A8205: Low-Dropout Regulators -- High Efficiency

PRELIMINARY INFORMATION
LOW-DROPOUT REGULATORS
— HIGH EFFICIENCY
OUT
NC
OR
ADJ*
(subject to change without notice)
December 6, 1999
5
4
Data Sheet
27468.20
8205
Designed specifically to meet the requirement for extended operation of battery-powered equipment such as cordless and cellular telephones, the A8205SLH voltage regulators offer the reduced dropout
voltage and quiescent current essential for maximum battery life.
Applicable also to palmtop computers and personal data assistants,
these devices deliver a regulated output at up to 200 mA (transient),
which is limited only by package power dissipation. Regulated output
voltages of 2.7, 2.8, 3.0, 3.3, 3.6, 4.0, and 5.0 V are currently provided.
Other voltages, down to 2.0 volts, are available on special order.
T
C
U
Y
D
L
O
N
R
P EO
D
C
E
N
U
E
N
R
I
E
T
F
N
E
O
R
C
S OR
I
D F
—
2
GND
3
ENABLE
1
IN
VR
Dwg. PS-021-5
*NO CONNECTION (fixed regulators) or
ADJUST (A8205SLH-ADJ only).
A PMOS pass element provides a typical dropout voltage of only
75 mV at 100 mA of load current. The low dropout voltage permits
deeper battery discharge before output regulation is lost. Quiescent
current does not increase significantly as the dropout voltage is approached, an ideal feature in standby/resume power systems where data
integrity is crucial. Regulator accuracy and excellent temperature
characteristics are provided by a bandgap reference. The A8205SLH
includes an ENABLE input to give the designer complete control over
power up, standby, or power down.
These devices are supplied in a thermally enhanced 5-lead smalloutline plastic package similar to the SOT-23, and fitting the SC-74A
footprint. All devices are rated for operation over a temperature range
of -20°C to +85°C.
FEATURES AND BENEFITS
ABSOLUTE MAXIMUM RATINGS
Input Voltage, VI . . . . . . . . . . . . . . . 7 V
Peak Output Current,
IOM . . . . . . . . . . . . . . . . . . 200 mA*
Enable Input Voltage, VE . . . . . . . . . . VI
Operating Temperature Range,
TA . . . . . . . . . . . . . -20°C to +85°C
Junction Temperature, TJ . . . . +150°C
Storage Temperature Range,
TS . . . . . . . . . . . . -40°C to +150°C
* Output current rating is limited by input
voltage, duty cycle, and ambient temperature.
Under any set of conditions, do not exceed a
junction temperature of +150°C. See following pages.
■ High Efficiency Provides Extended Battery Life
■ 75 mV Typical Dropout Voltage at IO = 100 mA
■ 55 µA Typical Quiescent Current
Less Than 1 µA “Sleep” Current
■ Low Output Noise
■ 200 mA Peak Output Current
■ Improved PSRR and Transient Performance
APPLICATIONS
■
■
■
■
Cordless and Cellular Telephones
Personal Data Assistants
Personal Communicators
Palmtop Computers
Always order by complete part number, e.g., A8205SLH-xx , where “xx”
is the required output voltage in tenths or “ADJ” for adjustable.
8205
LOW-DROPOUT
REGULATORS
FUNCTIONAL BLOCK DIAGRAM
IN
1
5
OUT
ADJUST
4
DRIVE
BIAS
ERROR
AMP
(SUFFIX "-ADJ" ONLY)
OTHERWISE
NO CONNECTION
ENABLE
ENABLE
(FIXED REG'S)
3
2
BANDGAP
REF.
GND
Dwg. FS-012-6
A8205SLH Maximum Allowable Average Output Current* with device mounted on 2.24" x 2.24"
(56.9 mm x 56.9 mm) solder-coated copper-clad board in still air.
Allowable Total Average (10 ms) Output Current in Milliamperes with TJ = 150°C, Duty Cycle = 100%†
VI - VO
TA
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0*
4.5*
25°C
200
200
200
200
200
189
162
142
126
50°C
200
200
200
200
182
152
130
114
101
70°C
200
200
200
182
145
121
104
91
81
85°C
200
200
197
148
118
98
84
74
66
* Absolute maximum peak output current rating is 200 mA; absolute maximum input voltage is 7 V.
† IO = (TJ – TA)/([VI – VO] RθJA x dc) = (150 – TA)/([VI – VO] x 220 x 1.00)
Output current rating can be increased (to 200 mA maximum) by additional heat sinking or reducing the duty cycle.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 1999, 2000 Allegro MicroSystems, Inc.
8205
LOW-DROPOUT
REGULATORS
ELECTRICAL CHARACTERISTICS at TA = +25°C, VE = VI (unless otherwise noted).
Limits
Characteristic
Symbol
Output Voltage
VO
Output Volt. Temp. Coeff.
aVO
Test Conditions
Min.
Typ.
Max.
Units
VI ≥ VO(nom) + 1 V, 1 mA ≤ IO ≤ 150 mA*,
reference specified VO(nom)
—
0.0
±1.5
%
VI = 6 V, IO = 10 mA, TJ ≤ 125°C
—
40
—
ppm/°C
Line Regulation
∆VO(∆VI)
VO(nom) + 1 V ≤ VI ≤ 7 V, IO = 3 mA
—
—
±1.5
%
Load Regulation
∆VO(∆IO)
VI = VO(nom) + 1 V, 1 mA ≤ IO ≤ 150 mA*
—
—
±1.5
%
VI = 7 V, 1 mA ≤ IO ≤ 150 mA*
—
—
±1.5
%
IO = 100 mA
—
75
200
mV
VI = VO(nom) + 1 V, IO = 1 mA
—
55
65
µA
VI = VO(nom) + 1 V, IO = 150 mA*
—
55
65
µA
VI = 7 V, IO = 1 mA
—
55
65
µA
VI = 7 V, IO = 150 mA*
—
55
65
µA
IQ
VI ≤ 7 V, VE ≤ 0.8 V, IO = 0 mA
—
—
1.0
µA
VEH
VI ≥ VO(nom) + 1 V, Output ON
2.0
—
—
V
VEL
VI ≥ VO(nom) + 1 V, Output OFF
—
—
0.4
V
VE = VI = 7 V
—
—
±1.0
µA
—
1.26
—
V
A8205SLH-ADJ only
—
0.10
—
µA
VI = VO(nom) + 1.5 V, Vi = 100 mV,
IO = 30 mA, f = 60 Hz
—
70
—
dB
10 Hz ≤ f ≤ 100 kHz, IO = 10 mA, CO = 10 µF
—
0.5
—
µV/√Hz
Dropout Voltage
Ground Terminal Current
ENABLE Input Voltage
ENABLE Input Current
VImin - VO
IGND
IE
Internal Reference Voltage
VREF
ADJUST Input Current
IADJ
Rejection Ratio
Output Noise
PSRR
en
Typical values are at TA = +25°C and are given for circuit design information only.
* Pulse test (≤20 ms). See previous page for duty cycle limitations.
www.allegromicro.com
8205
LOW-DROPOUT
REGULATORS
APPLICATIONS INFORMATION
Linear regulators require input and output capacitors in order to
maintain over-all loop stability. The recommended minimum
value for the input capacitor is 0.1 µF. The output capacitor is
the dominant pole that provides the high-frequency compensation required for over-all regulator loop stability. These devices
are stable with as little as 1 µF. However, to ensure stable
operation under all conditions and capacitor types, the recommended minimum value is 4.7 µF. The output capacitor may be
partially distributed through the load circuits. However, at least
1 µF should be connected at the regulator using the shortest and
widest foil pattern possible.
The A8205SLH-ADJ requires an external voltage divider to set
up the desired regulated output voltage between 2.0 V and 6.8 V
(VI ≤ 7 V). The two resistors are chosen such that
VO = 1.26 (R1 + R2)/R2.
The resistor values are usually as high as possible to maintain
high circuit efficiency, but R2 should be less than 300 kΩ.
OUTPUT (2.0 V TO 6.8 V)
5
1
INPUT
(7.0 V MAX)
VR
R1
4
3
ENABLE
(ACTIVE HIGH)
2
0.1 µF
(MIN)
1 µF
(MIN)
R2
(300 kΩ MAX)
Dwg. ES-015
Thermal Considerations
These devices are intended to provide more than 150 mA of
continuous current in a very small package. The table on page 2
of this data sheet gives the maximum allowable average output
current for a worst-case printed circuit design (RθJA = 220°C/W
with a minimum footprint). Performance improvement is easily
accomplished with the addition of 1 square inch of copper at
terminal 2 (RθJA = 170°C/W).
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
8205
LOW-DROPOUT
REGULATORS
THIS PAGE INTENTIONALLY LEFT BLANK
www.allegromicro.com
8205
LOW-DROPOUT
REGULATORS
THIS PAGE INTENTIONALLY LEFT BLANK
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
8205
LOW-DROPOUT
REGULATORS
Dimensions in Inches
(for reference only)
0.122
0.079
0.018
0.012
0.028
0.083
0.073
5
1
0.0079
0.0059
4
2
3
0.118
0.106
4
5
0.039
0.022
0° TO 8°
REF
0.037
0.095
1
0.0098 MIN
2
BSC
3
0.037
0.043
0.035
0.049
0.035
0.0059
0.00
Dwg. MA-010-15 in
Dwg. MA-011-5 in
Dimensions in Millimeters
(controlling dimensions)
3.10
2.90
0.45
0.30
0.70
5
2.10
1.85
5
1
0.20
0.15
4
2
3
3.00
2.70
4
0.55
1.00
0° TO 8°
REF
0.95
2.40
1
0.25 MIN
2
BSC
3
0.95
0.15
0.00
1.10
0.90
1.25
0.90
Dwg. MA-011-5 mm
NOTES: 1. Tolerances on package height and width represent allowable mold offsets.
Dimensions given are measured at the widest point (parting line).
2. Exact body and lead configuration at vendor’s option within limits shown.
3. Height does not include mold gate flash.
4. Where no tolerance is specified, dimension is nominal.
www.allegromicro.com
Dwg. MA-010-15 mm
8205
LOW-DROPOUT
REGULATORS
The products described here are manufactured under one or more
U.S. patents or U.S. patents pending.
Allegro MicroSystems, Inc. reserves the right to make, from time to
time, such departures from the detail specifications as may be required
to permit improvements in the performance, reliability, or
manufacturability of its products. Before placing an order, the user is
cautioned to verify that the information being relied upon is current.
Allegro products are not authorized for use as critical components
in life-support devices or systems without express written approval.
The information included herein is believed to be accurate and
reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringement of patents or other rights of
third parties which may result from its use.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
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