參數(shù)資料
型號(hào): PCA9545A
廠商: NXP Semiconductors N.V.
英文描述: 4-channel I2C switch with interrupt logic and reset
中文描述: 4通道的I2C中斷邏輯開(kāi)關(guān)和復(fù)位
文件頁(yè)數(shù): 8/27頁(yè)
文件大小: 155K
代理商: PCA9545A
9397 750 14311
Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Product data sheet
Rev. 03 — 3 March 2005
8 of 27
Philips Semiconductors
PCA9545A
4-channel I
2
C switch with interrupt logic and reset
7.4 Power-On Reset
When power is applied to V
DD
, an internal Power-On Reset (POR) holds the PCA9545A in
a reset condition until V
DD
has reached V
POR
. At this point, the reset condition is released
and the PCA9545A registers and I
2
C-bus 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.
7.5 Voltage translation
The pass gate transistors of the PCA9545A 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.
Figure 7
shows the voltage characteristics of the pass gate transistors (note that the graph
was generated using the data specified in
Section 11 “Static characteristics”
of this data
sheet). In order for the PCA9545A to act as a voltage translator, the V
o(sw)
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
o(sw)
should be
equal to or below 2.7 V to effectively clamp the downstream bus voltages. Looking at
Figure 7
, we see that V
o(sw)(max)
will be at 2.7 V when the PCA9545A supply voltage is
3.5 V or lower, so the PCA9545A 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 14
).
More Information can be found in Application Note AN262: PCA954X family of I2C/SMBus
multiplexers and switches
(1) maximum
(2) typical
(3) minimum
Fig 7.
Pass gate voltage versus supply voltage
V
DD
(V)
2.0
5.5
4.5
3.0
4.0
002aaa964
3.0
2.0
4.0
5.0
V
o(sw)
(V)
1.0
3.5
5.0
2.5
(1)
(2)
(3)
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PCA9545ABS 制造商:PHILIPS 制造商全稱(chēng):NXP Semiconductors 功能描述:4-channel I2C-bus switch with interrupt logic and reset
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PCA9545ABS-T 功能描述:多路器開(kāi)關(guān) IC I2C SWITCH 4CH RoHS:否 制造商:Texas Instruments 通道數(shù)量:1 開(kāi)關(guān)數(shù)量:4 開(kāi)啟電阻(最大值):7 Ohms 開(kāi)啟時(shí)間(最大值): 關(guān)閉時(shí)間(最大值): 傳播延遲時(shí)間:0.25 ns 工作電源電壓:2.3 V to 3.6 V 工作電源電流: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UQFN-16
PCA9545AD 功能描述:多路器開(kāi)關(guān) IC 4-CH I2C SWITCH W/INT+RESET RoHS:否 制造商:Texas Instruments 通道數(shù)量:1 開(kāi)關(guān)數(shù)量:4 開(kāi)啟電阻(最大值):7 Ohms 開(kāi)啟時(shí)間(最大值): 關(guān)閉時(shí)間(最大值): 傳播延遲時(shí)間:0.25 ns 工作電源電壓:2.3 V to 3.6 V 工作電源電流: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UQFN-16
PCA9545AD,112 功能描述:多路器開(kāi)關(guān) IC 4-CH I2C SWITCH RoHS:否 制造商:Texas Instruments 通道數(shù)量:1 開(kāi)關(guān)數(shù)量:4 開(kāi)啟電阻(最大值):7 Ohms 開(kāi)啟時(shí)間(最大值): 關(guān)閉時(shí)間(最大值): 傳播延遲時(shí)間:0.25 ns 工作電源電壓:2.3 V to 3.6 V 工作電源電流: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UQFN-16