LTAGL LINER [Linear Technology], LTAGL Datasheet - Page 8

• Manufacturer Part Number: LTAGL
• Description: 100mA, Low Voltage, Very Low Dropout Linear Regulator
• Manufacturer: LINER [Linear Technology]

LT3020/LT3020-1.2/
LT3020-1.5/LT3020-1.8
BLOCK DIAGRA
PI FU CTIO S
8
OUT (Pins 1, 2): These pins supply power to the load. Use
a minimum output capacitor of 2.2µF to prevent oscillations.
Applications with large load transients require larger out-
put capacitors to limit peak voltage transients. See the
Applications Information section for more information on
output capacitance and reverse output characteristics.
OUT (Pin 3, Fixed Voltage Device Only): This pin is the
sense point for the internal resistor divider. It should be
tied directly to the other OUT pins (1, 2) for best results.
ADJ (Pin 3, Adjustable Device Only): This pin is the
inverting terminal to the error amplifier. Its typical input
bias current of 20nA flows out of the pin (see curve of ADJ
Pin Bias Current vs Temperature in the Typical Perfor-
mance Characteristics). The ADJ pin reference voltage is
200mV (referred to GND).
GND (Pin 4): Ground.
SHDN (Pin 5): The SHDN pin puts the LT3020 into a low
power state. Pulling the SHDN pin low turns the output off.
Drive the SHDN pin with either logic or an open collector/
drain device with a pull-up resistor. The pull-up resistor
U
U
SHDN
(5)
NOTE:
FOR LT3020 ADJUST PIN 3 IS CONNECTED TO
THE ADJUST PIN, R1 AND R2 ARE EXTERNAL.
FOR LT3020-1.X PIN 3 IS CONNECTED TO THE
OUTPUT SENSE PIN, R1 AND R2 ARE INTERNAL.
BIAS CURRENT
GENERATOR
REFERENCE
U
AND
SHUTDOWN
W
200mV
212mV
RECOVERY
–
ERROR AMP
+
–
+
NO-LOAD
SHUTDOWN
THERMAL
FIXED
V
1.2V
1.5V
1.8V
supplies the pull-up current to the open collector/drain
logic, normally several microamperes, and the SHDN pin
current, typically 2.3µA. If unused, connect the SHDN pin
to V
connected.
IN (Pins 7, 8): These pins supply power to the device. The
LT3020 requires a bypass capacitor at IN if it is more than
six inches away from the main input filter capacitor. The
output impedance of a battery rises with frequency, so
include a bypass capacitor in battery-powered circuits. A
bypass capacitor in the range of 2.2µF to 10µF suffices. The
LT3020 withstands reverse voltages on the IN pin with
respect to ground and the OUT pin. In the case of a reversed
input, which occurs if a battery is plugged in backwards,
the LT3020 acts as if a diode is in series with its input. No
reverse current flows into the LT3020 and no reverse volt-
age appears at the load. The device protects itself and the
load.
GND (Pin 9, DD8 Package Only): Ground. Solder Pin 9
(the exposed pad) to the PCB. Connect directly to Pin 4 for
best performance.
OUT
CURRENT
GAIN
IN
20k
20k
20k
R1
. The LT3020 does not function if the SHDN pin is not
100k
130k
160k
R2
Q1
Q2
R3
D1
D2
Q3
R2
R1
3020 BD
25k
ADJ
(3)
IN
(7, 8)
OUT
(1, 2)
OUT SENSE
(3)
GND
(4,9)
sn3020 3020fas