERY
SHDN
C3
1µF
•
5
1
VIN
SW
4
SHDN
FB
3
GND
VOUT
5V
300mA
L1
10µH
VIN
5V
C1
4.7µF
•
243k
LT1930
5V to 24V Boost Converter
D1
L1B
10µH
C2
10µF
5
1
VIN
SW
4
SHDN
SHDN
FB
2
C1: TAIYO-YUDEN X5R LMK212BJ225MG
C2: TAIYO-YUDEN X5R JMK316BJ106ML
C3: TAIYO-YUDEN X5R LMK212BJ105MG
D1: ON SEMICONDUCTOR MBR0520
L1: SUMIDA CLS62-100
C1: TAIYO-YUDEN X5R EMK316BJ475ML
C2: TAIYO-YUDEN X5R JMK212BJ475MG
D1: ON SEMICONDUCTOR MBR0530
L1: SUMIDA CR43-100
1930/A TA03
±15V Dual Output Converter with Output Disconnect
C4
1µF
L1
3.3µH
VIN
5V
C1
2.2µF
OFF ON
5
1
VIN
SW
15V
70mA
C5
1µF
LT1930
4
SHDN
D1
R1
147k
D2
FB
C2
2.2µF
3
GND
2
C1: TAIYO-YUDEN X5R LMK212BJ225MG
D3 D4
C2, C3: TAIYO-YUDEN X5R EMK316BJ225ML
C4, C5: TAIYO-YUDEN X5R TMK316BJ105ML
(408) 573-4150
D1 TO D4: ON SEMICONDUCTOR MBR0520 (800) 282-9855
L1: SUMIDA CR43-3R3 (874) 956-0666
R2
13.3k
C6
2.2µF
1930/A TA05
–15V
70mA
C2
2.2µF
3
GND
82.5k
VOUT
24V
90mA
R1
665k
LT1930
2
8
D1
R2
36.5k
1930/A TA04
LT1930/LT1930A
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TYPICAL APPLICATIO S
Boost Converter with Reverse Battery Protection
L1
4.7µH
M1
VIN
3V to 6V
C1
2.2µF
D1
5
1
VIN
SW
R1
60.4k
LT1930
SHDN
4
SHDN
FB
VOUT
8V
520mA AT VIN = 6V
240mA AT VIN = 3V
C3
47pF
3
GND
2
C2
22µF
R2
11.3k
C1: TAIYO-YUDEN X5R LMK432BJ226MM
C2: TAIYO-YUDEN X5R LMK212BJ225MG
D1: ON SEMICONDUCTOR MBR0520
L1: SUMIDA CR43-4R7
M1: SILICONIX Si6433DQ
1930/A TA06
Efficiency
3.3V to 5V Boost Converter
VIN
3.3V
C1
4.7µF
OFF ON
90
D1
5
1
VIN
SW
VOUT
5V
480mA
SHDN
FB
80
R1
40.2k
LT1930
4
C2
10µF
3
R2
13.3k
GND
2
VIN = 3.3V
85
EFFICIENCY (%)
L1
5.6µH
VIN = 2.6V
75
70
65
60
C1: TAIYO-YUDEN X5R JMK212BJ475MG www.t-yuden.com
C2: TAIYO-YUDEN X5R JMK316BJ106ML
D1: ON SEMICONDUCTOR MBR0520 www.onsemi.com
L1: SUMIDA CR43-5R6 www.sumida.com
1930/A TA07a
55
50
0
100
200
400
300
LOAD CURRENT (mA)
500
1930/A TA07b
5V to 12V, 250mA Step-Up Converter
90
C1
2.2µF
SHDN
D1
5
1
VIN
SW
R1
115k
LT1930A
4
SHDN
FB
VOUT
12V
250mA
C2
2.2µF
3
GND
2
C1: TAIYO-YUDEN X5R LMK212BJ225MG
C2: TAIYO-YUDEN X5R EMK316BJ225ML
D1: ON SEMICONDUCTOR MBR0520
L1: MURATA LQH3C2R2M24
R2
13.3k
VIN = 5V
VOUT = 12V
85
80
EFFICIENCY (%)
L1
2.2µH
VIN
5V
Efficiency
75
70
65
60
1930/A TA08a
55
50
0
50
100
200
150
LOAD CURRENT (mA)
250
300
1930/A TA08b
9
LT1930/LT1930A
U
TYPICAL APPLICATIO S
9V, 18V, –9V Triple Output TFT-LCD Bias Supply with Soft-Start
D1
D2
18V
10mA
C4
1µF
C3
0.1µF
L1
4.7µH
VIN
3.3V
C1
2.2µF
5
+
RSS
30k
VSS
LT1930
4
SHDN
FB
C5
10µF
3
GND
0V
2
CSS
68nF
9V OUTPUT
5V/DIV
R1
124k
SW
DSS
1N4148
3.3V
9V
200mA
1
VIN
Start-Up Waveforms
D5
C2
0.1µF
C1: X5R OR X7R, 6.3V
C2,C3, C5: X5R OR X7R, 10V
C4: X5R OR X7R, 25V
D1- D4: BAT54S OR EQUIVALENT
D5: MBR0520 OR EQUIVALENT
L1: PANASONIC ELT5KT4R7M
–9V OUTPUT
5V/DIV
R2
20k
18V OUTPUT
10V/DIV
D4
IL1 0.5A/DIV
C6
1µF
D3
2ms/DIV
–9V
10mA
1930/A TA11a
8V, 23V, –8V Triple Output TFT-LCD Bias Supply with Soft-Start
D1
D2
C3
0.1µF
C1
2.2µF
VSS
3.3V
5
+
RSS
30k
DSS
1N4148
C1: X5R OR X7R, 6.3V
C2-C4, C7, C8: X5R OR X7R, 10V
C5: X5R OR X7R, 16V
C6: X5R OR X7R, 25V
D1- D6: BAT54S OR EQUIVALENT
D7: MBR0520 OR EQUIVALENT
L1: PANASONIC ELT5KT4R7M
FB
2
8V OUTPUT
5V/DIV
R1
113k
–8V OUTPUT
5V/DIV
C7
10µF
3
GND
CSS
68nF
Start-Up Waveforms
8V
220mA
SW
SHDN
23V
10mA
D7
LT1930
4
D4
C6
1µF
C5
0.1µF
1
VIN
0V
10
C4
0.1µF
L1
4.7µH
VIN
3.3V
D3
C2
0.1µF
R2
21k
23V OUTPUT
10V/DIV
IL1 0.5A/DIV
D5
D6
C8
1µF
2ms/DIV
–8V
10mA
1930/A TA12a
LT1930/LT1930A
U
PACKAGE DESCRIPTIO
S5 Package
5-Lead Plastic SOT-23
(Reference LTC DWG # 05-08-1633)
(Reference LTC DWG # 05-08-1635)
2.80 – 3.10
(.110 – .118)
(NOTE 3)
A
SOT-23
(Original)
.90 – 1.45
(.035 – .057)
SOT-23
(ThinSOT)
1.00 MAX
(.039 MAX)
A1
.00 – .15
(.00 – .006)
.01 – .10
(.0004 – .004)
A2
.90 – 1.30
(.035 – .051)
.80 – .90
(.031 – .035)
L
.35 – .55
(.014 – .021)
.30 – .50 REF
(.012 – .019 REF)
2.60 – 3.00
(.102 – .118)
1.50 – 1.75
(.059 – .069)
(NOTE 3)
PIN ONE
.95
(.037)
REF
.25 – .50
(.010 – .020)
(5PLCS, NOTE 2)
.20
(.008)
A
DATUM ‘A’
L
NOTE:
1. CONTROLLING DIMENSION: MILLIMETERS
MILLIMETERS
2. DIMENSIONS ARE IN
(INCHES)
.09 – .20
(.004 – .008)
(NOTE 2)
A2
1.90
(.074)
REF
A1
S5 SOT-23 0401
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:
SC-74A (EIAJ) FOR ORIGINAL
JEDEL MO-193 FOR THIN
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.
11
LT1930/LT1930A
U
TYPICAL APPLICATIO
3.3V to 5V, 450mA Step-Up Converter
L1
2.2µH
VIN
3.3V
C1
2.2µF
SHDN
D1
5
1
VIN
SW
R1
30.1k
LT1930A
4
SHDN
FB
VOUT
5V
450mA
C2
10µF
3
GND
2
R2
10k
C1: TAIYO-YUDEN X5R LMK212BJ225MG
C2: TAIYO-YUDEN X5R JMK316B106ML
D1: ON SEMICONDUCTOR MBR0520
L1: MURATA LQH3C2R2M24
1930/A TA09a
Efficiency
90
3.3V to 5V Transient Response
VIN = 3.3V
VOUT = 5V
85
80
EFFICIENCY (%)
VOUT
50mV/DIV
AC COUPLED
ILI
0.5A/DIV
AC COUPLED
LOAD 300mA
CURRENT 200mA
75
70
65
60
55
20µs/DIV
1930 F03
50
0
100
200
400
300
LOAD CURRENT (mA)
500
1930/A TA09b
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LT1307
Single Cell Micropower 600kHz PWM DC/DC Converter
3.3V at 75mA from Single Cell, MSOP Package
TM
LT1316
Burst Mode Operation DC/DC Converter with Programmable Current Limit
1.5V Minimum, Precise Control of Peak Current Limit
LT1317
2-Cell Micropower DC/DC Converter with Low-Battery Detector
3.3V at 200mA from 2 Cells, 600kHz Fixed Frequency
LT1610
Single Cell Micropower DC/DC Converter
3V at 30mA from 1V, 1.7MHz Fixed Frequency
LT1611
Inverting 1.4MHz Switching Regulator in 5-Lead ThinSOT
– 5V at 150mA from 5V Input, ThinSOT Package
LT1613
1.4MHz Switching Regulator in 5-Lead ThinSOT
5V at 200mA from 3.3V Input, ThinSOT Package
LT1615
Micropower Constant Off-Time DC/DC Converter in 5-Lead ThinSOT
20V at 12mA from 2.5V, ThinSOT Package
LT1617
Micropower Inverting DC/DC Converter in 5-Lead ThinSOT
–15V at 12mA from 2.5V Input, ThinSOT Package
LT1931/LT1931A
Inverting 1.2MHz/2.2MHz Switching Regulator in 5-Lead ThinSOT
– 5V at 350mA from 5V input, ThinSOT Package
Burst Mode is a trademark of Linear Technology Corporation.
12
Linear Technology Corporation
1930af LT/TP 0801 2K • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2001
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