MAX562EAI Maxim Integrated, MAX562EAI Datasheet - Page 6

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

Specifications of MAX562EAI

• 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
• Function: Transceiver
• 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

Complete 230kbps, 2.7V to 5.25V
Serial Interface for Notebook Computers
Figure 3. Transmitter-Output Disable Timing
The MAX562 has three sections: the charge-pump voltage
converter, the drivers (transmitters), and the receivers.
The charge-pump voltage converter is used to produce a
positive and a negative supply to drive the transmitters. The
positive voltage (V+) is generated by a regulated charge
pump working as either a doubler or a tripler (depending on
the V
Typical Operating Circuit ). The negative voltage (V-) derives
from V+ using a simple charge-pump inverter that employs
capacitors C2 and C4.
These charge-pump converters are regulated to give output
voltages of +5.8V and -5.2V. Having regulated supplies
generated on-chip makes the MAX562's performance insen-
sitive to variations in V
ing changes, and operating temperature changes.
When SHDN is low, the charge pumps are disabled, V+ is
internally connected to V
GND.
6
_______________Detailed Description
_______________________________________________________________________________________
A. TIMING DIAGRAM
CC
B. TEST CIRCUIT
TRANSMITTER
OUTPUTS
level) and using capacitors C1A, C1B and C3 (see
1 OR 0
SHDN
V
V
OH
OL
Charge-Pump Voltage Converter
+3V
CC
T
CC
X
from 2.7V to 5.25V, transmitter load-
, and V- is internally connected to
0V
OUTPUT DISABLE TIME (t
3k
+3V
-3V
50pF
0V
DT
)
Figure 4. Receiver-Output Enable and Disable Timing
The driver output voltage is guaranteed to meet the ±3.7V
EIA/TIA-562 specification over the full range of operating
temperatures and voltages, when each transmitter is
loaded with up to 3kΩ and operated up to 230kbps (see
Typical Operating Characteristics ). The typical driver out-
put voltage swing exceeds ±4V with a 3kΩ load on all
transmitter outputs. The open-circuit output voltage swing
is typically from (V+ - 0.7V) to (V- + 0.7V). Output swing is
not significantly dependent on V
pumps are regulated.
Input thresholds are CMOS and TTL compatible. Connect
unused inputs to V
When SHDN is low, the driver outputs are off and their leak-
age currents are less than 10µA, even if the transmitter
outputs are back-driven between -7V and +15V. Taking
SHDN low does not disable the receivers.
When SHDN and EN are both low, the entire chip is
disabled and all outputs are high impedance. Power
consumption is lowest in this condition. Exiting shutdown
takes about 100µs, but depends on V
C. DISABLE TIMING
B. ENABLE TIMING
A. TEST CIRCUIT
RECEIVER
OUTPUTS
EN INPUT
EN INPUT
RECEIVER
OUTPUTS
R_
EN
IN
V
V
OH
OL
CC
+3V
or to GND.
0V
R_
R_
OUT
150pF
0V
EIA/TIA-562 Drivers
+3V
1k
V
V
OUTPUT ENABLE TIME (t
OUTPUT DISABLE TIME (t
OH
OL
V
V
CC
OL
OH
CC
+0.5V
-0.5V
since the charge
. Figure 5 shows
EN
EN
V
V
OH
OL
+1.6V
-1V,
ER
DR
)
)