Datasheet

LT3462/LT3462A
3462af
3
TEMPERATURE (°C)
SDREF MINUS FB (V)
1.29
1.28
1.27
1.26
1.25
1.24
1.23
3462 G03
DUTY CYCLE (%)
10
CURRENT LIMIT (mA)
9080604020
3462 G02
30
50
70
480
360
240
120
0
3462 G05 3462 G06
TEMPERATURE (°C)
–40
FREQUENCY (MHz)
1.6
1.5
1.4
1.3
1.2
1.1
1.0
20 60
3462 G01
–20 0
40 80 100
TEMPERATURE (°C)
FREQUENCY (MHz)
3462 G04
3.2
3.0
2.8
2.6
2.4
2.2
2.0
T
A
= 25°C
SUPPLY VOLTAGE (V)
0
QUIESCENT CURRENT (µA)
16
4812
10
8
6
4
2
0
T
A
= 25°C
FB = N/C
TEMPERATURE (°C)
FB BIAS CURRENT (nA)
80 10040 60200–40 –20
0
–5
–10
–15
–20
–25
–30
–35
–40
–45
–50
–40 20 60
–20 0
40 80 100
–40 20 60
–20 0
40 80 100
T
A
= 25°C
LT3462
LT3462A
TYPICAL PERFOR A CE CHARACTERISTICS
UW
Oscillator Frequency (LT3462)
Current Limit SDREF Minus FB Pin Voltage
Oscillator Frequency (LT3462A)
FB Bias Current
Quiescent Current in
Shutdown Mode
UU
U
PI FU CTIO S
SW (Pin 1): Switch Pin. Connect to external inductor L1
and positive terminal of transfer cap.
GND (Pin 2): Ground. Tie directly to local ground plane.
FB (Pin 3): Feedback Pin. Connect resistive divider tap
here. Set R1 according to R1 = R2 • (V
OUT
/1.265V). In
shutdown, a proprietary shutdown bias current cancella-
tion circuit allows the internal 3µA source to pull up the
SDREF pin, even with residual negative voltage on V
OUT
.
SDREF (Pin 4): Dual Function Shutdown and 1.265V
Reference Output Pin. Pull to GND with external N-FET to
turn regulator off. Turn-off pull-down and a 2µA internal
source will pull SDREF up to turn-on the regulator. At turn-
on, a 180µA internal source pulls the pin to the regulation
voltage. The SDREF pin can supply up to 80µA at 1.265V
to bias the feedback resistor divider. An optional soft-start
circuit capacitor connects from this pin to –V
OUT
.
D (Pin 5): Anode Terminal of Integrated Schottky Diode.
Connect to negative terminal of transfer cap and external
inductor L2.
V
IN
(Pin 6): Input Supply Pin. Must be locally bypassed.