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MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
General Description
The MAX3224E/MAX3225E/MAX3226E/MAX3227E/
MAX3244E/MAX3245E are 3V-powered EIA/TIA-232 and
V.28/V.24 communications interfaces with automatic shutdown/wakeup features, high data-rate capabilities, and
enhanced electrostatic discharge (ESD) protection. All
transmitter outputs and receiver inputs are protected to
±15kV using IEC 1000-4-2 Air-Gap Discharge, ±8kV using
IEC 1000-4-2 Contact Discharge, and ±15kV using the
Human Body Model.
All devices achieve a 1μA supply current using Maxim’s
revolutionary AutoShutdown Plus™ feature. These devices automatically enter a low-power shutdown mode when
the RS-232 cable is disconnected or the transmitters of
the connected peripherals are inactive, and the UART
driving the transmitter inputs is inactive for more than 30
seconds. They turn on again when they sense a valid
transition at any transmitter or receiver input.
AutoShutdown Plus saves power without changes to the
existing BIOS or operating system.
The MAX3225E/MAX3227E/MAX3245E also feature MegaBaud™ operation, guaranteeing 1Mbps for
high-speed applications such as communicating with
ISDN modems. The MAX3224E/MAX3226E/MAX3244E
guarantee 250kbps operation. The transceivers have a
proprietary low-dropout transmitter output stage enabling
true RS-232 performance from a +3.0V to +5.5V supply
with a dual charge pump. The charge pump requires only
four small 0.1μF capacitors for operation from a 3.3V
supply. The MAX3224E–MAX3227E feature a logic-level
output (READY) that asserts when the charge pump is
regulating and the device is ready to begin transmitting.
All devices are available in a space-saving TQFN,
SSOP, and TSSOP (MAX3224E/MAX3225E/MAX3244E/
MAX3245E) packages.
Applications
●●
●●
●●
●●
●●
●●
●●
Notebook, Subnotebook, and Palmtop Computers
Cellular Phones
Battery-Powered Equipment
Hand-Held Equipment
Peripherals
Printers
Automotive
AutoShutdown Plus, MegaBaud, and UCSP are trademarks of
Maxim Integrated Products, Inc.
19-1339; Rev 11; 11/18
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Next Generation Device Features
●● For Space-Constrained Applications:
MAX3228E/MAX3229E: ±15kV ESD-Protected,
+2.5V to +5.5V, RS-232 Transceivers in UCSP™
MAX3222E/MAX3232E/MAX3241E/MAX3246E:
±15kV ESD-Protected, Down to 10nA, +3.0V to
+5.5V, Up to 1Mbps, True RS-232 Transceivers
(MAX3246E Available in UCSP)
●● For Low-Voltage or Data Cable Applications:
MAX3380E/MAX3381E: +2.35V to +5.5V, 1μA,
2Tx/2Rx RS-232 Transceivers with ±15kV
ESD-Protected I/O and Logic Pins
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX3224ECTP+
0°C to +70°C
20 TQFN-EP*
MAX3224ECUP+
0°C to +70°C
20 TSSOP
MAX3224ECAP+
0°C to +70°C
20 SSOP
MAX3224ECPP+
0°C to +70°C
20 Plastic DIP
MAX3224EETP+
-40°C to +85°C
20 TQFN-EP*
MAX3224EEUP+
-40°C to +85°C
20 TSSOP
MAX3224EEAP+
-40°C to +85°C
20 SSOP
MAX3224EEPP+
-40°C to +85°C
20 Plastic DIP
MAX3224EAAP+
-40°C to +125°C
20 SSOP
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Ordering Information continued at end of data sheet.
Selector Guide
PART
NO. OF
GUARANTEED
AutoREADY
DRIVERS/
DATA RATE
Shutdown
OUTPUT
RECEIVERS
(bps)
Plus
MAX3224E
2/2
250k
ü
ü
MAX3225E
MAX3226E
2/2
1M
ü
ü
1/1
250k
ü
ü
MAX3227E
1/1
1M
ü
ü
MAX3244E
3/5
250k
—
ü
MAX3245E
3/5
1M
—
ü
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Absolute Maximum Ratings
VCC to GND.............................................................-0.3V to +6V
V+ to GND (Note 1)..................................................-0.3V to +7V
V- to GND (Note 1)...................................................+0.3V to -7V
V+ +│V-│(Note 1).................................................................+13V
Input Voltages
T_IN, FORCEON, FORCEOFF to GND...............-0.3V to +6V
R_IN to GND....................................................................±25V
Output Voltages
T_OUT to GND..............................................................±13.2V
R_OUT, INVALID, READY to GND....... -0.3V to (VCC + 0.3V)
Short-Circuit Duration
T_OUT to GND.......................................................Continuous
Continuous Power Dissipation (TA = +70°C)
16-Pin SSOP (derate 7.10mW/°C above +70°C)......571.4mW
16-Pin TSSOP (derate 9.4 mW/°C above +70°C).....754.7mW
16-Pin TQFN (derate 20.8mW/°C above +70°C)....1666.7mW
20-Pin TQFN (derate 21.3mW/°C above +70°C) ....1702.1mW
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 (derate 11mW/°C above +70°C)......879.1 mW
28-Pin Wide SO (derate 12.5mW/°C above +70°C)...........1W
28-Pin SSOP (derate 9.1mW/°C above +70°C)........727.3mW
28-Pin TSSOP (derate 14mW/°C above +70°C).....1025.6mW
36-Pin TQFN (derate 26.3mW/°C above +70°C)...... 2105.3mW
Operating Temperature Ranges
MAX32_ _EC_ _..................................................0°C to +70°C
MAX32_ _EE_ _.............................................. -40°C to +85°C
MAX32_ _EAA_............................................. -40°C to +125°C
Storage Temperature Range............................. -65°C to +160°C
Lead Temperature (soldering, 10s).................................. +300°C
Soldering Temperature (reflow)........................................+260°C
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.
Package Information
16-SSOP
PACKAGE CODE
A16+2
Outline Number
21-0056
Land Pattern Number
90-0106
Thermal Resistance, Single layer board:
Junction to Ambient (θJA)
140
Junction to Case (θJC)
34
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA)
86
Junction to Case (θJC)
33
16-TSSOP
PACKAGE CODE
U16+1
Outline Number
21-0066
Land Pattern Number
90-0117
Thermal Resistance, Single layer board:
Junction to Ambient (θJA)
106
Junction to Case (θJC)
27
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA)
90
Junction to Case (θJC)
27
www.maximintegrated.com
Maxim Integrated │ 2
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Package Information (continued)
16-TQFN-EP
PACKAGE CODE
T1655+2
Outline Number
21-0140
Land Pattern Number
90-0072
Thermal Resistance, Single layer board:
Junction to Ambient (θJA)
48
Junction to Case (θJC)
2
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA)
30
Junction to Case (θJC)
2
20-DIP
PACKAGE CODE
P20+3
Outline Number
21-0043
Thermal Resistance, Single layer board:
Junction to Ambient (θJA)
90
Junction to Case (θJC)
30
20-SSOP
PACKAGE CODE
A20+1
Outline Number
21-0056
Land Pattern Number
90-0094
Thermal Resistance, Single layer board:
Junction to Ambient (θJA)
125
Junction to Case (θJC)
32
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA)
84
Junction to Case (θJC)
33
www.maximintegrated.com
Maxim Integrated │ 3
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Package Information (continued)
20-TSSOP
PACKAGE CODE
U20+2
Outline Number
21-0066
Land Pattern Number
90-0116
Thermal Resistance, Single layer board:
Junction to Ambient (θJA)
91
Junction to Case (θJC)
20
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA)
73.8
Junction to Case (θJC)
20
20-TQFN-EP
PACKAGE CODE
T2055+5
Outline Number
21-0140
Land Pattern Number
90-0010
Thermal Resistance, Single layer board:
Junction to Ambient (θJA)
47
Junction to Case (θJC)
2
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA)
29
Junction to Case (θJC)
2
28-WIDE SO
PACKAGE CODE
W28+6
Outline Number
21-0042
Land Pattern Number
90-0109
Thermal Resistance, Single layer board:
Junction to Ambient (θJA)
80
Junction to Case (θJC)
18
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA)
59
Junction to Case (θJC)
18
www.maximintegrated.com
Maxim Integrated │ 4
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Package Information (continued)
28-SSOP
PACKAGE CODE
A28+1
Outline Number
21-0056
Land Pattern Number
90-0095
Thermal Resistance, Single layer board:
Junction to Ambient (θJA)
110
Junction to Case (θJC)
25
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA)
67.1
Junction to Case (θJC)
25
28-TSSOP
PACKAGE CODE
U28+2
Outline Number
21-0066
Land Pattern Number
90-0171
Thermal Resistance, Single layer board:
Junction to Ambient (θJA)
78
Junction to Case (θJC)
13
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA)
71.6
Junction to Case (θJC)
13
36-TQFN
PACKAGE CODE
T3666+3
Outline Number
21-0141
Land Pattern Number
90-0050
Thermal Resistance, Single layer board:
Junction to Ambient (θJA)
38
Junction to Case (θJC)
1
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA)
28
Junction to Case (θJC)
1
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.
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board.
For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
www.maximintegrated.com
Maxim Integrated │ 5
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Electrical Characteristics
(VCC = +3V to +5.5V, C1–C4 = 0.1μF, tested at 3.3V ±10%; C1 = 0.047μF, C2–C4 = 0.33μF, tested at 5.0V ±10%; TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS (VCC = 3.3V or 5.0V, TA = +25°C)
Supply Current,
AutoShutdown Plus
FORCEON = GND, FORCEOFF = VCC,
all R_IN idle, all T_IN idle
1
10
μA
Supply Current, Shutdown
FORCEOFF = GND
1
10
μA
Supply Current,
AutoShutdown Plus Disabled
FORCEON = FORCEOFF = VCC, no load
0.3
1
mA
0.8
V
LOGIC INPUTS AND RECEIVER OUTPUTS
Input Logic Threshold Low
T_IN, FORCEON, FORCEOFF
Input Logic Threshold High
T_IN, FORCEON,
FORCEOFF
VCC = 3.3V
2
VCC = 5.0V
2.4
Transmitter Input Hysteresis
V
0.5
V
Input Leakage Current
T_IN, FORCEON, FORCEOFF
±0.01
±1
μA
Output Leakage Current
R_OUT (MAX3244E/MAX3245E),
receivers disabled
±0.05
±10
μA
Output Voltage Low
IOUT = 1.6mA
0.4
V
Output Voltage High
IOUT = -1.0mA
VCC
- 0.6
VCC
- 0.1
V
RECEIVER INPUTS
Input Voltage Range
-25
Input Threshold Low
TA = +25°C
Input Threshold High
TA = +25°C
VCC = 3.3V
0.6
1.2
VCC = 5.0V
0.8
1.5
V
V
VCC = 3.3V
1.5
2.4
VCC = 5.0V
1.8
2.4
Input Hysteresis
Input Resistance
+25
0.5
V
V
TA = +25°C
3
5
7
kΩ
Output Voltage Swing
All transmitter outputs loaded with 3kΩ
to ground
±5
±5.4
V
Output Resistance
VCC = V+ = V- = 0V, transmitter outputs = ±2V
300
10M
Ω
TRANSMITTER OUTPUTS
Output Short-Circuit Current
Output Leakage Current
www.maximintegrated.com
VCC = 0V or 3V to 5.5V, VOUT = ±12V,
Transmitters disabled
±60
mA
±25
µA
Maxim Integrated │ 6
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Electrical Characteristics (continued)
(VCC = +3V to +5.5V, C1–C4 = 0.1μF, tested at 3.3V ±10%; C1 = 0.047μF, C2–C4 = 0.33μF, tested at 5.0V ±10%; TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MOUSE DRIVEABILITY (MAX3244E/MAX3245E)
T1IN = T2IN = GND, T3IN = VCC,
T3OUT loaded with 3kΩ to GND,
T1OUT and T2OUT loaded with
2.5mA each
Transmitter Output Voltage
±5
V
ESD PROTECTION
R_IN, T_OUT
IEC 1000-4-2 Air Discharge
±15
IEC 1000-4-2 Contact Discharge
±8
Human Body Model
±15
kV
AutoShutdown Plus (FORCEON = GND, FORCEOFF = VCC)
Receiver Input Threshold to
INVALID Output High
Figure 4a
Receiver Input Threshold to
INVALID Output Low
Figure 4a
INVALID, READY
Output Voltage Low
(MAX3224E–MAX3227E)
IOUT = -1.6mA
INVALID, READY
Output Voltage Low
(MAX3224E–MAX3227E)
IOUT = -1.0mA
Positive threshold
Negative threshold
2.7
-2.7
-0.3
V
+0.3
V
0.4
V
VCC - 0.6
V
Receiver Positive or Negative
Threshold to INVALID High
tINVH
VCC = 5V, Figure 4b
1
μs
Receiver Positive or Negative
Threshold to INVALID Low
tINVL
VCC = 5V, Figure 4b
30
μs
Receiver or Transmitter Edge
to Transmitters Enabled
tWU
VCC = 5V, Figure 5b (Note 2)
100
μs
Receiver or Transmitter Edge
to Transmitters Shutdown
www.maximintegrated.com
tAUTOSHDN VCC = 5V, Figure 5b (Note 2)
15
30
60
s
Maxim Integrated │ 7
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Timing Characteristics—MAX3224E/MAX3226E/MAX3244E
(VCC = +3V to +5.5V, C1–C4 = 0.1μF, tested at 3.3V ±10%; C1 = 0.047μF, C2–C4 = 0.33μF, tested at 5.0V ±10%; TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
MIN
RL = 3kΩ, CL = 1000pF,
one transmitter switching
Maximum Data Rate
Receiver Propagation Delay
CONDITIONS
tPHL
tPLH
TYP
MAX
250
kbps
0.15
R_IN to R_OUT, CL = 150pF
UNITS
μs
0.15
Receiver Output Enable Time
Normal operation (MAX3244E only)
200
ns
Receiver Output Disable Time
Normal operation (MAX3244E only)
200
ns
Transmitter Skew
│tPHL - tPLH│ (Note 3)
100
ns
Receiver Skew
│tPHL - tPLH│
50
ns
VCC = 3.3V, TA = +25°C,
RL = 3kΩ to 7kΩ,
measured from +3V to -3V
or -3V to +3V, one
transmitter switching
Transition-Region Slew Rate
CL = 150pF
to 1000pF
6
30
V/μs
Timing Characteristics—MAX3225E/MAX3227E/MAX3245E
(VCC = +3V to +5.5V, C1–C4 = 0.1μF, tested at 3.3V ±10%; C1 = 0.047μF, C2–C4 = 0.33μF, tested at 5.0V ±10%; TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER
SYMBOL
Maximum Data Rate
Receiver Propagation Delay
tPHL
tPLH
CONDITIONS
MIN
RL = 3kΩ, CL = 1000pF,
one transmitter switching
250
VCC = 3.0V to 4.5V, RL = 3kΩ,
CL = 250pF, one transmitter switching
1000
VCC = 4.5V to 5.5V, RL = 3kΩ,
CL = 1000pF, one transmitter switching
1000
TYP
MAX
kbps
0.15
R_IN to R_OUT, CL = 150pF
UNITS
μs
0.15
Receiver Output Enable Time
Normal operation (MAX3245E only)
200
ns
Receiver Output Disable Time
Normal operation (MAX3245E only)
200
ns
Transmitter Skew
│tPHL - tPLH│ (Note 3)
25
ns
Receiver Skew
│tPHL - tPLH│
50
ns
Transition-Region Slew Rate
VCC = 3.3V, TA = +25°C,
RL = 3kΩ to 7kΩ, CL = 150pF to 1000pF,
measured from +3V to -3V or -3V to +3V,
one transmitter switching
24
150
V/μs
Note 2: A transmitter/receiver edge is defined as a transition through the transmitter/receiver input logic thresholds.
Note 3: Transmitter skew is measured at the transmitter zero cross points.
www.maximintegrated.com
Maxim Integrated │ 8
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Typical Operating Characteristics
(VCC = +3.3V, 250kbps data rate, 0.1μF capacitors, all transmitters loaded with 3kΩ and CL, TA = +25°C, unless otherwise noted.)
-SLEW
10
+SLEW
8
6
4
VOUT-
-5
-6
1000
2000
3000
4000
2
1000
3000
4000
1000
2000
3000
MAX3224-7/44/45E-03
4000
60
-SLEW
50
+SLEW
40
30
1 TRANSMITTER AT 1Mbps
1 TRANSMITTER AT 62.5kbps (MAX3225E)
1500
2000
2500
0
500
30
25
20
AVERAGE: 10 PARTS
10
30
1Mbps
0
0
500
2500
3000
1000
1500
2000
2500
LOAD CAPACITANCE (pF)
MAX3224E–MAX3227E
READY TURN-OFF TIME
vs. TEMPERATURE
MAX3224-7/44/45E-08
30
28
26
24
20
www.maximintegrated.com
1.5Mbps
40
2500
32
0
LOAD CAPACITANCE (pF)
2000
34
22
2000
1500
36
5
1500
1000
38
READY TURN-ON TIME (µs)
1 TRANSMITTER AT 512kbps
1 TRANSMITTER AT 30kbps
(MAX3225E)
LOAD = 3kΩ + CL
1000
50
MAX3224E–MAX3227E
READY TURN-ON TIME
vs. TEMPERATURE
MAX3224-7/44/45E-07
50
500
2Mbps
60
LOAD CAPACITANCE (pF)
MAX3225E/MAX3227E
TRANSMITTER SKEW
vs. LOAD CAPACITANCE
15
70
200
MAX3224-7/44/45E-09
1000
80
10
180
READY TURN-OFF TIME (ns)
500
1 TRANSMITTER AT FULL DATA RATE
1 TRANSMITTER AT 1/16 DATA RATE
(MAX3225E)
LOAD = 3kΩ + CL
90
20
0
5000
100
SUPPLY CURRENT (mA)
70
LOAD CAPACITANCE (pF)
0
0
5000
MAX3224-7/44/45E-05
MAX3224-7/44/45E-04
1.5Mbps
80
-7.5
TRANSMITTER SKEW (ns)
2000
MAX3225E/MAX3227E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
10
35
T1 TRANSMITTING AT 250kbps
T2 (MAX3224E) TRANSMITTING AT 15.6kbps
MAX3225E/MAX3227E
SLEW RATE vs. LOAD CAPACITANCE
-5.0
40
10
0
0
20
45
20kbps
15
MAX3225E/MAX3227E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
1Mbps
1 TRANSMITTER AT FULL DATA RATE
1 TRANSMITTER AT 1/16 DATA RATE
(MAX3225E)
LOAD = 3kΩ + CL
1.5Mbps 1Mbps
2Mbps
0
20
LOAD CAPACITANCE (pF)
2Mbps
-2.5
120kbps
25
LOAD CAPACITANCE (pF)
5.0
0
30
LOAD CAPACITANCE (pF)
7.5
2.5
250kbps
35
5
FOR DATA RATES UP TO 250kbps
0
5000
SLEW RATE (V/µs)
0
TRANSMITTER OUTPUT VOLTAGE (V)
12
40
MAX3224-7/44/45E-06
-2
-3
-4
14
45
SUPPLY CURRENT (mA)
T1 TRANSMITTING AT 250kbps
T2 (MAX3224E) TRANSMITTING AT 15.6kbps
16
MAX3224-7/44/45E-02
VOUT+
SLEW RATE (V/µs)
6
5
4
3
2
1
0
-1
MAX3224E/MAX3226E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3224E/MAX3226E
SLEW RATE vs. LOAD CAPACITANCE
MAX3224-7/44/45E-01
TRANSMITTER OUTPUT VOLTAGE (V)
MAX3224E/MAX3226E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
160
140
120
100
80
60
40
20
0
-40
-20
0
20
40
60
TEMPERATURE (°C)
80
100
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
Maxim Integrated │ 9
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Typical Operating Characteristics (continued)
(VCC = +3.3V, 250kbps data rate, 0.1μF capacitors, all transmitters loaded with 3kΩ and CL, TA = +25°C, unless otherwise noted.)
10
8
6
4
0
1000
2000
3000
4000
1000
2000
3000
4000
1.5Mbps
1Mbps
1 TRANSMITTER AT FULL DATA RATE
2 TRANSMITTERS AT 1/16 DATA RATE
2Mbps
1.5Mbps 1Mbps
60
-5.0
-7.5
1200
1600
400
800
1200
1600
40
30
1Mbps
2000
MAX3224-7/44/45E-16
50
45
TRANSMITTER SKEW (ns)
MAX3224-7/44/45E-15
1.5Mbps
40
35
30
25
20
15
10
1 TRANSMITTER AT FULL DATA RATE
2 TRANSMITTERS AT 1/16 DATA RATE
10
0
MAX3245E
TRANSMITTER SKEW
vs. LOAD CAPACITANCE
2Mbps
20
1 TRANSMITTER AT 1Mbps
2 TRANSMITTERS AT 62.5kbps
MAX3245E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
50
5000
20
LOAD CAPACITANCE (pF)
80
60
4000
30
LOAD CAPACITANCE (pF)
90
70
3000
40
0
2000
100
SUPPLY CURRENT (mA)
50
10
800
2000
LOAD CAPACITANCE (pF)
MAX3224-7/44/45E-14
2Mbps
1000
70
SLEW RATE (V/µs)
MAX3224-7/44/45E-13
TRANSMITTER OUTPUT VOLTAGE (V)
5.0
400
0
5000
MAX3245E
SLEW RATE vs. LOAD CAPACITANCE
7.5
0
20kbps
20
0
0
MAX3245E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
-2.5
30
LOAD CAPACITANCE (pF)
2.5
120kbps
10
LOAD CAPACITANCE (pF)
0
250kbps
40
0
5000
1 TRANSMITTER AT 250kbps
2 TRANSMITTERS AT 15.6kbps
50
2
VOUT-
-5
-6
MAX3224-7/44/45E-12
12
60
SUPPLY CURRENT (mA)
1 TRANSMITTER AT 250kbps
2 TRANSMITTERS AT 15.6kbps
MAX3224-7/44/45E-11
VOUT+
-2
-3
-4
14
SLEW RATE (V/µs)
6
5
4
3
2
1
0
-1
MAX3244E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3244E
SLEW RATE vs. LOAD CAPACITANCE
MAX3224-7/44/45E-10
TRANSMITTER OUTPUT VOLTAGE (V)
MAX3244E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
5
0
0
0
400
800
1200
1600
LOAD CAPACITANCE (pF)
www.maximintegrated.com
2000
0
1000
2000
3000
LOAD CAPACITANCE (pF)
Maxim Integrated │ 10
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Pin Description
PIN
MAX3224E
MAX3225E
TQFN
DIP/
SSOP/
TSSOP
MAX3226E
MAX3227E
TQFN
SSOP/
TSSOP
MAX3244E
MAX3245E
SO/ SSOP/ TSSOP
MAX3245E
TQFN
NAME
FUNCTION
19
1
14
1
—
—
READY
Ready to Transmit Output,
active-high. READY is enabled
high when V- goes below
-4V and the device is ready
to transmit.
1
2
16
2
28
31
C1+
Positive Terminal of
Voltage-Doubler Charge-Pump
Capacitor
20
3
15
3
27
30
V+
+5.5V generated by the charge
pump
2
4
1
4
24
26
C1-
Negative Terminal of
Voltage-Doubler Charge-Pump
Capacitor
3
5
2
5
1
33
C2+
Positive Terminal of Inverting
Charge-Pump Capacitor
4
6
3
6
2
34
C2-
Negative Terminal of Inverting
Charge-Pump Capacitor
5
7
4
7
3
35
V-
6, 15
8, 17
10
13
9, 10, 11
7, 8, 9
T_OUT
7, 14
9, 16
5
8
4-8
1-5
R_IN
8, 13
10, 15
6
9
15-19
15, 16, 17,
19, 20
R_OUT
TTL/CMOS Receiver Outputs
Valid Signal Detector Output,
active low. A logic high indicates
that a valid RS-232 level is
present on a receiver input.
-5.5V Generated by the Charge
Pump
RS-232 Transmitter Outputs
RS-232 Receiver Inputs
9
11
7
10
21
23
INVALID
10, 11
12, 13
8
11
12-14
11, 12, 13
T_IN
TTL/CMOS Transmitter Inputs
FORCEON
Force-On Input, ActiveHigh. Drive high to override
AutoShutdown Plus, keeping
transmitters and receivers on
(FORCEOFF must be high)
(Table 1).
12
14
www.maximintegrated.com
9
12
23
25
Maxim Integrated │ 11
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Pin Description (continued)
PIN
MAX3224E
MAX3225E
MAX3226E
MAX3227E
MAX3244E
MAX3245E
SO/ SSOP/ TSSOP
MAX3245E
TQFN
NAME
14
25
27
GND
Ground
15
26
29
VCC
+3.0V to +5.5V Single Supply
Voltage
Force-Off Input, Active-Low.
MAX3225E, MAX3227E:
When Force-Off input is
low, transmitters are in high
impedance, charge pumps are
shutdown, and receivers are
active.
MAX3244E, MAX3245E:
When Force-Off input is low,
transmitters and receivers are
in high impedance, charge
pumps are shutdown, and only
R2OUTB is active. Force-Off
overrides AutoShutdown Plus
and FORCEON (Table 1).
TQFN
DIP/
SSOP/
TSSOP
TQFN
SSOP/
TSSOP
16
18
11
17
19
12
FUNCTION
18
20
13
16
22
24
FORCEOFF
—
—
—
—
20
21
R2OUTB
—
—
—
—
—
6, 10, 14, 18,
22, 28, 32, 36
N.C.
No Connection. Not internally
connected.
—
—
—
—
—
—
EP
Exposed Pad. Solder the
exposed pad to the ground
plane or leave unconnected.
Detailed Description
Dual Charge-Pump Voltage Converter
The MAX3224E–MAX3227E/MAX3244E/MAX3245E’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), over
the +3.0V to +5.5V range. The charge pump operates in
discontinuous mode: if the output voltages are less than
www.maximintegrated.com
TTL/CMOS Noninverting
Complementary Receiver
Outputs. Always active.
5.5V, the charge pump is enabled; if the output voltages
exceed 5.5V, the charge-pump is disabled. Each charge
pump requires a flying capacitor (C1, C2) and a reservoir
capacitor (C3, C4) to generate the V+ and V- supplies.
The READY output (MAX3224E–MAX3227E) is low when
the charge pumps are disabled in shutdown mode. The
READY signal asserts high when V- goes below -4V.
Maxim Integrated │ 12
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
POWERMANAGEMENT
UNIT OR
KEYBOARD
CONTROLLER
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
FORCEOFF
FORCEON
VCC
INVALID
MAX3244E
MAX3245E
PROTECTION
DIODE
PREVIOUS
RS-232
VCC
I
Rx
5kΩ
UART
CPU
I/O
CHIP
WITH
UART
Tx
GND
RS-232
a)
SHDN = GND
OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM ACTIVE
RECEIVER OUTPUT IN SHUTDOWN.
VCC
TO
µP
LOGIC
TRANSITION
DETECTOR
Figure 1. Interface Under Control of PMU
I
RS-232 Transmitters
PROTECTION
DIODE
The transmitters are inverting level translators that convert CMOS-logic levels to 5.0V EIA/TIA-232 levels. The
MAX3224E/MAX3226E/MAX3244E guarantee a 250kbps
data rate (1Mbps, for the MAX3225E/MAX3227E/
MAX3245E) with worst-case loads of 3kΩ in parallel with
1000pF, providing compatibility with PC-to-PC communication software (such as LapLink®). Transmitters can be
paralleled to drive multiple receivers. Figure 1 shows a
complete system connection.
When FORCEOFF is driven to ground or when the AutoShutdown Plus circuitry senses that all receiver and
transmitter inputs are inactive for more than 30s, the
transmitters are disabled and the outputs go into a highimpedance state. When powered off or shut down, the
outputs can be driven to ±12V. The transmitter inputs do
not have pullup resistors. Connect unused inputs to GND
or VCC.
LapLink is a registered trademark of Laplink Software, Inc.
www.maximintegrated.com
MAX3244E
MAX3245E
R2OUTB
VCC
Rx
THREE-STATED
UART
5kΩ
Tx
GND
b)
R2IN
R2OUT
T1IN
T1OUT
FORCEOFF = GND
NEW MAX3244E/MAX3245E: IN SHUTDOWN, R2OUTB IS USED TO MONITOR
EXTERNAL DEVICES AND R2OUT IS THREE STATED, ELIMINATING A
CURRENT PATH THROUGH THE UART'S PROTECTION DIODE.
Figure 2. The MAX3244E/MAX3245E detect RS-232 activity
when the UART and interface are shut down.
Maxim Integrated │ 13
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Table 1. Output Control Truth Table
RECEIVER OR
TRANSMITTER
EDGE WITHIN
30s
T_OUT
R_OUT
(MAX3224E/
MAX3225E/
MAX3226E/
MAX3227E)
R_OUT
(MAX3244E/
MAX3245E)
R2OUTB
(MAX3244E/
MAX3245E)
FORCEON
FORCEOFF
VALID
RECEIVER
LEVEL
Shutdown
(Forced Off)
X
0
X
X
High-Z
Active
High-Z
Active
Normal
Operation
(Forced On)
1
1
X
X
Active
Active
Active
Active
Normal
Operation
(AutoShutdown
Plus)
0
1
X
Yes
Active
Active
Active
Active
Shutdown (AutoShutdown Plus)
0
1
X
No
High-Z
Active
Active
Active
Normal
Operation
INVALID*
1
Yes
X
Active
Active
Active
Active
Normal
Operation
INVALID*
1
X
Yes
Active
Active
Active
Active
Shutdown
INVALID*
1
No
No
High-Z
Active
Active
Active
Normal
Operation
(AutoShutdown)
INVALID*
INVALID**
Yes
X
Active
Active
Active
Active
Shutdown
(AutoShutdown)
INVALID*
INVALID**
No
X
High-Z
Active
High-Z
Active
OPERATION
STATUS
X = Don’t care
* INVALID connected to FORCEON
** INVALID connected to FORCEON and FORCEOFF
RS-232 Receivers
The receivers convert RS-232 signals to CMOS-logic
output levels. The MAX3224E–MAX3227E feature
inverting outputs that always remain active (Table 1). The
MAX3244E/MAX3245E have inverting three-state outputs
that are high impedance when shut down (FORCEOFF =
GND) (Table 1).
The MAX3244E/MAX3245E feature an extra, always
active, noninverting output, R2OUTB. R2OUTB output
monitors receiver activity while the other receivers are
high impedance, allowing ring indicator applications
to be monitored without forward biasing other devices
connected to the receiver outputs. This is ideal for
systems where VCC is set to ground in shutdown to
accommodate peripherals such as UARTs (Figure 2).
www.maximintegrated.com
The MAX3224E–MAX3227E/MAX3244E/MAX3245E
feature an INVALID output that is enabled low when no
valid RS-232 voltage levels have been detected on all
receiver inputs. Because INVALID indicates the receiver
input’s condition, it is independent of FORCEON and
FORCEOFF states (Figures 3 and 4).
AutoShutdown Plus Mode
The MAX3224E–MAX3227E/MAX3244E/MAX3245E
achieve a 1μA supply current with Maxim’s AutoShutdown
Plus feature, which operates when FORCEOFF is high
and a FORCEON is low. When these devices do not
sense a valid signal transition on any receiver and transmitter input for 30s, the on-board charge pumps are
shut down, reducing supply current to 1μA. This occurs
if the RS-232 cable is disconnected or if the connected
Maxim Integrated │ 14
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
+0.3V
T_IN
R_IN
30µs
TIMER
R
-0.3V
INVALID
R_IN
EDGE
DETECT
+2.7V
S
30s
TIMER
EDGE
DETECT
INVALID ASSERTED IF ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR
AT LEAST 30µs.
Figure 3a. INVALID Functional Diagram, INVALID Low
FORCEOFF
R
FORCEON
Figure 3c. AutoShutdown Plus Logic
FORCEOFF
30µs
TIMER
R
-2.7V
INVALID DEASSERTED IF ANY RECEIVER INPUT HAS BEEN BETWEEN +2.7V AND -2.7V
FOR LESS THAN 30µs.
Figure 3b. INVALID Functional Diagram, INVALID High
Table 2. INVALID Truth Table
RS-232 SIGNAL
PRESENT AT ANY
RECEIVER INPUT
INVALID OUTPUT
Yes
High
No
Low
peripheral transmitters are turned off, and the UART
driving the transmitter inputs is inactive. The system turns
on again when a valid transition is applied to any RS-232
receiver or transmitter input. As a result, the system saves
power without changes to the existing BIOS or operating
system.
Figures 3a and 3b depict valid and invalid RS-232
receiver voltage levels. INVALID indicates the receiver
input’s condition, and is independent of FORCEON and
FORCEOFF states. Figure 3 and Tables 1 and 2 summarize the operating modes of the MAX3224E–MAX3227E/
MAX3244E/MAX3245E. FORCEON and FORCEOFF
override AutoShutdown Plus circuitry. When neither
control is asserted, the IC selects between these states
automatically based on the last receiver or transmitter
input edge received.
www.maximintegrated.com
POWERDOWN*
FORCEON
INVALID
AUTOSHDN
* POWERDOWN IS ONLY AN INTERNAL SIGNAL.
IT CONTROLS THE OPERATIONAL STATUS OF
THE TRANSMITTERS AND THE POWER SUPPLIES.
Figure 3d. Power-Down Logic
When shut down, the device’s charge pumps turn off, V+
is pulled to VCC, V- is pulled to ground, the transmitter
outputs are high impedance, and READY (MAX3224E–
MAX3227E) is driven low. The time required to exit shutdown is typically 100μs (Figure 8).
By connecting FORCEON to INVALID, the MAX3224E–
MAX3227E/MAX3244E/MAX3245E shut down when no
valid receiver level and no receiver or transmitter edge is
detected for 30s, and wake up when a valid receiver level
or receiver or transmitter edge is detected.
INVALID HIGH
+2.7V
RECEIVER INPUT LEVELS
R_IN
AUTOSHDN
INDETERMINATE
+0.3V
0
INVALID LOW
-0.3V
INDETERMINATE
-2.7V
INVALID HIGH
Figure 4a. Receiver Positive/Negative Thresholds for INVALID
Maxim Integrated │ 15
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
RECEIVER
INPUTS
INVALID
} REGION
TRANSMITTER
INPUTS
TRANSMITTER
OUTPUTS
INVALID
OUTPUT
VCC
tINVL
0
tINVH
tAUTOSHDN
tAUTOSHDN
tWU
tWU
*VCC
READY
0
V+
VCC
0
V-
*MAX3224E–MAX3227E
Figure 4b. AutoShutdown Plus, INVALID, and READY Timing Diagram
By connecting FORCEON and FORCEOFF to INVALID,
the MAX3224E–MAX3227E/MAX3244E/MAX3245E shut
down when no valid receiver level is detected and wake
up when a valid receiver level is detected (same functionality as AutoShutdown feature on MAX3221E/MAX3223E/
MAX3243E).
A mouse or other system with AutoShutdown Plus may
need time to wake up. Figure 5 shows a circuit that
forces the transmitters on for 100ms, allowing enough
time for the other system to realize that the MAX3244E/
MAX3245E is awake. If the other system outputs valid
RS-232 signal transitions within that time, the RS-232
ports on both systems remain enabled.
Software-Controlled Shutdown
If direct software control is desired, use INVALID to indicate DTR or ring indicator signal. Tie FORCEOFF and
FORCEON together to bypass the AutoShutdown Plus so
the line acts like a SHDN input.
±15kV ESD Protection
As with all Maxim devices, ESD-protection structures are
incorporated on all pins to protect against electrostatic
www.maximintegrated.com
discharges encountered during handling and assembly.
The driver outputs and receiver inputs of the MAX3224E–
MAX3227E/MAX3244E/MAX3245E have extra protection against static electricity. Maxim’s engineers
have developed state-of-the-art structures to protect
POWERMANAGEMENT
UNIT
MASTER SHDN LINE
0.1µF
1MΩ
FORCEOFF FORCEON
MAX3224E
MAX3225E
MAX3226E
MAX3227E
MAX3244E
MAX3245E
Figure 5. AutoShutdown Plus Initial Turn-On to Wake Up a
Mouse or Another System
Maxim Integrated │ 16
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
RC 1MΩ
CHARGE-CURRENT
LIMIT RESISTOR
HIGHVOLTAGE
DC
SOURCE
Cs
100pF
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
RC 50MΩ to 100MΩ
RD 1500Ω
DISCHARGE
RESISTANCE
CHARGE CURRENT
LIMIT RESISTOR
DEVICE
UNDER
TEST
STORAGE
CAPACITOR
Figure 6a. Human Body ESD Test Model
HIGHVOLTAGE
DC
SOURCE
Cs
150pF
RD 330Ω
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
DEVICE
UNDER
TEST
Figure 7a. IEC 1000-4-2 ESD Test Model
I
IP 100%
90%
Ir
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
100%
90%
AMPERES
I PEAK
36.8%
10%
0
0
tRL
TIME
tDL
CURRENT WAVEFORM
10%
Figure 6b. Human Body Current Waveform
these pins against ESD of ±15kV without damage. The
ESD structures withstand high ESD in all states: normal
operation, shutdown, and powered down. After an ESD
event, Maxim’s E versions keep working without latchup,
whereas competing RS-232 products can latch and must
be powered down to remove latchup.
t r = 0.7ns to 1ns
t
30ns
60ns
Figure 7b. IEC 1000-4-2 ESD Generator Current Waveform
ESD Test Conditions
ESD protection can be tested in various ways; the
transmitter outputs and receiver inputs of this product
family are characterized for protection to the following
limits:
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents test
setup, test methodology, and test results.
1) ±15kV using the Human Body Model
Figure 6a shows the Human Body Model and Figure
6b shows the current waveform it generates when
discharged into a low impedance. This model consists of
a 100pF capacitor charged to the ESD voltage of interest,
which is then discharged into the test device through a
1.5kΩ resistor.
2) ±8kV using the Contact-Discharge Method specified
in IEC 1000-4-2
3) ±15kV using IEC 1000-4-2’s Air-Gap Method.
www.maximintegrated.com
Human Body Model
Maxim Integrated │ 17
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
IEC 1000-4-2
The IEC 1000-4-2 standard covers ESD testing and
performance of finished equipment; it does not specifically
refer to integrated circuits. The MAX3224E–MAX3227E,
MAX3244E/MAX3245E help you design equipment that
meets Level 4 (the highest level) of IEC 1000-4-2, without
the need for additional ESD-protection components.
The major difference between tests done using the
Human Body Model and IEC 1000-4-2 is higher peak
current in IEC 1000-4-2, because series resistance is
lower in the IEC 1000-4-2 model. Hence, the ESD withstand voltage measured to IEC 1000-4-2 is generally
lower than that measured using the Human Body Model.
Figure 7a shows the IEC 1000-4-2 model and Figure 7b
shows the current waveform for the 8kV, IEC 1000-4-2,
Level 4, ESD Contact-Discharge Method.
The Air-Gap Method involves approaching the device
with a charged probe. The Contact-Discharge Method
connects the probe to the device before the probe is
energized.
Machine Model
The Machine Model for ESD tests all pins using a 200pF
storage capacitor and zero discharge resistance. Its
objective is to emulate the stress caused by contact that
occurs with handling and assembly during manufacturing.
Of course, all pins require this protection during manufacturing, not just RS-232 inputs and outputs. Therefore,
after PC board assembly, the Machine Model is less
relevant to I/O ports.
Applications Information
Capacitor Selection
The capacitor type used for C1–C4 is not critical for
proper operation; polarized or nonpolarized capacitors
Table 3. Required Minimum Capacitance
Values
V CC
(V)
C1, C BYPASS
(μF)
C2, C3, C4
(μF)
3.0 to 3.6
0.22
0.22
3.15 to 3.6
0.1
0.1
4.5 to 5.5
0.047
0.33
3.0 to 5.5
0.22
1
www.maximintegrated.com
5V/div
0
FORCEON = FORCEOFF
T1OUT
2V/div
0
5V/div
0
VCC = 3.3V
C1–C4 = 0.1µF
T2OUT
READY
5µs/div
Figure 8. Transmitter Outputs when Exiting Shutdown or
Powering Up
can be used. The charge pump requires 0.1μF capacitors for 3.3V operation. For other supply voltages,
see 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, C4, and
CBYPASS, to maintain the proper ratios (C1 to the other
capacitors).
When using the minimum required capacitor values,
make sure the capacitor value does not degrade excessively with temperature. If in doubt, use capacitors with
a larger nominal value. The capacitor’s equivalent series
resistance (ESR), which usually rises at low temperatures, influences the amount of ripple on V+ and V-.
Power-Supply Decoupling
In most circumstances, a 0.1μF VCC bypass capacitor
is adequate. In applications that are sensitive to powersupply noise, use a capacitor of the same value as
charge-pump capacitor C1. Connect bypass capacitors
as close to the IC as possible.
Transmitter Outputs
when Exiting Shutdown
Figure 8 shows two transmitter outputs when exiting
shutdown mode. As they become active, the two transmitter outputs are shown going to opposite RS-232 levels
(one transmitter input is high, the other is low). Each
Maxim Integrated │ 18
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
transmitter is loaded with 3kΩ in parallel with 1000pF.
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.
5V/div
T1IN
High Data Rates
The MAX3224E/MAX3226E/MAX3244E maintain the
RS-232 ±5.0V minimum transmitter output voltage even
at high data rates. Figure 9 shows a transmitter loopback test circuit. Figure 10 shows a loop-back test result at
120kbps, and Figure 11 shows the same test at 250kbps.
For Figure 10, all transmitters were driven simultaneously
at 120kbps into RS-232 loads in parallel with 1000pF. For
Figure 11, a single transmitter was driven at 250kbps, and
all transmitters were loaded with an RS-232 receiver in
parallel with 250pF.
The MAX3225E/MAX3227E/MAX3245E maintain the
RS-232 ±5.0V minimum transmitter output voltage at data
rates up to 1Mbps (MegaBaud). Figure 12 shows a loopback test result with a single transmitter driven at 1Mbps
and all transmitters loaded with an RS-232 receiver in
parallel with 250pF.
5V/div
T1OUT
5V/div
R1OUT
VCC = 3.3V
2µs/div
Figure 10. MAX3224E/MAX3226E/MAX3244E Loopback Test
Result at 120kbps
T1IN
5V/div
T1OUT
5V/div
VCC
CBYPASS
5V/div
R1OUT
VCC
C1+
C1
C1C2+
C2
C2-
MAX3224E
MAX3225E
MAX3226E
MAX3227E
MAX3244E
MAX3245E
2µs/div
C3*
Figure 11. MAX3224E/MAX3226E/MAX3244E Loopback Test
Result at 250kbps
VC4
T1IN
5V/div
T1OUT
5V/div
R_ IN
R_ OUT
5kΩ
FORCEON
FORCEOFF
V+
T_ OUT
T_ IN
VCC
VCC = 3.3V
1000pF
GND
5V/div
R1OUT
VCC = 3.3V
*C3 CAN BE RETURNED TO VCC OR GND.
Figure 9. Loopback Test Circuit
www.maximintegrated.com
200ns/div
Figure 12. MAX3225E/MAX3227E/MAX3245E Loopback Test
Result at 1Mbps
Maxim Integrated │ 19
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
+3.3V
26
0.1µF
VCC
28 C1+
C1
0.1µF
24
1
C2
0.1µF
2
LOGIC
INPUTS
27
V+
C3
0.1µF
C1C2+
MAX3244E
MAX3245E
V-
COMPUTER SERIAL PORT
3
C4
0.1µF
C2-
14
T1IN
T1OUT
9
+V
13
T2IN
T2OUT
10
+V
12
T3IN
T3OUT
11
-V
20
R2OUTB
19
R1OUT
GND
R1IN
Tx
4
5kΩ
18
R2OUT
R2IN
LOGIC
OUTPUTS
5
5kΩ
17
R3OUT
R3IN
6
RS-232
INPUTS
5kΩ
16
R4OUT
R4IN
7
5kΩ
15
23
VCC
TO POWERMANAGEMENT
UNIT
22
21
R5OUT
R5IN
8
SERIAL
MOUSE
5kΩ
FORCEON
FORCEOFF
INVALID
GND
25
Figure 13a. Mouse Driver Test Circuit
www.maximintegrated.com
Maxim Integrated │ 20
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Mouse Driveability
VOUT+
VCC = 3.0V
The MAX3244E/MAX3245E are specifically designed
to power serial mice while operating from low-voltage
power supplies. They have been tested with leading
mouse brands from manufacturers such as Microsoft and
Logitech. The MAX3244E/MAX3245E successfully drove
all serial mice tested and met their respective current and
voltage requirements. The MAX3244E/MAX3245E dual
charge pump ensures the transmitters supply at least
±5V during worst-case conditions. Figure 13b shows the
transmitter output voltages under increasing load current.
Figure 13a shows a typical mouse connection.
MAX2343E-FIG15
TRANSMITTER OUTPUT VOLTAGE (V)
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
VOUT+
VCC
VOUTVOUT-
Interconnection with 3V and 5V Logic
0
1
2
3
4
5
6
7
8
9
The MAX3224E–MAX3227E/MAX3244E/MAX3245E can
directly interface with various 5V logic families, including
ACT and HCT CMOS. See Table 4 for more information
on possible combinations of interconnections.
10
LOAD CURRENT PER TRANSMITTER (mA)
Figure 13b. MAX324_E Transmitter Output Voltage vs. Load
Current per Transmitter
Table 5 lists other Maxim ESD-powered transceivers.
Table 4. Logic Family Compatibility with Various Supply Voltages
SYSTEM
POWER-SUPPLY
VOLTAGE (V
V CC SUPPLY
VOLTAGE
(V)
3.3
3.3
5
5
5
3.3
COMPATIBILITY
Compatible with all CMOS families
Compatible with all TTL and CMOS families
Compatible with ACT and HCT CMOS, and with AC, HC, or CD4000 CMOS
Table 5. ±15kV ESD-Protected, 3.0V to 5.5V Powered RS-232 Transceivers from Maxim
PART
SUPPLY
VOLTAGE
RANGE
(V)
NO.
OF
Tx/Rx
AutoShutdown
Human
Body
Model
(kV)
IEC 1000-4-2
Contact
Discharge
(kV)
IEC 1000-4-2
Air-Gap
Discharge
(kV)
GUARANTEED
DATA RATE
(kbps)
MAX3241E
+3.0 to +5.5
3/5
300
—
—
±15
±8
±15
250
MAX3243E
+3.0 to +5.5
3/5
MAX3244E
+3.0 to +5.5
3/5
1
—
Yes
±15
±8
±15
250
1
Yes
—
±15
±8
±15
250
MAX3245E
+3.0 to +5.5
3/5
1
Yes
—
±15
±8
±15
1Mbps
MAX3232E
MAX3222E
+3.0 to +5.5
2/2
300
—
—
±15
±8
±15
250
+3.0 to +5.5
2/2
300
—
—
±15
±8
±15
250
MAX3223E
+3.0 to +5.5
2/2
1
—
Yes
±15
±8
±15
250
MAX3224E
+3.0 to +5.5
2/2
1
Yes
—
±15
±8
±15
250
MAX3225E
+3.0 to +5.5
2/2
1
Yes
—
±15
±8
±15
1Mbps
MAX3221E
+3.0 to +5.5
1/1
1
—
Yes
±15
±8
±15
250
MAX3226E
+3.0 to +5.5
1/1
1
Yes
—
±15
±8
±15
250
MAX3227E
+3.0 to +5.5
1/1
1
Yes
—
±15
±8
±15
1Mbps
www.maximintegrated.com
SUPPLY
AutoCURRENT Shutdown
(μA)
Plus
Maxim Integrated │ 21
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Typical Operating Circuits
+3.3V
+3.3V
15
0.1µF
CBYPASS
2 C1+
C1
0.1µF
4 C15
C2
0.1µF
6
C2+
VCC
V+
MAX3226E*
MAX3227E
V-
3
7
C2-
11 T1IN
9 R1OUT
C3
0.1µF
C1
0.1µF
C4
0.1µF
C2
0.1µF
12
READY
1
2
27
C3
0.1µF
C1C2+
C2-
MAX3244E***
MAX3245E
V-
3
C4
0.1µF
T1OUT 9
R1IN 8
13 T2IN
T2OUT 10
12 T3IN
T3OUT 11
FORCEOFF 16
FORCEON
24
V+
14 T1IN
INVALID 10
AutoShutdown
Plus
28 C1+
VCC
T1OUT 13
5kΩ
1
26
CBYPASS
0.1µF
GND
TO POWERMANAGEMENT
UNIT
VCC
22 FORCEOFF
23 FORCEON
AutoShutdown
Plus
INVALID 21
20 R2OUTB
14
19 R1OUT
R1IN 4
18 R2OUT
R2IN
17 R3OUT
R3IN 6
16 R4OUT
R4IN 7
15 R5OUT
R5IN 8
+3.3V
CBYPASS
C1
0.1µF
2 C1+
4 C15
C2
0.1µF
TTL/CMOS
INPUTS
19
0.1µF
6
C2+
VCC
V+
MAX3224E**
MAX3225E
V-
3
C3
0.1µF
7
C2-
13 T1IN
T1OUT 17
12 T2IN
T2OUT 8
C4
0.1µF
RS-232
OUTPUTS
GND
R1IN 16
15 R1OUT
TTL/CMOS
OUTPUTS
RS-232
INPUTS
5kΩ
R2IN 9
10 R2OUT
5
25
5kΩ
1
14
READY
AutoShutdown
Plus
INVALID 11
FORCEOFF 20
FORCEON
GND
TO POWERMANAGEMENT
UNIT
VCC
*MAX3226E/MAX3227E PIN OUT REFERS TO SSOP/TSSOP PACKAGES.
**MAX3224E/MAX3225E PIN OUT REFERS TO DIP/ SSOP/TSSOP PACKAGES.
***MAX3244E/MAX3245E PIN OUT REFERS TO SO/SSOP/TSSOP PACKAGES.
18
www.maximintegrated.com
Maxim Integrated │ 22
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Pin Configurations
READY 1
+
20 FORCEOFF
C2+ 1
C2- 2
15 VCC
C1+ 2
19 VCC
14 GND
V+ 3
18 GND
13 T1OUT
C1- 4
C2+ 5
12 FORCEON
C2+ 5
C2- 6
11 T1IN
C2- 6
V+ 3
MAX3226E
MAX3227E
C1- 4
V- 7
V- 7
10 INVALID
T2OUT
9 R1OUT
R1IN 8
SSOP/TSSOP
R1IN
R1OUT
FORCEON
T1IN
15
14
13
12
11
VCC 17
MAX3224E
MAX3225E
FORCEOFF 18
READY 19
*EP
V+ 20
3
4
5
C1+
C1-
C2+
C2-
V-
12
11
T1OUT
GND
VCC
TOP VIEW
10
26 VCC
25 GND
16 R1IN
R2IN 5
15 R1OUT
R3IN 6
14 FORCEON
R4IN 7
22 FORCEOFF
MAX3244E 24 C1MAX3245E
23 FORCEON
13 T1IN
R5IN 8
21 INVALID
12 T2IN
T1OUT 9
20 R2OUTB
11 INVALID
T2OUT 10
19 R1OUT
T3OUT 11
18 R2OUT
T3IN 12
17 R3OUT
T2IN 13
16 R4OUT
T1IN 14
15 R5OUT
10
T2IN
9
INVALID
8
R2OUT
7
R2IN
6
T2OUT
FORCEON
2
TQFN
V- 3
R1IN 4
8
+
1
27 V+
17 T1OUT
DIP/SSOP/TSSOP
GND 16
28 C1+
R2IN 9
R2OUT 10
T1OUT
TOP VIEW
MAX3224E
MAX3225E
9
SO/SSOP/TSSOP
TOP VIEW
N.C.
C1+ 2
+
+
C2+
N.C.
C1+
V+
VCC
N.C.
16 FORCEOFF
VC2-
+
READY 1
36 35 34 33 32 31 30 29 28
R1IN
R2IN
1
27
2
26
R3IN
R4IN
R5IN
N.C.
3
T1OUT
T2OUT
T3OUT
25
MAX3245E
4
24
5
23
6
22
7
21
8
*EP
9
GND
C1FORCEON
FORCEOFF
INVALID
20
N.C.
R2OUTB
R1OUT
19
R2OUT
MAX3226E
MAX3227E
READY 14
V+ 15
C1+ 16
*EP
7
INVALID
6
R1OUT
5
R1IN
N.C.
T1IN
R3OUT
8
N.C.
FORCEOFF 13
T3IN
T2IN
T1IN
N.C.
R5OUT
R4OUT
10 11 12 13 14 15 16 17 18
TQFN
C2+
3
4
V-
2
C2-
1
C1-
+
TQFN
www.maximintegrated.com
*CONNECT EP TO GND.
Maxim Integrated │ 23
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Ordering Information (continued)
TEMP RANGE
PIN-PACKAGE
-40°C to +85°C
16 TQFN-EP*
MAX3227EEUE+
-40°C to +85°C
16 TSSOP
MAX3227EAAE+
-40°C to +125°C
16 SSOP
20 Plastic DIP
MAX3244ECWI+
0°C to +70°C
28 Wide SO
20 TQFN -EP*
MAX3244ECAI+
0°C to +70°C
28 SSOP
-40°C to +85°C
20 TSSOP
MAX3244ECUI+
0°C to +70°C
28 TSSOP
-40°C to +85°C
20 TSSOP
MAX3244EEWI+
-40°C to +85°C
28 Wide SO
MAX3225EEAP+
-40°C to +85°C
20 SSOP
MAX3244EEAI+
-40°C to +85°C
28 SSOP
MAX3225EEPP+
-40°C to +85°C
20 Plastic DIP
MAX3244EEUI+
-40°C to +85°C
28 TSSOP
MAX3225EAAP+
-40°C to +85°C
20 SSOP
MAX3245ECWI+
0°C to +70°C
28 Wide SO
MAX3226ECTE+
0°C to +70°C
16 TQFN-EP*
MAX3245ECAI+
0°C to +70°C
28 SSOP
MAX3226ECUE+
0°C to +70°C
16 TSSOP
MAX3245ECTX+
0°C to +70°C
36 TQFN- EP*
MAX3226ECAE+
0°C to +70°C
16 SSOP
MAX3245EEAI+
-40°C to +85°C
28 SSOP
MAX3226EEAE+
-40°C to +85°C
16 SSOP
MAX3245EEWI+
-40°C to +85°C
28 WIDE SO
MAX3226EETE+
-40°C to +85°C
16 TQFN-EP*
MAX3245EEUI+
-40°C to +85°C
28 TSSOP
MAX3226EEUE+
-40°C to +85°C
16 TSSOP
MAX3245EETX+
-40°C to +85°C
36 TQFN- EP*
MAX3226EAAE+
-40°C to +125°C
16 SSOP
MAX3227ECAE+
0°C to +70°C
16 SSOP
MAX3227ECTE+
0°C to +70°C
16 TQFN-EP*
MAX3227ECUE+
0°C to +70°C
16 TSSOP
MAX3227EEAE+
-40°C to +85°C
16 SSOP
MAX3227EEAE/V+
-40°C to +85°C
16 SSOP
PART
TEMP RANGE
PIN-PACKAGE
PART
MAX3225ECUP+
0°C to +70°C
20 TSSOP
MAX3227EETE+
MAX3225ECTP+
0°C to +70°C
20 TQFN-EP*
MAX3225ECAP+
0°C to +70°C
20 SSOP
MAX3225ECPP+
0°C to +70°C
MAX3225EETP+
-40°C to +85°C
MAX3225EEUP+
MAX3225EEUP/V+
www.maximintegrated.com
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
/V denotes an automotive qualified part.
Chip Information
PROCESS: BiCMOS
Maxim Integrated │ 24
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
10
3/11
Added an automotive qualified part to the Ordering Information; changed all
the parts listed in the Ordering Information to lead free
11
11/18
Updated Applications, Absolute Maximum Ratings, Package Information,
Electrical Characteristics, Pin Description, and Ordering Information
DESCRIPTION
1, 20
1–5, 12, 24
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.
© 2018 Maxim Integrated Products, Inc. │ 25
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