ADM3490ARZ Analog Devices Inc, ADM3490ARZ Datasheet - Page 14

• Manufacturer Part Number: ADM3490ARZ
• Description: IC TXRX RS-422/485 3.3V 8-SOIC
• Manufacturer: Analog Devices Inc
• Type: Transceiverr

Specifications of ADM3490ARZ

• Number Of Drivers/receivers: 1/1
• Protocol: RS422, RS485
• Voltage - Supply: 3 V ~ 3.6 V
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Device Type: Differential Line Transceiver
• Ic Interface Type: RS422, RS485
• No. Of Drivers: 2
• Supply Voltage Range: 3V To 3.6V
• Driver Case Style: SOIC
• No. Of Pins: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
CIRCUIT DESCRIPTION
The ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
are low power transceivers for RS-485 and RS-422 communi-
cations. The ADM3483/ADM3488 transmit and receive at data
rates up to 250 kbps; the ADM3485/ADM3490/ADM3491 trans-
mit at up to 10 Mbps. The ADM3488/ADM3490/ADM3491 are
full-duplex transceivers, while the ADM3483/ADM3485 are half-
duplex transceivers. Driver enable (DE) and receiver enable ( RE )
pins are included on the ADM3483/ADM3485/ADM3491. When
disabled, the driver and receiver outputs are high impedance.
DEVICES WITH RECEIVER/DRIVER ENABLES—
ADM3483/ADM3485/ADM3491
Table 8. Transmitting Truth Table
RE
X
X
0
1
1
2
3
Table 9. Receiving Truth Table
RE
0
0
0
1
1
2
3
DEVICES WITHOUT RECEIVER/DRIVER ENABLES—
ADM3488/ADM3490
Table 10. Transmitting Truth Table
Transmitting Input
DI
1
0
Table 11. Receiving Truth Table
Receiving Input
A – B
≥ +0.2 V
≤ −0.2 V
Inputs open
A and B outputs are Z and Y respectively, for full-duplex part (ADM3491).
X = don’t care.
High-Z = high impedance.
DE is a don’t care; X for the full-duplex part (ADM3491).
X = don’t care.
High-Z = high impedance.
2
2
Transmitting Input
Receiving Input
DE
0
0
0
0
1
DE
1
1
0
0
A – B
≥ +0.2 V
≤ −0.2 V
Inputs Open
X
2
DI
1
0
X
X
2
2
Transmitting Output
B
0
1
High-Z
High-Z
1
Transmitting Output
Z
0
1
Receiving Output
RO
1
0
1
Receiving Output
RO
1
0
1
High-Z
3
3
3
A
1
0
High-Z
High-Z
1
Y
1
0
3
3
Mode
Normal
Normal
Normal
Shutdown
Mode
Normal
Normal
Normal
Shutdown
Rev. D | Page 14 of 20
REDUCED EMI AND REFLECTIONS—
ADM3483/ADM3488
The ADM3483/ADM3488 are slew rate limited transceivers,
minimizing EMI and reducing reflections caused by improp-
erly terminated cables.
LOW POWER SHUTDOWN MODE
(ADM3483/ADM3485/ADM3491)
A low power shutdown mode is initiated by bringing RE high
and DE low. The devices do not shut down unless both the driver
and receiver are disabled (high impedance). In shutdown mode,
the devices typically draw only 2 nA of supply current. For these
devices, the t
low power shutdown mode; the t
the receiver or driver was disabled, but the part is not shut down.
DRIVER OUTPUT PROTECTION
Two methods are implemented to prevent excessive output
current and power dissipation caused by faults or by bus
contention. Current limit protection on the output stage
provides immediate protection against short circuits over
the whole common-mode voltage range (see the Typical
Performance Characteristics section). In addition, a ther-
mal shutdown circuit forces the driver outputs into a high
impedance state if the die temperature rises excessively.
PROPAGATION DELAY
Skew time is the difference between the low-to-high and high-
to-low propagation delays. Small driver/receiver skew times help
maintain a symmetrical mark-space ratio (50% duty cycle).
The receiver skew time (|t
for ADM3483/ADM3488). The driver skew times are 8 ns for
ADM3485/ADM3490/ADM3491 and typically under 100 ns for
ADM3483/ADM3488.
TYPICAL APPLICATIONS
The ADM3483/ADM3485/ADM3491 transceivers are designed
for half-duplex bidirectional data communications on multipoint
bus transmission lines, Figure 32 and Figure 33 show typical
network applications circuits. The ADM3488 and the ADM3490
full-duplex transceivers are designed to be used in a daisy-chain
network topology or in a point-to-point application, see Figure 34
and Figure 35. The ADM3491 can be used as line repeat Figure 36.
To minimize reflections, the line must be terminated at both
ends in its characteristic impedance, and stub lengths off the main
line must be kept as short as possible. The slew rate limited
ADM3483/ADM3488 are more tolerant of imperfect termination.
PSH
and t
PSL
enable times assume the part is in the
PRLH
− t
PZH
PRHL
and t
|) is under 10 ns (20 ns
PZL
enable times assume