參數(shù)資料
型號(hào)： PCA9540B
廠商： NXP Semiconductors N.V.
英文描述： 2-channel I2C multiplexer
中文描述： 2通道的I2C多路復(fù)用器
文件頁(yè)數(shù)： 4/14頁(yè)
文件大?。?/td> 138K
代理商： PCA9540B
Philips Semiconductors
Product data sheet
PCA9540B
2-channel I
2
C multiplexer
2004 Sep 29
4
DEVICE ADDRESSING
Following a START condition the bus master must output the
address of the slave it is accessing. The address of the PCA9540B
is shown in Figure 3.
0
0
1
1
0
0
SW00713
1
R/W
FIXED
Figure 3. Slave address
The last bit of the slave address defines the operation to be
performed. When set to logic 1, a read is selected while a logic 0
selects a write operation.
CONTROL REGISTER
Following the successful acknowledgement of the slave address,
the bus master will send a byte to the PCA9540B which will be
stored in the Control Register. If multiple bytes are received by the
PCA9540B, it will save the last byte received. This register can be
written and read via the I
2
C bus.
X
B2
B1 B0
CHANNEL SELECTION BITS
(READ/WRITE)
X
SW00839
X
6
5
4
2
1
0
7
3
X
X
ENABLE BIT
Figure 4. Control register
CONTROL REGISTER DEFINITION
A SCx/SDx downstream pair, or channel, is selected by the contents
of the control register. This register is written after the PCA9540B
has been addressed. The 2 LSBs of the control byte are used to
determine which channel is to be selected. When a channel is
selected, the channel will become active after a stop condition has
been placed on the I
2
C bus. This ensures that all SCx/SDx lines will
be in a HIGH state when the channel is made active, so that no
false conditions are generated at the time of connection.
Table 1. Control Register; Write — Channel Selection/
Read — Channel Status
D7
D6
D5
D4
D3
B2
B1
B0
COMMAND
X
X
X
X
X
0
X
X
No channel selected
X
X
X
X
X
1
0
0
Channel 0 enabled
X
X
X
X
X
1
0
1
Channel 1 enabled
X
X
X
X
X
1
1
X
No channel selected
0
0
0
0
0
0
0
0
No channel selected;
power-up default state
POWER-ON RESET
When power is applied to V
DD
, an internal Power-On Reset holds
the PCA9540B in a reset condition until V
DD
has reached V
POR
. At
this point, the reset condition is released and the PCA9540B
registers and I
2
C state machine are initialized to their default states,
all zeroes causing all the channels to be deselected. Thereafter,
V
DD
must be lowered below 0.2 V to reset the device.
VOLTAGE TRANSLATION
The pass gate transistors of the PCA9540B are constructed such
that the V
DD
voltage can be used to limit the maximum voltage that
will be passed from one I
2
C bus to another.
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
V
pass
vs. V
DD
2.5
3.0
3.5
4.0
4.5
5.0
5.5
V
pass
V
DD
MINIMUM
TYPICAL
MAXIMUM
SW00820
2.0
Figure 5. V
pass
voltage
Figure 5 shows the voltage characteristics of the pass gate
transistors (note that the graph was generated using the data
specified in the DC Characteristics section of this datasheet). In
order for the PCA9540B to act as a voltage translator, the V
pass
voltage should be equal to, or lower than the lowest bus voltage. For
example, if the main bus was running at 5 V, and the downstream
buses were 3.3 V and 2.7 V, then V
pass
should be equal to or below
2.7 V to effectively clamp the downstream bus voltages. Looking at
Figure 5, we see that V
pass
(max.) will be at 2.7 V when the
PCA9540B supply voltage is 3.5 V or lower so the PCA9540B
supply voltage could be set to 3.3 V. Pull-up resistors can then be
used to bring the bus voltages to their appropriate levels (see Figure
12).
More Information can be found in Application Note AN262 PCA954X
family of I
2
C/SMBus multiplexers and switches.
相關(guān)PDF資料
PDF描述
PCA9540PWDH 2-channel I2C multiplexer
PCA9540 2-channel I2C multiplexer
PCA9540D 2-channel I2C multiplexer
PCA9541 2-to-1 I2C master selector with interrupt logic and reset
PCA9542 2-channel IIC multiplexer and interrupt controller(2通道IIC多路復(fù)用器和中斷控制器)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
PCA9540BD 功能描述:編碼器、解碼器、復(fù)用器和解復(fù)用器 I2C MUX 2CH BI-DIR RoHS:否 制造商:Micrel 產(chǎn)品:Multiplexers 邏輯系列:CMOS 位數(shù): 線路數(shù)量（輸入/輸出）:2 / 12 傳播延遲時(shí)間:350 ps, 400 ps 電源電壓-最大:2.625 V, 3.6 V 電源電壓-最小:2.375 V, 3 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-44 封裝:Tray
PCA9540BD,112 功能描述:編碼器、解碼器、復(fù)用器和解復(fù)用器 I2C MUX 2CH BI-DIR RoHS:否 制造商:Micrel 產(chǎn)品:Multiplexers 邏輯系列:CMOS 位數(shù): 線路數(shù)量（輸入/輸出）:2 / 12 傳播延遲時(shí)間:350 ps, 400 ps 電源電壓-最大:2.625 V, 3.6 V 電源電壓-最小:2.375 V, 3 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-44 封裝:Tray
PCA9540BD,118 功能描述:編碼器、解碼器、復(fù)用器和解復(fù)用器 2-CHANNEL I2C MULTIPLEXER RoHS:否 制造商:Micrel 產(chǎn)品:Multiplexers 邏輯系列:CMOS 位數(shù): 線路數(shù)量（輸入/輸出）:2 / 12 傳播延遲時(shí)間:350 ps, 400 ps 電源電壓-最大:2.625 V, 3.6 V 電源電壓-最小:2.375 V, 3 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-44 封裝:Tray
PCA9540BD112 制造商:NXP Semiconductors 功能描述:IC 2CH I2C BUS MULTIPLEXER 5.5V SOIC-8
PCA9540BDP 制造商:NXP Semiconductors 功能描述:IC MUX 2CH I2C 8TSSOP 制造商:NXP Semiconductors 功能描述:IC, MUX, 2CH, I2C, 8TSSOP 制造商:NXP Semiconductors 功能描述:IC, MUX, 2CH, I2C, 8TSSOP; No. of Circuits:1; Supply Current:20A; On State Resistance Max:31ohm; Supply Voltage Range:2.3V to 5.5V; Analogue Switch Case Style:TSSOP; No. of Pins:8; Multiplexer Configuration:2:1; Operating ;RoHS Compliant: Yes
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫(xiě)一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*