MAX1480BCPI Maxim Integrated Products, MAX1480BCPI Datasheet - Page 13

• Manufacturer Part Number: MAX1480BCPI
• Description: RS-422/RS-485 Interface IC
• Manufacturer: Maxim Integrated Products

Specifications of MAX1480BCPI

• Data Rate: 250 Kbps
• Operating Supply Voltage: 5 V
• Supply Current: 95 mA
• Operating Temperature Range: 0 C to + 70 C
• Package / Case: PDIP-28
• Maximum Power Dissipation: 727 mW
• Mounting Style: Through Hole
• Supply Voltage (max): 5.5 V
• Lead Free Status / Rohs Status: No

Figure 2. MAX1490A/MAX1490B Detailed Block Diagram and Typical Application Circuit
Under these conditions, the MAX1480B/MAX1480C/
MAX1490B supply current is reduced to as low as 0.2µA.
The high-speed optocouplers on the MAX1480A/
MAX1480C/MAX1490A consume an additional 10mA
through V
completely shut down these devices, use an external P-
channel MOSFET as shown in Figure 3. In normal opera-
RO
DI
FS
OR EQUIVALENT
V
5V
IN
74HC86
CC5
1.07MHz/
1.45MHz
RECEIVER OUTPUT
DRIVER INPUT
C1
22μF
OSC
(V
CC4
______________________________________________________________________________________
V
CC3
0.1μF
C2
T F/F
for the MAX1490A). Therefore, to
DI
´
Q
Q
R1
Table 2. Pull-Up and LED Drive Resistors
R2
SD
MAX1490A
MAX1490B
PART
LOGIC GROUND
GND1
GND2
V
V
V
V
CC1
CC2
CC3
CC4
Complete, Isolated RS-485/RS-422
D1
SD
D2
FS
R0
DI
MAX845
10
11
12
1
2
3
4
5
6
7
8
9
ISOLATION BARRIER
MAX1490A/B
GND1
N
N
R1 (Ω)
200
200
D1
D2
21
18
17
24
23
22
20
19
16
15
14
13
ISO RO DRV
ISO DI DRV
AC1 (MAKE NO CONNECTION)
AC2 (MAKE NO CONNECTION)
ISO RO DRV
A
B
Z
Y
ISO COM1
ISO DI DRV
ISO V
ISO RO LED
ISO V
CC1
CC2
R3
R2 (Ω)
tion, SD is low, turning the MOSFET on and thereby pro-
viding power to all the V
the power oscillator is disabled and the switch is turned
off, disconnecting power from the DI and DE optocou-
plers. In normal operating mode, the switch carries only
the optocoupler currents, so an on-resistance of several
ohms will not significantly degrade efficiency.
1000
3000
MAX1490A: MAX490
MAX1490B: MAX488
R4
ISOLATED COMMON
D
R
R5, 100Ω
R6, 100Ω
R3 (Ω)
330
330
SH1
SH2
A
Y
B
Z
Data Interface
EXTERNAL RS-485/RS-422 WIRING
A
B
Z
Y
NOTE: RESISTORS R5 AND R6 PROTECT
CC_
R
L
THE MAX1490A/B FROM TRANSIENT
CURRENTS BETWEEN SHIELD AND
TRANSMISSION LINES.
R
pins. When SD is pulled high,
L
R4 (Ω)
TO OTHER TRANSCEIVERS
TO OTHER TRANSCEIVERS
1000
3000
(ONE RESISTOR ON EACH END)
TERMINATING RESISTOR
SHIELD (OPTIONAL)
SHIELD (OPTIONAL)
TWISTED PAIR
TWISTED PAIR
R
R
L
L
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