MAX3221E
SLLS686C – OCTOBER 2005 – REVISED JULY 2021
MAX3221E 3-V to 5.5-V Single-Channel RS-232 Line Driver/Receiver
With ±15-kV IEC ESD Protection
1 Features
3 Description
•
The MAX3221E is a single driver, single receiver
RS-232 solution operating from a single VCC supply.
The RS-232 pins provide IEC 61000-4-2 ESD
protection. The device meets the requirements of
TIA/EIA-232-F and provides the electrical interface
between an asynchronous communication controller
and the serial-port connector. The charge pump and
four small external capacitors allow operation from a
single 3-V to 5.5-V supply. These devices operate at
data signaling rates up to 250 kbit/s and a maximum
of 30-V/µs driver output slew rate.
•
•
•
•
•
•
•
•
ESD protection for RS-232 pins
– ±15-kV Human-body model (HBM)
– ±8 kV (IEC 61000-4-2, Contact discharge)
– ±15 kV (IEC 61000-4-2, Air-gap discharge)
Meets or exceeds the requirements of TIA/
EIA-232-F and ITU v.28 standards
Operates with 3-V to 5.5-V VCC upply
Operates up to 250 kbit/s
One driver and one receiver
Low standby current: 1 µA typical
Accepts 5-V logic input with 3.3-V supply
Auto-power-down feature automatically disables
drivers for power savings
Alternative high-speed device (1 Mbit/s)
– SN75C3221E and SN65C3221E
Flexible control options for power management are
available. Auto-power down disables driver and
charge pump when the receiver is disconnected or
the remote driver is power down. The drivers can be
manually enabled or disabled. INVALID output goes
low when receiver input is unconnected or power off.
2 Applications
•
•
•
•
•
•
•
•
•
Industrial PCs
Wired networking
Data center and enterprise computing
Battery-powered systems
PDAs
Notebooks
Laptops
Palmtop PCs
Hand-held equipment
Device Information
PART NUMBER
PACKAGE(1)
BODY SIZE (NOM)
MAX3221ECDB,
MAX3221EIDB
SSOP (16)
6.20 mm × 5.30 mm
MAX3221ECPW,
MAX3221EIPW
TSSOP (16)
5.00 mm × 4.40 mm
(1)
For all available packages, see the orderable addendum at
the end of the data sheet.
spacer
3.3V, 5V
POWER
AUTOPOWERDOWN
FORCEON
FORCEOFF
RX Enable
EN
DIN
1
1
TX
250 kb/s
ROUT
INVALID
1
RX
DOUT
RS-232
IEC 61000-4-2
1
RIN
RS-232
STATUS
Copyright © 2016, Texas Instruments Incorporated
Block Diagram
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
MAX3221E
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SLLS686C – OCTOBER 2005 – REVISED JULY 2021
Table of Contents
1 Features............................................................................1
2 Applications..................................................................... 1
3 Description.......................................................................1
4 Revision History.............................................................. 2
5 Pin Configuration and Functions...................................3
6 Specifications.................................................................. 4
6.1 Absolute Maximum Ratings........................................ 4
6.2 ESD Ratings............................................................... 4
6.3 ESD Ratings - IEC Specifications............................... 4
6.4 Recommended Operating Conditions.........................5
6.5 Thermal Information....................................................5
6.6 Electrical Characteristics.............................................5
6.7 Electrical Characteristics: Driver................................. 6
6.8 Electrical Characteristics: Receiver............................ 6
6.9 Electrical Characteristics: Auto-Power Down..............6
6.10 Switching Characteristics: Driver.............................. 7
6.11 Switching Characteristics: Receiver..........................7
6.12 Switching Characteristics: Auto-Power Down...........7
6.13 Typical Characteristics.............................................. 8
7 Parameter Measurement Information............................ 9
8 Detailed Description......................................................12
8.1 Overview................................................................... 12
8.2 Functional Block Diagram......................................... 12
8.3 Feature Description...................................................12
8.4 Device Functional Modes..........................................13
9 Application and Implementation.................................. 14
9.1 Application Information............................................. 14
9.2 Typical Application.................................................... 14
10 Power Supply Recommendations..............................17
11 Layout........................................................................... 17
11.1 Layout Guidelines................................................... 17
11.2 Layout Example...................................................... 17
12 Device and Documentation Support..........................18
12.1 Receiving Notification of Documentation Updates..18
12.2 Support Resources................................................. 18
12.3 Trademarks............................................................. 18
12.4 Electrostatic Discharge Caution..............................18
12.5 Glossary..................................................................18
13 Mechanical, Packaging, and Orderable
Information.................................................................... 18
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision B (March 2016) to Revision C (July 2021)
Page
• Changed the Applications list............................................................................................................................. 1
• Added ESD ratings IEC Specifications table and added a table note for the minimum requirement to meet the
IEC ESD level..................................................................................................................................................... 4
• Changed values in the Thermal Information table for DB and PW packages.....................................................5
Changes from Revision A (May 2006) to Revision B (March 2016)
Page
• Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and
Implementation section, Power Supply Recommendations section, Layout section, Device and
Documentation Support section, and Mechanical, Packaging, and Orderable Information section .................. 1
• Deleted Ordering Information table; see the POA at the end of the data sheet ................................................ 1
• Changed RθJA thermal values: 82 to 92 for DB package and 108 to 100.3 for PW Package.............................5
2
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5 Pin Configuration and Functions
C1+
1
2
16
15
FORCEOFF
VCC
V+
3
14
GND
C1–
4
13
DOUT
C2+
5
12
FORCEON
C2–
6
11
DIN
V–
7
10
INVALID
RIN
8
9
EN
ROUT
Not to scale
Figure 5-1. DB or PW Package, 16-Pin SSOP or TSSOP, Top View
Table 5-1. Pin Functions
PIN
NAME
NO.
I/O
DESCRIPTION
C1+
2
C2+
5
C1–
4
C2–
6
DIN
11
I
Driver input
DOUT
13
O
RS-232 driver output
EN
1
I
Low input enables receiver ROUT output. High input sets ROUT to high impedance.
FORCEOFF
16
I
Automatic power-down control input
FORCEON
12
I
Automatic power-down control input
GND
14
—
Ground
INVALID
10
O
Invalid output pin. Output low when RIN input is unpowered.
RIN
8
I
RS-232 receiver input
ROUT
9
O
Receiver output
VCC
15
—
3-V to 5.5-V supply voltage
V+
3
O
5.5-V supply generated by the charge pump
V–
7
O
–5.5-V supply generated by the charge pump
—
Positive terminals of the voltage-doubler charge pump capacitors
—
Negative terminals of the voltage-doubler charge pump capacitors
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)(1)
Supply voltage(2)
VCC
voltage(2)
V+
Positive output supply
V–
Negative output supply voltage(2)
V+ – V– Supply voltage
Input voltage
VO
Output voltage
TJ
Operating virtual junction temperature
Tstg
Storage temperature
(2)
MAX
UNIT
6
V
–0.3
7
V
0.3
–7
V
13
V
difference(2)
VI
(1)
MIN
–0.3
DIN, FORCEOFF, FORCEON, EN
–0.3
6
RIN
–25
25
DOUT
–13.2
13.2
ROUT, INVALID
–0.3
VCC + 0.3
–65
V
V
150
°C
150
°C
Operation outside the Absolute Maximum Ratings may cause permanent device damage. Absolute Maximum Ratings do not imply
functional operation of the device at these or any other conditions beyond those listed under Recommended Operating Conditions.
If used outside the Recommended Operating Conditions but within the Absolute Maximum Ratings, the device may not be fully
functional, and this may affect device reliability, functionality, performance, and shorten the device lifetime.
All voltages are with respect to network GND.
6.2 ESD Ratings
VALUE
V(ESD)
(1)
(2)
Electrostatic
discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1)
Charged-device model (CDM), per JEDEC specification JESD22-C101(2)
Pins 8 and 11
±15000
All other pins
±2000
All pins
±1500
UNIT
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
6.3 ESD Ratings - IEC Specifications
VALUE
V (ESD)
(1)
4
Electrostatic discharge
IEC 61000-4-2 Contact
Discharge, DOUT and
RIN (1)
IEC 61000-4-2 Air-Gap
Discharge, DOUT and
RIN (1)
UNIT
±8000
Pins 8 and 11
V
±15000
A minimum of 1-µF capacitor is required between VCC and GND to meet the specified IEC-ESD level.
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6.4 Recommended Operating Conditions
See Figure 9-1 (1)
VCC = 3.3 V
Supply voltage
VCC = 5 V
VIH
Driver and control high-level input voltage DIN, FORCEOFF, FORCEON, EN
VIL
Driver and control low-level input voltage
DIN, FORCEOFF, FORCEON, EN
VI
Driver and control input voltage
DIN, FORCEOFF, FORCEON
VI
Receiver input voltage
TA
(1)
Operating free-air temperature
VCC = 3.3 V
VCC = 5 V
MIN
NOM
MAX
3
3.3
3.6
4.5
5
5.5
2
MAX3221EI
V
V
2.4
MAX3221EC
UNIT
0.8
V
0
5.5
V
–25
25
V
0
70
–40
85
°C
Test conditions are C1–C4 = 0.1 µF at VCC = 3.3 V ± 0.3 V; C1 = 0.047 µF, C2–C4 = 0.33 µF at VCC = 5 V ± 0.5 V.
6.5 Thermal Information
MAX3221E
THERMAL METRIC(1)
DB (SSOP)
PW (TSSOP)
16 PINS
16 PINS
UNIT
RθJA
Junction-to-ambient thermal resistance
105.8
110.9
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
51.9
41.7
°C/W
RθJB
Junction-to-board thermal resistance
57.6
57.2
°C/W
ψJT
Junction-to-top characterization parameter
14.1
4.2
°C/W
ψJB
Junction-to-board characterization parameter
56.8
56.6
°C/W
(1)
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
6.6 Electrical Characteristics
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)(2)
PARAMETER
II
Input leakage current
Supply current
Powered off
Auto-power down
enabled
(1)
(2)
MAX
±0.01
±1
µA
0.3
1
mA
No load,
FORCEOFF at GND
1
10
No load, FORCEOFF at VCC,
FORCEON at GND,
All RIN are open or grounded
1
10
FORCEOFF,
FORCEON, EN
MIN
No load,
FORCEOFF and
FORCEON at VCC
Auto-power down
disabled
ICC
TYP(1)
TEST CONDITIONS
VCC = 3.3 V or 5 V,
TA = 25°C
UNIT
µA
All typical values are at VCC = 3.3 V or VCC = 5 V, and TA = 25°C.
Test conditions are C1–C4 = 0.1 µF at VCC = 3.3 V ± 0.3 V; C1 = 0.047 µF, C2–C4 = 0.33 µF at VCC = 5 V ± 0.5 V.
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6.7 Electrical Characteristics: Driver
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)(3)
PARAMETER
TEST CONDITIONS
MIN
TYP(1)
MAX
UNIT
VOH
High-level output voltage
DOUT at RL = 3 kΩ to GND,
DIN = GND
5
5.4
V
VOL
Low-level output voltage
DOUT at RL = 3 kΩ to GND,
DIN = VCC
–5
–5.4
V
IIH
High-level input current
VI = VCC
±0.01
±1
µA
IIL
Low-level input current
VI = GND
±0.01
±1
µA
IOS
Short-circuit
output current(2)
VCC = 3.6 V,
VO = 0 V
±35
±60
VCC = 5.5 V,
VO = 0 V
±35
±60
ro
Output resistance
VCC, V+, and V– = 0 V,
VO = ±2 V
Ioff
(1)
(2)
(3)
Output leakage current
FORCEOFF = GND
300
10M
mA
Ω
VO = ±12 V,
VCC = 3 V to 3.6 V
±25
VO = ±10 V,
VCC = 4.5 V to 5.5 V
±25
µA
All typical values are at VCC = 3.3 V or VCC = 5 V, and TA = 25°C.
Short-circuit durations should be controlled to prevent exceeding the device absolute power-dissipation ratings, and not more than one
output should be shorted at a time.
Test conditions are C1–C4 = 0.1 µF at VCC = 3.3 V ± 0.3 V; C1 = 0.047 µF, C2–C4 = 0.33 µF at VCC = 5 V ± 0.5 V.
6.8 Electrical Characteristics: Receiver
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)(2)
PARAMETER
VOH
High-level output voltage
IOH = –1 mA
VOL
Low-level output voltage
IOL = 1.6 mA
TYP(1)
VCC – 0.6
VCC – 0.1
MAX
0.4
1.6
2.4
VCC = 5 V
1.9
2.4
Positive-going input threshold voltage
VIT–
Negative-going input threshold voltage
Vhys
Input hysteresis (VIT+ – VIT–)
Ioff
Output leakage current
EN = VCC
ri
Input resistance
VI = ±3 V to ±25 V
VCC = 3.3 V
0.6
1.1
VCC = 5 V
0.8
1.4
UNIT
V
VCC = 3.3 V
VIT+
(1)
(2)
MIN
TEST CONDITIONS
V
V
V
0.5
V
±0.05
±10
µA
5
7
kΩ
3
All typical values are at VCC = 3.3 V or VCC = 5 V, and TA = 25°C.
Test conditions are C1–C4 = 0.1 µF at VCC = 3.3 V ± 0.3 V; C1 = 0.047 µF, C2–C4 = 0.33 µF at VCC = 5 V ± 0.5 V.
6.9 Electrical Characteristics: Auto-Power Down
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)
PARAMETER
6
TEST CONDITIONS
MIN
VT+(valid)
Receiver input threshold
for INVALID high-level output voltage
FORCEON = GND,
FORCEOFF = VCC
VT–(valid)
Receiver input threshold
for INVALID high-level output voltage
FORCEON = GND,
FORCEOFF = VCC
–2.7
VT(invalid)
Receiver input threshold
for I NVALID low-level output voltage
FORCEON = GND,
FORCEOFF = VCC
–0.3
VOH
INVALID high-level output voltage
IOH = –1 mA, FORCEON = GND,
FORCEOFF = VCC
VOL
INVALID low-level output voltage
IOL = 1.6 mA, FORCEON = GND,
FORCEOFF = VCC
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MAX
2.7
UNIT
V
V
0.3
VCC – 0.6
V
V
0.4
V
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6.10 Switching Characteristics: Driver
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)(3)
PARAMETER
TEST CONDITIONS
Maximum data rate
CL = 1000 pF,
RL = 3 kΩ,
tsk(p)
Pulse skew(2)
CL = 150 pF to 2500 pF,
RL = 3 kΩ to 7 kΩ,
SR(tr)
Slew rate,
transition region
(see Figure 7-1)
VCC = 3.3 V,
RL = 3 kΩ to 7 kΩ
(1)
(2)
(3)
MIN
TYP(1)
150
250
kbit/s
100
ns
See Figure 7-2
MAX
CL = 150 pF to 1000 pF
6
30
CL = 150 pF to 2500 pF
4
30
UNIT
V/µs
All typical values are at VCC = 3.3 V or VCC = 5 V, and TA = 25°C.
Pulse skew is defined as |tPLH – tPHL| of each channel of the same device.
Test conditions are C1–C4 = 0.1 µF at VCC = 3.3 V ± 0.3 V; C1 = 0.047 µF, C2–C4 = 0.33 µF at VCC = 5 V ± 0.5 V.
6.11 Switching Characteristics: Receiver
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)(3)
PARAMETER
TYP(1)
TEST CONDITIONS
UNIT
tPLH
Propagation delay time, low- to high-level output
CL = 150 pF, See Figure 7-3
150
ns
tPHL
Propagation delay time, high- to low-level output
CL = 150 pF, See Figure 7-3
150
ns
ten
Output enable time
CL = 150 pF, RL = 3 kΩ, See Figure 7-4
200
ns
tdis
Output disable time
CL = 150 pF, RL = 3 kΩ, See Figure 7-4
200
ns
50
ns
tsk(p)
(1)
(2)
(3)
Pulse
skew(2)
See Figure 7-3
All typical values are at VCC = 3.3 V or VCC = 5 V, and TA = 25°C.
Pulse skew is defined as |tPLH – tPHL| of each channel of the same device.
Test conditions are C1–C4 = 0.1 µF at VCC = 3.3 V ± 0.3 V; C1 = 0.047 µF, C2–C4 = 0.33 µF at VCC = 5 V ± 0.5 V.
6.12 Switching Characteristics: Auto-Power Down
over recommended ranges of supply voltage and operating free-air temperature (unless otherwise noted)
PARAMETER
tvalid
Propagation delay time, low- to high-level output
tinvalid
Propagation delay time, high- to low-level output
ten
Supply enable time
(1)
TYP(1)
UNIT
1
µs
30
µs
100
µs
All typical values are at VCC = 3.3 V or VCC = 5 V, and TA = 25°C.
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6.13 Typical Characteristics
1.2
3.5
1
3
ROUT Voltage (V)
ROUT Voltage (V)
TA = 25° C; VCC = 3.3V
0.8
0.6
0.4
0.2
2.5
2
1.5
1
0.5
0
0
0
1
2
3
4
5
6
7
ROUT Current (mA)
8
9
0
10
6
0
5
-1
DOUT Voltage (V)
DOUT Voltage (V)
2
3
4
5
6
7
ROUT Current (mA)
8
9
10
D002
Figure 6-2. Receiver VOH vs Load Current
Figure 6-1. Receiver VOL vs Load Current
4
3
2
1
-2
-3
-4
-5
0
-6
0
3
6
9
12
15
18
21
DOUT Current (mA)
24
27
30
0
3
D003
Figure 6-3. Driver VOH vs Load Current
8
1
D001
6
9
12
15
18
21
DOUT Current (mA)
24
27
30
D004
Figure 6-4. Driver VOL vs Load Current
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7 Parameter Measurement Information
3V
Generator
(see Note B)
RS-232
Output
50 Ω
RL
TEST CIRCUIT
0V
tTHL
CL
(see Note A)
3V
FORCEOFF
A.
B.
Input
tTLH
3V
3V
Output
−3 V
−3 V
6V
SR(tr) =
t THL or t TLH
VOH
VOL
VOLTAGE WAVEFORMS
CL includes probe and jig capacitance.
The pulse generator has the following characteristics: PRR = 250 kbps, ZO = 50 Ω, 50% duty cycle, tr ≤ 10 ns, tf ≤ 10 ns.
Figure 7-1. Driver Slew Rate
3V
Generator
(see Note B)
RS-232
Output
50 Ω
RL
Input
0V
CL
(see Note A)
tPHL
tPLH
VOH
3V
FORCEOFF
50%
50%
Output
VOL
TEST CIRCUIT
A.
B.
1.5 V
1.5 V
VOLTAGE WAVEFORMS
CL includes probe and jig capacitance.
The pulse generator has the following characteristics: PRR = 250 kbps, ZO = 50 Ω, 50% duty cycle, tr ≤ 10 ns, tf ≤ 10 ns.
Figure 7-2. Driver Pulse Skew
3 V or 0 V
FORCEON
3V
Input
1.5 V
1.5 V
−3 V
Output
Generator
(see Note B)
50 Ω
3V
FORCEOFF
tPHL
CL
(see Note A)
tPLH
VOH
50%
Output
50%
VOL
TEST CIRCUIT
A.
B.
VOLTAGE WAVEFORMS
CL includes probe and jig capacitance.
The pulse generator has the following characteristics: ZO = 50 Ω, 50% duty cycle, tr ≤ 10 ns, tf ≤ 10 ns.
Figure 7-3. Receiver Propagation Delay Times
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3V
Input
3 V or 0 V
FORCEON
VCC
S1
1.5 V
GND
0V
tPZH
(S1 at GND)
tPHZ
(S1 at GND)
RL
3 V or 0 V
1.5 V
VOH
Output
50%
Output
CL
(see Note A)
EN
Generator
(see Note B)
50 Ω
0.3 V
tPZL
(S1 at VCC)
tPLZ
(S1 at VCC)
0.3 V
Output
50%
VOL
TEST CIRCUIT
A.
B.
C.
D.
VOLTAGE WAVEFORMS
CL includes probe and jig capacitance.
The pulse generator has the following characteristics: ZO = 50 Ω, 50% duty cycle, tr ≤ 10 ns, tf ≤ 10 ns.
tPLZ and tPHZ are the same as tdis.
tPZL and tPZH are the same as ten.
Figure 7-4. Receiver Enable and Disable Times
10
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2.7 V
2.7 V
0V
Receiver
Input
ROUT
Generator
(see Note B)
3V
0V
−2.7 V
−2.7 V
−3 V
50 Ω
tvalid
tinvalid
VCC
Autopowerdown
INVALID
CL = 30 pF
(see Note A)
FORCEOFF
FORCEON
DIN
DOUT
INVALID
Output
50% VCC
50% VCC
0V
ten
V+
≈V+
Supply
Voltages
0.3 V
VCC
0V
0.3 V
V−
TEST CIRCUIT
≈V−
VOLTAGE WAVEFORMS
Valid RS-232 Level, INVALID High
2.7 V
Indeterminate
0.3 V
0V
If Signal Remains Within This Region
For More Than 30 µs, INVALID Is Low†
−0.3 V
Indeterminate
−2.7 V
Valid RS-232 Level, INVALID High
† Auto-powerdown disables drivers and reduces supply
current to 1 µA.
Figure 7-5. INVALID Propagation Delay Times and Driver Enabling Time
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8 Detailed Description
8.1 Overview
The MAX3221E is a single driver, single receiver RS-232 solution operating from a single VCC supply. The
RS-232 pins provide IEC 61000-4-2 ESD protection. The device meets the requirements of TIA/EIA-232-F
and provides the electrical interface between an asynchronous communication controller and the serial-port
connector. The charge pump and four small external capacitors allow operation from a single 3-V to 5.5-V
supply. These devices operate at data signaling rates up to 250 kbit/s and a maximum of 30-V/µs driver output
slew rate.
Flexible control options for power management are available when the serial port is inactive. The auto-powerdown feature functions when FORCEON is low and FORCEOFF is high. During this mode of operation, if the
device does not sense a valid RS-232 signal on the receiver input, the driver output is disabled. If FORCEOFF
is set low and EN is high, both the driver and receiver are shut off, and the supply current is reduced to 1 µA.
Disconnecting the serial port or turning off the peripheral drivers causes the auto-power-down condition to occur.
Auto-power down can be disabled when FORCEON and FORCEOFF are high. With auto-power down enabled,
the device is activated automatically when a valid signal is applied to the receiver input. The INVALID output
notifies the user if an RS-232 signal is present at the receiver input. INVALID is high (valid data) if the receiver
input voltage is greater than 2.7 V or less than –2.7 V, or has been between –0.3 V and 0.3 V for less than 30 µs.
INVALID is low (invalid data) if the receiver input voltage is between –0.3 V and 0.3 V for more than 30 µs. See
Figure 7-1 for receiver input levels.
8.2 Functional Block Diagram
3.3V, 5V
POWER
AUTOPOWERDOWN
FORCEON
FORCEOFF
RX Enable
EN
DIN
1
1
TX
250 kb/s
ROUT
INVALID
1
RX
DOUT
RS-232
IEC 61000-4-2
1
RIN
RS-232
STATUS
Copyright © 2016, Texas Instruments Incorporated
Figure 8-1. Logic Diagram (Positive Logic)
8.3 Feature Description
8.3.1 Power
The power block increases, inverts, and regulates voltage at V+ and V- pins using a charge pump that requires
four external capacitors. Auto-power-down feature for driver is controlled by FORCEON and FORCEOFF inputs.
Receiver is controlled by EN input. When MAX3221E is unpowered, it can be safely connected to an active
remote RS-232 device.
8.3.2 RS-232 Driver
One driver interfaces standard logic levels to RS-232 levels. DIN input must be valid high or low.
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8.3.3 RS-232 Receiver
One receiver interfaces RS-232 levels to standard logic levels. An open input results in a high output on ROUT.
RIN input includes an internal standard RS-232 load. A logic high input on the EN pin shuts down the receiver
output.
8.3.4 RS-232 Status
The INVALID output goes low when RIN input is unpowered for more than 30 µs. The INVALID output goes high
when receiver has a valid input. The INVALID output is active when Vcc is powered irregardless of FORCEON
and FORCEOFF inputs (see Table 8-3).
8.4 Device Functional Modes
Table 8-1, Table 8-2, and Table 8-3 show the behavior of the driver, receiver, and INVALID features under all
possible relevant combinations of inputs.
Table 8-1. Function Tables Each Driver(1)
INPUTS
(1)
OUTPUT
DOUT
DRIVER STATUS
X
Z
Powered off
Normal operation with
auto-power down disabled
DIN
FORCEON
FORCEOFF
VALID RIN
RS-232 LEVEL
X
X
L
L
H
H
X
H
H
H
H
X
L
L
L
H
Yes
H
H
L
H
Yes
L
L
L
H
No
Z
H
L
H
No
Z
Normal operation with
auto-power down enabled
Powered off by
auto-power down feature
H = high level, L = low level, X = irrelevant, Z = high impedance
Table 8-2. Each Receiver(1)
INPUTS
(1)
OUTPUT
ROUT
RIN
EN
VALID RIN
RS-232 LEVEL
L
L
X
H
L
X
L
X
H
X
Z
Open
L
No
H
H
H = high level, L = low level, X = irrelevant, Z = high impedance
(off), Open = disconnected input or connected driver off
Table 8-3. INVALID (1)
INPUTS
OUTPUT
RIN
(1)
FORCEON
FORCEOFF
EN
INVALID
L
X
X
X
H
H
X
X
X
H
Open
X
X
X
L
H = high level, L = low level, X = irrelevant, Z = high impedance (off), Open = input disconnected or connected driver off
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9 Application and Implementation
Note
Information in the following applications sections is not part of the TI component specification,
and TI does not warrant its accuracy or completeness. TI’s customers are responsible for
determining suitability of components for their purposes, as well as validating and testing their design
implementation to confirm system functionality.
9.1 Application Information
The MAX3221E line driver and receiver is a specialized device for 3-V to 5.5-V RS-232 communication
applications. This application is a generic implementation of this device with all required external components.
For proper operation, add capacitors as shown in Figure 9-1.
9.2 Typical Application
ROUT and DIN connect to UART or general purpose logic lines. FORCEON and FORCEOFF may be connected
general purpose logic lines or tied to ground or VCC. INVALID may be connected to a general purpose logic
line or left unconnected. RIN and DOUT lines connect to a RS-232 connector or cable. DIN, FORCEON, and
FORCEOFF inputs must not be left unconnected.
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EN
1
16
2
V CC
C1+
15
+
3
C1
+
+
−
−
V+
AutoPowerdown
C3 (1)
4
GND
−
14
13
12
C2
6
C2−
7
11
FORCEON
DIN
V−
10
C4
+
RIN
DOUT
C2+
+
−
C BYPASS = 0.1 mF
C1−
5
−
FORCEOFF
8
9
INVALID
ROUT
5 kW
(1) C3 can be connected to VCC or GND.
NOTES: A. Resistor values shown are nominal.
B. Nonpolarized ceramic capacitors are acceptable. If polarized tantalum or electrolytic capacitors are used, they should be connected
as shown.
V CC vs CAPACITOR VALUES
V CC
C1
C2, C3, and C4
3.3 V ± 0.3 V
5 V ± 0.5 V
3 V to 5.5 V
0.1 mF
0.047 mF
0.1 mF
0.1 mF
0.33 mF
0.47 mF
Copyright © 2016, Texas Instruments Incorporated
Figure 9-1. Typical Operating Circuit and Capacitor Values
9.2.1 Design Requirements
•
•
•
Recommended VCC is 3.3 V or 5 V.
– 3 V to 5.5 V is also possible
Maximum recommended bit rate is 250 kbps.
Use capacitors as shown in Figure 9-1.
9.2.2 Detailed Design Procedure
•
•
DIN, FORCEOFF and FORCEON inputs must be connected to valid low or high logic levels.
Select capacitor values based on VCC level for best performance.
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9.2.3 Application Curves
8
8
DIN
DOUT
ROUT
4
2
0
-2
-4
4
2
0
-2
-4
-6
-6
0
1
2
3
4
5
6
Time (us)
7
8
9
10
0
1
D005
Figure 9-2. Loopback Waveforms VCC = 3.3 V, Data
Rate 250 kbit/s
16
DIN
DOUT
ROUT
6
Waveform Voltage (V)
Waveform Voltage (V)
6
2
3
4
5
6
Time (us)
7
8
9
10
D006
Figure 9-3. Loopback Waveforms with 1-nF load
VCC = 3.3 V, Data Rate 250 kbit/s
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10 Power Supply Recommendations
TI recommends a 0.1-µF capacitor to filter noise on the power supply pin. For additional filter capability, a
0.01-μF capacitor may be added in parallel as well. Power supply input voltage is recommended to be any valid
level in Section 6.4.
11 Layout
11.1 Layout Guidelines
Keep the external capacitor traces short. This is more important on C1 and C2 nodes that have the fastest rise
and fall times. Make the impedance from MAX3221E ground pin and circuit board's ground plane as low as
possible for best ESD performance. Use wide metal and multiple vias on both sides of ground pin.
11.2 Layout Example
1 EN
FORCEOFF 16
Ground
C3
2 C1+
VCC 15
VCC
PF
C1
3 V+
GND 14
4 C1-
DOUT 13
5 C2+
FORCEON 12
6 C2-
DIN 11
Ground
C2
7 V-
Ground
INVALID 10
C4
8 RIN
ROUT 9
Figure 11-1. MAX3221E Layout Example
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12 Device and Documentation Support
12.1 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. Click on
Subscribe to updates to register and receive a weekly digest of any product information that has changed. For
change details, review the revision history included in any revised document.
12.2 Support Resources
TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight
from the experts. Search existing answers or ask your own question to get the quick design help you need.
Linked content is provided "AS IS" by the respective contributors. They do not constitute TI specifications and do
not necessarily reflect TI's views; see TI's Terms of Use.
12.3 Trademarks
TI E2E™ is a trademark of Texas Instruments.
All trademarks are the property of their respective owners.
12.4 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled
with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may
be more susceptible to damage because very small parametric changes could cause the device not to meet its published
specifications.
12.5 Glossary
TI Glossary
This glossary lists and explains terms, acronyms, and definitions.
13 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
Samples
(4/5)
(6)
MAX3221ECDBR
ACTIVE
SSOP
DB
16
2000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
0 to 70
MP221EC
Samples
MAX3221ECDBRG4
ACTIVE
SSOP
DB
16
2000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
0 to 70
MP221EC
Samples
MAX3221ECPWR
ACTIVE
TSSOP
PW
16
2000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
0 to 70
MP221EC
Samples
MAX3221EIDBR
ACTIVE
SSOP
DB
16
2000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
MP221EI
Samples
MAX3221EIDBRG4
ACTIVE
SSOP
DB
16
2000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
MP221EI
Samples
MAX3221EIPWR
ACTIVE
TSSOP
PW
16
2000
RoHS & Green
NIPDAU | SN
Level-1-260C-UNLIM
-40 to 85
MP221EI
Samples
MAX3221EIPWRG4
ACTIVE
TSSOP
PW
16
2000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 85
MP221EI
Samples
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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