PCA9521D118 데이터 시트보기 (PDF) - NXP Semiconductors.
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PCA9521D118 Datasheet PDF : 23 Pages
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NXP Semiconductors
PCA9521
Fast dual bidirectional bus buffer
1.8 V
R1
600 Ω
VCC
SCL
SDA
BUS MASTER
400 kHz
U1
3.3 V
10 V 10 V
R2
600 Ω
C1
0.01 μF
R3
3.9 kΩ
R4
3.9 kΩ
VCC
SA1
SA2
SB1
SB2
PCA9521
EN
backplane
U2
or cable run
5V
C2
0.01 μF
R5
1.1 kΩ
VCC
SA1
SA2
SB1
SB2
PCA9521
EN
U3
Fig 11. PCA9521 typical buffer application
3.3 V
R6
1.1 kΩ
VCC
SCL
SDA
SLAVE
100 kHz
U4
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Figure 12 shows the PCA9521 used in a radial (star) configuration on an AdvancedTCA
Shelf Management Controller board (ShMC). The PCA9521 is highly suited to this and
other backplane applications, providing excellent noise margins and I2C-bus compliant
switching levels.
fully bused compliant plug-in
(hot-insert) ShMC module (e.g., AMC)
(1)
R
R
RRA
µP
PCA9522
VI
VOL = VI + 0.08 V
Rd
PCA9521
Rd
enables
R
FET
switches
BACKPLANE
to ShMC #2
FRU with switching levels compliant
with the I2C-bus standard
R
PCA9522
µP
required VIL = 0.3VCC (max.) = 0.99 V
alternate
implementations
R
µP
I2C-bus
PCA9521
12 × PCA9521
isolating
bus buffers
Vmax = 0.5 V
(PICMG3.0)
Rd
ShMC1
ShMC2
PCA9521
Rd
PCA9521
enables
R
FET
switches
IPMB (× 24)
to ShMC #2
example of existing FRUs
built to PICMG3.0 R2.0
BUFFER
WITH RTA
R
µP
required VIL = 0.6 V (typ.)
etc.
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The system shown here uses FET switches, however a valid alternative is to simply use 24 PCA9521’s without FET switches.
Long track runs on the ShMC board and backplane can sometimes result in high frequency tuned circuits on either side of the
PCA9521. If your layout is prone to forming such tuned circuits, it is perfectly acceptable to use a ‘traditional’ damping resistor
(Rd) across the PCA9521.
(1) RRA = Rise Rate Accelerator.
Fig 12. AdvancedTCA style backplane application using PCA9521 in a radial Shelf Manager configuration
PCA9521
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 2 — 19 March 2013
© NXP B.V. 2013. All rights reserved.
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