LTC1518 Datasheet, PDF (1/12 Pages) Linear Technology – 52Mbps Precision Delay RS485 Quad Line Receivers

FEATURES
s _{Precision Propagation Delay: 18.5ns ±3.5ns Over}
Temperature
s _{High Data Rate: 52Mbps}
s _{Low tPLH/tPHL Skew: 500ps Typ}
s _{Low Channel-to-Channel Skew: 500ps Typ}
s _{–7V to 12V RS485 Input Common Mode Range}
s _{Input Resistance ≥ 22k, Even When Unpowered}
s _{Guaranteed Fail-Safe Operation over the Entire}
Common Mode Range
s _{Hot Swap}^TM _Capable
s _{High Common Mode Rejection to 26MHz}
s _{Short-Circuit Protection: 10mA Typ Output Current}
for an Indefinite Short
s _{Three-State Output Capability}
s _{Will Not Oscillate with Slow Moving Input Signals}
s _{Single 5V Supply}
s _{Pin Compatible with LTC488, LTC489}
U
APPLICATIONS
s _{High Speed RS485/RS422 Receivers}
s _{STS-1/OC-1 Data Receivers}
s _{PECL Line Receivers}
s _{Level Translators}
s _{Fast-20/Fast-40 SCSI Receiver}
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
LTC1518/LTC1519
52Mbps Precision Delay
RS485 Quad Line Receivers
DESCRIPTION
The LTC^®1518/LTC1519 are high speed, precision delay
differential quad bus/line receivers that can operate at data
rates as high as 52Mbps. They are pin compatible with the
LTC488/LTC489 RS485 line receivers and operate over the
entire – 7V to 12V common mode range. A unique architec-
ture provides very stable propagation delays and low skew
over wide input common mode, input overdrive and ambi-
ent temperature ranges. Propagation delay is 18.5ns
±3.5ns. Typical t_PLH/t_PHL and channel-to-channel skew is
500ps.
Each receiver translates differential input levels (V_ID ≥
300mV) into valid CMOS and TTL output levels. Its high
input resistance (≥ 22k) allows many receivers to be con-
nected to the same driver. The receiver outputs go into a
high impedance state when disabled.
The receivers have a fail-safe feature that guarantees a high
output state when the inputs are shorted or left floating.
Other protection features include thermal shutdown and a
controlled maximum short-circuit current (50mA Max).
Input resistance remains ≥ 22k when the device is
unpowered or disabled, thus allowing hot swapping with-
out loading the data lines.
The LTC1518/LTC1519 operate from a single 5V supply
and draw 12mA of supply current.
TYPICAL APPLICATION
52Mbps Data Communication over Twisted Pair
RE
2
RO ¹
4
DI
7
6
3
DE
LTC1685
100Ω
100Ω
EN ^{4 A 1}
EN
12
2B
1/4 LTC1518
3
RO
RE
2
1 _RO
7
4
6
DI
3
DE
LTC1685
1518/19 F08
Propagation Delay Guaranteed to Fall
Within Shaded Area (±3.5ns)
V_IN =
3V/DIV
V_OUT =
5V/DIV
RECEIVER
OUTPUT
V_DD = 5V
RECEIVER
INPUT
V_ID = 1.5V
–5 0
5 10 15 20 25 30 35 40 45
TIME (ns)
1518/19 TA02
1