MAX234EJE ,+5V-powered, multichannel RS-232 driver-receiver.FeaturesMAX220 +5 2/2 4 4.7/10 No — 120 Ultra-low-power, industry-standard pinoutMAX222 +5 2/2 4 0. ..
MAX234EPE ,+5V-Powered, Multichannel RS-232 Drivers/ReceiversFeaturesThe MAX220–MAX249 family of line drivers/receivers isSuperior to Bipolarintended for all EI ..
MAX234EWE ,+5V-Powered, Multichannel RS-232 Drivers/ReceiversGeneral Description ________
MAX234EWE ,+5V-Powered, Multichannel RS-232 Drivers/Receiversapplications where ±12V is(+5V and +12V—MAX231/MAX239)not available. Low-Power Receive Mode in Sh ..
MAX234EWE ,+5V-Powered, Multichannel RS-232 Drivers/ReceiversMAX220–MAX24919-4323; Rev 9; 4/00+5V-Powered, Multichannel RS-232Drivers/Receivers
MAX234EWE+ ,+5V-Powered, Multichannel RS-232 Drivers/Receiversapplications where ±12V is• Eliminates the Need for a Bipolar ±12V Supplynot available.• Enables Si ..
MAX548ACUA ,+2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in レMAX PackageMAX548A/MAX549A/MAX550A19-1206; Rev 0; 3/97+2.5V to +5.5V, Low-Power, Single/Dual,8-Bit Voltage-Out ..
MAX548AEPA ,+2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in レMAX PackageApplicationsMAX548AC/D 0°C to +70°C Dice*Battery-Powered SystemsMAX548AEPA -40°C to +85°C 8 Plastic ..
MAX548AEUA ,+2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in レMAX PackageGeneral Description ________
MAX548AEUA+T ,+2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX PackageELECTRICAL CHARACTERISTICS(V = +2.5V to +5.5V, T = T to T , unless otherwise noted. Typical values ..
MAX548AEUA-T ,+2.5V to +5.5V, Low-Power, Single/Dual, 8-Bit Voltage-Output DACs in µMAX PackageMAX548A/MAX549A/MAX550A19-1206; Rev 0; 3/97+2.5V to +5.5V, Low -Pow er, Single/Dual,8-Bit Voltage-O ..
MAX5490XC25000+T ,100kΩ Precision-Matched Resistor-Divider in SOT23ELECTRICAL CHARACTERISTICS(T = -55°C to +125°C, unless otherwise noted. Typical values are at T = + ..
MAX234EJE
+5V-powered, multichannel RS-232 driver-receiver.
General DescriptionThe MAX220–MAX249 family of line drivers/receivers is
intended for all EIA/TIA-232E and V.28/V.24 communica-
tions interfaces, particularly applications where ±12V is
not available.
These parts are especially useful in battery-powered sys-
tems, since their low-power shutdown mode reduces
power dissipation to less than 5µW. The MAX225,
MAX233, MAX235, and MAX245/MAX246/MAX247 use
no external components and are recommended for appli-
cations where printed circuit board space is critical.
________________________ApplicationsPortable Computers
Low-Power Modems
Interface Translation
Battery-Powered RS-232 Systems
Multidrop RS-232 Networks
____________________________Features
Superior to BipolarOperate from Single +5V Power Supply
(+5V and +12V—MAX231/MAX239)Low-Power Receive Mode in Shutdown
(MAX223/MAX242)Meet All EIA/TIA-232E and V.28 SpecificationsMultiple Drivers and Receivers3-State Driver and Receiver OutputsOpen-Line Detection (MAX243)
Ordering Information
Ordering Information continued at end of data sheet.*Contact factory for dice specifications.
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/Receivers
Selection Table19-4323; Rev 9; 4/00
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/Receivers
ABSOLUTE MAXIMUM RATINGS—MAX220/222/232A/233A/242/243
ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243(VCC= +5V ±10%, C1–C4 = 0.1µF‚ MAX220, C1 = 0.047µF, C2–C4 = 0.33µF, TA= TMINto TMAX‚ unless otherwise noted.)
Note 1:Input voltage measured with TOUTin high-impedance state, SHDNor VCC= 0V.
Note 2:For the MAX220, V+ and V- can have a maximum magnitude of 7V, but their absolute difference cannot exceed 13V.
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.
Supply Voltage (VCC)...............................................-0.3V to +6V
Input Voltages
TIN..............................................................-0.3V to (VCC- 0.3V)
RIN (Except MAX220)........................................................±30V
RIN (MAX220).....................................................................±25V
TOUT(Except MAX220) (Note 1).......................................±15V
TOUT (MAX220)...............................................................±13.2V
Output Voltages
TOUT...................................................................................±15V
ROUT.........................................................-0.3V to (VCC+ 0.3V)
Driver/Receiver Output Short Circuited to GND.........Continuous
Continuous Power Dissipation (TA= +70°C)
16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)....842mW
18-Pin Plastic DIP (derate 11.11mW/°C above +70°C)....889mW
20-Pin Plastic DIP (derate 8.00mW/°C above +70°C)..440mW
16-Pin Narrow SO (derate 8.70mW/°C above +70°C)...696mW
16-Pin Wide SO (derate 9.52mW/°C above +70°C)......762mW
18-Pin Wide SO (derate 9.52mW/°C above +70°C)......762mW
20-Pin Wide SO (derate 10.00mW/°C above +70°C)....800mW
20-Pin SSOP (derate 8.00mW/°C above +70°C)..........640mW
16-Pin CERDIP (derate 10.00mW/°C above +70°C).....800mW
18-Pin CERDIP (derate 10.53mW/°C above +70°C).....842mW
Operating Temperature Ranges
MAX2_ _AC_ _, MAX2_ _C_ _.............................0°C to +70°C
MAX2_ _AE_ _, MAX2_ _E_ _..........................-40°C to +85°C
MAX2_ _AM_ _, MAX2_ _M_ _.......................-55°C to +125°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10sec).............................+300°C
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/Receivers
Note 3:MAX243 R2OUTis guaranteed to be low when R2INis ≥0V or is floating.
ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243 (continued)(VCC= +5V ±10%, C1–C4 = 0.1µF‚ MAX220, C1 = 0.047µF, C2–C4 = 0.33µF, TA= TMINto TMAX‚ unless otherwise noted.)
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/Receivers
__________________________________________Typical Operating Characteristics
MAX220/MAX222/MAX232A/MAX233A/MAX242/MAX243
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/ReceiversVCC...........................................................................-0.3V to +6V
V+................................................................(VCC- 0.3V) to +14V
V-............................................................................+0.3V to -14V
Input Voltages
TIN............................................................-0.3V to (VCC+ 0.3V)
RIN......................................................................................±30V
Output Voltages
TOUT...................................................(V+ + 0.3V) to (V- - 0.3V)
ROUT.........................................................-0.3V to (VCC+ 0.3V)
Short-Circuit Duration, TOUT......................................Continuous
Continuous Power Dissipation (TA= +70°C)
14-Pin Plastic DIP (derate 10.00mW/°C above +70°C)....800mW
16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)....842mW
20-Pin Plastic DIP (derate 11.11mW/°C above +70°C)....889mW
24-Pin Narrow Plastic DIP
(derate 13.33mW/°C above +70°C)..........1.07W
24-Pin Plastic DIP (derate 9.09mW/°C above +70°C)......500mW
16-Pin Wide SO (derate 9.52mW/°C above +70°C).........762mW
20-Pin Wide SO (derate 10 00mW/°C above +70°C).......800mW
24-Pin Wide SO (derate 11.76mW/°C above +70°C).......941mW
28-Pin Wide SO (derate 12.50mW/°C above +70°C) .............1W
44-Pin Plastic FP (derate 11.11mW/°C above +70°C).....889mW
14-Pin CERDIP (derate 9.09mW/°C above +70°C)..........727mW
16-Pin CERDIP (derate 10.00mW/°C above +70°C)........800mW
20-Pin CERDIP (derate 11.11mW/°C above +70°C)........889mW
24-Pin Narrow CERDIP
(derate 12.50mW/°C above +70°C)..............1W
24-Pin Sidebraze (derate 20.0mW/°C above +70°C)..........1.6W
28-Pin SSOP (derate 9.52mW/°C above +70°C).............762mW
Operating Temperature Ranges
MAX2 _ _ C _ _......................................................0°C to +70°C
MAX2 _ _ E _ _...................................................-40°C to +85°C
MAX2 _ _ M _ _ ...............................................-55°C to +125°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10sec).............................+300°C
ABSOLUTE MAXIMUM RATINGS—MAX223/MAX230–MAX241
ELECTRICAL CHARACTERISTICS—MAX223/MAX230–MAX241(MAX223/230/232/234/236/237/238/240/241, VCC= +5V ±10; MAX233/MAX235, VCC= 5V ±5%‚ C1–C4 = 1.0µF; MAX231/MAX239,
VCC= 5V ±10%; V+ = 7.5V to 13.2V; TA= TMINto TMAX; 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.
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/Receivers
ELECTRICAL CHARACTERISTICS—MAX223/MAX230–MAX241 (continued)(MAX223/230/232/234/236/237/238/240/241, VCC= +5V ±10; MAX233/MAX235, VCC= 5V ±5%‚ C1–C4 = 1.0µF; MAX231/MAX239,
VCC= 5V ±10%; V+ = 7.5V to 13.2V; TA= TMINto TMAX; unless otherwise noted.)
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/ReceiversTRANSMITTER OUTPUT
VOLTAGE (VOH) vs. VCC
MAX220-04
VCC (V)
(V)
TRANSMITTER OUTPUT VOLTAGE (VOH)
vs. LOAD CAPACITANCE AT
DIFFERENT DATA RATES
MAX220-05
LOAD CAPACITANCE (pF)
(V)
TRANSMITTER SLEW RATE
vs. LOAD CAPACITANCE
MAX220-06
LOAD CAPACITANCE (pF)
SLEW RATE (V/
TRANSMITTER OUTPUT
VOLTAGE (VOL) vs. VCC
MAX220-07
VCC (V)
(V)
TRANSMITTER OUTPUT VOLTAGE (VOL)
vs. LOAD CAPACITANCE AT
DIFFERENT DATA RATES
MAX220-08
(V)
TRANSMITTER OUTPUT VOLTAGE (V+, V-)
vs. LOAD CURRENT
MAX220-09
CURRENT (mA)
V+, V- (V)
__________________________________________Typical Operating Characteristics
MAX223/MAX230–MAX241
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/Receivers
ABSOLUTE MAXIMUM RATINGS—MAX225/MAX244–MAX249
ELECTRICAL CHARACTERISTICS—MAX225/MAX244–MAX249(MAX225, VCC= 5.0V ±5%; MAX244–MAX249, VCC= +5.0V ±10%, external capacitors C1–C4 = 1µF; TA= TMINto TMAX; unless oth-
erwise noted.)
Note 4:Input voltage measured with transmitter output in a high-impedance state, shutdown, or VCC= 0V.
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.
Supply Voltage (VCC)...............................................-0.3V to +6V
Input Voltages
TIN‚ ENA, ENB, ENR, ENT, ENRA,ENRB, ENTA, ENTB..................................-0.3V to (VCC+ 0.3V)
RIN.....................................................................................±25V
TOUT(Note 3).....................................................................±15V
ROUT........................................................-0.3V to (VCC+ 0.3V)
Short Circuit (one output at a time)
TOUTto GND............................................................Continuous
ROUTto GND............................................................Continuous
Continuous Power Dissipation (TA= +70°C)
28-Pin Wide SO (derate 12.50mW/°C above +70°C).............1W
40-Pin Plastic DIP (derate 11.11mW/°C above +70°C)...611mW
44-Pin PLCC (derate 13.33mW/°C above +70°C)...........1.07W
Operating Temperature Ranges
MAX225C_ _, MAX24_C_ _ ..................................0°C to +70°C
MAX225E_ _, MAX24_E_ _ ...............................-40°C to +85°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering,10sec)..............................+300°C
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/Receivers
Note 5:The 300Ωminimum specification complies with EIA/TIA-232E, but the actual resistance when in shutdown mode or VCC=
0V is 10MΩas is implied by the leakage specification.
ELECTRICAL CHARACTERISTICS—MAX225/MAX244–MAX249 (continued)(MAX225, VCC= 5.0V ±5%; MAX244–MAX249, VCC= +5.0V ±10%, external capacitors C1–C4 = 1µF; TA= TMINto TMAX; unless oth-
erwise noted.)
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/Receivers
__________________________________________Typical Operating Characteristics
MAX225/MAX244–MAX249
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/ReceiversFigure 1. Transmitter Propagation-Delay TimingFigure 2. Receiver Propagation-Delay Timing
Figure 3. Receiver-Output Enable and Disable TimingFigure 4. Transmitter-Output Disable Timing
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/Receivers
Table 1a. MAX245 Control Pin Configurations
Table 1b. MAX245 Control Pin Configurations
Table 1c. MAX246 Control Pin Configurations
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/Receivers
Table 1d. MAX247/MAX248/MAX249 Control Pin Configurations
MAX220–MAX249
_______________Detailed DescriptionThe MAX220–MAX249 contain four sections: dual
charge-pump DC-DC voltage converters, RS-232 dri-
vers, RS-232 receivers, and receiver and transmitter
enable control inputs.
Dual Charge-Pump Voltage ConverterThe MAX220–MAX249 have two internal charge-pumps
that convert +5V to ±10V (unloaded) for RS-232 driver
operation. The first converter uses capacitor C1 to dou-
ble the +5V input to +10V on C3 at the V+ output. The
second converter uses capacitor C2 to invert +10V to
-10V on C4 at the V- output.
A small amount of power may be drawn from the +10V
(V+) and -10V (V-) outputs to power external circuitry
(see the Typical Operating Characteristicssection),
except on the MAX225 and MAX245–MAX247, where
these pins are not available. V+ and V- are not regulated,
so the output voltage drops with increasing load current.
Do not load V+ and V- to a point that violates the mini-
mum ±5V EIA/TIA-232E driver output voltage when
sourcing current from V+ and V- to external circuitry.
When using the shutdown feature in the MAX222,
MAX225, MAX230, MAX235, MAX236, MAX240,
MAX241, and MAX245–MAX249, avoid using V+ and V-
to power external circuitry. When these parts are shut
down, V- falls to 0V, and V+ falls to +5V. For applica-
tions where a +10V external supply is applied to the V+
pin (instead of using the internal charge pump to gen-
erate +10V), the C1 capacitor must not be installed and
the SHDNpin must be tied to VCC. This is because V+
is internally connected to VCCin shutdown mode.
RS-232 DriversThe typical driver output voltage swing is ±8V when
loaded with a nominal 5kΩRS-232 receiver and VCC=
+5V. Output swing is guaranteed to meet the EIA/TIA-
232E and V.28 specification, which calls for ±5V mini-
mum driver output levels under worst-case conditions.
These include a minimum 3kΩload, VCC= +4.5V, and
maximum operating temperature. Unloaded driver out-
put voltage ranges from (V+ -1.3V) to (V- +0.5V).
Input thresholds are both TTL and CMOS compatible.
The inputs of unused drivers can be left unconnected
since 400kΩinput pull-up resistors to VCCare built in
(except for the MAX220). The pull-up resistors force the
outputs of unused drivers low because all drivers invert.
The internal input pull-up resistors typically source 12µA,
except in shutdown mode where the pull-ups are dis-
abled. Driver outputs turn off and enter a high-imped-
ance state—where leakage current is typically
microamperes (maximum 25µA)—when in shutdown
mode, in three-state mode, or when device power is
removed. Outputs can be driven to ±15V. The power-
supply current typically drops to 8µA in shutdown mode.
The MAX220 does not have pull-up resistors to force the
ouputs of the unused drivers low. Connect unused inputs
to GND or VCC.
The MAX239 has a receiver three-state control line, and
the MAX223, MAX225, MAX235, MAX236, MAX240,
and MAX241 have both a receiver three-state control
line and a low-power shutdown control. Table 2 shows
the effects of the shutdown control and receiver three-
state control on the receiver outputs.
The receiver TTL/CMOS outputs are in a high-imped-
ance, three-state mode whenever the three-state enable
line is high (for the MAX225/MAX235/MAX236/MAX239–
MAX241), and are also high-impedance whenever the
shutdown control line is high.
When in low-power shutdown mode, the driver outputs
are turned off and their leakage current is less than 1µA
with the driver output pulled to ground. The driver output
leakage remains less than 1µA, even if the transmitter
output is backdriven between 0V and (VCC+ 6V). Below
-0.5V, the transmitter is diode clamped to ground with
1kΩseries impedance. The transmitter is also zener
clamped to approximately VCC+ 6V, with a series
impedance of 1kΩ.
The driver output slew rate is limited to less than 30V/µs
as required by the EIA/TIA-232E and V.28 specifica-
tions. Typical slew rates are 24V/µs unloaded and
10V/µs loaded with 3Ωand 2500pF.
RS-232 ReceiversEIA/TIA-232E and V.28 specifications define a voltage
level greater than 3V as a logic 0, so all receivers invert.
Input thresholds are set at 0.8V and 2.4V, so receivers
respond to TTL level inputs as well as EIA/TIA-232E and
V.28 levels.
The receiver inputs withstand an input overvoltage up
to ±25V and provide input terminating resistors with
+5V-Powered, Multichannel RS-232
Drivers/Receivers
Table 2. Three-State Control of Receivers
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/Receiversnominal 5kΩvalues. The receivers implement Type 1
interpretation of the fault conditions of V.28 and
EIA/TIA-232E.
The receiver input hysteresis is typically 0.5V with a
guaranteed minimum of 0.2V. This produces clear out-
put transitions with slow-moving input signals, even
with moderate amounts of noise and ringing. The
receiver propagation delay is typically 600ns and is
independent of input swing direction.
Low-Power Receive ModeThe low-power receive-mode feature of the MAX223,
MAX242, and MAX245–MAX249 puts the IC into shut-
down mode but still allows it to receive information. This
is important for applications where systems are periodi-
cally awakened to look for activity. Using low-power
receive mode, the system can still receive a signal that
will activate it on command and prepare it for communi-
cation at faster data rates. This operation conserves
system power.
Negative Threshold—MAX243The MAX243 is pin compatible with the MAX232A, differ-
ing only in that RS-232 cable fault protection is removed
on one of the two receiver inputs. This means that control
lines such as CTS and RTS can either be driven or left
floating without interrupting communication. Different
cables are not needed to interface with different pieces of
equipment.
The input threshold of the receiver without cable fault
protection is -0.8V rather than +1.4V. Its output goes
positive only if the input is connected to a control line
that is actively driven negative. If not driven, it defaults
to the 0 or “OK to send” state. Normally‚ the MAX243’s
other receiver (+1.4V threshold) is used for the data line
(TD or RD)‚ while the negative threshold receiver is con-
nected to the control line (DTR‚ DTS‚ CTS‚ RTS, etc.).
Other members of the RS-232 family implement the
optional cable fault protection as specified by EIA/TIA-
232E specifications. This means a receiver output goes
high whenever its input is driven negative‚ left floating‚
or shorted to ground. The high output tells the serial
communications IC to stop sending data. To avoid this‚
the control lines must either be driven or connected
with jumpers to an appropriate positive voltage level.
Shutdown—MAX222–MAX242 On the MAX222‚ MAX235‚ MAX236‚ MAX240‚ and
MAX241‚ all receivers are disabled during shutdown.
On the MAX223 and MAX242‚ two receivers continue to
operate in a reduced power mode when the chip is in
shutdown. Under these conditions‚ the propagation
delay increases to about 2.5µs for a high-to-low input
transition. When in shutdown, the receiver acts as a
CMOS inverter with no hysteresis. The MAX223 and
MAX242 also have a receiver output enable input (EN
for the MAX242 and EN for the MAX223) that allows
receiver output control independent of SHDN(SHDN
for MAX241). With all other devices‚ SHDN(SHDN for
MAX241) also disables the receiver outputs.
The MAX225 provides five transmitters and five
receivers‚ while the MAX245 provides ten receivers and
eight transmitters. Both devices have separate receiver
and transmitter-enable controls. The charge pumps
turn off and the devices shut down when a logic high is
applied to the ENT input. In this state, the supply cur-
rent drops to less than 25µA and the receivers continue
to operate in a low-power receive mode. Driver outputs
enter a high-impedance state (three-state mode). On
the MAX225‚ all five receivers are controlled by theENRinput. On the MAX245‚ eight of the receiver out-
puts are controlled by the ENRinput‚ while the remain-
ing two receivers (RA5 and RB5) are always active.
RA1–RA4 and RB1–RB4 are put in a three-state mode
when ENRis a logic high.
Receiver and Transmitter Enable
Control Inputs The MAX225 and MAX245–MAX249 feature transmitter
and receiver enable controls.
The receivers have three modes of operation: full-speed
receive (normal active)‚ three-state (disabled)‚ and low-
power receive (enabled receivers continue to function
at lower data rates). The receiver enable inputs control
the full-speed receive and three-state modes. The
transmitters have two modes of operation: full-speed
transmit (normal active) and three-state (disabled). The
transmitter enable inputs also control the shutdown
mode. The device enters shutdown mode when all
transmitters are disabled. Enabled receivers function in
the low-power receive mode when in shutdown.
MAX220–MAX249Tables 1a–1d define the control states. The MAX244
has no control pins and is not included in these tables.
The MAX246 has ten receivers and eight drivers with
two control pins, each controlling one side of the
device. A logic high at the A-side control input (ENA)
causes the four A-side receivers and drivers to go into
a three-state mode. Similarly, the B-side control input
(ENB) causes the four B-side drivers and receivers to
go into a three-state mode. As in the MAX245, one A-
side and one B-side receiver (RA5 and RB5) remain
active at all times. The entire device is put into shut-
down mode when both the A and B sides are disabled
(ENA= ENB= +5V).
The MAX247 provides nine receivers and eight drivers
with four control pins. The ENRAand ENRBreceiver
enable inputs each control four receiver outputs. The
ENTAand ENTBtransmitter enable inputs each control
four drivers. The ninth receiver (RB5) is always active.
The device enters shutdown mode with a logic high on
both ENTAand ENTB.
The MAX248 provides eight receivers and eight drivers
with four control pins. The ENRAand ENRBreceiver
enable inputs each control four receiver outputs. TheENTAand ENTBtransmitter enable inputs control four
drivers each. This part does not have an always-active
receiver. The device enters shutdown mode and trans-
mitters go into a three-state mode with a logic high on
both ENTAand ENTB.
The MAX249 provides ten receivers and six drivers with
four control pins. The ENRAand ENRBreceiver enable
inputs each control five receiver outputs. The ENTA
and ENTBtransmitter enable inputs control three dri-
vers each. There is no always-active receiver. The
device enters shutdown mode and transmitters go into
a three-state mode with a logic high on both ENTAandENTB. In shutdown mode, active receivers operate in a
low-power receive mode at data rates up to
20kbits/sec.
__________Applications InformationFigures 5 through 25 show pin configurations and typi-
cal operating circuits. In applications that are sensitive
to power-supply noise, VCCshould be decoupled to
ground with a capacitor of the same value as C1 and
C2 connected as close as possible to the device.
+5V-Powered, Multichannel RS-232
Drivers/Receivers
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/ReceiversFigure 5. MAX220/MAX232/MAX232A Pin Configuration and Typical Operating Circuit
Figure 6. MAX222/MAX242 Pin Configurations and Typical Operating Circuit
MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/ReceiversFigure 7. MAX225 Pin Configuration and Typical Operating Circuit
