LTC485IN8 Linear Technology, LTC485IN8 Datasheet - Page 9

• Manufacturer Part Number: LTC485IN8
• Description: IC TXRX INTERFACE RS485 LP 8DIP
• Manufacturer: Linear Technology
• Type: Transceiverr

Specifications of LTC485IN8

• Number Of Drivers/receivers: 1/1
• Protocol: RS485
• Voltage - Supply: 4.75 V ~ 5.25 V
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIONS INFORMATION
The LTC485 output stage will maintain a high impedance
state until the breakdown of the N-channel or P-channel
is reached when going positive or negative respectively.
The output will be clamped to either V
Zener voltage plus a Schottky diode drop, but this voltage
is way beyond the RS485 operating range. This clamp
protects the MOS gates from ESD voltages well over
2000V. Because the ESD injected current in the N-well or
substrate consists of majority carriers, latchup is prevented
by careful layout techniques.
RECEIVER
OUTPUTS
OUTPUTS
DRIVER
RO
A
B
Figure 11. Receiver t
t
r
, t
TTL IN
f
PHL
< 6ns
Figure 13. Receiver Propagation Delay Test Circuit
CC
485 F11
or ground by a
D
100pF
R
100Ω
100pF
Propagation Delay
Many digital encoding schemes are dependent upon the
difference in the propagation delay times of the driver and
the receiver. Using the test circuit of Figure 13, Figures 11
and 12 show the typical LTC485 receiver propagation
delay.
The receiver delay times are:
The driver skew times are:
RECEIVER
OUTPUTS
OUTPUTS
|t
Skew = 5ns Typ, V
DRIVER
PLH
BR
485 F13
– t
RO
A
B
PHL
10ns Max, V
R
| = 9ns Typ, V
RECEIVER
OUT
Figure 12. Receiver t
CC
CC
= 5V
= 5V, T
CC
= 5V
A
= –40°C to 85°C
PLH
485 F12
LTC485
9
485fh