LT1529-3.3 Linear Technology, LT1529-3.3 Datasheet - Page 11

• Manufacturer Part Number: LT1529-3.3
• Description: 3A Low Dropout Regulators with Micropower Quiescent Current and Shutdown
• Manufacturer: Linear Technology

PACKAGE DESCRIPTIO
A
In some applications it may be necessary to leave the input
to the LT1529 unconnected when the output is held high.
This can happen when the LT1529 is powered from a
rectified AC source. If the AC source is removed, then the
input of the LT1529 is effectively left floating. The reverse
output current also follows the curve in Figure 3 if the V
pin is left open. The state of the SHDN pin will have no
effect on the reverse output current when the V
floating.
When the input of the LT1529 is forced to a voltage below
its nominal output voltage and its output is held high, the
output current will follow the curve shown in Figure 3 . This
can happen if the input of the LT1529 is connected to a
discharged (low voltage) battery and the output is held up
by either a backup battery or by a second regulator circuit.
When the V
OUTPUT pin is pulled above the V
(1.524)
PPLICATI
0.060
HATCHED AREA IS SOLDER PLATED
BOTTOM VIEW OF DD PAK
COPPER HEAT SINK
IN
(6.502)
(7.620)
0.256
0.300
pin is forced below the OUTPUT pin or the
O
U
(1.524)
(1.905)
S
0.060
0.075
(4.648)
0.183
I FOR ATIO
U
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of circuits as described herein will not infringe on existing patent rights.
IN
pin, the input current
W
U
(1.524)
0.060
TYP
(8.382 – 9.398)
0.330 – 0.370
3.632
0.143
Dimensions in inches (millimeters) unless otherwise noted.
+0.305
–0.508
+0.012
–0.020
U
IN
5-Lead Plastic DD Pak
(LTC DWG # 05-08-1461)
pin is
Q Package
IN
(0.711 – 0.965)
will typically drop to less than 2 A (see Figure 4). The state
of the SHDN pin will have no effect on the reverse output
current when the output is pulled above the input.
0.028 – 0.038
(1.447 – 1.955)
0.057 – 0.077
(9.906 – 10.541)
0.390 – 0.415
15 TYP
5
4
2
1
0
3
0
V
V
OUT
OUT
= 3.3V (LT1529-3.3)
= 5V (LT1529-5)
Figure 4. Input Current
1
LT1529-3.3/LT1529-5
INPUT VOLTAGE (V)
(4.191 – 4.572)
0.165 – 0.180
2
LT1529-3.3
(0.330 – 0.584)
0.013 – 0.023
(1.499)
0.059
TYP
3
LT1529-5
4
LT1529 • F04
5
(1.143 – 1.397)
0.045 – 0.055
LT1529
0.102
0.004
(2.413 – 2.921)
0.095 – 0.115
(1.270 0.305)
0.050
+0.203
–0.102
+0.008
–0.004
11
Q(DD5) 0396
0.012