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參數資料
| 型號： | ADP1147AN-3.3 |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 穩壓器 |
| 英文描述： | Current-Mode SMPS Controller |
| 中文描述： | SWITCHING CONTROLLER, 250 kHz SWITCHING FREQ-MAX, PDIP8 |
| 封裝： | PLASTIC, DIP-8 |
| 文件頁數： | 11/12頁 |
| 文件大小： | 195K |
| 代理商： | ADP1147AN-3.3 |
ADP1147-3.3/ADP1147-5
–11–
REV. 0
T o obtain optimum efficiency the required ESR value of C
OUT
is 100 m
or less.
T he circuit should also be evaluated with the minimum input
voltage. T his is done to assure that the power dissipation and
junction temperature of the P-channel MOSFET are not ex-
ceeded. At lower input voltages the operating frequency of the
ADP1147 decreases. T his causes the P-channel MOSFET to
remain in conduction for longer periods of time, resulting in
more power dissipation in the MOSFET .
T he effects of V
IN(MIN)
can be evaluated if we assume the
following:
V
IN(MIN)
= 4.5 V
V
OUT
= 3.3 V
V
D
= 0.4 V
f
MIN
= (1/3.15
μ
s)
×
(1– (3.7/4.9)) = 78 kHz.
P
D
=
3.3(0.125
)(1
A
)
2
(1.2625)
4.5
=
116
mW
T roubleshooting Hints
Efficiency is the primary reason for choosing the ADP1147 for
use in an application, and it is critical to determine that all por-
tions of the circuit are functioning properly in all modes. After
the design is complete the voltage waveforms on the timing
capacitor, C
T
, at Pin 2 of the device, should be compared to the
waveforms in Figures 19a and 19b.
In the continuous mode of operation the dc voltage level of the
waveform on C
T
should never fall below the 2 V level and it
should have a 0.9 V peak-to-peak sawtooth on it (see Figure
19a).
In the Power Savings Mode the sawtooth waveform on C
T
will
decay to ground for extended periods of time (see Figure 19b).
During the time that the capacitor voltage is at ground the
ADP1147 is in the power savings or sleep mode and the qui-
escent current is reduced to 160
μ
A typical.
T he ripple current in the inductor should also be monitored to
determine that it is approximately the same in both modes of
operation. With a higher output currents the voltage level on C
T
should never decay to ground as this would indicate poor
grounding and or decoupling.
Printed Wire Board Layout Considerations
T he PWB layout is extremely critical for proper circuit opera-
tion and the items listed below should be carefully considered
(see Figure 20)
1. T he signal and power grounds should be separate from each
other. T hey should be tied together only at ground Pin 7 of
the ADP1147. T he power ground should be tied to the an-
ode of the Schottky diode, and the (–) side of the C
IN
capaci-
tor. T he connections should be made with traces that are as
wide and as short as possible. T he signal ground should be
connected to the (–) side of capacitor C
OUT
using the same
type of runs as above.
2. T he sense(–) run to Pin 4 of the ADP1147 should be con-
nected directly to the junction point of R
SENSE
and the + side
of C
OUT
.
3. T he sense(–) and sense(+) traces should be routed together
with minimum track spacing and run lengths. T he 1000 pF
filter capacitor across Pins 4 and 5 of the ADP1147 should
be located as close to the device as possible.
4. In order to supply sufficient ac current the (+) side of capaci-
tor C
IN
should be connected with wide short traces and must
be located as close to the source of the P-MOSFET as possible.
5. In order to supply high frequency peak currents the input
decoupling capacitors should range from 0.1
μ
F to 1.0
μ
F
and must be located as close to the V
IN
pin and the ground
Pin 7 as possible.
6. T he shutdown Pin (6) is a high impedance input and it must
not be allowed to float. T he normal mode of operation of the
device requires that this pin be pulled low.
相關PDF資料 |
PDF描述 |
|---|---|
| ADP1147AR-3.3 | Current-Mode SMPS Controller |
| ADP1147AN-33 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| ADP1147AN-5 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| ADP1147AR-33 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| ADP1147AR-5 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
相關代理商/技術參數 |
參數描述 |
|---|---|
| ADP1147AN-5 | 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Analog Devices 功能描述:High Efficiency Step-Down Switching Regulator Controllers 制造商:Analog Devices Inc. 功能描述:High Efficiency Step-Down Switching Regulator Controllers |
| ADP1147AR-3.3 | 制造商:Rochester Electronics LLC 功能描述:HI EFF STEP-DWN SWTCH REG CONTRLR - 3.3V - Bulk |
| ADP1147AR-33 | 制造商:AD 制造商全稱:Analog Devices 功能描述:High Efficiency Step-Down Switching Regulator Controllers |
| ADP1147AR-5 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| ADP1147AR-5-REEL7 | 制造商:Rochester Electronics LLC 功能描述:- Tape and Reel |
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