ADP3338AKC-1.5-RL7 [ADI]
High Accuracy, Ultralow I Low Dropout Regulator; 高精度，超低我低压差稳压器
| 型号： | ADP3338AKC-1.5-RL7 |
| 厂家： | 
ADI |
| 描述： | High Accuracy, Ultralow I Low Dropout Regulator |
| 文件： | 总16页 (文件大小：295K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
High Accuracy, Ultralow IQ, 1 A,
anyCAP® Low Dropout Regulator
ADP3338
FUNCTIONAL BLOCK DIAGRAM
FEATURES
High accuracy over line and load: 0.8% @ 25°C,
1.4% over temperature
Ultralow dropout voltage: 190 mV (typ) @ 1 A
Requires only CO = 1.0 µF for stability
anyCAP is stable with any type of capacitor (including MLCC)
Current and thermal limiting
Q1
OUT
IN
ADP3338
R1
R2
THERMAL
PROTECTION
CC
g
DRIVER
m
Low noise
2.7 V to 8 V supply range
BANDGAP
REF
−40°C to +85°C ambient temperature range
SOT-223 package
GND
Figure 1.
APPLICATIONS
Notebook, palmtop computers
SCSI terminators
ADP3338
V
IN
V
OUT
OUT
IN
Battery-powered systems
Bar code scanners
1µF
1µF
GND
Camcorders, cameras
Home entertainment systems
Networking systems
DSP/ASIC supplies
Figure 2. Typical Application Circuit
GENERAL DESCRIPTION
with any good quality capacitor, including ceramic (MLCC)
The ADP3338 is a member of the ADP33xx family of precision,
low dropout (LDO), anyCAP voltage regulators. The ADP3338
operates with an input voltage range of 2.7 V to 8 V and delivers
a load current up to 1 A. The ADP3338 stands out from
conventional LDOs with a novel architecture and an enhanced
process that offers performance advantages and higher output
current than its competition. Its patented design requires only a
1 µF output capacitor for stability. This device is insensitive to
output capacitor equivalent series resistance (ESR), and is stable
types for space-restricted applications. The ADP3338 achieves
exceptional accuracy of ±±.8ꢀ at room temperature and ±1.ꢁꢀ
over temperature, line, and load variations. The dropout voltage
of the ADP3338 is only 19± mV (typical) at 1 A. The device also
includes a safety current limit and thermal overload protection.
The ADP3338 has ultralow quiescent current: 11± µA (typical)
in light load situations.
Rev. B
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 that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
www.analog.com
©2005 Analog Devices, Inc. All rights reserved.
ADP3338
TABLE OF CONTENTS
Specifications..................................................................................... 3
Capacitor Selection .................................................................... 1±
Output Current Limit ................................................................ 1±
Thermal Overload Protection .................................................. 1±
Calculating Power Dissipation ................................................. 1±
Printed Circuit Board Layout Considerations ....................... 1±
Outline Dimensions....................................................................... 12
Ordering Guide .......................................................................... 13
Absolute Maximum Ratings............................................................ ꢁ
ESD Caution.................................................................................. ꢁ
Pin Configuration and Function Descriptions............................. 5
Typical Performance Characteristics ............................................. 6
Theory of Operation ........................................................................ 9
Application Information................................................................ 1±
REVISION HISTORY
6/05—Data Sheet Changed from Rev. A to Rev. B
Added Pin Function Descriptions Table ....................................... 5
Changes to Ordering Guide .......................................................... 13
6/04—Data Sheet Changed from Rev. 0 to Rev. A
Updated Format..............................................................Universal
Changes to Figures 5, 11, 12, 13, 1ꢁ, 15 ..................................... 6
Updated Outline Dimensions................................................... 12
Changes to Ordering Guide ...................................................... 12
6/01—Rev. 0: Initial Version
Rev. B | Page 2 of 16
ADP3338
SPECIFICATIONS
VIN = 6.± V, CIN = COUT = 1 µF, TJ = −ꢁ±°C to +125°C, unless otherwise noted.
Table 1.
Parameter1, 2, 3
OUTPUT
Symbol Conditions
Min Typ
Max Unit
Voltage Accuracy
VOUT
VIN = VOUTNOM + 0.4 V to 8 V, IL = 0.1 mA to 1 A, TJ = 25°C
−0.8
−1.4
−1.6
0.04
0.006
+0.8
+1.4
+1.6
%
%
%
mV/V
mV/mA
VIN = VOUTNOM + 0.4 V to 8 V, IL = 0.1 mA to 1 A, TJ = −40°C to +125°C
VIN = VOUTNOM + 0.4 V to 8 V, IL = 50 mA to 1 A, TJ = 150°C
VIN = VOUTNOM + 0.4 V to 8 V, TJ = 25°C
IL = 0.1 mA to 1 A, TJ = 25°C
VOUT = 98% of VOUTNOM
Line Regulation
Load Regulation
Dropout Voltage
VDROP
IL = 1 A
IL = 500 mA
IL = 100 mA
190
125
70
400
200
150
mV
mV
mV
Peak Load Current
Output Noise
ILDPK
VNOISE
VIN = VOUTNOM + 1 V
f = 10 Hz to 100 kHz, CL = 10 µF, IL = 1 A
1.6
95
A
µV rms
GROUND CURRENT
In Regulation
IGND
IL = 1 A
IL = 500 mA
IL = 100 mA
IL = 0.1 mA
9
30
15
3
190
600
mA
mA
mA
µA
4.5
0.9
110
190
In Dropout
IGND
VIN = VOUTNOM – 100 mV, IL = 0.1 mA
µA
1 All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC) methods.
2 Application stable with no load.
3 VIN = 2.7 V for models with VOUTNOM ≤ 2.2 V.
Rev. B | Page 3 of 16
ADP3338
ABSOLUTE MAXIMUM RATINGS
Unless otherwise specified, all voltages are referenced to GND.
Table 2.
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Parameter
Rating
Input Supply Voltage
Power Dissipation
Operating Ambient Temperature Range
Operating Junction Temperature Range
θJA
−0.3 V to +8.5 V
Internally limited
−40°C to +85°C
−40°C to +150°C
62.3°C/W
Only one absolute maximum rating may be applied at any one
time.
θJC
26.8°C/W
Storage Temperature Range
Lead Temperature (Soldering 10 sec)
Vapor Phase (60 sec)
Infrared (15 sec)
−65°C to +150°C
300°C
215°C
220°C
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Rev. B | Page 4 of 16
ADP3338
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
3
2
1
IN
ADP3338
TOP VIEW
(Not to Scale)
2
OUT
GND
OUT
NOTE: PIN 2 AND TAB ARE INTERNALLY CONNECTED
Figure 3. Pin Configuration
Table 3. Pin Function Descriptions
Pin No.
Mnemonic
Description
1
2
3
GND
OUT
IN
Ground Pin.
Regulator Output. Bypass to ground with a 1 µF or larger capacitor.
Regulator Input. Bypass to ground with a 1 µF or larger capacitor.
Rev. B | Page 5 of 16
ADP3338
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25°C, unless otherwise noted.
2.515
12
10
8
V
V
= 2.5V
= 6V
OUT
V
= 2.5V
OUT
IN
2.510
2.505
2.500
2.495
2.490
I
= 0A
= 1A
L
L
I
= 0.5A
L
6
I
4
2
0
0
0.2
0.4
0.6
0.8
1.0
2.5
4.5
INPUT VOLTAGE (V)
6.5
8.0
OUTPUT LOAD (A)
Figure 4. Line Regulation Output Voltage vs. Input Voltage
Figure 7. Ground Current vs. Load Current
0.4
0.3
0.2
0.1
2.504
2.503
2.502
2.501
2.500
2.499
2.498
2.497
2.496
2.495
V
V
= 2.5V
OUT
= 6V
V
= 6V
IN
IN
I
= 1A
L
I
= 0.7A
L
I
= 0.5A
L
I
= 0.3A
L
I
= 0A
L
0
–0.05
–40
–20
0
20
40
60
80
C)
100
120
0
0.2
0.4
0.6
0.8
1.0
JUNCTION TEMPERATURE (
°
LOAD CURRENT (A)
Figure 5. Output Voltage vs. Load Current
Figure 8. Output Voltage Variation % vs. Junction Temperature
300
250
200
150
100
50
18
I
= 1A
LOAD
V
I
= 2.5V
= 0A
OUT
16
14
12
10
8
LOAD
I
= 700mA
LOAD
I
= 500mA
LOAD
I
= 300mA
LOAD
6
4
2
0
0
–40 –20
0
20
40
60
80
100 120 140 160
0
2
4
6
8
JUNCTION TEMPERATURE (°C)
INPUT VOLTAGE (V)
Figure 6. Ground Current vs. Supply Voltage
Figure 9. Ground Current vs. Junction Temperature
Rev. B | Page 6 of 16
ADP3338
250
200
150
100
50
V
C
= 2.5V
= 10µF
OUT
OUT
V
= 2.5V
OUT
2.51
2.50
2.49
I
LOAD = 1A
4.5
3.5
40
80
120
TIME (
160
200
240
0
0
0.2
0.4
0.6
0.8
1.0
µ
s)
LOAD CURRENT (A)
Figure 13. Line Transient Response
Figure 10. Dropout Voltage vs. Load Current
V
C
= 6V
= 1µF
V
= 2.5V
= 1A
IN
OUT
OUT
I
LOAD
2.6
2.5
3
2
1
0
2.4
1
0
0
200
400
600
s)
800
1000
10
0
1
3
4
5
6
7
8
9
2
TIME (
µ
TIME (sec)
Figure 14. Load Transient Response
Figure 11. Power-Up/Power-Down
V = 6V
IN
OUT
V
= 2.5V
OUT
C
= 10µF
C
= 1µF
= 1A
2.6
2.5
2.4
2.51
2.50
2.49
OUT
I
LOAD
1
0
4.5
3.5
0
200
400
600
s)
800
1000
40
80
120
TIME (µs)
160
200
240
TIME (
µ
Figure 15. Load Transient Response
Figure 12. Line Transient Response
Rev. B | Page 7 of 16
ADP3338
300
250
200
150
100
50
2.5
0
400mΩ
SHORT
FULL SHORT
1.5
1.0
V
= 6V
IN
I
= 1A
= 0A
L
0.5
0
I
L
0
0.4
0.6
0.8
1.0
0
10
20
30
40
50
TIME (s)
C
(µF)
L
Figure 16. Short-Circuit Current
Figure 18. RMS Noise vs. CL
100
0
V
= 2.5V
OUT
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
10
1
C
= 1µF
L
I
= 1A
L
C
= 10µF
L
I
= 1A
L
C
= 1µF
L
0.1
C
= 10µF
L
0.01
C
= 10µF
= 0
L
C
= 1
= 0
µ
F
I
L
L
I
L
0.001
10k
10
100
1k
100k
1M
10
100
1k
10k
100k
1M
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 19. Output Noise Density (10 Hz to 100 kHz)
Figure 17. Power Supply Ripple Rejection
Rev. B | Page 8 of 16
ADP3338
THEORY OF OPERATION
The ADP3338 anyCAP LDO uses a single control loop for
regulation and reference functions. The output voltage is sensed
by a resistive voltage divider, consisting of R1 and R2, which is
varied to provide the available output voltage option. Feedback
is taken from this network by way of a series diode (D1) and a
second resistor divider (R3 and Rꢁ) to the input of an amplifier.
include the load capacitor in a pole-splitting arrangement to
achieve reduced sensitivity to the value, type, and ESR of the
load capacitance.
Most LDOs place very strict requirements on the range of ESR
values for the output capacitor because they are difficult to
stabilize due to the uncertainty of load capacitance and resis-
tance. Moreover, the ESR value required to keep conventional
LDOs stable changes depending on load and temperature.
These ESR limitations make designing with LDOs more
difficult because of their unclear specifications and extreme
variations over temperature.
A very high gain error amplifier is used to control this loop. The
amplifier is constructed in such a way that equilibrium produces
a large, temperature-proportional input offset voltage that is
repeatable and very well controlled. The temperature-propor-
tional offset voltage is combined with the complementary diode
voltage to form a virtual band gap voltage that is implicit in the
network, although it never appears explicitly in the circuit.
Ultimately, this patented design makes it possible to control the
loop with only one amplifier. This technique also improves the
noise characteristics of the amplifier by providing more flexi-
bility on the trade off of noise sources that leads to a low noise
design.
With the ADP3338 anyCAP LDO, this is no longer true. It can
be used with virtually any good quality capacitor, with no
constraint on the minimum ESR. This innovative design
provides circuit stability with just a small 1 µF capacitor on the
output. Additional advantages of the pole-splitting scheme
include superior line noise rejection and very high regulator
gain to achieve excellent line and load regulation. An impressive
±1.ꢁꢀ accuracy is guaranteed over line, load, and temperature.
The R1, R2 divider is chosen in the same ratio as the band gap
voltage to the output voltage. Although the R1, R2 resistor
divider is loaded by Diode D1 and a second divider consisting
of R3 and Rꢁ, the values can be chosen to produce a tempera-
ture-stable output. This unique arrangement specifically corrects
for the loading of the divider, thus avoiding the error resulting
from base current loading in conventional circuits.
Additional features of the circuit include current limit and
thermal shutdown.
V
V
OUT
IN
C1
C2
1µF
1µF
IN
OUT
GND
ADP3338
The patented amplifier controls a new and unique noninverting
driver that drives the pass transistor, Q1. The use of this special
noninverting driver enables the frequency compensation to
Figure 20. Typical Application Circuit
INPUT
OUTPUT
COMPENSATION
CAPACITOR
Q1
ATTENUATION
R1
(a)
(V
/V
)
BANDGAP OUT
R3 D1
C
R
PTAT
LOAD
NONINVERTING
WIDEBAND
DRIVER
V
OS
g
m
PTAT
LOAD
CURRENT
R4
R2
ADP3338
GND
Figure 21. Functional Block Diagram
Rev. B | Page 9 of 16
ADP3338
APPLICATION INFORMATION
CAPACITOR SELECTION
CALCULATING POWER DISSIPATION
Output Capacitor
Device power dissipation is calculated as
The stability and transient response of the LDO is a function of
the output capacitor. The ADP3338 is stable with a wide range
of capacitor values, types, and ESR (anyCAP). A capacitor as
low as 1 µF is the only requirement for stability. A higher ca-
pacitance may be necessary if high output current surges are
anticipated, or if the output capacitor cannot be located near the
output and ground pins. The ADP3338 is stable with extremely
low ESR capacitors (ESR ≈ ±) such as multilayer ceramic capacitors
(MLCC) or OSCON. Note that the effective capacitance of some
capacitor types falls below the minimum over temperature or
with dc voltage.
PD = (VIN – VOUT) × ILOAD + (VIN × IGND
)
Where ILOAD and IGND are load current and ground current, and
IN and VOUT are the input and output voltages, respectively.
Assuming the worst-case operating conditions are ILOAD = 1.± A,
IGND = 1± mA, VIN = 3.3 V, and VOUT = 2.5 V, the device power
dissipation is
V
PD = (3.3 V – 2.5 V) × 1±±± mA + (3.3 V × 1± mA) = 833 mW
So, for a junction temperature of 125°C and a maximum
ambient temperature of 85°C, the required thermal resistance
from junction to ambient is
Input Capacitor
An input bypass capacitor is not strictly required, but is recom-
mended in any application involving long input wires or high
source impedance. Connecting a 1 µF capacitor from the input
to ground reduces the sensitivity of the circuit to PC board
layout and input transients. If a larger output capacitor is
necessary, a larger value input capacitor is recommended.
125°C − 85°C
θJA
=
= ꢁ8°C/W
±.833 W
PRINTED CIRCUIT BOARD LAYOUT
CONSIDERATIONS
The thermal resistance, θJA, of the SOT-223 is determined by the
sum of the junction-to-case and the case-to-ambient thermal
resistances. The junction-to-case thermal resistance, θJC, is
determined by the package design and is specified at 26.8°C/W.
However, the case-to-ambient thermal resistance is determined
by the printed circuit board design.
OUTPUT CURRENT LIMIT
The ADP3338 is short-circuit protected by limiting the pass
transistor’s base drive current. The maximum output current is
limited to approximately 2 A (see Figure 16).
THERMAL OVERLOAD PROTECTION
As shown in Figure 22, the amount of copper to which the
ADP3338 is mounted affects thermal performance. When
mounted to the minimal pads of 2 oz. copper, as shown in
Figure 22 (a), θJA is 126.6°C/W. Adding a small copper pad
under the ADP3338, as shown in Figure 22 (b), reduces the θJA to
1±2.9°C/W. Increasing the copper pad to one square inch, as
shown in Figure 22 (c), reduces the θJA even further to 52.8°C/W.
The ADP3338 is protected against damage due to excessive
power dissipation by its thermal overload protection circuit.
Thermal protection limits the die temperature to a maximum of
16±°C. Under extreme conditions, such as high ambient
temperature and power dissipation where the die temperature
starts to rise above 16±°C, the output current is reduced until
the die temperature has dropped to a safe level.
Current and thermal limit protections are intended to protect
the device against accidental overload conditions. For normal
operation, externally limit the power dissipation of the device
so the junction temperature does not exceed 15±°C.
a
b
c
Figure 22. PCB Layouts
Rev. B | Page 10 of 16
ADP3338
•
•
Use the adjacent area to the ADP3338 to add more copper
around it. Connecting the copper area to the output of the
ADP3338, as shown in Figure 22 (c), is best, but thermal
performance will be improved even if it is connected to
other signals.
Use the following general guidelines when designing printed
circuit boards:
•
•
•
Keep the output capacitor as close as possible to the output
and ground pins.
Keep the input capacitor as close as possible to the input
and ground pins.
Use additional copper layers or planes to reduce the
thermal resistance. Again, connecting the other layers to
the output of the ADP3338 is best, but is not necessary.
When connecting the output pad to other layers, use
multiple vias.
Specify thick copper and use wide traces for optimum heat
transfer. PC board traces with larger cross sectional areas
remove more heat from the ADP3338.
•
Decrease thermal resistance by adding a copper pad under
the ADP3338, as shown in Figure 22 (b).
Rev. B | Page 11 of 16
ADP3338
OUTLINE DIMENSIONS
3.10
3.00
2.90
7.30
7.00
6.70
3.70
3.50
3.30
1
2
3
0.84
0.76
0.66
2.30
BSC
1.05
0.85
16°
10°
1.70
1.60
1.50
1.30
1.10
6.50 BSC
4.60 BSC
0.35
0.30
0.23
0.10
0.02
16°
10°
10° MAX
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS TO-261-AA
Figure 23. 3-Lead Small Outline Transistor Package [SOT-223]
(KC-3)
Dimensions shown in millimeters
Rev. B | Page 12 of 16
ADP3338
ORDERING GUIDE
Model
Temperature Range
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
Output Voltage (V)
Package Option
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
KC-3
Package Description
ADP3338AKC-1.5-RL
ADP3338AKC-1.5-RL7
ADP3338AKCZ-1.5-RL1
ADP3338AKCZ-1.5-RL71
ADP3338AKC-1.8-RL
ADP3338AKC-1.8-RL7
ADP3338AKCZ-1.8-RL1
ADP3338AKCZ-1.8-R71
ADP3338AKC-2.5-RL
ADP3338AKC-2.5-RL7
ADP3338AKCZ-2.5-RL1
ADP3338AKCZ-2.5RL71
ADP3338AKC-2.85-RL
ADP3338AKC-2.85-RL7
ADP3338AKCZ-2.85R71
ADP3338AKC-3-RL
ADP3338AKC-3-RL7
ADP3338AKCZ-3-RL71
ADP3338AKC-3.3-RL
ADP3338AKC-3.3-RL7
ADP3338AKCZ-3.3-RL1
ADP3338AKCZ-3.3RL71
ADP3338AKC-5-REEL
ADP3338AKC-5-REEL7
ADP3338AKCZ-5-REEL1
ADP3338AKCZ-5-R71
1.5
1.5
1.5
1.5
1.8
1.8
1.8
1.8
2.5
2.5
2.5
2.5
2.85
2.85
2.85
3.0
3.0
3.0
3.3
3.3
3.3
3.3
5
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
3-Lead SOT-223
5
5
5
1 Z = Pb-free part.
Rev. B | Page 13 of 16
ADP3338
NOTES
Rev. B | Page 14 of 16
ADP3338
NOTES
Rev. B | Page 15 of 16
ADP3338
NOTES
©
2005 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
C02050–0–6/05(B)
Rev. B | Page 16 of 16
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ROCHESTER
ADP3338AKC-2.85-R7
2.85V FIXED POSITIVE LDO REGULATOR, 0.4V DROPOUT, PDSO4, PLASTIC, SOT-223, 3 PIN
ADI
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