MAX562EAI-T Maxim Integrated, MAX562EAI-T Datasheet - Page 7

• Manufacturer Part Number: MAX562EAI-T
• Description: RS-232 Interface IC
• Manufacturer: Maxim Integrated
• Series: MAX562r

Specifications of MAX562EAI-T

• Data Rate: 230 Kbps
• Operating Supply Voltage: 2.7 V to 5.25 V
• Supply Current: 33 mA
• Operating Temperature Range: 0 C to + 70 C
• Mounting Style: SMD/SMT
• Function: Transceiver
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Number Of Drivers: 3
• Number Of I/os: 16
• Number Of Receivers: 5
• Propagation Delay Time Ns: 0.5 us, 1.7 us
• Shutdown: Yes

the MAX562 transmitter outputs when SHDN rises. Two
transmitter outputs are shown going to opposite EIA/TIA-
562 levels (one transmitter input is high, the other is low).
Each transmitter is loaded with 3kΩ in parallel with
2500pF. The transmitter outputs are well behaved, with
no ringing or undesirable transients as they come out of
shutdown.
Each transmitter is designed to drive a single receiver.
Transmitters can be paralleled to drive multiple
receivers.
All 5 receivers are identical and accept EIA/TIA-562 or
EIA/TIA-232 signals. The CMOS receiver outputs swing
between V
compatibility with the driver outputs.
Figure 5. Time for Transmitters to Exit Shutdown
Table 1. MAX562 Control Pin Configurations
* Active, but with reduced performance (see EIA/TIA-562 Receivers section). This is “keep-awake” mode.
-2
-4
5
0
6
4
2
0
SHDN
0
0
1
1
CC
0
and GND. They are inverting, maintaining
V
CC
Serial Interface for Notebook Computers
= +2.2V V
_______________________________________________________________________________________
SHDN
EN
100
0
1
0
1
CC
TIME ( s)
EIA/TIA-562 Receivers
= +2.7V
Driving Multiple Receivers
V
CC
Complete 230kbps, 2.7V to 5.25V
200
Normal Operation
Normal Operation
CHARGE-PUMP
= +3.3V
OPERATION
Shutdown
Shutdown
STATUS
V
CC
300
= +5.0V
TRANSMITTERS
The guaranteed 0.8V and 2.4V receiver input thresh-
olds are significantly tighter than the ±3.0V thresholds
required by the EIA/TIA-562 specification. This allows
the receiver inputs to respond to TTL/CMOS logic lev-
els as well as EIA/TIA-562/232 levels. Also, the
MAX562's guaranteed 0.8V lower threshold ensures
that receivers shorted to ground will have a logic 1 out-
put. The 5kΩ input resistance to ground ensures that a
receiver with its input left open will also have a logic 1
output.
The receiver inputs have approximately 0.3V hysteresis
when SHDN is high. This provides clean output transi-
tions, even with slowly moving input signals with mod-
erate noise and ringing.
The receivers are active when EN is high. When EN is
low, the receiver outputs are high impedance. This
allows wire-OR connection of two EIA/TIA-562 ports (or
ports of different types) at the UART.
The receivers are always active,when EN is high, irre-
spective of SHDN's state. When SHDN is high, the
receivers have hysteresis and experience the shortest
propagation delays (typically 100ns falling, 250ns ris-
ing). When SHDN is low, the receivers have longer
propagation delays (typically 3µs falling, 2µs rising)
and have no hysteresis. The receiver outputs are not
valid for 50µs after SHDN goes low.
SHDN and EN determine the operation of the MAX562
as shown in Table 1.
The capacitor type is not critical for proper MAX562
operation. Any low cost ceramic capacitor (e.g., Z5U,
Y5V) is acceptable for operating at room temperature,
__________Applications Information
High-Z
High-Z
Active
Active
T1-T3
Shutdown and Enable Control
RECEIVERS
Active*
High-Z
High-Z
Active
R1-R5
Capacitor Selection
CURRENT
SUPPLY
TYP (A)
24m
24m
45µ
1µ
7