Datasheet

4
LT1302/LT1302-5
TYPICAL PERFORMANCE CHARACTERISTICS
UW
TEMPERATURE (°C)
–50
DUTY CYCLE (%)
100
90
80
70
60
50
–25
02550
1302 G10
75 100
TEMPERATURE (°C)
–50
FREQUENCY (kHz)
300
275
250
225
200
175
150
–25
02550
1302 G11
75 100
SHUTDOWN VOLTAGE (V)
0
SHUTDOWN CURRENT (µA)
20
18
16
14
12
10
8
6
4
2
0
4
5
1302 G12
132
6
7
8
T
A
= 25°C
GND (Pin 1): Signal Ground. Feedback resistor and 0.1µF
ceramic bypass capacitor from V
IN
should be connected
directly to this pin.
V
C
(Pin 2): Frequency Compensation Pin. Connect series
RC to GND. Keep trace short.
SHDN (Pin 3): Shutdown. Pull high to effect shutdown; tie
to ground for normal operation.
FB/Sense (Pin 4): Feedback/Sense. On the LT1302 this
pin connects to CMP1 input. On the LT1302-5 this pin
connects to the output resistor string.
PI FU CTIO S
U
UU
I
T
(Pin 5): Normally left floating. Addition of a 3.3k resistor
to GND forces the LT1302 into current mode at light loads.
Efficiency drops at light load but increases at medium
loads. See Applications Information section.
V
IN
(Pin 6): Supply Pin. Must be bypassed with: (1) a 0.1µF
ceramic to GND, and (2) a large value electrolytic to PGND.
When V
IN
is greater than 5V, a low value resistor (2Ω to
10Ω) is recommended to isolate the V
IN
pin from input
supply noise.
Maximum Duty Cycle
Oscillator Frequency
Shutdown Pin Bias Current
LT1302-5 Output Voltage vs
Load Current
LOAD CURRENT (A)
0
OUTPUT VOLTAGE (V)
5.20
5.15
5.10
5.05
5.00
4.95
4.90
4.85
4.80
0.1
0.2 0.3 0.4
1302 G13
0.5 0.6 0.7 0.8 0.9 1.0
V
IN
= 2.2V
V
IN
= 3V
V
IN
= 4V
Maximum Output Power*
Boost Mode
INPUT VOLTAGE (V)
0
OUTPUT POWER (W)
20
16
12
8
4
0
8
1302 G14
2
4
* APPROXIMATE
6
10