Datasheet
PCA9511A_4 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 04 — 19 August 2009 4 of 24
NXP Semiconductors
PCA9511A
Hot swappable I
2
C-bus and SMBus bus buffer
7. Pinning information
7.1 Pinning
7.2 Pin description
8. Functional description
Refer to Figure 1 “Block diagram of PCA9511A”.
8.1 Start-up
An undervoltage/initialization circuit holds the parts in a disconnected state which
presents high-impedance to all SDA and SCL pins during power-up. A LOW on the
ENABLE pin also forces the parts into the low current disconnected state when the I
CC
is
essentially zero. As the power supply is brought up and the ENABLE is HIGH or the part is
powered and the ENABLE is taken from LOW to HIGH it enters an initialization state
where the internal references are stabilized and the precharge circuit is enabled. At the
end of the initialization state the ‘Stop Bit And Bus Idle’ detect circuit is enabled. With the
ENABLE pin HIGH long enough to complete the initialization state (t
en
) and remaining
HIGH when all the SDA and SCL pins have been HIGH for the bus idle time or when all
pins are HIGH and a STOP condition is seen on the SDAIN and SCLIN pins, SDAIN is
connected to SDAOUT and SCLIN is connected to SCLOUT. The 1 V precharge circuitry
Fig 2. Pin configuration for SO8 Fig 3. Pin configuration for TSSOP8
ENABLE V
CC
SCLOUT SDAOUT
SCLIN SDAIN
GND READY
002aab577
1
2
3
4
6
5
8
7
PCA9511AD
PCA9511ADP
ENABLE V
CC
SCLOUT SDAOUT
SCLIN SDAIN
GND READY
002aab578
1
2
3
4
6
5
8
7
Table 3. Pin description
Symbol Pin Description
ENABLE 1 Chip enable. Grounding this input puts the part in a low current (< 1 µA)
mode. It also disables the rise time accelerators, isolates SDAIN from
SDAOUT and isolates SCLIN from SCLOUT.
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. Connect this pin to a ground plane for best results.
READY 5 open-drain output which pulls LOW when SDAIN and SCLIN are
disconnected from SDAOUT and SCLOUT, and goes HIGH when the two
sides are connected
SDAIN 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
V
CC
8 power supply