LTC2872
Typical perForMance characTerisTics
RS485 Receiver Propagation
Delay vs Temperature
80
V
CC
= 3.3V, V
L
= 1.7V
V
CC
= 5V, V
L
= 1.7V
V
CC
= 3.3V, V
L
= 3.3V
V
CC
= 5V, V
L
= 5V
6
5
OUTPUT VOLTAGE (V)
4
3
2
1
40
–50
0
RS485 Receiver Output Voltage
vs Load Current
V
L
= 5V
V
L
= 3.3V
V
L
= 1.7V
THRESHOLD VOLTAGE (V)
2.0
RS232 Receiver Input Threshold
vs Temperature
70
DELAY (ns)
1.8
INPUT HIGH
1.6
60
1.4
INPUT LOW
50
1.2
V
CC
= 5V
V
CC
= 3.3V
–25
0
25
50
TEMPERATURE (°C)
75
100
2872 G12
–25
50
0
25
TEMPERATURE (°C)
75
100
2872 G10
0
2
8
4
6
OUTPUT CURRENT (mA)
10
2872 G11
1.0
–50
RS232 Receiver Output Voltage
vs Load Current
6
5
OUTPUT VOLTAGE (V)
4
3
2
1
0
V
L
= 5V
V
L
= 3.3V
V
L
= 1.7V
RESISTANCE ( )
130
128
126
124
122
120
118
116
114
112
0
2
8
4
6
OUTPUT CURRENT (mA)
10
2872 G13
RS485 Termination Resistance
vs Temperature
V
CM
= –7V
V
CM
= 2V
V
CM
= 12V
RS232 Operation at 500kbps
DY
DZ
Z
5V/DIV
Y
RA
RB
WRAPPING DATA
DOUT LOADS: 5kΩ + 50pF
1µs/DIV
2872 G15
110
–50
–25
50
0
25
TEMPERATURE (°C)
75
100
2872 G14
RS485 Operation at 20Mbps
5V/DIV
DY
RS232 Driver Outputs Enabling
and Disabling
DXEN
V
DD
and V
EE
Powering Up
Z
1V/DIV
Y
5V/DIV
RA
2872 G16
Y
5V/DIV
FEN = VL
Z
Y
Z
40ns/DIV
FEN = 0V
2V/DIV
FEN
5V/DIV
V
DD
V
EE
H/F HIGH
Y, Z LOADS: 120Ω (DIFF) + 50pF
20ns/DIV
2872 G17
100µs/DIV
2872 G18
2872f
7
LINEAR [ LINEAR INTEGRATED SYSTEMS ]
