Datasheet

LTC4314
6
4314f
PIN FUNCTIONS
ACC: Three-State Acceleration and Buffer Mode Selec-
tor. This pin controls the turn on voltage of the rise time
accelerators and their current strength on both the input
and output sides. It also controls the turn-off voltage of
the buffers. See Table 1 in the Applications Information
section.
DISCEN: Disconnect Stuck Bus Enable Input. When this
pin is high, stuck busses are automatically disconnected
and FAULT is pulled low after a timeout period of 45ms.
Up to sixteen clock pulses are subsequently applied to the
stuck output channels. When DISCEN is low, stuck busses
are neither disconnected nor clocked but FAULT is pulled
low. Connect to GND if unused.
ENABLE1-ENABLE4: Connection Enable Inputs. These
input pins enable or disable the corresponding output
channel. Driving an ENABLE pin low isolates SDAIN and
SCLIN from the corresponding SDAOUT and SCLOUT.
Only enable and disable a channel when all busses are
idle. During bus stuck low fault condition, a falling edge
on all ENABLE pins followed by a rising edge on one or
more ENABLE pins forces a connection from SDAIN to
the selected SDAOUT and SCLIN to the selected SCLOUT.
Connect to GND if unused.
Exposed Pad (QFN Package Only): Exposed pad may be
left open or connected to device GND.
FAULT: Stuck Bus Fault Output. This open drain N-channel
MOSFET output pulls low if a simultaneous high on the
enabled SCLOUT and SDAOUT channels does not occur in
45ms. In normal operation FAULT is high. Connect a pull
up resistor, typically 10k, from this pin to the bus pull-up
supply. Leave open or tie to GND if unused.
GND: Device Ground.
SCLIN: Upstream Serial Bus Clock Input/Output. Connect
this pin to the SCL line on the upstream bus. Connect an
external pull-up resistor or current source between this
pin and the bus supply. Do not leave open.
SCLOUT1-SCLOUT4: Downstream Serial Bus Clock Input/
Output Channels 1-4. Connect pins SCLOUT1-SCLOUT4
to the SCL lines on the downstream channels 1-4, respec-
tively. When in use, an external pull-up resistor or current
source is required between the pin and the corresponding
bus supply. Leave open or tie to GND and connect the
corresponding ENABLE pin to GND if unused.
SDAIN: Upstream Serial Bus Data Input/Output. Connect
this pin to the SDA line on the upstream bus. Connect an
external pull-up resistor or current source between this
pin and the bus supply. Do not leave open.
SDAOUT1-SDAOUT4: Downstream Serial Bus Data Input/
Output Channels 1-4. Connect pins SDAOUT1-SDAOUT4 to
the SDA lines on downstream channels 1-4, respectively.
When in use, an external pull-up resistor or current source
is required between the pin and the corresponding bus
supply. Leave open or tie to GND and connect the cor-
responding ENABLE pin to GND if unused.
V
CC
: Power Supply Voltage. Power this pin from a sup-
ply between 2.9V and 5.5V. Bypass with at least 0.01μF
to GND.
V
CC2
: Output Side Rise Time Accelerator (RTA) Power
Supply Voltage. When powering V
CC2
, use a supply volt-
age ranging from 2.25V to 5.5V and bypass with at least
0.01μF to GND. If the downstream busses are powered
from multiple supply voltages, power V
CC2
from the low-
est supply voltage. Output side RTAs are active if V
CC2
≥
2.25V and ACC is low or open. Grounding V
CC2
disables
output side RTAs.