8405 Datasheet, PDF (1/8 Pages) Allegro MicroSystems – LOW-DROPOUT REGULATORS . HIGH EFFICIENCY

8405
PRELIMINARY INFORMATION
(subject to change without notice)
June 25, 1999
LOW-DROPOUT REGULATORS
— HIGH EFFICIENCY
Designed specifically to meet the requirement for extended opera-
tion of battery-powered equipment such as cordless and cellular tele-
phones, the A8405SLH voltage regulators offer the reduced dropout
voltage and quiescent current essential for maximum battery life.
5
4
Applicable also to palmtop computers and personal data assistants,
these devices deliver a regulated output at up to 200 mA (transient),
which is internally limited, providing short-circuit protection. Regu-
lated output voltages of 2.7, 2.8, 3.0, 3.2, 3.3, 3.6, 3.8, 4.0, and 5.0 V
VR
UCT 1
2
3
ROD ^NLY _Dwg.PS-021-6
P ^O _{*BYPASS (fixed regulators) or}
D ^{E ADJUST (A8405SLH-ADJ only).}
TINUEERENC _{ABSOLUTE MAXIMUM RATINGS}
N ^F _{Input Voltage, VI . . . . . . . . . . . . . . . 7 V}
O ^{E Peak Output Current,}
C ^{R IOM . . . . . . . . . . . . . . . . . . 200 mA*}
Enable Input Voltage, V_E . . . . . . . . . . V_I
IS R Operating Temperature Range,
T_A . . . . . . . . . . . . . -20°C to +85°C
D ^{O Junction Temperature, T}J ^{. . . . +150°C}
F _{Storage Temperature Range,}
T_S . . . . . . . . . . . . -40°C to +150°C
* Output current rating is limited by input
— _{voltage, duty cycle, and ambient temperature.}
are currently provided. Other voltages, down to 2.0 volts, are available
on special order.
A PMOS pass element provides a typical dropout voltage of only
100 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 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 A8405SLH
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 small-
outline 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
I High Efficiency Provides Extended Battery Life
I 100 mV Typical Dropout Voltage at I_O = 100 mA
I 80 µA Typical Quiescent Current
I Low Output Noise
I 200 mA Current-Limited Output
I Improved PSRR and Transient Performance
APPLICATIONS
I Cordless/Cellular/GSM/PHS Telephones
I Personal Data Assistants
I Personal Communicators
I Palmtop Computers
I GPS
I Pagers
Under any set of conditions, do not exceed a
junction temperature of +150°C. See follow-
Always order by complete part number, e.g., A8405SLH-xx , where “xx”
ing pages.
is the required output voltage in tenths or “ADJ” for adjustable.