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부품번호 | ADP3308ART-285 기능 |
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기능 | anyCAP 50 mA Low Dropout Linear Regulator | ||
제조업체 | Analog Devices | ||
로고 | |||
전체 8 페이지수
a
FEATURES
؎1.2% Accuracy Over Line and Load Regulations
@ 25؇C
Ultralow Dropout Voltage: 80 mV Typical @ 50 mA
Requires Only CO = 0.47 F for Stability
anyCAP = Stable with All Types of Capacitors
(Including MLCC)
Current and Thermal Limiting
Low Noise
Low Shutdown Current: 1 A
3.0 V to 12 V Supply Range
–20؇C to +85؇C Ambient Temperature Range
Several Fixed Voltage Options
Ultrasmall SOT-23-5 Package
Excellent Line and Load Regulations
APPLICATIONS
Cellular Telephones
Notebook, Palmtop Computers
Battery Powered Systems
PCMCIA Regulator
Bar Code Scanners
Camcorders, Cameras
GENERAL DESCRIPTION
The ADP3308 is a member of the ADP330x family of precision
low dropout anyCAP voltage regulators. It is pin-for-pin and
functionally compatible with National’s LP2980, but offers
performance advantages. The ADP3308 stands out from the
conventional LDOs with a novel architecture and an enhanced
process. Its patented design requires only a 0.47 µF output
capacitor for stability. This device is stable with any type of
capacitor regardless of its ESR (Equivalent Serial Resistance)
value, including ceramic types for space restricted applications.
The ADP3308 achieves ± 1.2% accuracy at room temperature
and ± 2.2% overall accuracy over temperature, line and load
regulations. The dropout voltage of the ADP3308 is only
80 mV (typical) at 50 mA. This device also includes a current
limit and a shutdown feature. In shutdown mode, the ground
current is reduced to ~1 µA.
The ADP3308 operates with a wide input voltage range from
3.0 V to 12 V and delivers a load current in excess of 100 mA.
The ADP3308 anyCAP LDO offers a wide range of output
voltages. For 100 mA version, refer to the ADP3309 data sheet.
anyCAP™ 50 mA
Low Dropout Linear Regulator
ADP3308
FUNCTIONAL BLOCK DIAGRAM
IN Q1
ERR/NC
THERMAL
PROTECTION
Q2 DRIVER
SD
GND
ADP3308
CC
Gm
BANDGAP
REF
OUT
R1
R2
ERR/NC 4
ADP3308-3.3
VIN
C1
0.47F
1 IN
OUT 5
32
ON
OFF
VOUT = +3.3V
C2
0.47F
SD GND
Figure 1. Typical Application Circuit
anyCAP is a trademark of Analog Devices, Inc.
REV. A
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 1998
ADP3308–Typical Performance Characteristics
3.302
3.301
3.300
IL = 0mA
IL = 10mA
3.299
3.298
3.297
VOUT = 3.3V
IL = 50mA
3.296
3.295
3.3 4
5 6 7 8 9 10 11 12 13 14
INPUT VOLTAGE – Volts
Figure 2. Line Regulation: Output
Voltage vs. Supply Voltage
3.302
3.301
3.300
VOUT = 3.3V
VIN = 7V
3.299
3.298
3.297
3.296
3.295
0 8 16 24 32 40 48 56 64 72 80
OUTPUT LOAD – mA
Figure 3. Output Voltage vs. Load
Current
1150
900
VOUT = 3.3V
IL = 0mA
650
400
160
0
0 1.2 2.4 3.6 4.8 6.0 7.2 8.4 9.6 10.8 12.0
INPUT VOLTAGE – Volts
Figure 4. Quiescent Current vs.
Supply Voltage
800
675
550
425
IL = 0 TO 80mA
300
175
0
20 40 60
OUTPUT LOAD – mA
80
Figure 5. Quiescent Current vs. Load
Current
0.2
0.1
0.0
IL = 30mA
–0.1
IL = 0mA
–0.2
IL = 50mA
–0.3
–0.4
–45 –25 –5 15 35 55 75 95 115 135
TEMPERATURE – ؇C
Figure 6. Output Voltage Variation %
vs. Temperature
700
VIN = 7V
600
IL = 50mA
500
400
300
200 IL = 0mA
100
0
–45 –25 –5 15 35 55 75 95 115 135
TEMPERATURE – ؇C
Figure 7. Quiescent Current vs.
Temperature
120
96
72
48
24
0
0 20 40 60 80
OUTPUT LOAD – mA
Figure 8. Dropout Voltage vs. Output
Current
5
VOUT = 3.3V
RL = 66⍀
4
3
2
1
0
01 23 4 3 21 0
INPUT VOLTAGE – Volts
Figure 9. Power-Up/Power-Down
8.0
VIN
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0
0
VOUT
VSD = VIN
CL = 0.47F
RL = 66⍀
VOUT = 3.3V
20 40 60 80 100 120 140 160 180 200
TIME – s
Figure 10. Power-Up Overshoot
–4– REV. A
4페이지 ADP3308
The following general guidelines will be helpful when designing
a board layout:
1. PC board traces with larger cross section areas will remove
more heat. For optimum results, use PC boards with thicker
copper and or wider traces.
2. Increase the surface area exposed to open air so heat can be
removed by convection or forced air flow.
3. Do not use solder mask or silk screen on the heat dissipating
traces because it will increase the junction to ambient
thermal resistance of the package.
Shutdown Mode
Applying a TTL high signal to the shutdown pin or tying it to
the input pin will turn the output ON. Pulling the shutdown pin
down to a TTL low signal or tying it to ground will turn the
output OFF. In shutdown mode, quiescent current is reduced
to less than 1 µA.
APPLICATION CIRCUITS
Crossover Switch
The circuit in Figure 21 shows that two ADP3308s can be used
to form a mixed supply voltage system. The output switches
between two different levels selected by an external digital input.
Output voltages can be any combination of voltages from the
Ordering Guide of the data sheet.
Higher Output Current
The ADP3308 can source up to 50 mA without any heatsink or
pass transistor. If higher current is needed, an appropriate pass
transistor can be used, as in Figure 22, to increase the output
current to 1 A.
VIN = 4V TO 8V
C1
47F
MJE253*
R1
50⍀
VOUT = 3.0V @ 1A
IN
OUT
ADP3308-3.0
SD
GND
C2
10F
*AAVID531002 HEAT SINK IS USED
Figure 22. Higher Output Current Linear Regulator␣
Constant Dropout Post Regulator
The circuit in Figure 23 provides high precision with low drop-
out for any regulated output voltage. It significantly reduces the
ripple from a switching regulator while providing a constant
dropout voltage, which limits the power dissipation of the LDO
to 30 mW. The ADP3000 used in this circuit is a switching
regulator in the step-up configuration.
VIN = 4V TO 12V
OUTPUT SELECT
4V
0V
IN OUT
ADP3308-3.0
SD
GND
VOUT = 3.0V/3.3V
C1
1.0F
IN OUT
ADP3308-3.3
SD GND
C2
0.47F
Figure 21. Crossover Switch
VIN = 2.5V TO 3.5V
L1
6.8H
C1
100F
10V
R1
120⍀
ILIM VIN SW1
ADP3000-ADJ
GND
FB
SW2
D1
1N5817
C2
100F
10V
R2
30.1k⍀
1%
Q1
2N3906
R3
124k⍀
1%
ADP3308-3.0
IN OUT
SD
GND
3.0V@50mA
C3
2.2F
Q2
2N3906
R4
274k⍀
Figure 23. Constant Dropout Post Regulator
REV. A
–7–
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부품번호 | 상세설명 및 기능 | 제조사 |
ADP3308ART-285 | anyCAP 50 mA Low Dropout Linear Regulator | Analog Devices |
DataSheet.kr | 2020 | 연락처 | 링크모음 | 검색 | 사이트맵 |