ltc3025edc-1 Linear Technology Corporation, ltc3025edc-1 Datasheet - Page 6

• Manufacturer Part Number: ltc3025edc-1
• Description: 500ma Micropower Vldo Linear Regulator
• Manufacturer: Linear Technology Corporation

PIN FUNCTIONS
LTC3025-1/LTC3025-2
BIAS (Pin 1): BIAS Input Voltage. BIAS provides internal
power for LTC3025-1/LTC3025-2 circuitry. The BIAS pin
should be locally bypassed to ground if the LTC3025-1/
LTC3025-2 is more than a few inches away from another
source of bulk capacitance. In general, the output imped-
ance of a battery rises with frequency, so it is usually
advisable to include an input bypass capacitor in battery-
powered circuits. A capacitor in the range of 0.01μF to
0.1μF is usually suffi cient.
GND (Pin 2): Ground. Connect to a ground plane.
IN (Pin 3): Input Supply Voltage. The output load cur-
rent is supplied directly from IN. The IN pin should be
locally bypassed to ground if the LTC3025-1/LTC3025-2
is more than a few inches away from another source of
bulk capacitance. In general, the output impedance of a
battery rises with frequency, so it is usually advisable
to include an input bypass capacitor when supplying IN
from a battery. A capacitor in the range of 0.1μF to 1μF is
usually suffi cient.
OUT (Pin 4): Regulated Output Voltage. The OUT pin
supplies power to the load. A minimum ceramic output
capacitor of at least 1μF is required to ensure stability.
BLOCK DIAGRAM
6
1
6
2
BIAS
SHDN
GND
SHDN
REFERENCE
0.4V
SOFT-START
LTC3025-1
+
–
6μA
OUT
ADJ
IN
3
4
5
Larger output capacitors may be required for applications
with large transient loads to limit peak voltage transients.
See the Applications Information section for more informa-
tion on output capacitance.
ADJ (Pin 5) LTC3025-1: Adjust Input. This is the input to
the error amplifi er. The ADJ pin reference voltage is 0.4V
referenced to ground. The output voltage range is 0.4V to
3.6V and is typically set by connecting ADJ to a resistor
divider from OUT to GND. See Figure 2.
SENSE (Pin 5) LTC3025-2: Output Sense. The sense is
the input to the resistor divider driving the error amplifi er.
Optimum regulation will be obtained at the point where
SENSE is connected to OUT. The SENSE pin bias current
is 10μA at the nominal rated output voltage.
SHDN (Pin 6): Shutdown Input, Active Low. This pin is
used to put the LTC3025-1/LTC3025-2 into shutdown. The
SHDN pin current is typically less than 10nA. The SHDN
pin cannot be left fl oating and must be tied to a valid logic
level (such as BIAS) if not used.
Exposed Pad (Pin 7): Ground and Heat Sink. Must be
soldered to PCB ground plane or large pad for optimal
thermal performance.
1
6
2
BIAS
SHDN
GND
SHDN
REFERENCE
0.4V
SOFT-START
LTC3025-2
R1
40k
+
–
6μA
R2
80k
SENSE
OUT
302512 BD
IN
302512fa
3
4
5