ADM1072 Просмотр технического описания (PDF) - Analog Devices
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ADM1072 Datasheet PDF : 8 Pages
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ADM1072
PRELIMINARY TECHNICAL DATA
APPLICATIONS INFORMATION
INPUT FILTERING
To prevent the input voltage being pulled below the minimum
operating voltage under transient short-circuit conditions,
before the current limit has had time to operate, a reservoir
capacitor should be connected from MAIN_IN to GND. This
does not need to be large, but should have a low ESR. A value
of around 10 - 22µF is suitable. Larger values will reduce the
voltage drop still further. The STBY_IN input requires a
proportionately smaller value, typically 2.2 to 4.7µF.
OUTPUT CAPACITANCE
120µF capacitors should be connected between OP1 and OP2
and GND to prevent the back e.m.f. of parasitic inductance
from pulling OP1 and OP2 below ground during turn-off and
to provide adequate turn- on current for Universal Serial Bus
(USB) applications that are hot plugged to OP! or OP2. This
causes the output rise and fall times to be longer, as shown in
the typical operating characteristics, but does not affect the
turn-off time of the ADM1072 itself.
LAYOUT CONSIDERATIONS
Printed circuit board tracks to and from the ADM1072 should
be as thick and as short as possible to minimise parasitic induc-
tance and take full advantage of the fast response time of the
switch. Input and output capacitors should be placed as close
to the device as possible (less than 5mm).
THERMAL CONSIDERATIONS
Under normal operating conditions, the worst-case power
dissipation will be 135mW with the 135m⍀ on resistance and
3V supply (W = (1A)2 ϫ 0.135⍀). The package is capable of
handling and dissipating this power, but heat dissipation can
further be improved by providing a large area of copper in
contact with the device pins, particularly MAIN_IN and
OP1,OP2.
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
16-Pin QSOP Package (RQ-16)
0.197 (5.00)
0.189 (4.80)
16
0.157 (3.99)
0.150 (3.81)
1
9
0.244 (6.20)
0.228 (5.79)
8
PIN 1
0.059 (1.50)
MAX
0.069 (1.75)
0.053 (1.35)
0.010 (0.25)
0.004 (0.10)
0 .0 2 5
( 0. 6 4 )
BSC
8&
0.012 (0.30) S EAT ING 0.010 (0.20) 0&
0.008 (0.20) P LAN E
0.007 (0.18)
–8–
0.050 (1.27)
0.016 (0.41)
Rev. PrE 1/02
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