MAX3221_V01 [MAXIM]
3V to 5.5V RS-232 Transceivers with AutoShutdown;
| 型号： | MAX3221_V01 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | 3V to 5.5V RS-232 Transceivers with AutoShutdown |
| 文件： | 总16页 (文件大小：1390K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Click here for production status of specific part numbers.
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
General Description
Benefits and Features
● Integrated Charge Pump Circuitry Simplifies Power
The MAX3221/MAX3223/MAX3243 achieve 1µA supply
current with Maxim’s revolutionary AutoShutdown™
feature. When the MAX3221/MAX3223/MAX3243 do not
sense a valid signal level on their receiver inputs, the on-
board power supply and drivers shut down. This occurs
if the RS-232 cable is disconnected or if the transmitters
of the connected peripheral are turned off. The system
turns on again when a valid level is applied to any RS-232
receiver input.
Requirements
• Eliminates the Need for a ±12 Supply
• Operation From a Single +3.3V or +5V Supply
● 1µA Supply Current in Shutdown Mode Saves Power
• AutoShutdown Feature is Enabled After No Activity
on Receiver Inputs for 30µs
• Software Control Option for Shutdown
The MAX3221/MAX3223/MAX3243 require only 0.1µF
capacitors in 3.3V operation, and can operate from input
voltages ranging from +3.0V to +5.5V.
Ordering Information
PART
TEMP RANGE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
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
-40°C to +85°C
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
-40°C to +85°C
PIN-PACKAGE
16 SSOP
A proprietary, high-efficiency, dual charge-pump power
supply and a low-dropout transmitter combine to deliver
true RS-232 performance from a single +3.0V to +5.5V
supply.
MAX3221CAE
MAX3221CUE
MAX3221EAE
†
16 TSSOP
16 SSOP
†
The MAX3221 is a 1-driver/1-receiver 16-pin SSOP
version of the 20-pin 2-driver/2-receiver MAX3223.
MAX3221EUE
MAX3223CPP
MAX3223CAP
16 TSSOP
20 Plastic DIP
20 SSOP
The MAX3243 is a 3-driver/5-receiver with a complementary
always-active receiver for external monitoring in a variety
of 28 pin packages. See Order Information table for
package offerings.
MAX3223CUP
MAX3223EPP
MAX3223EAP
MAX3223EUP
MAX3243CWI
MAX3243CAI
MAX3243CUI
MAX3243EWI
MAX3243EAI
MAX3243EUI
20 TSSOP
20 Plastic DIP
20 SSOP
Applications
● Battery-Powered Equipment
● Hand-Held Equipment
● Peripherals
20 TSSOP
28 Wide SO
28 SSOP
● Portable Diagnostics Equipment
28 TSSOP
28 Wide SO
28 SSOP
Selector Guide
PART
Tx Rx
V
RANGE (V) AutoShutdown
CC
28 TSSOP
MAX3221
MAX3223
MAX3243
1
2
3
1
2
5
3.0 to 5.5
Yes
Yes
Yes
†
Future product—contact factory for availability.
3.0 to 5.5
3.0 to 5.5
Pin Configurations appear at end of data sheet.
Typical Operating Circuits appear at end of data sheet.
AutoShutdown and UCSP are trademarks of Maxim Integrated
Products, Inc.
19-0306; Rev 10; 5/19
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
Absolute Maximum Ratings
V
..........................................................................-0.3V to +6V
16-Pin TSSOP (derate 6.70mW/°C above +70°C)......533mW
20-Pin Plastic DIP
(derate 11.11mW/°C above +70°C).............................889mW
20-Pin SSOP (derate 8.00mW/°C above +70°C)........640mW
20-Pin TSSOP DIP
CC
V+ (Note 1)..............................................................-0.3V to +7V
V- (Note 1)..............................................................+0.3V to -7V
V+ + |V-| (Note 1) ................................................................+13V
Input Voltages
T_IN, FORCEOFF, FORCEON, EN (MAX3223).. -0.3V to +6V
R_IN.................................................................................±25V
Output Voltages
(derate 7.00mW/°C above +70°C) ..............................559mW
28-Pin Wide SO (derate 12.50mW/°C above +70°C) ........1W
28-Pin SSOP (derate 9.52mW/°C above +70°C)........762mW
28-Pin TSSOP (derate 8.70mW/°C above +70°C)......696mW
Operating Temperature Ranges
MAX32_ _C_ _...................................................0°C to +70°C
MAX32_ _E_ _ ............................................... -40°C to +85°C
Storage Temperature Range............................ -65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
T_OUT..........................................................................±13.2V
R_OUT, INVALID .................................. -0.3V to (V
Short-Circuit Duration
+ 0.3V)
CC
T_OUT...................................................................Continuous
Continuous Power Dissipation (T = +70°C)
A
16-Pin SSOP (derate 7.14mW/°C above +70°C)........571mW
Note 1: V+ and V- can have maximum magnitudes 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.
Electrical Characteristics
CC
(V
= +3.0V to +5.5V, C1–C4 = 0.1μF (Note 2), T = T
to T
, unless otherwise noted. Typical values are at T = +25°C.)
A
MIN
MAX A
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS
Supply Current, AutoShutdown
Supply Current, Shutdown
All R_IN open, FORCEON = GND,
1.0
1.0
0.3
10
10
µA
µA
FORCEOFF = V
CC
V
= 3.3V
CC
or 5.0V,
= +25°C
FORCEOFF = GND
T
A
Supply Current,
AutoShutdown Disabled
FORCEON = FORCEOFF = V
,
CC
1.0
mA
no load
LOGIC INPUTS AND RECEIVER OUTPUTS
Input Logic Threshold Low
T_IN, FORCEON, FORCEOFF, EN (MAX3223)
0.8
V
V
V
= 3.3V
= 5.0V
2.0
2.4
CC
CC
Input Logic Threshold High
T_IN, EN, FORCEON, FORCEOFF
V
Input Leakage Current
Output Leakage Current
Output Voltage Low
T_IN, EN, FORCEON, FORCEOFF
±0.01
±0.05
±1.0
±10
0.4
µA
µA
V
Receivers disabled
I
= 1.6mA
OUT
OUT
V
CC
0.6
-
V
-
CC
Output Voltage High
I
= -1.0mA
V
0.1
AUTOSHUTDOWN (FORCEON = GND, FORCEOFF = V
)
CC
Positive threshold
Negative threshold
2.7
Receiver Input Thresholds to
Figure 5
V
V
Transmitters Enabled
-2.7
-0.3
Receiver Input Thresholds to
Transmitters Disabled
1μA supply current, Figure 5
+0.3
0.4
INVALID Output Voltage Low
INVALID Output Voltage High
Receiver Threshold to
I
I
= 1.6mA
= 1.0mA
V
V
OUT
OUT
V
- 0.6
CC
Figure 5
250
µs
Transmitters Enabled (t
)
WU
Maxim Integrated
│ 2
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
Electrical Characteristics (continued)
(V
= +3.0V to +5.5V, C1–C4 = 0.1μF (Note 2), T = T
to T
, unless otherwise noted. Typical values are at T = +25°C.)
CC
A
MIN
MAX A
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Receiver Positive or Negative
Figure 5
Figure 5
1
µs
Threshold to INVALID High (t
)
INVH
Receiver Positive or Negative
30
µs
Threshold to INVALID Low (t
)
INVL
RECEIVER INPUTS
Input Voltage Range
-25
0.6
0.8
+25
V
V
V
CC
V
CC
V
CC
V
CC
= 3.3V
= 5.0V
= 3.3V
= 5.0V
1.2
1.5
1.5
1.8
0.3
5
Input Threshold Low
Input Threshold High
T
T
= +25°C
= +25°C
A
A
2.4
2.4
V
Input Hysteresis
V
Input Resistance
T
= +25°C
3
7
kΩ
A
TRANSMITTER OUTPUTS
Output Voltage Swing
Output Resistance
All transmitter outputs loaded with 3kΩ to ground
±5.0
300
±5.4
10M
±35
V
Ω
V
= V+ = V- = 0V, transmitter output = ±2V
CC
Output Short-Circuit Current
±60
±25
mA
V
= ±12V, V
= 0V or 3.0V to 5.5V,
OUT
CC
Output Leakage Current
μA
transmitters disabled
MOUSE DRIVEABILITY (MAX3243)
T1IN = T2IN = GND, T3IN = V
,
CC
Transmitter Output Voltage
T3OUT loaded with 3kΩ to GND, T1OUT and
±5
V
T2OUT loaded with 2.5mA each
TIMING CHARACTERISTICS
Maximum Data Rate
R = 3kΩ, C = 1000pF, one transmitter switching
120
235
0.3
kbps
L
L
t
t
Receiver input to receiver output,
C = 150pF
L
PHL
PLH
Receiver Propagation Delay
μs
0.3
Receiver Output Enable Time
Receiver Output Disable Time
Normal operation
Normal operation
200
200
200
200
100
100
ns
ns
MAX3221/MAX3223
MAX3243
Transmitter Skew
Receiver Skew
│t
│t
– t
│
│
ns
ns
PHL
PHL
PLH
PLH
1000
MAX3221/MAX3223
MAX3243
– t
500
30
C = 200pF to
L
2500pF
4
6
8.0
V
= 3.3V, R = 3kΩ to 7kΩ,
L
CC
Transition-Region Slew Rate
T
= +25°C, measured from
V/μs
A
C = 200pF to
L
1000pF
+3V to -3V or -3V to +3V
30
Note 2: C1–C4 = 0.1μF, tested at 3.3V ±10%. C1 = 0.047μF, C2–C4 = 0.33μF, tested at 5.0V ±10%.
Maxim Integrated
│ 3
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
Typical Operating Characteristics
(V
= +3.3V, 235kbps data rate, 0.1μF capacitors, all transmitters loaded with 3kΩ, T = +25°C, unless otherwise noted.)
CC
A
MAX3221/MAX3223
SLEW RATE
vs. LOAD CAPACITANCE
MAX3221/MAX3223
SUPPLY CURRENT vs. LOAD CAPACITANCE
MAX3221/MAX3223
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
WHEN TRANSMITTING DATA
MAX3221/3223-03
6
22
20
18
16
40
35
30
5
4
V
OUT+
35
235kbps
120kbps
3
30
25
20
15
25
20
15
10
2
14
12
10
8
-SLEW
+SLEW
1
0
-1
-2
-3
-4
-5
-6
6
4
2
0
20kbps
3000
FOR DATA RATES UP TO 235kbps
V
OUT-
10
5
5
0
0
1000
2000
3000
4000
5000
150 500 1000
2000
3000
4000
5000
0
1000
2000
4000
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
MAX3243
SLEW RATE
vs. LOAD CAPACITANCE
MAX3243
SUPPLY CURRENT vs. LOAD
CAPACITANCE WHEN TRANSMITTING DATA
MAX3243
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
7.5
5.0
2.5
0
24
22
45
235kbps
V
+
OUT
40
35
30
25
20
15
10
5
20
18
16
120kbps
20kbps
-SLEW
+SLEW
1 TRANSMITTER AT 235kbps
2 TRANSMITTERS AT 30kbps
14
12
10
-2.5
-5.0
-7.5
V
OUT
-
8
1000 2000 3000 4000
LOAD CAPACITANCE (pF)
6
4
0
0
1000
2000
3000
4000
5000
0
5000
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
Maxim Integrated
│ 4
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
Pin Description
PIN
NAME
FUNCTION
MAX3221
MAX3223
MAX3243
Receiver Enable Control. Drive low for normal operation. Drive high to
force the receiver outputs into a high-Z state.
1
1
—
EN
5
6
5
6
1
2
C2+
C2-
Positive terminal of inverting charge-pump capacitor
Negative terminal of inverting charge-pump capacitor
-5.5V generated by the charge pump
RS-232 Receiver Inputs
7
7
3
V-
8
9, 16
8, 17
12, 13
10, 15
—
4–8
R_IN
13
11
9
9, 10, 11
12, 13, 14
15–19
20
T_OUT
T_IN
RS-232 Transmitter Outputs
TTL/CMOS Transmitter Inputs
R_OUT
R2OUTB
TTL/CMOS Receiver Outputs
—
Noninverting Receiver Output—active in shutdown
Output of the valid signal detector. Indicates if a valid RS-232 level is
present on receiver inputs logic “1”.
10
16
12
11
20
14
21
22
23
INVALID
FORCEOFF
FORCEON
Drive low to shut down transmitters and on-board power supply.
This overrides all automatic circuitry and FORCEON (Table 1).
Drive high to override automatic circuitry keeping transmitters on
(FORCEOFF must be high) (Table 1).
4
14
15
3
4
18
19
3
24
25
26
27
28
C1-
Negative terminal of the voltage doubler charge-pump capacitor
Ground
GND
V
CC
+3.0V to +5.5V Supply Voltage
V+
C1+
+5.5V generated by the charge pump
Positive terminal of the voltage doubler charge-pump capacitor
2
2
RS-232 Transmitters
Detailed Description
The transmitters are inverting level translators that
convert CMOS-logic levels to 5.0V EIA/TIA-232 levels.
Dual Charge-Pump Voltage Converter
The MAX3221/MAX3223/MAX3243’s internal power supply
consists of a regulated dual charge pump that provides
output voltages of +5.5V (doubling charge pump) and
-5.5V (inverting charge pump), regardless of the input
They guarantee a 120kbps data rate with worst-case
loads of 3kΩ in parallel with 1000pF, providing compatibility with
PC-to-PC communication software (such as Laplink™).
Typically, the MAX3221/MAX3223/MAX3243 can operate
at data rates of 235kbps. Transmitters can be paralleled
to drive multiple receivers or mice (MAX3243). Figure 1
shows a complete system connection.
voltage (V ) over the +3.0V to +5.5V range. The charge
CC
pumps operate in a discontinuous mode: if the output
voltages are less than 5.5V, the charge pumps are
enabled; if the output voltages exceed 5.5V, the charge
pumps are disabled. Each charge pump requires a flying
capacitor (C1, C2) and a reservoir capacitor (C3, C4) to
generate the V+ and V- supplies.
When FORCEOFF is driven to ground, or the auto-shut-
down circuitry senses invalid voltage levels at all receiver
inputs, the transmitters are disabled and the outputs are
forced into a high-impedance state.
LapLink is a trademark of Traveling Software.
Maxim Integrated
│ 5
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
POWER
MANAGEMENT
UNIT OR
KEYBOARD
CONTROLLER
FORCEOFF
FORCEON
INVALID
V
CC
PROTECTION
DIODE
MAX3243
PREVIOUS
RS-232
V
CC
I
Rx
Tx
5kΩ
UART
I/O
GND
SHDN = GND
CHIP
WITH
UART
CPU
RS-232
(a) OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM ACTIVE
RECEIVER OUTPUT IN SHUTDOWN.
V
CC
TO
µP
LOGIC
TRANSITION
DETECTOR
MAX3243
Figure 1. Interface Under Control of PMU
I
PROTECTION
DIODE
R2OUTB
RS-232 Receivers
V
The MAX3221/MAX3223/MAX3243’s receivers convert
RS-232 signals to CMOS-logic output levels. All receiv-
ers have one inverting three-state output. In shutdown
(FORCEOFF = low) or in AutoShutdown, the MAX3221/
MAX3223’s receivers are active (Table 1). Driving EN high
places the receiver(s) in a high-impedance state. The
MAX3243’s receivers are high impedance when the part
is shut down.
CC
R2IN
Rx
R2OUT
THREE-STATED
UART
5kΩ
T1OUT
T1IN
Tx
GND
FORCEOFF = GND
The MAX3243 has an always-active complementary
output (R2OUTB). R2OUTB is an extra output that
monitors receiver activity while the other receivers
are high impedance. This allows Ring Indicator to be
monitored without forward biasing other devices
connected to the receiver outputs. This is ideal for
(b) NEW MAX3243: IN SHUTDOWN, R2OUTB IS USED TO MONITOR EXTERNAL
DEVICES AND R2OUT IS THREE STATED, ELIMINATING A CURRENT PATH
THROUGH THE UART'S PROTECTION DIODE.
systems where V
is set to 0V in shutdown to
accommodate peripherals, such as UARTs (Figure 2).
CC
Figure 2. The MAX3243 Detects RS-232 Activity When the
UART and Interface Are Shut Down.
Maxim Integrated
│ 6
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
Table 1a. MAX3221/MAX3223 FORCEOFF
+0.3V
and Enable Control Truth Table
TO MAX32_ _
POWER SUPPLY
AND TRANSMITTERS
FORCEOFF
EN
0
T_OUT
High-Z
High-Z
Active*
Active*
R_OUT
Active
High-Z
Active
High-Z
R_IN
-0.3V
30µs
COUNTER
INVALID
0
0
1
1
R
1
0
* TRANSMITTERS ARE DISABLED, REDUCING SUPPLY CURRENT TO 1µA IF
ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30µs.
1
Figure 3a. MAX32_ _ Entering 1μA Supply Mode Through
AutoShutdown
Table 1b. MAX3243 FORCEOFF Control
Truth Table
+2.7V
FORCEOFF
T_OUT
High-Z
Active*
R_OUT
High-Z
Active*
R2OUTB
Active
TO MAX32_ _
0
R_IN
POWER SUPPLY
30µs
COUNTER
R
1
Active
INVALID
-2.7V
*Note: If the part is in AutoShutdown mode (FORCEOFF
= V , FORCEON = GND), it is shut down if no valid RS-232
CC
* TRANSMITTERS ARE ENABLED IF:
ANY RECEIVER INPUT IS GREATER THAN +2.7V OR LESS THAN -2.7V.
levels are present on all receiver inputs.
ANY RECEIVER INPUT HAS BEEN BETWEEN +0.3V AND -0.3V FOR LESS THAN 30µs.
Figure 3b. MAX32_ _ with Transmitters Enabled Using
AutoShutdown
AutoShutdown
A 1µA supply current is achieved with Maxim’s new
AutoShutdown feature, which operates when FORCEON
is low and FORCEOFF is high. When the MAX3221/
MAX3223/MAX3243 sense no valid signal levels on all
receiver inputs for 30µs, the on-board power supply and
drivers are shut off, reducing supply current to 1µA. This
occurs if the RS-232 cable is disconnected or the con-
nected peripheral transmitters are turned off. The system
turns on again when a valid level is applied to any RS-232
receiver input. As a result, the system saves power with-
out changes to the existing BIOS or operating system.
When using AutoShutdown, the INVALID output is high
when the device is on and low when the device is shut
down. Because INVALID indicates the receiver inputs’
condition, it can be used in any mode (Figure 3).
FORCEOFF
POWER DOWN
FORCEON
INVALID
INVALID IS AN INTERNALLY GENERATED SIGNAL
THAT IS USED BY THE AUTOSHUTDOWN LOGIC
AND APPEARS AS AN OUTPUT OF THE DEVICE.
POWER DOWN IS ONLY AN INTERNAL SIGNAL.
IT CONTROLS THE OPERATIONAL STATUS OF
THE TRANSMITTERS AND THE POWER SUPPLIES.
Figure 3c. AutoShutdown Logic
Table 2 and Figure 3c summarize the MAX3221/
MAX3223/MAX3243 operating modes. FORCEON and
FORCEOFF override the automatic circuitry and force the
transceiver into its normal operating state or into its low-
power standby state. When neither control is asserted,
the IC selects between these states automatically based
on receiver input levels. Figures 3a, 3b, and 5a depict
valid and invalid RS-232 receiver levels.
POWER
MANAGEMENT
MASTER SHDN LINE
0.1µF 1MΩ
UNIT
FORCEOFF FORCEON
MAX3221
MAX3223
MAX3243
A mouse or other system with AutoShutdown may need
time to wake up. Figure 4 shows a circuit that forces the
transmitters on for 100ms, allowing enough time for the
other system to realize that the MAX3221/MAX3223/
Figure 4. AutoShutdown with Initial Turn-On to Wake Up a
Mouse or Another System
Maxim Integrated
│ 7
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
Table 2. AutoShutdown Logic
RS-232 SIGNAL
FORCEOFF
RECEIVER INPUT
FORCEON
INPUT
INVALID
TRANSCEIVER
STATUS
PRESENT AT
INPUT
INPUT
Yes
No
H
H
H
L
X
H
L
H
L
Normal Operation
Normal Operation (Forced On)
Shutdown (AutoShutdown)
Shutdown (Forced Off)
No
L
Yes
No
X
X
H
L
L
Shutdown (Forced Off)
MAX3243 is awake. If the other system outputs valid
RS-232 signals within that time, the RS-232 ports on both
systems remain enabled.
When shut down, the device’s charge pumps are turned
TRANSMITTERS ENABLED, INVALID HIGH
off, V+ decays to V , V- decays to ground, and
CC
+2.7V
the transmitter outputs are disabled (high impedance).
The time required to exit shutdown is typically 100µs
(Figure 5b).
INDETERMINATE
+0.3V
0V
AUTOSHUTDOWN, TRANSMITTERS DISABLED,
1µA SUPPLY CURRENT, INVALID LOW
Software-Controlled Shutdown
-0.3V
If direct software control is desired, INVALID can be used
to indicate DTR or Ring Indicator signal. Tie FORCEOFF
and FORCEON together to bypass AutoShutdown so the
line acts like a SHDN input.
INDETERMINATE
-2.7V
TRANSMITTERS ENABLED, INVALID HIGH
(a)
Applications Information
Capacitor Selection
The capacitor type used for C1–C4 is not critical for
proper operation; either polarized or nonpolarized capaci-
tors may be used. The charge pump requires 0.1µF
capacitors for 3.3V operation. For other supply voltages,
refer to Table 3 for required capacitor values. Do not use
values smaller than those listed in Table 3. Increasing
the capacitor values (e.g., by a factor of 2) reduces ripple
on the transmitter outputs and slightly reduces power
consumption. C2, C3, and C4 can be increased without
changing C1’s value. However, do not increase C1
without also increasing the values of C2, C3, and
C4 to maintain the proper ratios (C1 to the other
capacitors).
RECEIVER
INPUT
VOLTAGE
(V)
INVALID
REGION
V
CC
INVALID
OUTPUT
(V)
0
t
INVH
t
INVL
t
WU
V+
V
CC
0
When using the minimum required capacitor values,
make sure the capacitor value does not degrade exces-
sively with temperature. If in doubt, use capacitors with
a larger nominal value. The capacitor’s equivalent series
resistance (ESR) usually rises at low temperatures and
influences the amount of ripple on V+ and V-.
V-
(b)
Figure 5. AutoShutdown Trip Levels
Maxim Integrated
│ 8
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
6
5
5V/div
2V/div
V
OUT
+
4
3
T2
V
CC
= 3.0V
2
T
T
T
1
2
3
1
V
+
-
OUT
0
-1
-2
-3
-4
-5
-6
V
V
CC
1
OUT
T1
V
OUT
-
50µs/div
0
2
3
4
5
6
7
V
= +3.3V
CC
LOAD CURRENT PER TRANSMITTER (mA)
C1–C4 = 0.1µF
Figure 6. Transmitter Outputs When Exiting Shutdown or
Powering Up
Figure 7a. MAX3243 Transmitter Output Voltage vs. Load
Current per Transmitter
serial mice and met their respective current and voltage
requirements. Figure 7a shows the transmitter outputs
under increasing load current. The MAX3243’s switching
regulator ensures the transmitters will supply at least
±5V during worst-case conditions. The AutoShutdown
feature does not work with a mouse, so FORCEOFF and
Power-Supply Decoupling
In most circumstances a 0.1µF bypass capacitor is adequate.
In applications that are sensitive to power-supply noise,
decouple V
to ground with a capacitor of the same
CC
value as the charge-pump capacitor C1. Connect bypass
capacitors as close to the IC as possible.
FORCEON should be connected to V
.
CC
Transmitter Outputs
when Exiting Shutdown
High Data Rates
The MAX3221/MAX3223/MAX3243 maintain the RS-232
±5.0V minimum transmitter output voltage even at high
data rates. Figure 8 shows a transmitter loopback test
circuit. Figure 9 shows a loopback test result at 120kbps,
and Figure 10 shows the same test at 235kbps. For
Figure 9, all three transmitters were driv-en simultaneously
at 120kbps into RS-232 loads in parallel with 1000pF. For
Figure 10, a single transmitter was driven at 235kbps,
but all three transmitters were loaded with an RS-232
receiver in parallel with 1000pF.
Figure 6 shows two transmitter outputs when exiting
shutdown mode. As they become active, the two trans-
mitter outputs are shown going to opposite RS-232
levels. Each transmitter is loaded with 3kΩ in parallel
with 2500pF. The transmitter outputs display no ringing
or undesirable transients as they come out of shutdown.
Note that the transmitters are enabled only when the
magnitude of V- exceeds approximately 3V. Figure 7a
shows the MAX3243’s transmitter output voltage vs.
current per transmitter. Figure 7b is a mouse driver test
circuit.
Interconnection with
3V and 5V Logic
Mouse Driveability (MAX3243)
The MAX3221/MAX3223/MAX3243 can directly interface
with various 5V logic families, including ACT and HCT
CMOS. See Table 4 for more information on possible
combinations of interconnections.
The MAX3243 has been specifically designed to power
serial mice while operating from low-voltage power
supplies. It has been tested with samples of ten major
mouse models from six manufacturers including the
leading three: Logitech (5 models), Mouse Systems,
and Microsoft. The MAX3243 successfully drove all
Maxim Integrated
│ 9
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
+3.3V
0.1µF
26
V
CC
27
3
28
C1+
V+
C1
0.1µF
C3
0.1µF
24
C1-
COMPUTER SERIAL PORT
MAX3243
1
C2+
V-
C4
C2
0.1µF
0.1µF
2
C2-
+V
+V
-V
T1IN
T1OUT
9
14
T2IN
T3IN
LOGIC
INPUTS
T2OUT 10
13
12
11
T3OUT
GND
Tx
R2OUTB
20
R1OUT
R2OUT
R3OUT
R1IN
5kΩ
R2IN
4
5
19
18
17
LOGIC
OUTPUTS
5kΩ
R3IN
5kΩ
R4IN
5kΩ
R5IN
6
7
8
RS-232
INPUTS
R4OUT
R5OUT
16
SERIAL
MOUSE
15
23
5kΩ
FORCEON
FORCEOFF
INVALID
22
21
V
CC
TO POWER
MANAGEMENT
UNIT
GND
25
Figure 7b. Mouse Driver Test Circuit
Maxim Integrated
│ 10
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
Table 3. Required Capacitor Values
V
(V)
C1
(μF)
C2, C3, C4
(μF)
CC
V
CC
0.1µF
3.0 to 3.6
4.5 to 5.5
3.0 to 5.5
0.1
0.047
0.1
0.1
0.33
0.47
V
CC
C1+
V+
V-
C3
C4
C1
C2
C1-
MAX3221
MAX3223
MAX3243
Table 4. Logic Family Compatibility with
Various Supply Voltages
C2+
C2-
SYSTEM
T_ OUT
T_ IN
POWER-
SUPPLY
VOLTAGE
(V)
V
SUPPLY
CC
VOLTAGE
COMPATIBILITY
(V)
R_ IN
R_ OUT
EN (MAX3221/3)
Compatible with all CMOS
families.
5kΩ
0V
1000pF
3.3
5
3.3
5
V
CC
FORCEOFF
Compatible with all TTL and
CMOS-logic families.
GND
Compatible with ACT and
HCT CMOS, and with TTL.
Incompatible with AC, HC,
or CD4000 CMOS.
5
3.3
Figure 8. Loopback Test Circuit
5V/div
5V/div
T1IN
T1IN
5V/div
5V/div
5V/div
5V/div
T1OUT
R1OUT
T1OUT
R1OUT
2µs/div
5µs/div
V
CC
= +3.3V, 120kbps
V
CC
= +3.3V, 235kbps
C1–C4 = 0.1µF
C1–C4 = 0.1µF
Figure 9. Loopback Test Result at 120kbps
Figure 10. Loopback Test Result at 235kbps
Maxim Integrated
│ 11
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
Typical Operating Circuits
+3.3V
15
0.1µF
2
C5
V
CC
3
7
C1+
V+
V-
C1
C3
0.1µF
4
5
6
0.1µF
C1-
+3.3V
MAX3221
26
C2+
0.1µF
C4
0.1µF
C2
0.1µF
V
CC
27
3
28
C1+
C2-
V+
C1
C3
0.1µF
0.1µF
11
9
T1IN
24
1
T1OUT 13
C1-
MAX3243
C2+
V-
C4
0.1µF
C2
0.1µF
R1OUT
R1IN 8
2
C2-
5kΩ
T1IN
T1OUT
9
14
TO POWER
MANAGEMENT
UNIT
RS-232
OUTPUTS
T2IN
T3IN
LOGIC
INPUTS
T2OUT 10
EN
INVALID 10
13
12
1
11
T3OUT
FORCEOFF
FORCEON
16
12
V
CC
GND
14
R2OUTB
R1OUT
20
19
R1IN
4
5
+3.3V
5kΩ
19
0.1µF
2
C5
V
R2OUT
R3OUT
R4OUT
R2IN
CC
18
17
16
3
7
C1+
V+
V-
C1
0.1µF
C3
0.1µF
5kΩ
4
5
6
LOGIC
OUTPUTS
C1-
MAX3223
6
7
8
R3IN
RS-232
INPUTS
C2+
C4
0.1µF
C2
0.1µF
5kΩ
C2-
R4IN
13
T1IN
T1OUT 17
TTL/CMOS
INPUTS
RS-232
OUTPUTS
5kΩ
8
T2IN
T2OUT
12
R5OUT
15
23
R5IN
5kΩ
FORCEON
FORCEOFF
INVALID
16
15 R1OUT
R1IN
22
21
TTL/CMOS
OUTPUTS
RS-232
INPUTS
V
5kΩ
CC
R2IN
10 R2OUT
9
TO POWER
MANAGEMENT UNIT
GND
25
5kΩ
TO POWER
MANAGEMENT
UNIT
EN
INVALID 11
1
FORCEOFF
FORCEON
20
14
V
CC
GND
18
Maxim Integrated
│ 12
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
3V-Powered EIA/TIA-232 and EIA/TIA-562 Transceivers from Maxim
POWER-
SUPPLY
VOLTAGE
(V)
NUMBER OF
RECEIVERS
ACTIVE IN
NUMBER OF
TRANSMITTERS/
RECEIVERS
GUARANTEED
DATA RATE
(kbps)
EIA/
TIA-232
OR 562
PART
FEATURES
SHUTDOWN
MAX212
MAX218
3.0 to 3.6
3/5
2/2
5
2
120
120
232
232
Drives mice
Operates directly from batteries
without a voltage regulator
1.8 to 4.25
MAX562
MAX563
2.7 to 5.25
3.0 to 3.6
3/5
2/2
5
2
230
120
562
562
230kbps guaranteed data rate
0.1μF capacitors
AutoShutdown, complementary
receiver, drives mice, transient
detection
MAX3212
2.7 to 3.6
3/5
5
235
232
MAX3221
MAX3222
MAX3223
MAX3232
3.0 to 5.5
3.0 to 5.5
3.0 to 5.5
3.0 to 5.5
1/1
2/2
2/2
2/2
1
2
120
120
120
120
232
232
232
232
0.1μF capacitors, 16-pin SSOP
0.1μF capacitors, MAX242 pinout
0.1μF capacitors, AutoShutdown
0.1μF capacitors, MAX232 pinout
2
N/A
0.1μF capacitors, 2 complementary
receivers, drives mice
MAX3241
3.0 to 5.5
3/5
5
120
232
0.1μF capacitors, AutoShutdown
complementary receiver, drives
mice
MAX3243
3.0 to 5.5
3/5
1
120
232
Maxim Integrated
│ 13
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
Pin Configurations
TOP VIEW
EN
C1+
V+
FORCEOFF
1
2
20
19
18
17
16
15
14
13
12
11
V
CC
EN
16 FORCEOFF
1
2
3
4
5
6
7
8
GND
3
15
14
C1+
V+
V
CC
C1-
T1OUT
R1IN
4
GND
MAX3223
C2+
C2-
V-
5
C1-
C2+
C2-
V-
13 T1OUT
MAX3221
R1OUT
FORCEON
T1IN
6
FORCEON
12
7
11 T1IN
10 INVALID
T2OUT
R2IN
8
T2IN
9
9
R1IN
R1OUT
R2OUT
INVALID
10
SSOP/TSSOP
DIP/SSOP/TSSOP
C2+
C1+
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
C2-
V-
V+
V
2
3
CC
R1IN
R2IN
R3IN
R4IN
R5IN
GND
4
C1-
5
FORCEON
FORCEOFF
INVALID
R2OUTB
R1OUT
R2OUT
R3OUT
R4OUT
R5OUT
6
MAX3243
7
8
T1OUT
T2OUT
T3OUT
T3IN
9
10
11
12
13
14
T2IN
T1IN
SO/SSOP/TSSOP
Maxim Integrated
│ 14
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
Package Information
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
THERMAL RESISTANCE
(SINGLE LAYER BOARD)
THERMAL RESISTANCE
(MULTI LAYER BOARD)
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
θ
(°C/W)
140
106
90
θ
(°C/W)
34
θ
(°C/W)
86
θ
JC
(°C/W)
33
JA
JC
JA
16 SSOP
16 TSSOP
20 Plastic DIP
20 SSOP
A16+2
U16+1
P20+2
A20+1
U20+2
W28+1
A28+1
U28+2
21-0056
21-0066
21-0043
21-0056
21-0066
21-0042
21-0056
21-0066
90-0106
90-0117
—
27
90
27
30
NA
NA
32
90-0094
90-0116
90-0109
90-0095
90-0171
125
91
33
84
20 TSSOP
28 Wide SO
28 SSOP
20
73.8
59
20
80
18
18
110
78
25
67.1
71.6
25
28 TSSOP
13
13
Maxim Integrated
│ 15
www.maximintegrated.com
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
REVISION REVISION
PAGES
CHANGED
DESCRIPTION
NUMBER
DATE
9
1/15
Updated General Description and Benefits and Features sections
Added Package Information table
1
10
5/2019
15
For pricing, delivery, and ordering information, please visit Maxim Integrated’s online storefront at https://www.maximintegrated.com/en/storefront/storefront.html.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
©
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
2019 Maxim Integrated Products, Inc.
│ 16
相关型号：
MAX3222
3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1レF External Capacitors
MAXIM
MAX3222C/D
3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1レF External Capacitors
MAXIM
MAX3222CAP
3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1レF External Capacitors
MAXIM
©2020 ICPDF网 联系我们和版权申明