Datasheet

LT3460/LT3460-1
4
3460fb
(ThinSOT/SC70/DFN Packages)
SW (Pin 1/Pin 1/Pin 3): Switch Pin. Connect inductor/diode
here. Minimize trace at this pin to reduce EMI.
GND (Pin 2/Pins 2 and 5/Exposed Pad Pin 7): Ground
Pin. Tie directly to local ground plane.
FB (Pin 3/Pin 3/Pin 1): Feedback Pin. Reference
voltage is 1.255V. Connect resistor divider tap here.
Minimize trace area at FB. Set V
OUT
according to
V
OUT
= 1.255V (1 + R1/R2).
SHDN (Pin 4/Pin 4/Pin 6): Shutdown Pin. Tie to 1.5V or
higher to enable device; 0.4V or less to disable device.
Also functions as soft-start. Use RC fi lter (47k, 47nF typ)
as shown in Figure 1.
V
IN
(Pin 5/Pin 6/Pin 4): Input Supply Pin. Must be locally
bypassed.
NC (NA/NA/Pins 2, 5): No-Connects. These pins are not
connected to internal circuitry. They should be tied to
ground to improve thermal and electrical performance.
TYPICAL PERFORMANCE CHARACTERISTICS
Feedback Bias Current Feedback Voltage
TEMPERATURE (°C)
–50
15
20
25
25 75
3460 G04
10
5
–25 0
50 100
0
FEEDBACK BIAS CURRENT (nA)
30
TEMPERATURE (°C)
–50
1.255
25 75
3460 G05
1.250
1.245
–25 0
50 100
1.240
V
FB
(V)
1.260
Switch Saturation Voltage
(V
CESAT
) Current Limit vs Duty Cycle
TEMPERATURE (°C)
–50
250
300
350
25 75
3460 G06
200
150
100
–25 0
50 100
50
0
V
CESAT
(mV)
400
(LT3460)
(LT3460)
(LT3460)
(LT3460-1)
I
C
= 100mA
I
C
= 200mA
I
C
= 250mA
I
C
= 50mA
DUTY CYCLE
0
250
300
350
0.6
3460 G07
200
150
100
0.2 0.4
0.8 1.0
50
0
CURRENT LIMIT (mA)
450
400
LT3460
LT3460-1
PIN FUNCTIONS