LT1934/LT1934-1
5
1934fe
TYPICAL PERFORMANCE CHARACTERISTICS
Minimum Input Voltage
V
OUT
= 5V
Quiescent Current
vs Temperature
Undervoltage Lockout
vs Temperature
Minimum Input Voltage
V
OUT
= 3.3V
TEMPERATURE (°C)
–50
0
QUIESCENT CURRENT (μA)
5
10
15
20
–25 0 25 50
1934 G10
75 100 125
TEMPERATURE (°C)
–50
2.0
UVLO (V)
2.5
3.0
3.5
4.0
–25 0 25 50
1934 G11
75 100 125
LOAD CURRENT (mA)
3.5
INPUT VOLTAGE (V)
4.0
4.5
5.0
5.5
6.0
0.1 10 100
1934 G12
3.0
1
LT1934
V
OUT
= 3.3V
T
A
= 25°C
BOOST DIODE TIED TO OUTPUT
V
IN
TO START
V
IN
TO RUN
LOAD CURRENT (mA)
5
INPUT VOLTAGE (V)
6
7
8
0.1 10 100
1934 G13
4
1
LT1934
V
OUT
= 5V
T
A
= 25°C
BOOST DIODE TIED TO OUTPUT
V
IN
TO START
V
IN
TO RUN
PIN FUNCTIONS
BOOST (Pin 1/Pin 1): The BOOST pin is used to provide a
drive voltage, higher than the input voltage, to the internal
bipolar NPN power switch.
GND (Pin 2/Pin 5): Tie the GND pin to a local ground plane
below the LT1934 and the circuit components. Return the
feedback divider to this pin.
FB (Pin 3/Pin 6): The LT1934 regulates its feedback pin
to 1.25V. Connect the feedback resistor divider tap to this
pin. Set the output voltage according to V
OUT
= 1.25V
(1 + R1/R2) or R1 = R2 (V
OUT
/1.25 – 1).
SHDN (Pin 4/Pin 4): The SHDN pin is used to put the LT1934
in shutdown mode. Tie to ground to shut down the LT1934.
Apply 2.3V or more for normal operation. If the shutdown
feature is not used, tie this pin to the V
IN
pin.
VIN (Pin 5/Pin 3): The V
IN
pin supplies current to the
LT1934’s internal regulator and to the internal power
switch. This pin must be locally bypassed.
SW (Pin 6/Pin 2): The SW pin is the output of the internal
power switch. Connect this pin to the inductor, catch diode
and boost capacitor.
Exposed Pad (Pin 7, DFN Package): This pin must be
soldered to ground plane.
(TSOT-23/DFN)
