lt1432 Linear Technology Corporation, lt1432 Datasheet - Page 8

• Manufacturer Part Number: lt1432
• Description: 3.3v High Efficiency Step-down Switching Regulator Controller
• Manufacturer: Linear Technology Corporation

PACKAGE DESCRIPTIO
A
LT1432-3.3
normal mode, then switching to normal mode, pausing for
1ms, followed by return to full load.
If this sequence is not possible, an alternative is to
increase the output capacitor to > 680 F. This modifica-
tion will often allow the power-down sequence to consist
of simultaneous turn-off of load current and switch to
Burst Mode operation. Power-up is accomplished by
switching to normal mode and simultaneously increasing
load current to the lowest possible value (30mA to 500mA),
followed by a short pause and return to full load current.
RELATED PARTS
PART NUMBER
LTC1148
LT1432
LT1507
8
PPLICATI
(0.203 – 0.254)
**
0.008 – 0.010
*
DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
[phone]
(0.254 – 0.508)
0.010 – 0.020
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
DESCRIPTION
High Efficiency Step-Down Switching Regulator Controller
High Efficiency Synchronous Step-Down Switching Regulator
1.5A, 500kHz Step-Down Switching Regulator
O
0.016 – 0.050
0.406 – 1.270
(7.620 – 8.255)
(0.229 – 0.381)
0.300 – 0.325
0.009 – 0.015
0.325
8.255
U
FAX
S
: [phone]
+0.635
–0.381
+0.025
–0.015
45
I FOR ATIO
U
0 – 8 TYP
(1.651)
0.065
TYP
TELEX
(2.540 0.254)
0.100 0.010
(0.127)
W
0.005
MIN
(1.346 – 1.752)
: 499-3977
0.053 – 0.069
U
(0.355 – 0.483)
0.014 – 0.019
(1.143 – 1.651)
0.045 – 0.065
Dimensions in inches (millimeters) unless otherwise noted.
U
8-Lead Plastic SOIC
8-Lead Plastic DIP
N8 Package
S8 Package
(0.457 0.076)
0.018 0.003
Full Shutdown
When the Mode pin is driven high, full shutdown of the
regulator occurs. Regulator input current will then consist
of the LT1432 shutdown current ( 15 A) plus the switch
leakage of the switching IC ( 1 A to 25 A). Mode input
current ( 15 A at 5V) must also be considered. Start-up
from shutdown can be in either normal or Burst Mode
operation, but one should always check start-up over-
shoot, especially if the output capacitor or frequency
compensation components have been changed.
(3.302 0.127)
(1.270)
0.130 0.005
0.050
(3.175)
BSC
0.125
MIN
(0.101 – 0.254)
0.004 – 0.010
Adjustable and Fixed 5V or 3.3V Outputs
Fixed Frequency PWM for Low Input Voltages from 4.5V to 12V
COMMENTS
5V Regulated Output Voltage
(0.380)
0.015
MIN
(6.477 0.381)
0.255 0.015*
(5.791 – 6.197)
0.228 – 0.244
8
1
1
8
(4.801 – 5.004)
0.189 – 0.197*
2
(10.160)
7
7
2
0.400*
MAX
LINEAR TECHNOLOGY CORPORATION 1992
LT/GP 0895 2K REV A • PRINTED IN USA
6
3
6
3
5
4
N8 0695
5
4
(3.810 – 3.988)
0.150 – 0.157**
SO8 0695