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參數(shù)資料
| 型號(hào)： | MAX3228E-MAX3229E |
| 廠商： | Maxim Integrated Products, Inc. |
| 元件分類： | RS-232 |
| 英文描述： | 5V High-Speed RS-232 Transceivers with 0.1uF Capacitors |
| 中文描述： | 5V的高速RS - 232收發(fā)器與0.1uF電容 |
| 文件頁數(shù)： | 8/15頁 |
| 文件大?。?/td> | 227K |
| 代理商： | MAX3228E-MAX3229E |
AutoShutdown
The MAX3228E/MAX3229E achieve a 1μA supply cur-
rent with Maxim’s AutoShutdown feature, which oper-
ates when FORCEON is low and
FORCEOFF
is high.
When these devices sense no valid signal levels on all
receiver inputs for 30μs, the on-board charge pump
and drivers are shut off, reducing V
CC
supply current to
1μA. This occurs if the RS-232 cable is disconnected or
the connected peripheral transmitters are turned off.
The device turns on again when a valid level is applied
to any RS-232 receiver input. As a result, the system
saves power without changes to the existing BIOS or
operating system.
Table 3 and Figure 2c summarize the MAX3228E/
MAX3229E operating modes. FORCEON and
FORCE-
OFF
override AutoShutdown. When neither control is
asserted, the IC selects between these states automati-
cally, based on receiver input levels. Figures 2a, 2b,
and 3a depict valid and invalid RS-232 receiver levels.
Figures 3a and 3b show the input levels and timing dia-
gram for AutoShutdown operation.
A system with AutoShutdown may need time to wake
up. Figure 4 shows a circuit that forces the transmitters
on for 100ms, allowing enough time for the other sys-
tem to realize that the MAX3228E/MAX3229E are
active. If the other system transmits valid RS-232 sig-
nals within that time, the RS-232 ports on both systems
remain enabled.
When shut down, the device’s charge pumps are off,
V+ is pulled to V
CC
, V- is pulled to ground, and the
transmitter outputs are high-impedance. The time
required to exit shutdown is typically 100μs (Figure 3b).
FORCEON and
FORCEOFF
In case FORCEON and
FORCEOFF
are inaccessible,
these pins have 60k
(typ) pullup resistors connected to
V
L
(Table 2). Therefore, if FORCEON and
FORCEOFF
are not connected, the MAX3228E and MAX3229E will
always be active. Pulling these pins to ground will draw
current from the V
L
supply. This current can be calculat-
ed from the voltage supplied at V
L
and the 60k
(typ)
pullup resistor.
V
L
Logic Supply Input
Unlike other RS-232 interface devices, where the
receiver outputs swing between 0 and V
CC
, the
M
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
8
_______________________________________________________________________________________
Figure 3. AutoShutdown Trip Levels
V-
V
CC
0
V+
0
V
CC
t
INVL
t
WU
INVALID
REGION
RECEIVER
INPUT
VOLTAGE
(V)
INVALID
OUTPUT
(V)
t
INVH
TRANSMITTERS ENABLED, INVALID HIGH
R
AUTOSHUTDOWN, TRANSMITTERS DISABLED,
1
μ
A SUPPLY CURRENT, INVALID LOW
TRANSMITTERS ENABLED, INVALID HIGH
a)
b)
-2.7V
-0.3V
+2.7V
+0.3V
0
INDETERMINATE
INDETERMINATE
Figure 4. AutoShutdown with Initial Turn-On to Wake Up a
Mouse or Another System
FORCEON
MASTER SHDN LINE
0.1
μ
F
1M
FORCEOFF
MAX3228E
MAX3229E
POWER-
MANAGEMENT
UNIT
PIN NAME
FORCEON
FORCEOFF
POWER-ON DEFAULT
High
High
MECHANISM
Internal pullup
Internal pullup
Table 2. Power-On Default States
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MAX3228E | 【15kV ESD-Protected @.5V to %.5V RS-232 Transceivers in UCSP |
| MAX3228EEBV | 【15kV ESD-Protected @.5V to %.5V RS-232 Transceivers in UCSP |
| MAX3232 | 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1μF External Capacitors(3V~5.5V,關(guān)閉方式下接收器有效,120kbps，RS-232收發(fā)器) |
| MAX3237 | 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1μF External Capacitors(3V~5.5V,關(guān)閉方式下接收器有效,120kbps，RS-232收發(fā)器) |
| MAX323 | Precision, Single-Supply, SPST Analog Switches |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX3229AEEWV+ | 制造商:Maxim Integrated Products 功能描述:- Rail/Tube |
| MAX3229AEEWV+T | 制造商:Maxim Integrated Products 功能描述:+2.5V TO +5.5V RS-232 TRANSCEIVERS - Tape and Reel |
| MAX3229EBV | 制造商:Maxim Integrated Products 功能描述:+2.5V TO +5.5V RS-232 TRANSCEIVERS IN UCSP (E - Rail/Tube |
| MAX3229EBV-T | 功能描述:RS-232接口集成電路 RoHS:否 制造商:Exar 數(shù)據(jù)速率:52 Mbps 工作電源電壓:5 V 電源電流:300 mA 工作溫度范圍:- 40 C to + 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:LQFP-100 封裝: |
| MAX3229EEBV | 制造商:Maxim Integrated Products 功能描述::15KV ESD, +2.5V TO +5.5V 1TX/1RX RS-232 TRA - Rail/Tube |
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