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參數資料
| 型號： | MAX780A |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | Dual-Slot PCMCIA Analog Power Controller(雙組插口,PCMCIA標準模擬電源控制器) |
| 中文描述： | 雙槽、PCMCIA模擬電源控制器 |
| 文件頁數： | 7/12頁 |
| 文件大?。?/td> | 168K |
| 代理商： | MAX780A |
M
Dual-S lot PCMCIA Analog Power Controller
_______________________________________________________________________________________
7
If a mechanical interlock switch cannot be used, an
extra MOSFET must be added, as shown in Figure 1.
Placing two N-channel MOSFETs in series with their
body diodes facing in opposite directions allows V
CC
to
be shut down to 0V without using a mechanical switch.
Switching Speed
The drive to the external MOSFETs ensures that the
3.3V supply is never connected to the 5V supply. This
is done by turning these transistors off quickly (using
active pull-down circuitry), and on more slowly (using
external pull-up resistors). The turn-on delay depends
on the value of the pull-up resistors, and on the gate
capacitance of the switching transistors. To save
power, use high-value resistors of up to 10M
.
However, note that high-value resistors will increase the
time it takes to turn on the switched supplies
__________Applic ations Information
The MAX780 can be used with PCMCIA controllers
other than the Intel 82365SL DF. Figure 2 shows the
logic connections to the Cirrus Logic CL-PD6720
PCMCIA Host Adapter.
The MAX780 does not need a PCMCIA controller to
function. Tie C2 to VCCIN to allow direct V
CC
and V
PP
control from the system bus. Figure 3 shows the con-
nection to the system bus. Figure 4 shows the timing
requirements.
Reading from a PCMCIA Port
without Using the V
PP
S upply
In the Typical Operating Circuit, V
CC
is switched to
the PCMCIA ports using the 12V V
PP
supply, which
provides the gate drive needed to turn on the external
N-channel MOSFETs. In some cases, the high-power
V
PP
supply is only available when information has to be
written to the PCMCIA port, not when data is being
read. The V
PP
supply may have a quiescent current of
several milliamps, so it consumes more power than is
necessary simply to provide gate drive for some FETs.
In these circumstances, a separate gate-drive supply is
needed to turn on the external FETs. Ideally it should
have a low quiescent current and be capable of being
turned off when read access to the PCMCIA port is not
required. Doubling or tripling charge pumps can easily
be built using a convenient clock signal from elsewhere
in the system. Buffering the clock signal with a suitable
gate provides on/off control, as shown in Figure 5.
When driven at 100kHz or more by a CMOS gate pow-
ered from 5V, the doubler circuit outputs 8.6V when
loaded with 25k
(equivalent to four 100k
pull-up
resistors). Under similar conditions, but when running
from 3.3V, the tripler circuit produces 7.9V.
BDRV3
ADRV3
ADRV5
VCCIN
MAX780_
+12V
100k
+12V
100k
+5V
1
μ
F
AVCC
1
μ
F
BVCC
+12V
100k
+3.3V
BDRV5
* EXTRA MOSFET
NOTE:
BODY DIODES OF MOSFETS SHOWN FOR CLARITY.
*
*
+12V
100k
Figure 1. Using an Extra MOSFET to Replace the Mechanical
Interlock
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| MAX781 | PDA/Hand-Held Computer Power Controller |
| MAX781CBX | PDA/Hand-Held Computer Power Controller |
| MAX781EBX | PDA/Hand-Held Computer Power Controller |
| MAX783 | Triple-Output Power-Supply Controller for Notebook Computers(3.3V/5V,具有雙組PCMCIA標準VPP輸出的筆記本電腦電源控制器) |
| MAX786 | Dual-Output Power-Supply Controller for Notebook Computers(具有25μA關斷的,3.3V/5V筆記本型電腦電源) |
相關代理商/技術參數 |
參數描述 |
|---|---|
| MAX780ACAG | 功能描述:電源開關 IC - 配電 RoHS:否 制造商:Exar 輸出端數量:1 開啟電阻（最大值）:85 mOhms 開啟時間（最大值）:400 us 關閉時間（最大值）:20 us 工作電源電壓:3.2 V to 6.5 V 電源電流（最大值）: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOT-23-5 |
| MAX780ACAG+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX780ACAG-T | 功能描述:電源開關 IC - 配電 RoHS:否 制造商:Exar 輸出端數量:1 開啟電阻（最大值）:85 mOhms 開啟時間（最大值）:400 us 關閉時間（最大值）:20 us 工作電源電壓:3.2 V to 6.5 V 電源電流（最大值）: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOT-23-5 |
| MAX780ACNG | 功能描述:電源開關 IC - 配電 RoHS:否 制造商:Exar 輸出端數量:1 開啟電阻（最大值）:85 mOhms 開啟時間（最大值）:400 us 關閉時間（最大值）:20 us 工作電源電壓:3.2 V to 6.5 V 電源電流（最大值）: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOT-23-5 |
| MAX780AEAG | 功能描述:電源開關 IC - 配電 RoHS:否 制造商:Exar 輸出端數量:1 開啟電阻（最大值）:85 mOhms 開啟時間（最大值）:400 us 關閉時間（最大值）:20 us 工作電源電壓:3.2 V to 6.5 V 電源電流（最大值）: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOT-23-5 |
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