LESHAN RADIO COMPANY, LTD.
LR1 1 1 7 A
1 A Ad ju s t a b le /Fix e d Lo w Dro p o u t Lin e a r Re g u la t o r
Features
Description
• Low dropout voltage
• Load regulation: 0.05% typical
• Trimmed current limit
The LR1117A and LR1117A-1.8, -2.5, -2.85, -3.3 and -5
are low dropout three-terminal regulators with 1A output
current capability. These devices have been optimized for low
voltage where transient response and minimum input voltage
are critical. The 2.85V version is designed specifically to be
used in Active Terminators for SCSI bus.
• On-chip thermal limiting
• Standard SOT-223, TO-220, and TO-252 packages
• Three-terminal adjustable or fixed 1.8V, 2.5V, 2.85V,
3.3V, 5V
Current limit is trimmed to ensure specified output current
and controlled short-circuit current. On-chip thermal limiting
provides protection against any combination of overload and
ambient temperatures that would create excessive junction
temperatures.
Applications
• Active SCSI terminators
• High efficiency linear regulators
• Post regulators for switching supplies
• Battery chargers
• 12V to 5V linear regulators
• Motherboard clock supplies
Unlike PNP type regulators where up to 10% of the output
current is wasted as quiescent current, the quiescent current
of the LR1117A flows into the load, increasing efficiency.
The LR1117A series regulators are available in the
industry-standard SOT-223, TO-220, and TO-252 (DPAK)
power packages.
Typical Applications
LR1117A
VIN = 12V
VIN
VOUT
9V at 1A
+
+
10µF
22µF
R1
124Ω
ADJ
R2
768Ω
VOUT = VREF(1+R2/R1) + IADJ • R2
LR1117A-5
VIN = 12V
VIN
VOUT
5V at 1A
+
+
10µF
22µF
GND
1/9