DISCONTINUED PRODUCT
-- FOR REFERENCE ONLY
8188
Designed specifically to meet the requirement for extended opera-
tion of battery-powered equipment such as cordless and cellular tele-
phones, the A8188S-- 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 250 mA (transient),
which is limited only by package power dissipation. Regulated output
voltages between 2.5 V and 3.3 V are trimmed at wafer probe.
A PMOS pass element provides a typical dropout voltage of only
90 mV at 60 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 ap-
proached, 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 A8188SL-xx
includes ENABLE inputs to give the designer complete control over
power up, standby, or power down.
These devices are supplied, without the ENABLE function, in a
standard 3-lead SOT-89/TO-243AA small-outline plastic transistor
package (suffix `LT'). Dual regulators (A8188SL-xx) are provided in
an 8-lead SOIC package. All devices are rated for operation over a
temperature range of -20
C to +85C.
FEATURES AND BENEFITS
I High Efficiency Provides Extended Battery Life
I 90 mV Typical Dropout Voltage at I
O
= 60 mA
I 55 A Typical Quiescent Current
Less Than 1
A "Sleep" Current
I 250 mA Peak Output Current
I Improved PSRR and Transient Performance
I Internal Thermal Protection
APPLICATIONS
I Cordless and Cellular Telephones
I Personal Data Assistants
I Personal Communicators
I Palmtop Computers
LOW-DROPOUT REGULATORS
-- HIGH EFFICIENCY
Always order by complete part number, e.g., A8188SLT-30 .
A8188SLT-xx
PRELIMINARY INFORMATION
(subject to change without notice)
July 13, 1999
Dwg. PS-022-2
VR
2
3
1
GND
OUT
IN
where "-xx" is the required output voltage in tenths
Data Sheet
27468.8
ABSOLUTE MAXIMUM RATINGS
Input Voltage, V
I
. . . . . . . . . . . . . . 10 V
Peak Output Current,
I
OM
. . . . . . . . . . . . . . . . . . 250 mA*
Enable Input Voltage, V
E
. . . . . . . . . V
I
Operating Temperature Range,
T
A
. . . . . . . . . . . . . -20
C to +85
C
Junction Temperature, T
J
. . . . +150
C
Storage Temperature Range,
T
S
. . . . . . . . . . . . -40
C to +150
C
* Output current rating is limited by input
voltage, duty cycle, and ambient tempera-
ture. Under any set of conditions, do not
exceed a junction temperature of +150
C.
See following pages.
Fault conditions that produce excessive
junction temperature will activate device
thermal shutdown circuitry. These condi-
tions can be tolerated but should be
avoided.
8188
LOW-DROPOUT
REGULATORS
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
FUNCTIONAL BLOCK DIAGRAM
(1/2 of A8188SL-xx shown)
Dwg. FS-012-8
BIAS
DRIVE
ENABLE
BANDGAP
REF.
ERROR
AMP
IN
ENABLE
OUT
8
1
7
2
GND
A8188SL-xx
1
2
3
Dwg. PS-023
6
7
8
GND
GND
OUT
OUT
ENABLE
IN
IN
ENABLE
1
1
2
2
VR
4
5
VR
1
1
2
2
Always order by complete part number:
Part Number
Package
R
JA
A8188SL-xx
8-Lead SOIC
108
C/W
A8188SLT-xx
3-Lead SOT-89/TO-243AA
258
C/W
where "-xx" is the required output voltage (V
O(nom)
) in tenths
(25 through 33), e.g., -30 = 3.0 volts.
Copyright 1999, 2000 Allegro MicroSystems, Inc.
NOTE -- There is an indeterminate resistance between terminals
2 and 4. For proper operation, terminals 2 and 4 must be
externally connected together.
8188
LOW-DROPOUT
REGULATORS
www.allegromicro.com
A8188SL-xx Maximum Allowable Total 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 T
J
= 150
C, Duty Cycle = 100%
V
I
- V
O
T
A
1.0
1.5
2.0
2.5
3.0
4.0
5 .0
6.0
7.0*
25
C
500
500
500
460
385
285
230
190
165
50
C
500
500
460
370
305
230
185
150
130
70
C
500
490
370
295
245
185
145
120
105
85
C
500
400
300
240
200
150
120
100
85
* Absolute maximum peak output current rating for either output is 250 mA; absolute maximum input voltage is 10 V.
I
O
= (T
J
T
A
)/([V
I
V
O
] R
JA
x dc) = (150 T
A
)/([V
I
V
O
] x 108 x 1.00)
Output current rating can be increased (to 250 mA maximum per output) by additional heat sinking or reducing the duty
cycle. Conditions that produce excessive junction temperature will activate device thermal shutdown circuitry. These
conditions can be tolerated but should be avoided.
A8188SLT-xx Maximum Allowable 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 Average (10 ms) Output Current in Milliamperes with T
J
= 150
C, Duty Cycle = 100%
V
I
- V
O
T
A
1.0
1.5
2.0
2.5
3.0
4.0
5.0
6.0
7.0*
25
C
250
250
240
190
160
120
95
80
65
50
C
250
250
190
155
125
95
75
65
55
70
C
250
205
155
120
100
75
60
50
40
85
C
250
165
125
100
80
60
50
40
35
* Absolute maximum input voltage is 10 V.
I
O
= (T
J
T
A
)/([V
I
V
O
] R
JA
x dc) = (150 T
A
)/([V
I
V
O
] x 258 x 1.00)
Output current rating can be increased (to 250 mA maximum) by additional heat sinking or reducing the duty cycle.
Conditions that produce excessive junction temperature will activate device thermal shutdown circuitry. These conditions
can be tolerated but should be avoided.
8188
LOW-DROPOUT
REGULATORS
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
ELECTRICAL CHARACTERISTICS at T
A
= +25
C (unless otherwise noted).
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Output Voltage
V
O
4 V
V
I
8 V, 10 A I
O
100 mA*
-0.05
0.00
+0.05
V
(reference specified V
O(nom)
)
V
I
= V
O(nom)
, I
O
= 60 mA
-0.30
--
--
V
Output Volt. Temp. Coeff.
a
VO
V
I
= 6 V, I
O
= 10 mA, T
J
125C
--
-0.30
--
mV/
C
Line Regulation
V
O(
VI)
4 V
V
I
8 V, I
O
= 1 mA
--
--
10
mV
Load Regulation
V
O(
IO)
1 mA
I
O
100 mA*, V
I
= 8 V
--
--
40
mV
1 mA
I
O
100 mA*, V
I
= 6 V
--
--
40
mV
1 mA
I
O
100 mA*, V
I
= 4 V
--
--
40
mV
Dropout Voltage
V
I
min V
O
I
O
= 60 mA
--
90
150
mV
I
O
= 125 mA*
--
190
300
mV
Quiescent Current
I
Q
V
I
= 8 V, I
O
1 mA, V
E
2.0 V
--
55
70
A
(GND terminal current)
V
I
= 8 V, I
O
100 mA*, V
E
2.0 V
--
70
85
A
V
I
= V
O(nom)
, I
O
= 60 mA
--
200
--
A
I
Q(off)
4 V
V
I
8 V, V
E
0.8 V
--
--
1.0
A
ENABLE Input Voltage
V
EH
4 V
V
I
8 V, Output ON
2.0
--
--
V
V
EL
4 V
V
I
8 V, Output OFF
--
--
0.8
V
ENABLE Input Current
I
E
V
E
= V
I
= 8 V
--
--
1.0
A
Thermal Shutdown Temp.
T
J
150
--
--
C
Rejection Ratio
PSRR
V
I
= V
O(nom)
+ 1.5 V, V
i
= 100 mV, I
O
= 10 mA:
f = 1 kHz
--
60
--
dB
f = 10 kHz
50
--
dB
Noise
e
n
10 Hz
f 100 kHz, I
O
= 10 mA, C
O
= 10
F
--
2.0
--
V/
Hz
Typical values are at T
A
= +25
C and are given for circuit design information only.
* Pulse test (
20 ms). See previous page for duty cycle limitations.
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