lt3060 Linear Technology Corporation, lt3060 Datasheet - Page 10

• Manufacturer Part Number: lt3060
• Description: 45v Vin, Micropower, Low Noise, 100ma Low Dropout, Linear Regulator
• Manufacturer: Linear Technology Corporation

PIN FUNCTIONS
LT3060
REF/BYP (Pin 1 / Pin 8): Reference/Bypass. Connecting
a single capacitor from this pin to GND bypasses the
LT3060’s reference noise and soft-starts the reference.
A 10nF bypass capacitor typically reduces output voltage
noise to 30μV
start time is directly proportional to the REF/BYP capacitor
value. If the LT3060 is placed in shutdown, REF/BYP is
actively pulled low by an internal device to reset soft-start.
If low noise or soft-start performance is not required, this
pin must be left fl oating (unconnected). Do not drive this
pin with any active circuitry.
ADJ (Pin 2 / Pin 7): Adjust. This pin is the error amplifi er’s
inverting terminal. It’s typical bias current of 15nA fl ows out
of the pin (see curve of ADJ Pin Bias Current vs Temperature
in the Typical Performance Characteristics section). The
ADJ pin voltage is 600mV referenced to GND.
OUT (Pins 3, 4 / Pin 6): Output. These pin(s) supply power
to the load. Stability requirements demand a minimum
2.2μF ceramic output capacitor to prevent oscillations.
Large load transient applications require larger output
capacitors to limit peak voltage transients. See the
Applications Information section for details on transient
response and reverse output characteristics. Permissible
output voltage range is 600mV to 44.5V.
IN (Pins 5, 6 / Pin 5): Input. These pin(s) supply power to
the device. The LT3060 requires a local IN bypass capacitor
if it is located more than six inches from the main input
fi lter capacitor. In general, battery output impedance rises
with frequency, so adding a bypass capacitor in battery-
powered circuits is advisable.
10
RMS
in a 10Hz to 100kHz bandwidth. Soft-
(DC8/TS8)
An input bypass capacitor in the range of 1μF to 10μF
suffi ces. The LT3060 withstands reverse voltages on the
IN pin with respect to its GND and OUT pins. In a reversed
input situation, such as a battery plugged in backwards,
the LT3060 behaves as if a large resistor is in series with
its input. Limited reverse current fl ows into the LT3060
and no reverse voltage appears at the load. The device
protects itself and the load.
SHDN (Pin 7 / Pin 1): Shutdown. Pulling the SHDN pin
low puts the LT3060 into a low power state and turns
the output off. Drive the SHDN pin with either logic or an
open collector/drain with a pull-up resistor. The resistor
supplies the pull-up current to the open collector/drain
logic, normally several microamperes, and the SHDN
pin current, typically less than 3μA. If unused, connect
the SHDN pin to IN. The LT3060 does not function if the
SHDN pin is not connected. The SHDN pin cannot be
driven below GND unless tied to the IN pin. If the SHDN
pin is driven below GND while IN is powered, the output
may turn on. SHDN pin logic cannot be referenced to a
negative supply voltage.
GND (Pin 8, Exposed Pad Pin 9 / Pins 2, 3, 4): Ground.
Connect the bottom of the external resistor divider that sets
the output voltage directly to GND for optimum regulation.
For the DFN package, tie exposed pad Pin 9 directly to Pin 8
and the PCB ground. This exposed pad provides enhanced
thermal performance with its connection to the PCB ground.
See the Applications Information section for thermal
considerations and calculating junction temperature.
3060f