SP4446 [SIPEX]
High Output Voltage Boost Regulator LCD Bias Regulator; 高输出电压升压稳压器LCD偏置稳压器
| 型号： | SP4446 |
| 厂家： | 
SIPEX CORPORATION |
| 描述： | High Output Voltage Boost Regulator LCD Bias Regulator |
| 文件： | 总10页 (文件大小：169K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
®
SP4446
PRELIMINARY
High Output Voltage Boost Regulator
LCD Bias Regulator
FEATURES
■ High Output Voltage: Up to 30V
V
IN
SHDN
5
4
■ High Efficiency
■ Low Quiescent Current: ~20uA
■ Miniature Package: (5-lead SOT-23)
■ Single Battery Cell Operation
■ Programmable Output Voltage
■ 1Ω Switch (150mV at 150mA)
SP4446
5 Pin SOT-23
1
SW
2
GND
3
FB
APPLICATIONS
■ LCD Bias
Now Available in Lead Free Packaging
■ Tuner Pin Voltage
■ White LED Driver
■ High Voltage Bias
■ Digital Cameras
■ Cell Phone
■ Battery Backup
■ Handheld Computers
DESCRIPTION
TheSP4446 isamicropowerBoostRegualtorina5-leadSOT-23package. Itisacurrentlimited,
fixed off time regulator configured for use in boost mode applications. The operating voltage can
be less than 3V and is capable of generating voltages as high as 30 Volts.
The SP4446 is to be supplied in a SOT-23-5 and permits the construction of complete regulators
that occupy < 0.2 square inches of board space.
TYPICAL APPLICATION SCHEMATIC
L1
D1
VIN
High
Voltage Output
2 to 7V
10µH
R1
R2
C2
VIN
SW
SP4446
2.2 µF
SHDN
FB
GND
C1
4.7µF
Rev. 7/14/03
SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator
© Copyright 2003 Sipex Corporation
1
ABSOLUTE MAXIMUM RATINGS
Lead Temperature (Soldering, 10 sec) ............ 300°C
ESD Rating................................................. 2kV HBM
VIN ....................................................................... 15V
SW Voltage .............................................. -0.4 to 34V
FB Voltage.......................................................... 2.5V
All other pins .................................. -0.3 to VCC + 0.3V
Current into FB ................................................. ±1mA
TJ Max ............................................................. 125°C
Operating Temperature Range ............ -40°C to 85°C
Peak Output Current < 10us SW .................... 500mA
Storage Temperature ...................... -65°C to +150°C
Power Dissipation. ......................................... 200mW
These are stress ratings only and functional operation of
the device at these ratings or any other above those
indicated in the operation sections of the specifications
below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may affect
reliability.
ELECTRICAL CHARACTERISTICS
Specifications are at VIN = 3.3V, VSHDN = VIN, TA = 25°C, ♦ denotes the specifications which apply over the full operating
temperature range, unless otherwise specified.
PARAMETER
SYMBOL MIN
TYP MAX UNITS
CONDITIONS
Input voltage
VIN
1.0
8.0
V
Switch Current Limit =
150mA
Supply Current
IQ
20
30
1
µA
µA
V
♦
♦
♦
No Switching
SHDN = 0V
0.01
Reference Voltage
FB Hysteresis
VFB
HYST
IFB
1.17
1.22 1.27
8
mV
nA
%/V
nS
nS
mV
mV
mA
µA
V
VFB Input Bias Current
Line Regulation
15
0.04
300
1200
50
80
VFB = 1.22V
1.2 ≤ VIN ≤ 8V
VFB > 1V
∆Vo/∆VI
TOFF
Switch Off Time
VFB < 0.3V
ISW = 50mA
ISW = 150mA
Switch Saturation Voltage
VCESAT
♦
150
Switch Current Limit
ILIM
ISHDN
VIH
100
0.9
150 200
♦
♦
SHDN Bias Current
5
2
12
VSHDN = 5V
SHDN High Threshold (on)
SHDN Low Threshold (off)
Switch Leakage Current
VIL
0.25
5
V
ISWLK
µA
♦
Switch Off, VSW = 5V
PIN DESCRIPTION
PIN NUMBER
PIN NAME
DESCRIPTION
1
2
3
4
5
SW
GND
FB
Switch input to the internal power switch.
Ground
Feedback
SHDN
VIN
Shutdown. Pull high (on) to enable. Pull low (off) for shutdown.
Input Voltage. Bypass this pin with a capacitor as close to the device
as possible.
Rev. 7/14/03
SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator
© Copyright 2003 Sipex Corporation
2
FUNCTIONAL DIAGRAM
VOUT
L1
D1
VI
VIN
C2
SW
5
1
C1
R1
(EXTERNAL)
R6
R5
Q1
X1
DISABLE
SET
+
-
POWER
TRANSISTOR
Q2
300ns
ONE-SHOT
3
FB
R2
DRIVER
CLEAR
X2
(EXTERNAL)
R3
+
-
52.5mV
0.35
R4
GND
Shutdown
Logic
2
4
SHDN
THEORY OF OPERATION
General Overview:
Operationcanbebestunderstoodbyreferringto
the above block diagram. Q1 and Q2 along with
R3 and R4 form a band gap reference. The input
to this circuit completes a feedback path from
the high voltage output through a voltage di-
vider, andisusedastheregulationcontrolinput.
When the voltage at the FB pin is slightly above
1.22V, comparator X1 disables most of the
internal circuitry. Current is then provided by
capacitor C2, which slowly discharges until the
voltage at the FB pin drops below the lower
hysteresis point of X1, about 6mV. X1 then
enables the internal circuitry, turns on chip
power, and the current in the inductor begins to
ramp up. When the current through the driver
transistorreachesabout150mA, comparatorX2
clears the latch, which turns off the driver tran-
sistorforapreset0.3µs. Attheinstantofshutoff,
inductorcurrentisdivertedtotheoutputthrough
diode D1. During this 0.3µs time limit, inductor
current decreases while its energy charges C2.
At the end of the 0.3µs time period, driver
transistor is again allowed to turn on which
ramps the current back up to the 150mA level.
Comparator X2 clears the latch, it’s output turns
off the driver transistor, and this allows delivery
ofL1’sstoredkineticenergytoC2. Thisswitch-
ing action continues until the output capacitor
voltage is charged to the point where FB is at
band gap (1.22V). When this condition is
reached, X1 turns off the internal circuitry and
thecyclerepeats. TheSP4446containscircuitry
to provide protection during start-up and while
in short-circuit conditions. When FB pin volt-
ageislessthanapproximately300mV,theswitch
off time is increased to about 1.2µs and the
current limit is reduced to about 70% of its
normal value. While in this mode, the average
inductor current is reduced and helps minimize
power dissipation in the SP4446, the external
inductor and diode.
Rev. 7/14/03
SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator
© Copyright 2003 Sipex Corporation
3
APPLICATION INFORMAMTION
Inductor Selection
Capacitor Selection
For SP4446, the internal switch will be turned off
only after the inductor current reaches the typical
dc current limit (ILIM=150mA). However, there is
typically propagation delay of 200nS between the
time when the current limit is reached and when
theswitchisactuallyturnedoff.Duringthis200nS
delay, the peak inductor current will increase,
exceedingthecurrentlimitbyasmallamount.The
peak inductor current can be estimated by:
Ceramic capacitors are recommended for their
inherently low ESR, which will help produce low
peak to peak output ripple, and reduce high fre-
quency spikes.
For the typical application, 4.7µF input capacitor
and 2.2µF output capacitor are sufficient. The
inputandoutputripplecouldbefurtherreducedby
increasingthevalueoftheinputandoutputcapaci-
tors. PlaceallthecapacitorsasclosetotheSP4446
as possible for layout. For use as a voltage source,
to reduce the output ripple, a small feedforward
(47pF)acrossthetopfeedbackresistorcanbeused
to provide sufficient overdrive for the error com-
parator, thus reduce the output ripple.
VIN(MAX)
IPK = ILIM
+
• 200nS
L
The larger the input voltage and the lower the
inductor value, the greater the peak current.
In selecting an inductor, the saturation current
specified for the inductor needs to be greater than
the SP4446 peak current to avoid saturating the
inductor, whichwouldresultinalossinefficiency
and could damage the inductor.
Refer to Table 2 for some suggested low ESR
capacitors.
Table 2. Suggested Low ESR Capacitor
Choosing an inductor with low DCR decreases
power losses and increase efficiency.
MANUF.
PART
CAP/
SIZE/
TYPE
NUMBER
VOLTAGE
Refer to Table 1 for some suggested low ESR
inductors.
MURATA
770-436-1300
GRM32RR71E 2.2µF/25V
225KC01B
1210/X5R
1206/X5R
1206/X7R
1206/X5R
MURATA
770-436-1300
GRM31CR61A 4.7µF/10V
475KA01B
Table 1. Suggested Low ESR inductor
TDK
847-803-6100
C3225X7R1E
225M
2.2µF/25V
4.7µF/10V
MANUF.
PART NUMBER
DCR
(Ω)
Current
Rating
(mA)
TDK
847-803-6100
C3216X5R1A
475K
MURATA
LQH32CN100K21
0.44
0.71
300
770-436-1300
(10µH)
Output Voltage Program
MURATA
LQH32CN220K21
250
TheSP4446canbeprogrammedasvoltagesource,
the SP4446 requires 2 feedback resistors R1 & R2
to control the output voltage. As shown in Fig. 19.
770-436-1300
(22µH)
TDK
847-803-6100
NLFC453232T-100K
(10µH)
0.273
0.9
250
370
VIN
D1
TDK
NLC453232T-100K
L1
847-803-6100
(22µH)
VOUT
C2
R1
R2
Diode Selection
C1
U1
5
VIN
1
SW
A schottky diode with a low forward drop and fast
switching speed is ideally used here to achieve
high efficiency. In selecting a Schottky diode, the
current rating of the schottky diode should be
larger than the peak inductor current. Moreover,
the reverse breakdown voltage of the schottky
diode should be larger than the output voltage.
SP4446
4
3
SHDN
FB
1.22V
GND
2
Figure 19. Using SP4446 as Voltage Source
Rev. 7/14/03
SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator
© Copyright 2003 Sipex Corporation
4
APPLICATION INFORMAMTION: Continued
The formula and table for the resistor selection
are shown below:
will be slightly sacrificed because of the satura-
tionvoltageandbasecurrentofthePNPtransistor.
R3
R1 =( VOUT - 1 ) • R2
1.22
154K
L1
10uH
Q1
DS
VIN
VOUT
20V
MMBT2907A
C1
4.7uF
U1
R1
C2
47pF
1
SW
5
VIN
1M
R2
Table 3. Divider Resistor Selection
C3
2.2uF
SP4446
SHDN
4
3
FB
1.22V
GND
2
64.9K
V
OUT (V)
12
R1 (Ω)
1M
R2 (Ω)
113K
15
1M
88.7K
73.2K
64.9K
42.2K
18
1M
Fig. 20. Load Disconnect in Shutdown
20
1M
30
1M
PIN Diode Driver
Layout Consideration
The SP4446 can be used as PIN diode driver as
shown in Fig. 21. Two Resistors (R1=1MΩ,
R2=42.2KΩ) are used to program the output volt-
age to be 30V. When input voltage is 3.3V or 5V,
itcansupplyamaximumcurrentof3mAand5mA
to the load.
Both the input capacitor and the output capacitor
should be placed as close as possible to the IC.
This can reduce the copper trace resistance which
directly effects the input and output ripples. The
feedback resistor network should be kept close to
the FB pin to minimize copper trace connections
that can inject noise into the system. The ground
connectionforthefeedbackresistornetworkshould
connect directly to the GND pin or to an analog
ground plane that is tied directly to the GND pin.
The inductor and the schottky diode should be
placed as close as possible to the switch pin to
minimize the noise coupling to the other circuits,
especially the feedback network.
Murata LQH32CN100K21
DS
V
OUT
L1 10uH 0.3A
30V
VIN
3.3V or 5V
MBR0530
3 to 5 mA
C2
47pF
R1
1M
C1
4.7uF
U1
5
V
C3
2.2uF
1
S
W
IN
SP4446
SHDN
4
3
FB
1.22V
GND
2
R2
42.2K
Load Disconnect in Shutdown
When SP4446 was shut down, the load is still
connected to the input. In applications that re-
quire output isolation during shutdown, an ex-
ternalPNPtransistor(forexampleMMBT2907A)
can be added as shown in Figure 20. When the
SP4446 is active, the voltage set at the emitter of
the transistor exceeds the input voltage, forcing
the transistor into the saturation region. When
the SP4446 is shut down, the input voltage
exceeds the emitter voltage, thus the transistor
becomes inactive and provides high-impedance
isolation between the input and load. Efficiency
Fig. 21. Pin Diode Driver
Rev. 7/14/03
SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator
© Copyright 2003 Sipex Corporation
5
PERFORMANCE CHARACTERISTICS
Refer to the typical application circuit, TAMB = 25°C, unless otherwise specified.
Vin=3.3V;Vout =12V Efficiency
Vin=5.0V;Vout =12V Efficiency
85
85
80
80
75
75
70
70
65
60
55
65
60
55
10 uH
22 uH
10 uH
22 uH
50
50
0
3
6
9
12
15
18
0
5
10
15
20
25
30
Iout (mA)
Iout (mA)
Figure 1. 12V Output Efficiency (VIN=3.3V)
Figure 2. 12V Output Efficiency (VIN=5V)
Vin=3.3V;Vout =15V Efficiency
Vin=5.0V;Vout =15V Efficiency
80
80
75
70
75
70
65
60
55
65
60
55
50
10 uH
22 uH
10 uH
22 uH
50
0
2
4
6
8
10
12
0
3
6
9
12
15
18
Iout (mA)
Iout (mA)
Figure 3. 15V Output Efficiency (VIN=3.3V)
Figure 4. 15V Output Efficiency (VIN=5V)
Vin=3.3V; Vout = 18V Efficiency
Vin=5.0V; Vout = 18V Efficiency
80
80
75
70
75
70
65
65
60
60
55
50
55
50
10 uH
10 uH
22 uH
45
40
45
22 uH
40
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
Iout (mA)
Iout (mA)
Figure 5. 18V Output Efficiency (VIN=3.3V)
Figure 6. 18V Output Efficiency (VIN=5V)
Rev. 7/14/03
SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator
© Copyright 2003 Sipex Corporation
6
PERFORMANCE CHARACTERISTICS: Continued
Refer to the typical application circuit, TAMB = 25°C, unless otherwise specified.
Vin=3.3V;Vout = 20V Efficiency
Vin=5V;Vout = 20V Efficiency
75
70
65
75
70
65
60
60
55
55
50
50
45
40
35
30
45
10 uH
10 uH
40
35
22 uH
22 uH
6
0
2
4
6
8
10
12
0
1
2
3
4
5
7
Iout (mA)
Iout (mA)
Figure 7. 20V Output Efficiency (VIN=3.3V)
Figure 8. 20V Output Efficiency (VIN=5V)
12
6
10uH
10uH
10
5
22uH
22uH
8
6
4
2
0
4
3
2
1
0
2.7
3
3.3
3.6
3.9
4.2
4.5
4.8
5.1
2.7
3
3.3
3.6
3.9
4.2
4.5
4.8
5.1
Input Voltage (V)
Input Voltage (V)
Figure 9. Maximum Output Current vs. VIN (VOUT=20V)
Figure 10. Maximum Output Current vs. VIN (VOUT=30V)
10
30
25
20
15
8
6
4
2
0
10
Tamb=-40°C
5
Tamb=25°C
Tamb=85°C
0
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
Input Voltage (V)
Input Voltage (V)
Figure 11. Quiescent Current IQ vs. VIN
Figure 12. Shutdown Pin Current vs. VIN
Rev. 7/14/03
SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator
© Copyright 2003 Sipex Corporation
7
PERFORMANCE CHARACTERISTICS: Continued
Refer to the typical application circuit, TAMB = 25°C, unless otherwise specified.
250
1.25
1.24
1.23
1.22
200
150
100
1.21
1.20
50
0
1.19
1.18
1
2
3
4
5
6
7
8
-40
-15
10
35
60
85
Temperature (C)
Input Voltage (V)
Figure 13. IPK Current Limit vs. VIN
Figure 14. Feedback Voltage vs. Temperature
60
50
40
VIN
30
20
VOUT
10
IIN (100mA/DIV)
0
-40
-15
10
35
60
85
Temperature (C)
Figure 16. Startup Waveform (VIN=3.3V, VOUT=20V,
IOUT=2mA)
Figure 15. Switch Saturation Voltage VCESAT vs.
Temperature (ISW=50mA)
V
SW
I
(5mA/DIV)
OUT
V
OUT
(AC)
I
L
(0.1A/DIV)
V
OUT
(AC)
V
SW
Figure 17. Typical Switching Waveforms (VIN=3.3V,
VOUT=20V, IOUT=5mA)
Figure 18. Load Step Transient (VIN=3.3V, VOUT=20V,
1O=100µA∼5mA)
Rev. 7/14/03
SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator
© Copyright 2003 Sipex Corporation
8
PACKAGE: 5 PIN SOT-23
D
e1
N
N/2
+1
E/2
E1/2
B
B
E
E1
SEE VIEW C
VIEW A-A
1
e
2
N/2
Ø1
b
Gauge Plane
L2
5 PIN SOT-23
JEDEC MO-178
(AA) Variation
Seating Plane
Ø1
Dimensions in (mm)
MIN NOM MAX
L
Ø
L1
VIEW C
A
-
-
1.45
0.15
0
-
A1
A2
0.90 1.15
1.30
0.50
0.22
A2
A
b
c
0.30
0.08
-
Seating Plane
-
A1
SIDE VIEW
D
2.90 BSC
2.80 BSC
E
b
E1
1.60 BSC
0.95 BSC
1.90 BSC
0.45
WITH PLATING
e
e1
L
0.30
0.60
c
L1
L2
0.60 REF
0.25 BSC
4º
BASE METAL
Ø
0º
5º
8º
SECTION B-B
Ø1
10º
15º
5 PIN SOT-23
Rev. 7/14/03
SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator
© Copyright 2003 Sipex Corporation
9
ORDERING INFORMATION
Operating Temperature Range Package Type
Part Number
SP4446EK .................................................. -40°C to +85°C ........................................................ 5 Pin SOT-23
SP4446EK/TR ............................................ -40°C to +85°C ........................................................ 5 Pin SOT-23
Available in lead free packaging. To order add "-L" suffix to part number.
Example: SP4446EK/TR = standard; SP4446EK-L/TR = lead free
/TR = Tape and Reel
Pack quantity is 2,500 for SOT-23.
Corporation
ANALOGEXCELLENCE
Sipex Corporation
Headquarters and
Sales Office
233 South Hillview Drive
Milpitas, CA 95035
TEL: (408) 934-7500
FAX: (408) 935-7600
Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the
application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.
Rev. 7/14/03
SP4446 High Output Voltage Boost Regualtor, LCD Bias Regulator
© Copyright 2003 Sipex Corporation
10
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