PCA9512B(2011) Просмотр технического описания (PDF) - NXP Semiconductors.
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PCA9512B Datasheet PDF : 24 Pages
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NXP Semiconductors
7. Pinning information
7.1 Pinning
PCA9512A; PCA9512B
Level shifting hot swappable I2C-bus and SMBus bus buffer
VCC2 1
8 VCC
SCLOUT 2 PCA9512AD 7 SDAOUT
SCLIN 3 PCA9512BD 6 SDAIN
GND 4
5 ACC
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Fig 2. Pin configuration for SO8
VCC2 1
SCLOUT 2
SCLIN 3
GND 4
PCA9512ADP
PCA9512BDP
8 VCC
7 SDAOUT
6 SDAIN
5 ACC
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Fig 3. Pin configuration for TSSOP8
7.2 Pin description
Table 3. Pin description
Symbol Pin Description
VCC2
1
Supply voltage for devices on the card I2C-bus. Connect pull-up resistors
from SDAOUT and SCLOUT to this pin.
SCLOUT 2
serial clock output to and from the SCL bus on the card
SCLIN
3
serial clock input to and from the SCL bus on the backplane
GND
4
ground supply; connect this pin to a ground plane for best results.
ACC
SDAIN
5
CMOS threshold digital input pin that enables and disables the rise time
accelerators on all four SDAn and SCLn pins. ACC enables all accelerators
when set to VCC2, and turns them off when set to GND.
6
serial data input to and from the SDA bus on the backplane
SDAOUT 7
serial data output to and from the SDA bus on the card
VCC
8
supply voltage; from the backplane, connect pull-up resistors from SDAIN
and SCLIN to this pin.
8. Functional description
Refer to Figure 1 “Block diagram of PCA9512A/B”.
8.1 Start-up
When the PCA9512A/B is powered up, either VCC or VCC2 may rise first, within a short
time of each other and either may be more positive or they may be equal, however the
PCA9512A/B will not leave the undervoltage lockout or initialization state until both VCC
and VCC2 have gone above 2.5 V. If either VCC or VCC2 drops below 2.0 V it will return to
the undervoltage lockout state. Use of PCA9512B is required where the interval
between rise of VCC and VCC2 is not simultaneous. In the undervoltage lockout state
the connection circuitry is disabled, the rise time accelerators are disabled, and the
precharge circuitry is also disabled. After both VCC and VCC2 are valid, independent of
which is higher, the PCA9512A/B enters the initialization state; during this state the 1 V
precharge circuitry is activated and pulls up the SDAn and SCLn pins to 1 V through
individual 100 kΩ nominal resistors. At the end of the initialization state the ‘Stop bit and
PCA9512A_PCA9512B
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 5 — 5 January 2011
© NXP B.V. 2011. All rights reserved.
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