LTC1685_15 Datasheet, PDF (1/12 Pages) Linear Technology – 52Mbps, Precision Delay, RS485 Fail-Safe Transceiver

LTC1685
52Mbps, Precision Delay,
RS485 Fail-Safe Transceiver
FEATURES
s _{Precision Propagation Delay Over Temperature:}
Receiver/Driver: 18.5ns ±3.5ns
s _{High Data Rate: 52Mbps}
s _{Low tPLH/tPHL Skew:}
Receiver/Driver: 500ps Typ
s _{–7V to 12V RS485 Input Common Mode Range}
s _{Guaranteed Fail-Safe Receiver Operation Over the}
Entire Common Mode Range
s _{High Receiver Input Resistance: ≥ 22k, Even When}
Unpowered
s _{Short-Circuit Protected}
s _{Thermal Shutdown Protected}
s _{Driver Maintains High Impedance in Three-State or}
with Power Off
s _{Single 5V Supply}
s _{Pin Compatible with LTC485}
s _{45dB CMRR at 26MHz}
U
APPLICATIO S
s _{High Speed RS485/RS422 Transceivers}
s _{Level Translator}
s _{Backplane Transceiver}
s _{STS-1/OC-1 Data Transceiver}
s _{Fast-20, Fast-40 SCSI Transceivers}
DESCRIPTIO
The LTC^®1685 is a high speed, precision delay RS485
transceiver that can operate at data rates as high as 52Mbps.
The device also meets the requirements of RS422.
A unique architecture provides very stable propagation
delays and low skew over a wide common mode and
ambient temperature range.
The driver and receiver feature three-state outputs, with
disabled driver outputs maintaining high impedance over
the entire common mode range. A short circuit feature
detects shorted outputs and substantially reduces driver
output current. A similar feature also protects the receiver
output from short circuits. Thermal shutdown circuitry
protects from excessive power dissipation.
The receiver has a fail-safe feature that guarantees a high
output state when the inputs are shorted or are left floating.
The LTC1685 RS485 transceiver guarantees receiver fail-
safe operation over the entire common mode range (– 7V
to 12V). Input resistance will remain ≥ 22k when the device
is unpowered or disabled.
The LTC1685 operates from a single 5V supply and draws
only 7mA of supply current.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
RO1
R
RE1
DE1
DI1
D
V_CC1
Rt
GND1
RO2
R
RE2
DE2
DI2
D
Rt
V_CC2
GND2
1685 TA01
2V/DIV
10Mbps Data Pulse
400ft Category 5 UTP
CABLE DELAY
DRIVER INPUT
1V/DIV
RECEIVER
INPUT
5V/DIV
100ns/DIV
RECEIVER
OUTPUT
1685 TA02
1