Transformer Driver for
Isolated RS-485 Interface
__________________________________________Typical Operating Characteristics
(Circuit of Figure 6, V
IN
= 5V ±10%, T
A
= +25°C, unless otherwise noted.)
OUTPUT RESISTANCE vs. TEMPERATURE
(FS = LOW)
plot01
MAX253
OUTPUT RESISTANCE vs. TEMPERATURE
(FS = HIGH)
plot02
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
INCLUDES SWITCH LEAKAGE CURRENTS
SHUTDOWN CURRENT (µA)
0.8
plot03
10.5
MEASURED AT TP1
10.0
OUTPUT RESISTANCE (Ω)
9.5
9.0
8.5
8.0
7.5
7.0
6.5
6.0
V
IN
= 5.0V
V
IN
= 4.5V
15
MEASURED AT TP1
OUTPUT RESISTANCE (Ω)
1.0
12
V
IN
= 4.5V
V
IN
= 5.0V
9
0.6
0.4
0.2
6
-60 -40 -20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
-60 -40 -20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
0
-60 -40 -20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
D1, D2 FREQUENCY vs. TEMPERATURE
(FS = LOW)
plot04
D1, D2 FREQUENCY vs. TEMPERATURE
(FS = HIGH)
plot05
SUPPLY CURRENT vs. TEMPERATURE
(FS = LOW)
V
IN
= 6.0V
plot06
260
480
600
550
SUPPLY CURRENT (µA)
500
V
IN
= 5.5V
450
400
350
300
V
IN
= 5.0V
240
FREQUENCY (kHz)
V
IN
= 6.0V
FREQUENCY (kHz)
440
V
IN
= 6.0V
220
V
IN
= 5.5V
400
V
IN
= 5.5V
360
V
IN
= 5.0V
V
IN
= 4.5V
280
200
180
V
IN
= 5.0V
V
IN
= 4.5V
320
V
IN
= 4.5V
250
-60 -40 -20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
160
-60 -40 -20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
-60 -40 -20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
SUPPLY CURRENT vs. TEMPERATURE
(FS = HIGH)
plot07
EFFICIENCY vs. LOAD CURRENT
(FS = LOW)
90
plot08
850
800
SUPPLY CURRENT (µA)
750
700
650
600
550
500
450
400
V
IN
= 4.5V
V
IN
= 5.0V
V
IN
= 5.5V
V
IN
= 6.0V
100
V
IN
= 5.5V
V
IN
= 4.5V
80
EFFICIENCY (%)
70
60
50
40
30
20
10
0
-60 -40 -20 0 20 40 60 80 100 120 140
TEMPERATURE (°C)
0
200
20 40 60 80 100120 140 160 180
LOAD CURRENT (mA)
_______________________________________________________________________________________
3
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
