_______________General Description
The MAX563 is a +3.3V-powered EIA/TIA-562 transceiver
with two transmitters and two receivers. Because it imple-
ments the EIA/TIA-562 standard, the MAX563 communi-
cates with RS-232 transceivers, yet consumes far less
power; this makes it ideal for battery-powered, hand-held
computers. And, the MAX563 guarantees a 116kbps data
rate while maintaining 3.7V EIA/TIA-562 signal levels,
which makes it compatible with LapLinkTM software.
An on-board charge pump converts the +3.3V supply to
the 6.6V needed to produce the EIA/TIA-562 output volt-
age levels. Four 0.1F charge-pump capacitors and a
bypass capacitor of similar size are the only external com-
ponents required.
When the MAX563's charge pumps and transmitters are
shut down to save power, the receivers remain active to
continuously monitor signals from external devices (for
example, ring indicator from modems). The two receivers'
outputs can be enabled and disabled independently of the
shutdown function to allow two ports--generally of different
types--to be wire-OR connected at the UART.
________________________Applications
Handiterminals
Battery-Powered Equipment
Bar-Code Readers
Notebook and Palmtop Computers
____________________________Features
o
Guaranteed Interoperability with RS-232
o
Operates from a Single +3.0V to +3.6V Supply
o
2 Drivers, 2 Receivers
o
Receivers Active in Shutdown Mode
o
Low-Power Shutdown: 10A Max
o
Small Package--18-Pin Wide SO
o
Three-State TTL/CMOS Receiver Outputs
o
116kbps Guaranteed Data Rate
______________Ordering Information
MAX563
+3.3V-Powered, EIA/TIA-562 Dual Transceiver
with Receivers Active in Shutdown
________________________________________________________________
Maxim Integrated Products
1
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
C1+
V+
C1-
C2+
C2-
V-
T2
OUT
R2
IN
V
CC
GND
T1
OUT
R1
IN
R1
OUT
T1
IN
T2
IN
R2
OUT
MAX563
DIP/SO
TOP VIEW
EN
SHDN
__________________Pin Configuration
V+
GND
VCC
+3.3V
C1-
V
CC
ALL CAPACITORS 0.1F
5k
V-
5k
VOLTAGE DOUBLER
VOLTAGE INVERTER
CMOS
INPUTS
CMOS
OUTPUTS
1
10
13
11
12
6
5
4
2
3
7
15
8
14
9
18
RS-562/RS-232
INPUTS
RS-562
OUTPUTS
C1+
C2+
C2-
V
CC
C3
R2
IN
R1
IN
T2
OUT
T1
OUT
T1
IN
T2
IN
R1
OUT
R2
OUT
EN
400k
400k
SHDN
+6.6V
-6.6V
C4
17
C1
C2
ON/OFF
__________Typical Operating Circuit
Call toll free 1-800-998-8800 for free samples or literature.
19-0198; Rev 0; 10/93
PART
TEMP. RANGE
PIN-PACKAGE
MAX563CPN
0C to +70C
18 Plastic DIP
MAX563CWN
0C to +70C
18 Wide SO
MAX563C/D
0C to +70C
Dice *
TM LapLink is a registered trademark of Traveling Software, Inc.
* Dice are specified at T
A
= +25C.
MAX563
+3.3V-Powered, EIA/TIA-562 Dual Transceiver
with Receivers Active in Shutdown
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
Power Supply Ranges
Supply Voltage (V
CC
) ...........................................-0.3V to +6V
Input Voltages
T
IN
.........................................................-0.3V to (V
CC
-0.3V)
R
IN
...............................................................................25V
T
OUT
(Note 1)...................................................................15V
Output Voltages
T
OUT
.............................................................................15V
R
OUT
....................................................-0.3V to (V
CC
+0.3V)
Driver/Receiver Output Short Circuit to GND.........Continuous
Continuous Power Dissipation (T
A
= +70C)
Plastic DIP ....................................................................889mW
Wide SO .......................................................................762mW
Operating Temperature Range...............................0C to +70C
Storage Temperature Range .............................-65C to +160C
Lead Temperature (soldering, 10sec) .............................+300C
ELECTRICAL CHARACTERISTICS
(V
CC
= 3.0V to 3.6V, C1-C4 = 0.1F, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Input Voltage Operating Range
SYMBOL
MIN
TYP
MAX
25
UNITS
V
Input Threshold Low
V
IL
0.4
Logic Pull-Up/Input Current
2
20
V
A
Input Logic Threshold High
V
IH
2.4
V
Input Threshold High
Output Leakage Current
0.01
10
A
V
IH
2.4
V
Transmitter Output Resistance
300
10M
Input Hysteresis
0.1
0.5
1.0
V
Input Resistance
Output Voltage Swing
R
IN
3
5
7
k
Output Voltage Low
V
OL
0.2
0.4
V
Output Voltage High
V
OH
V
CC
-0.6 V
CC
-0.2
V
Output Leakage Current
3.7
4.5
V
0.05
10
A
EN Input Threshold Low
Input Logic Threshold Low
V
IL
0.6
V
V
IL
0.6
V
EN Input Threshold High
V
IH
2.4
V
CONDITIONS
V
CC
= 3.3V
SHDN = V
CC
V
CC
= 3.6V,
SHDN = 0V, V
OUT
= 15V
V
CC
= 3.3V
V
CC
= V+ = V- = 0V, V
OUT
= 2V
SHDN = V
CC
= 3.3V (no hysteresis when
SHDN = 0V)
I
OUT
= 3.2mA
I
OUT
= -0.5mA
All transmitter outputs loaded with 3k
to
GND
EN = V
CC
, 0V
V
OUT
V
CC
Note 1:
Input voltage measured with T
OUT
in high-impedance state.
SHDN or V
CC
= 0V.
V
CC
=
SHDN = 0V, V
OUT
= 15V
0.01
10
SHDN = 0V
0.01
1
Data Rate
200
116
kbps
R
L
= 3k
, C
L
= 1000pF, T
A
= +25C
Output Short-Circuit Current
V
OUT
= 0V
PARAMETER
15
60
mA
RS-562 TRANSMITTERS
RS-232/RS-562 RECEIVERS
MAX563
+3.3V-Powered, EIA/TIA-562 Dual Transceiver
with Receivers Active in Shutdown
__________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 3.0V to 3.6V, C1-C4 = 0.1F, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
SHDN Threshold Low
V
IL
0.6
V
SHDN Input Leakage Current
0.1
1
A
Shutdown Supply Current
I
CC
2
50
A
0.1
10
SHDN Threshold High
V
IH
2.4
V
3
8
V
CC
Supply Current
I
CC
8
mA
Transition Slew Rate
4
6
30
V/s
t
PHLT
1.3
3.5
Transmitter Propagation Delay
t
PLHT
1.5
3.5
s
t
PHLR
0.5
1.0
Receiver Propagation Delay
(Normal Operation)
t
PLHR
0.6
1.0
s
t
PHLS
0.5
10.0
Receiver Propagation Delay
(Shutdown)
t
PLHS
2.5
10.0
s
Receiver-Output Enable Time
t
ER
125
500
ns
Receiver-Output Disable Time
t
DR
160
500
ns
Transmitter-Output Enable
Time
t
ET
300
s
Transmitter-Output Disable
Time
t
DT
600
ns
CONDITIONS
C
L
= 50pF to 2500pF, R
L
= 3k
to 7k
,
V
CC
= 3.3V, T
A
= +25C, measured from
+3V to -3V or -3V to +3V (Note 2)
Figure 1
Figure 2
Figure 3
Figure 3
Figure 4
No load
Figure 4
R
L
= 3k
on both outputs, inputs static
Includes charge pump start-up
Figure 5
Transmitter Propagation Delay
Skew
t
PHLT
t
PLHT
300
ns
Receiver Propagation Delay
Skew (Normal Operation)
t
PHLR
t
PLHR
100
ns
Operating Supply Voltage
V
CC
3.0
3.6
V
T
A
= +25C
T
A
= T
MIN
to T
MAX
Note 2:
Minimum slew rate is specified with C
L
= 1000pF for data rates above 20kbps, corresponding with EIA/TIA-562.
POWER SUPPLY
AC CHARACTERISTICS
MAX563
_______________Detailed Description
The MAX563 consists of three sections: charge-pump
voltage converters, transmitters (drivers), and
receivers. Both the transmitters and the receivers are
inverting.
+3V to 6V, Dual Charge-Pump Voltage
Converter
Two charge pumps either invert or double the incoming
V
CC
to generate the voltages required by the transmit-
ters. The first charge pump uses capacitor C1 to
double V
CC
; the resulting voltage is stored on the V+
reservoir capacitor. The second charge pump uses
capacitor C2 to invert V+; this negative voltage is
stored on the V- capacitor.
When
SHDN is low, the charge pumps are turned off,
V+ is pulled down to V
CC
by a 1k
resistor, and V-
rises to GND.
It is possible to draw some power from the V+ and V-
pins for external use. However, doing so diminishes the
charge-pump output voltages and reduces noise mar-
gins, so it is not recommended.
EIA/TIA-562 Transmitters
The MAX563's drivers are inverting level translators that
convert +3V logic inputs to EIA/TIA-562 voltage levels.
With a VCC supply of only 3.0V, the driver outputs
deliver the EIA/TIA-562 3.7V minimum specification
under worst-case conditions--when both transmitters
are loaded with 3k
receivers (either EIA/TIA-232 or
EIA/TIA-562).
The transmitters are fast: the guaranteed data rate with
standard loads is 116kbps, which is the highest rate
commonly used by PC-to-PC communication software,
such as LapLink. The highest practical data rate may
be reduced if the other communicating device (RS-562
or RS-232) is not as fast, or if the cables present an
excessive capacitive load (>1000pF). Each transmitter
is designed to drive a single receiver; transmitters can
be paralleled to drive multiple receivers.
When
SHDN is low, the driver outputs are turned off.
Their output leakage currents are less than 10A when
pulled to GND or when driven to 15V. This enables
two transmitters to be connected to the same line, pro-
vided that one of them is always disabled by taking
SHDN low.
+3.3V-Powered, EIA/TIA-562 Dual Transceiver
with Receivers Active in Shutdown
4
_______________________________________________________________________________________
______________________________________________________________Pin Description
10, 13
NAME
FUNCTION
R2
OUT
, R1
OUT
EN
Receiver enable. Connect
EN to GND to enable receivers, and take EN high to disable receivers.
CMOS receiver outputs. These outputs are active regardless of the state of
SHDN. They
are enabled when
EN is low, and disabled (Hi-Z) when EN is high.
C1+
Positive terminal of positive charge-pump capacitor.
11, 12
V+
+2V
CC
voltage generated by the positive charge pump. The voltage on V+ collapses to
V
CC
when
SHDN is low.
PIN
1
2
T2
IN
, T1
IN
C1-
Negative terminal of positive charge-pump capacitor.
CMOS driver inputs.
C2+
Positive terminal of inverting charge-pump capacitor.
16
C2-
Negative terminal of inverting charge-pump capacitor.
GND
V-
-2V
CC
voltage generated by the inverting charge pump. The voltage on V- collapses to
GND when
SHDN is low.
3
4
5
Ground.
T2
OUT
, T1
OUT
EIA/TIA-562 voltage-level transmitter outputs. These outputs are disabled (Hi-Z) when
SHDN is low.
17
R2
IN
, R1
IN
EIA/TIA-562 and EIA/TIA-232 voltage-level receiver inputs.
6
7
8, 15
9, 14
V
CC
+3.0V to +3.6V supply voltage.
18
SHDN
Shutdown control. Connect to GND to shut down the charge pumps and the transmitters.
Take high to turn on the charge pumps and to enable the transmitters.
The inputs of unused drivers may be left unconnected
because they have internal 400k
pull-ups to V
CC
.
Unused inputs may also be connected to GND or V
CC
,
but V
CC
provides lower power consumption because of
the internal pull-ups.
EIA/TIA-562 and EIA/TIA-232 Receivers
The MAX563's receivers convert 3.7V to 13.2V
EIA/TIA-562 signal levels into +3V logic levels; they are
rated to receive signals up to 25V to accommodate
EIA/TIA-232 signals as well. Both receivers invert. Their
inputs are each equipped with an internal 5k
(nomi-
nal) terminating resistor connected to ground, and the
input logic thresholds are 0.4V and 2.4V. The positive
logic-low threshold (V
IL
) ensures the receiver outputs
remain high whenever their inputs are left open.
The receivers are active when
EN is low, and have
high-impedance outputs when
EN is high.
When
SHDN is high, the receivers have hysteresis.
This produces clean output transitions, even with slow-
moving input signals that exhibit moderate amounts of
noise and ringing. When shut down, the receivers have
no hysteresis, and the propagation delay increases.
Shutdown and Enable Control
The
SHDN and EN controls are independent. Both
receivers are always active when
EN is low. With EN
low and
SHDN high, the receivers operate at full speed
and have hysteresis. When active in shutdown mode
(
EN = SHDN = low), the receivers operate at reduced
power and speed, and without hysteresis.
The charge pumps and transmitters operate only when
SHDN is high; they are unaffected by EN. When shut
down (
SHDN = low) or unpowered (V
CC
= 0V), the
transmitter outputs are high impedance if they are
backdriven with voltages not exceeding 15V. The pull-
up resistors at the driver inputs are disconnected in
shutdown mode to save power. During shutdown, V+ is
pulled down to V
CC
, and V- rises to GND.
_______________________________________________________________________________________
5
MAX563
+3.3V-Powered, EIA/TIA-562 Dual Transceiver
with Receivers Active in Shutdown
V+
GND
MAX563
0.1F
V
CC
0.1F
R1 & R2
T1 & T2
0.1F
C1+
C1-
C2+
C2-
V
CC
+3.6V
T
OUT
R
OUT
400k
5k
I
SHDN
0V +3.6V
DRIVE
0.1F
0.1F
3k
+3.6V
R
IN
T
IN
EN
SHDN
V-
+3.6V
V+
OV
V-
t
PHLT
OV
INPUT
OUTPUT
t
PLHT
+3V
INPUT
OUTPUT
50%
50%
+3V
50%
50%
V
CC
GND
t
PLHR
t
PLHS
t
PHLR
t
PHLS
0V
Figure 1. Shutdown Current Test Circuit
Figure 2. Transmitter Propagation Delay Timing
Figure 3. Receiver Propagation Delay Timing
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