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鍙冩暩(sh霉)璩囨枡
| 鍨嬭櫉锛� | MAX3218CPP+ |
| 寤犲晢锛� | Maxim Integrated Products |
| 鏂囦欢闋佹暩(sh霉)锛� | 10/12闋� |
| 鏂囦欢澶у皬锛� | 0K |
| 鎻忚堪锛� | IC TXRS RS-232 W/SHTDWN 20-DIP |
| 鐢�(ch菐n)鍝佸煿瑷撴ā濉婏細 | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 妯欐簴鍖呰锛� | 18 |
| 椤炲瀷锛� | 绶氳矾鏀剁櫦(f膩)鍣� |
| 椹�(q奴)鍕曞櫒/鎺ユ敹鍣ㄦ暩(sh霉)锛� | 2/2 |
| 瑕�(gu墨)绋嬶細 | RS232 |
| 闆绘簮闆诲锛� | 1.8 V ~ 4.25 V |
| 瀹夎椤炲瀷锛� | 閫氬瓟 |
| 灏佽/澶栨锛� | 20-DIP锛�0.300"锛�7.62mm锛� |
| 渚涙噳鍟嗚ō鍌欏皝瑁濓細 | 20-PDIP |
| 鍖呰锛� | 绠′欢 |
| 鐢�(ch菐n)鍝佺洰閷勯爜闈細 | 1405 (CN2011-ZH PDF) |
RS-232 Drivers
The two drivers are identical, and deliver EIA/TIA-232E
and EIA/TIA-562 output voltage levels when V CC is
between 1.8V and 4.25V. One transmitter can drive up
to 3k
in parallel with 2500pF at up to 120kbps.
Connect unused drivers to either GND or V CC. When
FORCEOFF is driven low, or when AutoShutdown circuit-
ry senses invalid voltage levels at all receiver inputs, the
drivers are disabled and their outputs are forced into a
high-impedance state. Driver inputs do not have internal
pull-up resistors.
RS-232 Receivers
The two receivers are identical, and accept both
EIA/TIA-232E and EIA/TIA-562 input signals. The
CMOS receiver outputs are inverting and swing rail-to-
rail. Receivers are disabled only when FORCEON and
FORCEOFF inputs are low. (See Table 2.)
Shutdown
When FORCEOFF is low, power supplies are disabled
and the transmitters are placed in a high-impedance
state. Receiver operation is not affected by taking
FORCEOFF low. Power consumption is dramatically
reduced in shutdown mode. Supply current is minimized
when the receiver inputs are static in any one of three
states: floating (ground), GND, or VCC.
AutoShutdown
A 1A supply current is achieved with Maxim鈥檚 new
AutoShutdown feature, which operates when FORCEON
is low and FORCEOFF is high. When the MAX3218
senses no valid signal level on either receiver input for
typically 30s, the on-board power supply and drivers
shut down, reducing supply current to 1A. Internal 5k
resistors pull undriven receiver inputs to ground. This
occurs if the RS-232 cable is disconnected or if the con -
nected peripheral transmitters are turned off. The sys -
tem turns on again when a valid level is applied to either
RS-232 receiver input. As a result, the system saves
power without changes to the existing BIOS or operating
system. When using the AutoShutdown feature, INVALID
is high when the device is on and low when the device is
shut down. The INVALID output indicates the condition
of the receiver inputs.
Table 3 summarizes the MAX3218 operating modes.
FORCEON and FORCEOFF override the automatic cir-
cuitry and force the transceiver into its normal operating
state or into its low-power standby state. When neither
control is asserted, the IC selects between these states
automatically based on receiver input levels. Figure 4
depicts valid and invalid RS-232 receiver levels. The
MAX3218
1A Supply Current, 1.8V to 4.25V-Powered
RS-232 Transceiver with AutoShutdown
_______________________________________________________________________________________
7
Table 3. AutoShutdown Logic
L
H
No
Normal Operation (Forced On)
L
H
No
Shutdown (AutoShutdown)
H
L
Yes
Shutdown (Forced Off)
L
No
Shutdown (Forced Off)
H
Yes
Normal Operation
RS-232 SIGNAL
PRESENT AT
RECEIVER INPUT
INVALID OUTPUT
FORCEOFF INPUT
TRANSCEIVER STATUS
FORCEON INPUT
H
L
X
POWER
MANAGEMENT
UNIT OR
KEYBOARD
CONTROLLER
CPU
I/O
CHIP
WITH
UART
MAX3218
RS-232
FORCEOFF
FORCEON
INVALID
Figure 2. Interface Under Control of PMU
Table 2. Receiver Status
FORCEON
FORCEOFF
RECEIVER STATUS
Receiver Enabled
Receiver Disabled
X
H
L
H
X
鐩搁棞PDF璩囨枡 |
PDF鎻忚堪 |
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鐩搁棞浠ｇ悊鍟�/鎶€琛�(sh霉)鍙冩暩(sh霉) |
鍙冩暩(sh霉)鎻忚堪 |
|---|---|
| MAX3218CPP+ | 鍔熻兘鎻忚堪:RS-232鎺ュ彛闆嗘垚闆昏矾 1uA 1.8-4.25V Tcvr w/AutoShutdown RoHS:鍚� 鍒堕€犲晢:Exar 鏁�(sh霉)鎿�(j霉)閫熺巼:52 Mbps 宸ヤ綔闆绘簮闆诲:5 V 闆绘簮闆绘祦:300 mA 宸ヤ綔婧害鑼冨湇:- 40 C to + 85 C 瀹夎棰ㄦ牸:SMD/SMT 灏佽 / 绠遍珨:LQFP-100 灏佽: |
| MAX3218CWP | 鍔熻兘鎻忚堪:RS-232鎺ュ彛闆嗘垚闆昏矾 RoHS:鍚� 鍒堕€犲晢:Exar 鏁�(sh霉)鎿�(j霉)閫熺巼:52 Mbps 宸ヤ綔闆绘簮闆诲:5 V 闆绘簮闆绘祦:300 mA 宸ヤ綔婧害鑼冨湇:- 40 C to + 85 C 瀹夎棰ㄦ牸:SMD/SMT 灏佽 / 绠遍珨:LQFP-100 灏佽: |
| MAX3218CWP+ | 鍔熻兘鎻忚堪:RS-232鎺ュ彛闆嗘垚闆昏矾 RoHS:鍚� 鍒堕€犲晢:Exar 鏁�(sh霉)鎿�(j霉)閫熺巼:52 Mbps 宸ヤ綔闆绘簮闆诲:5 V 闆绘簮闆绘祦:300 mA 宸ヤ綔婧害鑼冨湇:- 40 C to + 85 C 瀹夎棰ㄦ牸:SMD/SMT 灏佽 / 绠遍珨:LQFP-100 灏佽: |
| MAX3218CWP+T | 鍔熻兘鎻忚堪:RS-232鎺ュ彛闆嗘垚闆昏矾 RoHS:鍚� 鍒堕€犲晢:Exar 鏁�(sh霉)鎿�(j霉)閫熺巼:52 Mbps 宸ヤ綔闆绘簮闆诲:5 V 闆绘簮闆绘祦:300 mA 宸ヤ綔婧害鑼冨湇:- 40 C to + 85 C 瀹夎棰ㄦ牸:SMD/SMT 灏佽 / 绠遍珨:LQFP-100 灏佽: |
| MAX3218CWP-T | 鍔熻兘鎻忚堪:RS-232鎺ュ彛闆嗘垚闆昏矾 RoHS:鍚� 鍒堕€犲晢:Exar 鏁�(sh霉)鎿�(j霉)閫熺巼:52 Mbps 宸ヤ綔闆绘簮闆诲:5 V 闆绘簮闆绘祦:300 mA 宸ヤ綔婧害鑼冨湇:- 40 C to + 85 C 瀹夎棰ㄦ牸:SMD/SMT 灏佽 / 绠遍珨:LQFP-100 灏佽: |
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