19-0199; Rev 1; 8/95
Programmable DTE/DCE,
+5V RS-232 Transceiver
_______________General Description
The MAX214 +5V RS-232 transceiver provides a com-
plete, 8-line, software-configurable, DTE or DCE port
RS-232 interface. Tx, Rx, RTS, CTS, DTR, DSR, DCD,
and RI circuits can be configured as either Data
Terminal Equipment (DTE) or Data Circuit-Terminating
Equipment (DCE) using the DTE/DCE control pin. The
MAX214 eliminates the need to swap cables when
switching between DTE and DCE configurations.
____________________________Features
o
Eliminates Null Modem Cables
o
Programmable DTE or DCE Serial Port
o
1µF Charge-Pump Capacitors
o
116kbps Data Rate—Guaranteed
o
20µA Shutdown Mode
o
Receivers Active in Shutdown
MAX214
________________________Applications
AT-Compatible Laptop Computers
AT-Compatible Desktop Computers
Modems, Printers, and Other Peripherals
______________Ordering Information
PART
MAX214CPI
MAX214CWI
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
28 Plastic DIP
28 Wide SO
Dice*
28 Plastic DIP
28 Wide SO
__________Typical Operating Circuit
+5V
1µF
16
27
1µF
C1+
V
CC
V+
28
C1-
1
C2+
2
C2-
DTE
DCE
6 RA
DTE
25 TB
23 RB
DTE
24
TC
DTE
DCE
22 RC
DCE
7 RDC
DTE
8
21
26
3
RE
DTE/DCE
SHDN
HI-Z
GND
13
DTE
DCE
RTC 17
RDTC 11
RRE 12
TRC 18
DTE
DCE
RTB 19
TRB 20
RTA 10
TRA 9
1µF
15
MAX214C/D
MAX214EPI
MAX214EWI
* Dice are specified at T
A
= +25°C.
__________________Pin Configuration
TOP VIEW
MAX214
V-
1µF
14
1µF
5 TA
C2+
C2-
HI-Z
N.C.
TA
RA
RDC
RE
TRA
1
2
3
4
5
6
7
8
9
28
27
26
25
C1-
C1+
SHDN
TB
TC
RB
RC
DTE/DCE
TRB
RTB
TRC
RTC
V
CC
V+
MAX214
24
23
22
21
20
19
18
17
16
15
RTA
10
RDTC
11
RRE
12
GND
13
V-
14
DTE
DIP/SO
________________________________________________________________
Maxim Integrated Products
1
Call toll free 1-800-998-8800 for free samples or literature.
Programmable DTE/DCE,
+5V RS-232 Transceiver
MAX214
ABSOLUTE MAXIMUM RATINGS
V
CC
...........................................................................-0.3V to +6V
Input Voltages
T
IN
, DTE/DCE, SHDN HI-Z ......................-0.3V to (V
CC
+ 0.3V)
R
IN
....................................................................................±15V
Output Voltages:
T
OUT
..................................................................................±15V
R
OUT
........................................................-0.3V to (V
CC
+ 0.3V)
Short-Circuit (one output at a time)
T
OUT
to GND ...........................................................Continuous
R
OUT
to GND...........................................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
Plastic DIP (derate 9.09mW/°C above +70°C) .............727mW
Wide SO (derate 12.50mW/°C above +70°C) ............1000mW
Operating Temperature Ranges:
MAX214C–I ..............................................0°C to +70°C
MAX214E –I ..........................................-40°C to +85°C
Storage Temperature Range ......................-65°C to +150°C
Lead Temperature (soldering, 10sec) .......................+300°C
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.
ELECTRICAL CHARACTERISTICS
(V
CC
= 4.5V to 5.5V, C1 to C4 = 1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
RS-232 TRANSMITTERS
Logic Input Threshold Low
Logic Input Threshold High
Logic Input Pull-Up Current
Output Voltage Swing
Transmitter Output Resistance
Output Short-Circuit Current
RS-232 RECEIVERS
Input Voltage Operating Range
Positive Threshold Input Low
Positive Threshold Input High
Positive Threshold Input
Hysteresis
Negative Threshold Input Low
T
A
= +25°C, V
CC
= 5V, normal operation, SHDN = 0V
T
A
= +25°C, V
CC
= 5V, normal operation, SHDN = 0V
V
CC
= 5V, normal operation, SHDN = 0V (no hysteresis
in shutdown)
T
A
= +25°C, V
CC
= 5V
T
A
= +25°C, V
CC
= 5V
Normal operation, SHDN = 0V
Shutdown, SHDN = 5V
Normal operation, SHDN = 0V
Shutdown, SHDN = 5V
0.2
3
100
3.5
0.2
-2.6
0.8
0.8
1.3
1.8
0.5
-1.9
1.3
-1.5
1.3
0.4
5
300
0.2
V
CC
- 0.2
-0.2
2.4
1.0
7
0.4
2.4
1.0
±15
V
V
V
V
Normal operation
Shutdown
All transmitter outputs loaded with 3kΩ to ground
V
CC
= V+ = V- = 0V, V
OUT
= ±2V (Note 1)
V
OUT
= 0V
±5.0
300
±7
1
0.8
1.4
1.4
10
±0.01
±7.5
300k
±25
2.0
50
±1
V
V
µA
V
Ω
mA
CONDITIONS
MIN
TYP
MAX
UNITS
V
Negative Threshold Input High
Negative Threshold Input
Hysteresis
Input Resistance
TTL/CMOS Output Voltage Low
TTL/CMOS Output Voltage High
V
V
kΩ
V
V
V
CC
= 5V, normal operation, SHDN = 0V (no hysteresis
in shutdown)
HI-Z = 0V and SHDN = 0V
HI-Z = 5V or SHDN = 5V
I
OUT
= 3.2mA
I
OUT
= -1.0mA
2
_______________________________________________________________________________________
Programmable DTE/DCE,
+5V RS-232 Transceiver
MAX214
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 4.5V to 5.5V, C1 to C4 = 1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
PARAMETER
POWER SUPPLY
V
CC
Supply Current
Shutdown Supply Current
No load, T
A
= +25°C
DTE/DCE = 0V, SHDN =
HI-Z = V
CC
, Figure 1
T
A
= +25°C
T
A
= T
MIN
to T
MAX
0.8
1.3
1.3
2.0
±1
9
4
20
20
50
mA
µA
CONDITIONS
MIN
TYP
MAX
UNITS
CONTROL LOGIC
(DTE/DCE,
SHDN, HI-Z)
Logic Input Threshold Low
Logic Input Threshold High
Input Leakage Current
AC CHARACTERISTICS
Data Rate
Normal operation, transmitters and receivers
Receivers in shutdown mode
T
A
= +25°C, V
CC
= 5V, R
L
= 3kΩ to 7kΩ,
C
L
= to 2500pF,
measured from 3V to -3V or -3V to 3V
t
PHLT
t
PLHT
t
PHLT
- t
PLHT
t
PHLR
, t
PLHR
t
PHLR
t
PLHR
6
200
20
12
1.3
1.4
100
0.4
0.4
1.5
100
1.5
10
10
30
3.5
3.5
116
kbps
V
V
µA
Transition-Region Slew Rate
Transmitter Propagation Delay,
TTL to RS-232 (Normal Operation)
Transmitter + to - Propagation-Delay
Difference (Normal Operation)
Receiver Propagation Delay,
RS-232 to TTL (Normal Operation)
Receiver Propagation Delay,
RS-232 to TTL (Shutdown Mode)
V/µs
µs
ns
µs
µs
ns
Receiver Propagation-Delay Difference
t
PHLT
- t
PLHT
(Normal Operation)
MODE-CHANGE TIMING (DTE/DCE)
Transmitter Enable Time
Transmitter Disable Time
Transmitter DTE/DCE Switch Time
Receiver DTE/DCE Switch Time
Receiver Termination-Resistor
Connect/Disconnect Time
Receiver Termination-Resistor Connect
Entering SHDN Time
Receiver Termination-Resistor
Disconnect Exiting SHDN Time
t
TEN
(includes charge-pump start-up time)
t
TTR
t
TSW
t
RSW
(SHDN = 0V)
250
600
600
300
300
250
300
µs
ns
ns
ns
ns
µs
ns
Note 1:
The 300Ω minimum is the EIA/TIA-232E specification, but the actual resistance when in shutdown mode or when V
CC
= 0V
is typically 300kΩ.
_______________________________________________________________________________________
3
Programmable DTE/DCE,
+5V RS-232 Transceiver
MAX214
__________________________________________Typical Operating Characteristics
(V
CC
= 5V, C1 to C4 = 1µF, all transmitters loaded with 3kΩ in parallel with 2.5nF, T
A
= +25°C, unless otherwise noted.)
TRANSMITTER OUTPUT VOLTAGE (V
OL
)
vs. LOAD CAPACITANCE
AT DIFFERENT DATA RATES
MAX214-01
TRANSMITTER OUTPUT VOLTAGE (V
OH
)
vs. LOAD CAPACITANCE
AT DIFFERENT DATA RATES
MAX214-02
TRANSMITTER OUTPUT VOLTAGE (V
OH
)
vs. V
CC
POSITIVE SUPPLY VOLTAGE
1 TRANSMITTER LOADED
8.5
2 TRANSMITTERS LOADED
3 TRANSMITTERS LOADED
MAX214-03
MAX214-06
-5.5
-6.0
-6.5
V
OL
(V)
7.6
20kbps
7.4
7.2
64kbps
7.0
V
OH
(V)
6.8
6.6
120kbps
9.0
120kbps
-7.0
-7.5
64kbps
V
OH
(V)
8.0
7.5
20kbps
-8.0
-8.5
0
1000 2000 3000 4000 5000 6000 7000
LOAD CAPACITANCE (pF)
6.4
7.0
6.2
6.0
0
1000 2000 3000 4000 5000 6000 7000
LOAD CAPACITANCE (pF)
DATA RATE = 0kbps
6.5
4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5
V
CC
(V)
TRANSMITTER OUTPUT VOLTAGE (V
OL)
vs. POSITIVE SUPPLY VOLTAGE
MAX214-04
TRANSMITTER OUTPUT VOLTAGES
vs. V+, V- LOAD CURRENT
MAX214-05
SLEW RATE vs. LOAD CAPACITANCE
20
18
16
SLEW+
3 TRANSMITTERS LOADED
SLEW-
3 TRANSMITTERS LOADED
SLEW+
1 TRANSMITTER LOADED
-7.0
3 TRANSMITTERS LOADED
-7.5
2 TRANSMITTERS LOADED
1 TRANSMITTER LOADED
V
OL
(V)
-8.0
10
8
6
T
OUT
+, T
OUT
-
(V)
V+ AND V-
2 EQUALLY
0 LOADED
-2
-4
-6
ALL TRANSMITTERS UNLOADED, 0kbps
V- LOADED,
NO LOAD
ON V+
V+ LOADED,
NO LOAD
ON V-
SLEW RATE (V/µs)
4
14
12
10
8
-8.5
-9.0
DATA RATE = 0kbps
-9.5
4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5
V
CC
(V)
-8
-10
0
20
40
60
LOAD CURRENT (mA)
80
SLEW-
6 1 TRANSMITTER LOADED
4
0
2000
4000
6000
LOAD CAPACITANCE (pF)
4
_______________________________________________________________________________________
Programmable DTE/DCE,
+5V RS-232 Transceiver
______________________________________________________________Pin Description
PIN
1, 2
3
4
5, 24, 25
6, 8, 22, 23
7
9, 18, 20
10, 17, 19
11
12
13
14
15
16
21
26
27, 28
NAME
C2+, C2-
HI-Z
N.C.
TA, TC, TB
RA, RE, RC, RB
RDC
TRA, TRC, TRB
RTA, RTC, RTB
RDTC
RRE
GND
V-
V+
V
CC
DTE/DCE
SHDN
C1+, C1-
FUNCTION
Terminals for negative charge-pump capacitor
RS-232 receiver impedance control. Take high to disconnect the termination resistor.
No connect—not internally connected
TTL/CMOS driver A, C, B inputs
TTL/CMOS receiver A, E, C, B outputs
TTL/CMOS DTE receiver output D for DTE/DCE = 0V, or TTL/CMOS DCE receiver output C for
DTE/DCE = +5V
RS-232 DTE driver output for DTE/DCE= 0V, or RS-232 DCE receiver input for DTE/DCE = +5V
RS-232 DTE receiver input for DTE/DCE = 0V, or RS-232 DCE driver output for DTE/DCE = +5V
RS-232 DTE receiver input D for DTE/DCE = 0V, or RS-232 DCE driver output C for
DTE/DCE = +5V
RS-232 receiver input
Ground
-2V
CC
voltage generated by the charge pump
+2V
CC
voltage generated by the charge pump
+4.5V to +5.5V supply voltage
Data terminal equipment (DTE) and data circuit-terminating equipment (DCE) control pin.
DCE active high and DTE active low.
Shutdown control; shutdown high, normal operation low
Terminals for positive charge-pump capacitor
MAX214
_______________Detailed Description
The MAX214 RS-232 transceiver provides a complete,
8-line, software-configurable, DTE or DCE port RS-232
interface. Tx, Rx, RTS, CTS, DTR, DSR, DCD, and RI
circuits can be configured as either Data Terminal
Equipment (DTE) or Data Circuit-Terminating
Equipment (DCE) using the DTE/DCE control pin. The
MAX214 eliminates the need to swap cables when
switching between DTE and DCE configurations. This
is useful when, for example, a portable computer is
required to communicate with printers, modems, and
other computers without carrying multiple cables.
The MAX214 runs from a single +5V supply and incor-
porates a dual charge-pump voltage converter to gener-
ate the necessary voltages for the RS-232 transmitters.
A shutdown mode is provided to save power when
transmission is not required, but the receivers always
stay active for simple detection of ring indicator signals.
DTE/DCE Operation
The DTE/DCE pin allows circuit configuration under
software control. Tables 1a and 1b show the pin defini-
tions of the MAX214 in both DTE and DCE modes. The
Function columns show the direction of data flow from
the input pin to the output pin of the MAX214, and onto
the corresponding DB-25 connector’s pin.
+5V to ±10V Dual Charge-Pump
Voltage Converter
The +5V to ±10V conversion is performed by two
charge-pump voltage converters (Figure 2). The first
uses capacitor C1 to double the +5V to +10V, storing
the +10V on the output filter capacitor, C3. The second
charge-pump voltage converter uses C2 to invert the
+10V to -10V, storing the -10V on the V- output filter
capacitor, C4.
In shutdown mode, V+ is pulled to V
CC
by an internal
resistor, and V- falls to GND.
5
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