MAX3223EEPP [MAXIM]
【15kV ESD-Protected, 1レA, 3.0V to 5.5V, 250kbps, RS-232 Transceivers with AutoShutdown; ± 15kV ESD保护， 1μA ， 3.0V至5.5V ， 250kbps的， RS - 232收发器，具有自动关机
| 型号： | MAX3223EEPP |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | 【15kV ESD-Protected, 1レA, 3.0V to 5.5V, 250kbps, RS-232 Transceivers with AutoShutdown |
| 文件： | 总16页 (文件大小：154K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-1283; Rev 2; 1/98
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
1/MAX243E
Ge n e ra l De s c rip t io n
Fe a t u re s
The MAX3221E/MAX3223E/MAX3243E 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, to ±8kV using IEC 1000-4-2 Contact
Discharge, and to ±15kV using the Human Body Model.
♦ ESD Protection for RS-232 I/O Pins:
±15kV—Human Body Model
±8kV—IEC1000-4-2, Contact Discharge
±15kV—IEC1000-4-2, Air-Gap Discharge
♦ Latchup Free
♦ 1µA Supply Current
♦ 250kbps Guaranteed Data Rate
♦ 6V/µs Guaranteed Slew Rate
♦ Meets EIA/TIA-232 Specifications Down to 3.0V
The MAX3221E/MAX3223E/MAX3243E a c hie ve a
1µA s up p ly c urre nt with Ma xim’s re volutiona ry
AutoShutd own™ fe a ture . The y s a ve p owe r without
changes to the existing BIOS or operating system by enter-
ing low-power shutdown mode when the RS-232 cable is
disconnected, or when the transmitters of the connected
peripherals are off.
♦ Smallest Single-Supply RS-232 Transceiver
(MAX3221E)
♦ Guaranteed Mouse Driveability (MAX3243E)
♦ Small 0.1µF Capacitors
The transceivers have a proprietary low-dropout trans-
mitter output stage, delivering 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 capaci-
tors for operation from a +3.3V supply. Each device is
guaranteed to run at data rates of 250kbps while main-
taining RS-232 output levels.
Ord e rin g In fo rm a t io n
PART
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
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
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
16 SSOP
The MAX3221E contains just one driver and one receiver,
making it the smallest single-supply RS-232 transceiver.
The MAX3223E has two drivers and two receivers. The
MAX3243E is a complete 3-driver/5-receiver serial port
ideal for notebook or subnotebook computers. It also
includes two noninverting receiver outputs that are always
active, allowing external devices to be monitored without
forward biasing the protection diodes in circuitry that may
be powered down.
MAX3221ECAE
MAX3221EEAE
MAX3223ECPP
MAX3223ECAP
MAX3223EEPP
MAX3223EEAP
MAX3243ECWI
MAX3243ECAI
MAX3243EEWI
MAX3243EEAI
16 SSOP
20 Plastic DIP
20 SSOP
20 Plastic DIP
20 SSOP
28 Wide SO
28 SSOP
The MAX3221E, MAX3223E, and MAX3243E are avail-
able in space-saving SSOP packages.
28 Wide SO
28 SSOP
Ap p lic a t io n s
S e le c t o r Gu id e
Notebook, Subnotebook, and Palmtop Computers
Cellular Phones
NO. OF
DRIVERS/
RECEIVERS
V
RANGE
(V)
CC
PART
AUTOSHUTDOWN
Battery-Powered Equipment
Hand-Held Equipment
Peripherals
✔
✔
✔
MAX3221E
MAX3223E
MAX3243E
1/1
2/2
3/5
3.0 to 5.5
3.0 to 5.5
3.0 to 5.5
Printers
Pin Configurations appear at end of data sheet.
Typical Operating Circuits appear at end of data sheet.
AutoShutdown is a trademark of Maxim Integrated Products.
†
Covered by U.S. Patent numbers 4,636,930; 4,679,134; 4,777,577; 4,797,899; 4,809,152; 4,897,774; 4,999,761; 5,649,210; and other patents pending.
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
ABSOLUTE MAXIMUM RATINGS
CC
E
V
to GND..............................................................-0.3V to +6V
Continuous Power Dissipation (T = +70°C)
A
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, EN, FORCEON, FORCEOFF to GND ............-0.3V to +6V
R_IN to GND ......................................................................±25V
Output Voltages
16-Pin SSOP (derate 7.14mW/°C above +70°C) ...........571mW
20-Pin Plastic DIP (derate 11.11mW/°C above +70°C)....889mW
20-Pin SSOP (derate 8.00mW/°C above +70°C) ...........640mW
28-Pin Wide SO (derate 12.50mW/°C above +70°C)............1W
28-Pin SSOP (derate 9.52mW/°C above +70°C)............762mW
Operating Temperature Ranges
MAX32_ _EC_ _ ....................................................0°C to +70°C
MAX32_ _EE_ _..................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
T_OUT to GND................................................................±13.2V
R_OUT, R2OUTB, INVALID to GND.........-0.3V to (V + 0.3V)
CC
Short-Circuit Duration
T_OUT to GND .........................................................Continuous
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
(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
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS (V = 3.3V or 5.0V, T = +25°C)
CC
A
FORCEON = GND,
Supply Current, AutoShutdown
1.0
1.0
0.3
10
10
1
µA
µA
FORCEOFF = V
all R_IN open
CC,
Supply Current, Shutdown
FORCEOFF = GND
Supply Current,
AutoShutdown Disabled
FORCEON = FORCEOFF = V
no load
,
CC
mA
LOGIC INPUTS
Input Logic Threshold Low
0.8
V
V
T_IN, EN, FORCEON, FORCEOFF
1E/MAX243
V
= 3.3V
= 5.0V
2.0
2.4
CC
T_IN, EN, FORCEON,
Input Logic Threshold High
FORCEOFF
V
CC
Transmitter Input Hysteresis
Input Leakage Current
RECEIVER OUTPUTS
Output Leakage Current
Output Voltage Low
0.5
V
±0.01
±1
µA
T_IN, EN, FORCEON, FORCEOFF
R_OUT receivers disabled
±0.05
±10
0.4
µA
V
I
= 1.6mA
= -1.0mA
OUT
Output Voltage High
I
V
CC
- 0.6
V - 0.1
CC
V
OUT
AUTOSHUTDOWN (FORCEON = GND, FORCEOFF = V
)
CC
Positive threshold
Negative threshold
2.7
Receiver Input Threshold to
INVALID Output High
Figure 5a
Figure 5a
V
V
-2.7
-0.3
Receiver Input Threshold to
INVALID Output Low
0.3
0.4
I
= 1.6mA
= -1.0mA
V
V
INVALID Output Voltage Low
INVALID Output Voltage High
OUT
I
V
- 0.6
OUT
CC
2
_______________________________________________________________________________________
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
1E/MAX243
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.)
MAX A
CC
A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Receiver Positive or Negative
Threshold to INVALID High
t
V
= 5V, Figure 5b
= 5V, Figure 5b
= 5V, Figure 5b
1
µs
INVH
CC
Receiver Positive or Negative
Threshold to INVALID Low
t
V
CC
30
µs
µs
INVL
Receiver or Transmitter Edge to
Transmitters Enabled
t
V
CC
100
WU
RECEIVERINPUTS
-25
0.6
0.8
25
V
Input Voltage Range
V
= 3.3V
= 5.0V
= 3.3V
= 5.0V
1.2
1.5
1.5
1.8
0.5
5
CC
Input Threshold Low
Input Threshold High
T
= +25°C
= +25°C
V
V
A
V
CC
V
CC
2.4
2.4
T
A
V
CC
Input Hysteresis
V
Input Resistance
3
7
kΩ
TRANSMITTER OUTPUTS
All transmitter outputs loaded with
3kΩ to ground
Output Voltage Swing
±5
±5.4
10M
V
Output Resistance
V
CC
= V+ = V- = 0, T
= ±2V
300
Ω
OUT
Output Short-Circuit Current
±60
±25
mA
V
= ±12V, V = 0 or 3V to
CC
OUT
Output Leakage Current
µA
5.5V, transmitters disabled
MOUSE DRIVEABILITY (MAX3243E)
E
T1IN = T2IN = GND, T3IN = V
,
CC
T3OUT loaded with 3kΩ to GND,
T1OUT and T2OUT loaded with
2.5mA each
Transmitter Output Voltage
±5.0
V
ESD PROTECTION
IEC 1000-4-2 Air-Gap Discharge
IEC 1000-4-2 Contact Discharge
Human Body Model
±15
±8
kV
R_IN, T_OUT
±15
_______________________________________________________________________________________
3
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
TIMING CHARACTERISTICS—MAX3221E/MAX3223E/MAX3243E
E
(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
SYMBOL
CONDITIONS
= 3kΩ, C = 1000pF,
MIN
TYP
MAX
UNITS
R
L
L
Maximum Data Rate
250
kbps
one transmitter switching
t
t
0.15
0.15
200
200
100
50
PHL
PLH
Receiver Propagation Delay
C
= 150pF
µs
L
Receiver Output Enable Time
Receiver Output Disable Time
Transmitter Skew
Normal operation
Normal operation
(Note 3)
ns
ns
ns
ns
t
t
- t
PHL PLH
- t
Receiver Skew
PHL PLH
V
= 3.3V,
CC
C
= 150pF to
L
6
4
30
30
R = 3kΩ to 7kΩ,
L
1000pF
T = +25°C,
A
Transition-Region Slew Rate
V/µs
measured from
+3V to -3V or
-3V to +3V
C
= 150pF to
L
2500pF
Note 2: C1–C4 = 0.1µF, tested at 3.3V ±10%. C1 = 0.047µF, C2–C4 = 0.33µF, tested at 5.0V ±10%.
Note 3: Transmitter skew is measured at the transmitter zero cross points.
Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s
(V = +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ and C , T = +25°C, unless otherwise noted.)
L
CC
A
MAX3221E/MAX3223E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
1E/MAX243
MAX3221E/MAX3223E
SLEW RATE vs. LOAD CAPACITANCE
16
14
12
10
8
6
5
V
OUT+
4
3
-SLEW
2
T1 TRANSMITTING AT 250kbps
T2 (MAX3223E) TRANSMITTING AT 15.6kbps
1
+SLEW
0
-1
-2
-3
-4
-5
-6
6
4
2
V
OUT-
FOR DATA RATES UP TO 250kbps
0
0
1000
2000
3000
4000
5000
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
4
_______________________________________________________________________________________
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
1E/MAX243
Typ ic a l Op e ra t in g Ch a ra c t e ris t ic s (c o n t in u e d )
(V = +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ and C , T = +25°C, unless otherwise noted.)
CC
L
A
MAX3221E/MAX3223E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3243E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
6
5
45
40
35
30
25
20
15
10
5
V
OUT+
4
250kbps
3
1 TRANSMITTER AT 250kbps
2 TRANSMITTERS AT 15.6kbps
2
120kbps
1
0
-1
-2
-3
-4
-5
-6
20kbps
V
OUT-
T1 TRANSMITTING AT 250kbps
T2 (MAX3223E) TRANSMITTING AT 15.6kbps
0
0
1000
2000
3000
4000
5000
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
MAX3243E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3243E
SLEW RATE vs. LOAD CAPACITANCE
14
12
10
8
60
50
40
30
20
10
0
E
250kbps
120kbps
6
20kbps
4
T1 TRANSMITTING AT 250kbps
T2 (MAX3223E) TRANSMITTING AT 15.6kbps
2
0
0
1000
2000
3000
4000
5000
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
_______________________________________________________________________________________
5
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
P in De s c rip t io n
E
PIN
NAME
FUNCTION
MAX3221E MAX3223E MAX3243E
Receiver Enable Control. Drive low for normal operation. Drive high to
force the receiver outputs (R_OUT) into a high-impedance state.
1
1
—
EN
2
3
4
5
6
7
8
9
2
28
27
C1+
V+
Positive terminal of the voltage doubler Charge-Pump Capacitor
+5.5V generated by the charge pump
3
4
24
C1-
Negative terminal of the voltage doubler Charge-Pump Capacitor
Positive terminal of inverting Charge-Pump Capacitor
Negative terminal of inverting Charge-Pump Capacitor
-5.5V generated by the charge pump
5
6
1
C2+
C2-
2
7
3
V-
9, 16
10, 15
4–8
15–19
R_IN
R_OUT
RS-232 Receiver Inputs
TTL/CMOS Receiver Outputs
Output of the Valid Signal Detector. INVALID is enabled high if a valid
RS-232 level is present on any receiver input.
10
11
12
13
—
11
12, 13
14
21
12, 13, 14
23
INVALID
T_IN
TTL/CMOS Transmitter Inputs
Drive high to override automatic circuitry keeping transmitters and
charge pump on (FORCEOFF must be high) (Table 1).
FORCEON
T_OUT
R2OUTB
GND
8, 17
—
9, 10, 11
20
RS-232 Transmitter Outputs
TTL/CMOS Noninverting Complementary Receiver Output. Always
active.
14
15
18
19
25
26
Ground
V
CC
+3.0V to +5.5V Supply Voltage
Force-Off Input, active low. Drive low to shut down transmitters,
receivers (MAX3243E, except R2OUTB), and on-board charge pump.
This overrides all automatic circuitry and FORCEON (Table 1).
1E/MAX243
16
20
22
FORCEOFF
RS -2 3 2 Tra n s m it t e rs
The transmitters are inverting level translators that con-
vert CMOS-logic levels to 5.0V EIA/TIA-232 levels. They
guarantee a 250kbps data rate with worst-case loads
of 3kΩ in parallel with 1000pF, providing compatibility
with PC-to-PC c ommunic a tion s oftwa re s uc h a s
LapLink™. Transmitters can be paralleled to drive mul-
tiple receivers. The MAX3243E has been specifically
designed to drive serial mice. Figure 1 shows a com-
plete system connection.
_______________De t a ile d De s c rip t io n
Du a l Ch a rg e -P u m p Vo lt a g e Co n ve rt e r
The MAX3221E/MAX3223E/MAX3243E’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 V range. The charge pumps operate
CC
in 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.
Whe n FORCEOFF is d rive n to g round , or the
AutoShutdown circuitry senses invalid voltage levels on
all receiver inputs, the transmitters are disabled and the
outputs are forced into a high-impedance state. When
powered off or shut down, the output can be driven up
to ±12V. The transmitter inputs do not have pull-up
resistors.
LapLink is a trademark of Traveling Software.
6
_______________________________________________________________________________________
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
1E/MAX243
V
CC
POWER-
MANAGEMENT
UNIT OR
KEYBOARD
CONTROLLER
FORCEOFF
FORCEON
INVALID
PROTECTION
DIODE
PREVIOUS
RS-232
MAX3243E
V
CC
I
Rx
Tx
5k
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
Figure 1. Interface Under Control of PMU
E
I
MAX3243E
PROTECTION
DIODE
RS -2 3 2 Re c e ive rs
The MAX3221E/MAX3223E/MAX3243E’s receivers con-
vert RS-232 signals to CMOS-logic output levels. All
receivers have inverting three-state outputs and can be
active or inactive. In shutdown (FORCEOFF = low) or in
AutoShutdown, the MAX3221E/MAX3223E’s receivers
are active (Table 1). Drive EN high to place the receiv-
e r(s ) in a hig h-imp e d a nc e s ta te . The MAX3243E’s
receivers are high-impedance when the part is in shut-
down (FORCEOFF = low).
R2OUTB
V
CC
R2IN
Rx
R2OUT
THREE-STATED
UART
5k
T1OUT
T1IN
Tx
GND
FORCEOFF = GND
The MAX3243E features an extra, always-active com-
p le me nta ry outp ut (R2OUTB). R2OUTB 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
b) NEW MAX3243E: IN SHUTDOWN, R2OUTB IS USED TO MONITOR EXTERNAL
DEVICES AND R2OUT IS THREE STATED, ELIMINATING A CURRENT PATH
THROUGH THE UART'S PROTECTION DIODE.
receiver outputs. This is ideal for systems where V
CC
drops to 0 in shutdown to accommodate peripherals
such as UARTs (Figure 2).
Figure 2. The MAX3243E detects RS-232 activity when the
UART and interface are shut down.
_______________________________________________________________________________________
7
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
Table 1. Output Control Truth Table
E
VALID
RECEIVER
LEVEL
R_OUT
(MAX3221E/
MAX3223E)
EN
OPERATION
STATUS
R_OUT
(MAX3243E) (MAX3243E)
R2OUTB
FORCEON
(MAX3221E/
MAX3223E)
T_OUT
FORCEOFF
X
X
1
0
0
1
1
1
1
1
1
0
1
0
1
0
1
0
1
X
X
High-Z
High-Z
Active
Active
Active
Active
High-Z
High-Z
Active
High-Z
Active
High-Z
Active
High-Z
Active
High-Z
High-Z
High-Z
Active
Active
Active
Active
High-Z
High-Z
Active
Active
Active
Active
Active
Active
Active
Active
Shutdown
(Forced Off)
X
Normal Operation
(Forced On)
1
X
0
Yes
Yes
No
No
Normal Operation
(AutoShutdown)
0
0
Shutdown
(AutoShutdown)
0
X = Don’t Care
+2.7V
+0.3V
TO MAX32_ _E
POWER SUPPLY
AND TRANSMITTERS
TO MAX32_ _E
POWER SUPPLY
R_IN
R_IN
30µs
COUNTER
30µs
COUNTER
R
INVALID
INVALID
R
-2.7V
-0.3V
* TRANSMITTERS ARE ENABLED IF:
ANY RECEIVER INPUT IS GREATER THAN +2.7V OR LESS THAN -2.7V.
ANY RECEIVER INPUT HAS BEEN BETWEEN +0.3V AND -0.3V FOR LESS THAN 30µs.
1E/MAX243
* TRANSMITTERS ARE DISABLED, REDUCING SUPPLY CURRENT TO 1µA IF
ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30µs.
Figure 3b. MAX32__E with Transmitters Enabled Using
AutoShutdown
Figure 3a. MAX32_ _E Entering 1µA Supply Mode via
AutoShutdown
The MAX3221E/MAX3223E/MAX3243E fe a ture a n
INVALID output that is enabled low when no valid RS-232
signal levels have been detected on all receiver inputs.
INVALID is functional in any mode (Figures 3 and 5).
signal levels on all receiver inputs for 30µs, the on-
board charge pump and drivers are shut off, reducing
supply current to 1µA. This occurs if the RS-232 cable
is disconnected or the connected peripheral transmit-
ters are turned off. The device turns on again when a
valid level is applied to any RS-232 receiver input. As a
result, the system saves power without changes to the
existing BIOS or operating system.
Au t o S h u t d o w n
The MAX3221E/MAX3223E/MAX3243E achieve a 1µA
supply current with Maxim’s new AutoShutdown fea-
ture , whic h op e ra te s whe n FORCEON is low a nd
FORCEOFF is high. When these devices sense no valid
8
_______________________________________________________________________________________
1 µA S u p p ly-Cu rre n t , Tru e +3 V t o +5 .5 V
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n ™
1E/MAX243
FORCEOFF
Table 2. INVALID Truth Table
POWER DOWN
FORCEON
INVALID
RS-232 SIGNAL PRESENT
AT ANY RECEIVER INPUT
INVALID OUTPUT
INVALID IS AN INTERNALLY GENERATED SIGNAL
THAT IS USED BY THE AUTOSHUTDOWN LOGIC
AND APPEARS AS AN OUTPUT OF THE DEVICE.
Yes
No
High
Low
POWER DOWN IS ONLY AN INTERNAL SIGNAL.
IT CONTROLS THE OPERATIONAL STATUS OF
THE TRANSMITTERS AND THE POWER SUPPLIES.
Figure 3c. MAX32_ _E AutoShutdown Logic
TRANSMITTERS ENABLED, INVALID HIGH
POWER-
MANAGEMENT
MASTER SHDN LINE
+2.7V
0.1µF
1M
UNIT
INDETERMINATE
+0.3V
0
AUTOSHUTDOWN, TRANSMITTERS DISABLED,
FORCEOFF FORCEON
1µA SUPPLY CURRENT, INVALID LOW
-0.3V
MAX3221E
MAX3223E
MAX3243E
INDETERMINATE
-2.7V
TRANSMITTERS ENABLED, INVALID HIGH
Figure 4. AutoShutdown with Initial Turn-On to Wake Up a
Mouse or Another System
a)
Ta b le 2 a nd Fig ure 3c s umma rize the MAX3221E/
MAX3223E/MAX3243E operating modes. FORCEON
and FORCEOFF override AutoShutdown. 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. Figure 5 shows the input levels and timing dia-
gram for AutoShutdown operation.
E
RECEIVER
INPUT
VOLTAGE
(V)
INVALID
REGION
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 MAX3221E/MAX3223E/
MAX3243E are awake. If the other system transmits
valid RS-232 signals within that time, the RS-232 ports
on both systems remain enabled.
V
CC
INVALID
OUTPUT
(V)
0
t
t
INVH
INVL
t
WU
V+
When shut down, the device’s charge pumps are off, V+
is pulled to V , V- is pulled to ground, and the trans-
CC
V
CC
0
mitter outputs are high impedance. The time required to
exit shutdown is typically 100µs (Figure 5b).
V-
S o ft w a re -Co n t ro lle d S h u t d o w n
If direct software control is desired, INVALID can be
used to indicate DTR or Ring Indicator signal. Connect
FORCEOFF and FORCEON together to disable Auto-
Shutdown so the line acts like a SHDN input.
b)
Figure 5. AutoShutdown Trip Levels
_______________________________________________________________________________________
9
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
R 50M to 100M
C
R 330Ω
D
E
R 1M
C
R 1500Ω
D
DISCHARGE
RESISTANCE
CHARGE CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
CHARGE-CURRENT
LIMIT RESISTOR
HIGH-
VOLTAGE
DC
HIGH-
VOLTAGE
DC
DEVICE
UNDER
TEST
DEVICE
UNDER
TEST
C
s
100pF
STORAGE
CAPACITOR
C
s
150pF
STORAGE
CAPACITOR
SOURCE
SOURCE
Figure 7a. IEC1000-4-2 ESD Test Model
Figure 6a. Human Body ESD Test Models
I
I 100%
90%
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
100%
I
r
P
90%
AMPERES
36.8%
10%
0
TIME
0
t
RL
t
DL
CURRENT WAVEFORM
10%
t = 0.7ns to 1ns
Figure 6b. Human Body Model Current Waveform
r
t
30ns
60ns
±1 5 k V ES D P ro t e c t io n
As with all Maxim devices, ESD-protection structures are
incorporated on all pins to protect against electrostatic
discharges encountered during handling and assembly.
The d rive r outp uts a nd re c e ive r inp uts of the
MAX3221E/MAX3223E/MAX3243E have extra protection
against static electricity. Maxim’s engineers have devel-
oped state-of-the-art structures to protect these pins
against ESD of ±15kV without damage. The ESD struc-
tures withstand high ESD in all states: normal operation,
shutdown, and powered down. After an ESD event,
Maxim’s E versions keep working without latchup, where-
as competing RS-232 products can latch and must be
powered down to remove latchup.
1E/MAX243
Figure 7b. IEC1000-4-2 ESD Generator Current Waveform
ESD Test Conditions
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents
test setup, test methodology, and test results.
Human Body Model
Figure 6a shows the Human Body Model, and Figure
6b shows the current waveform it generates when dis-
charged into a low impedance. This model consists of
a 100pF capacitor charged to the ESD voltage of inter-
e s t, whic h is the n d is c ha rg e d into the te s t d e vic e
through a 1.5kΩ resistor.
ESD protection can be tested in various ways; the trans-
mitter outputs and receiver inputs of this product family
are characterized for protection to the following limits:
IEC1000-4-2
The IEC1000-4-2 standard covers ESD testing and per-
formance of finished equipment; it does not specifi-
c a lly re fe r to inte g ra te d c irc uits . The MAX3221E/
MAX3223E/MAX3243E help you design equipment that
meets Level 4 (the highest level) of IEC1000-4-2, with-
out the need for additional ESD-protection components.
1) ±15kV using the Human Body Model
2) ±8kV using the contact-discharge method specified in
IEC1000-4-2
3) ±15kV using IEC1000-4-2’s air-gap method
10 ______________________________________________________________________________________
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
1E/MAX243
The major difference between tests done using the
Human Body Model and IEC1000-4-2 is higher peak
Table 3. Required Capacitor Values
V
(V)
C1, C
C2, C3, C4
(µF)
BYPASS
CC
current in IEC1000-4-2, because series resistance is
lower in the IEC1000-4-2 model. Hence, the ESD with-
stand voltage measured to IEC1000-4-2 is generally
lowe r tha n tha t me a s ure d us ing the Huma n Bod y
Model. Figure 7a shows the IEEE1000-4-2 model and
Figure 7b shows the current waveform for the ±8kV
IEC1000-4-2 Level 4 ESD contact-discharge test.
(µF)
0.22
0.1
3.0 to 3.6
3.15 to 3.6
4.5 to 5.5
3.0 to 5.5
0.22
0.1
0.33
1
0.047
0.22
The air-gap test involves approaching the device with a
charged probe. The contact-discharge method connects
the probe to the device before the probe is energized.
Table 4. Logic Family Compatibility with
Various Supply Voltages
SYSTEM
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 manufactur-
ing. 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.
POWER-
SUPPLY
VOLTAGE
(V)
V
SUPPLY
CC
VOLTAGE
(V)
COMPATIBILITY
Compatible with all CMOS
families.
3.3
5
3.3
5
Compatible with all TTL and
CMOS-logic families.
Compatible with ACT and
HCT CMOS, and with TTL.
Incompatible with AC, HC,
or CD4000 CMOS.
___________Ap p lic a t io n s In fo rm a t io n
5
3.3
Ca p a c it o r S e le c t io n
The capacitor type used for C1–C4 is not critical for
p rop e r op e ra tion; e ithe r p ola rize d or nonp ola rize d
capacitors 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).
FORCEON =
FORCEOFF
T2OUT
5V/div
2V/div
E
T1OUT
V
= 3.3V
CC
C1–C4 = 0.1µF
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-.
40µs/div
Figure 8. Transmitter Outputs Exiting Shutdown or Powering Up
Tra n s m it t e r Ou t p u t s
w h e n Ex it in g S h u t d o w n
Figure 8 shows two transmitter outputs when exiting
shut down mode. As they become active, the two trans-
mitter outputs are shown going to opposite RS-232 lev-
els (one transmitter output is high, the other is low).
Each transmitter is loaded with 3kΩ in parallel with
1000pF. The transmitter outputs display no ringing or
undesirable transients as they come out of shutdown,
a nd a re e na b le d only whe n the ma g nitud e of V-
exceeds approximately -3V.
P o w e r-S u p p ly De c o u p lin g
In most circumstances, a 0.1µF V bypass capacitor is
CC
adequate. In applications that are sensitive to power-
supply noise, use a capacitor of the same value as the
charge-pump capacitor C1. Connect bypass capacitors
as close to the IC as possible.
______________________________________________________________________________________ 11
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
High Da ta Ra te s
The MAX3221E/MAX3223E/MAX3243E 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 loopback test result at
120kbps, and Figure 11 shows the same test at 250kbps.
For Figure 10, all three transmitters were driven simulta-
neously at 120kbps into RS-232 loads in parallel with
1000pF. For Figure 11, a single transmitter was driven at
250kbps, and all three transmitters were loaded with an
RS-232 receiver in parallel with 1000pF.
Mo u s e Drive a b ilit y (MAX3 2 4 3 E)
The MAX3243E has been specifically designed to power
serial mice while operating from low-voltage power sup-
plies. It has been tested with leading mouse brands such
as Logitech and Microsoft. When tested, the MAX3243E
successfully drove all serial mice and met their respective
current and voltage requirements. The MAX3243E’s regu-
lated dual charge pump ensures the transmitters will sup-
ply at least ±5V during worst-case conditions. Figure 12a
shows the transmitter outputs under increasing load cur-
rent. The AutoShutdown feature does not work with a
mouse, so FORCEOFF and FORCEON should be con-
E
nected to V . Figure 12b (on the following page) shows
CC
a mouse driver test circuit. To achieve mouse driveability
with 1µA supply current when the port is inactive, use
parts with the AutoShutdown Plus feature (such as the
MAX3244E and MAX3245E).
V
CC
0.1µF
V
CC
C1+
V+
V-
C3
C4
C1
C1-
MAX3221E
MAX3223E
MAX3243E
C2+
5V/div
T1IN
C2
C2-
T_ OUT
R_ IN
5k
T_ IN
5V/div
T1OUT
R_ OUT
5V/div
EN (MAX3221/3E)
R1OUT
0V
V
CC
= 3.3V
1000pF
V
CC
FORCEOFF
GND
2µs/div
1E/MAX243
Figure 11. Loopback Test Result at 250kbps
Figure 9. Loopback Test Circuit
6
5
4
V
OUT+
V
CC
= 3.0V
3
2
5V/div
5V/div
5V/div
T1IN
V
1
OUT+
0
-1
-2
-3
-4
-5
-6
T1OUT
R1OUT
V
V
OUT-
CC
V
OUT-
V
CC
= 3.3V
0
1
2
3
4
5
6
7
8
9
10
LOAD CURRENT PER TRANSMITTER (mA)
2µs/div
Figure 12a. Transmitter Output Voltage vs. Load Current per
Transmitter
Figure 10. Loopback Test Result at 120kbps
12 ______________________________________________________________________________________
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
1E/MAX243
+3.3V
26
0.1µF
V
CC
27
3
28
C1+
V+
C1
0.1µF
C3
0.1µF
24
1
C1-
COMPUTER SERIAL PORT
MAX3243E
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
R1IN
R2IN
4
5
19
18
5k
5k
5k
E
LOGIC
OUTPUTS
R3OUT
R4OUT
6
7
8
R3IN
R4IN
R5IN
17
16
RS-232
INPUTS
5k
5k
SERIAL
MOUSE
R5OUT
15
23
FORCEON
FORCEOFF
INVALID
V
CC
22
21
V
CC
TO POWER-
MANAGEMENT
UNIT
GND
25
Figure 12b. Mouse Driver Test Circuit
______________________________________________________________________________________ 13
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
HCT CMOS. See Table 4 for more information on possi-
ble combinations of interconnections.
Inte rc onne c tion w ith 3V a nd 5V Logic
E
The MAX3221E/MAX3223E/MAX3243E can directly inter-
face with various 5V logic families, including ACT and
Table 5. ±15kV ESD-Protected, 3.0V to 5.5V Powered RS-232 Transceivers from Maxim
Supply
Voltage
Range
(V)
Human
Body
Model
(kV)
IEC 1000-4-2 IEC 1000-4-2
No.
of
Tx/Rx
Supply
Auto-
Auto-
Guaranteed
Data Rate
(kbps)
Contact
Discharge
(kV)
Air-Gap
Discharge
(kV)
PART
Current Shutdown Shutdown
(µA)
Plus
MAX3241E +3.0 to +5.5
MAX3243E +3.0 to +5.5
MAX3244E +3.0 to +5.5
MAX3245E +3.0 to +5.5
MAX3232E +3.0 to +5.5
MAX3222E +3.0 to +5.5
MAX3223E +3.0 to +5.5
MAX3224E +3.0 to +5.5
MAX3225E +3.0 to +5.5
MAX3221E +3.0 to +5.5
MAX3226E +3.0 to +5.5
MAX3227E +3.0 to +5.5
3/5
3/5
3/5
3/5
2/2
2/2
2/2
2/2
2/2
1/1
1/1
1/1
300
1
—
—
—
Yes
—
±15
±15
±15
±15
±15
±15
±15
±15
±15
±15
±15
±15
±8
±8
±8
±8
±8
±8
±8
±8
±8
±8
±8
±8
±15
±15
±15
±15
±15
±15
±15
±15
±15
±15
±15
±15
250
250
1
Yes
Yes
—
250
1
—
1Mbps
250
300
300
1
—
—
—
250
—
Yes
—
250
1
Yes
Yes
—
250
1
—
1Mbps
250
1
Yes
—
1
Yes
Yes
250
1
—
1Mbps
1E/MAX243
___________________Ch ip In fo rm a t io n
MAX3221E
TRANSISTOR COUNT: 269
MAX3223E
TRANSISTOR COUNT: 339
MAX3243E
TRANSISTOR COUNT: 476
14 ______________________________________________________________________________________
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
1E/MAX243
Typ ic a l Op e ra t in g Circ u it s
+3.3V
15
0.1µF
C
BYPASS
V
CC
3
7
2
C1+
V+
V-
C1
C3
0.1µF
4
5
6
0.1µF
C1-
+3.3V
0.1µF
BYPASS
E
MAX3221
26
C
C2+
C4
0.1µF
C2
0.1µF
V
CC
27
3
28
C1+
C2-
V+
C1
C3
0.1µF
0.1µF
24
1
11
9
T1IN
T1OUT 13
C1-
MAX3243E
C2+
V-
C4
0.1µF
C2
0.1µF
R1OUT
R1IN
5k
8
2
C2-
T1IN
T1OUT
9
14
TO POWER-
MANAGEMENT
UNIT
RS-232
OUTPUTS
T2IN
T3IN
LOGIC
INPUTS
T2OUT 10
13
12
EN
INVALID 10
1
11
T3OUT
FORCEOFF
FORCEON
16
12
V
CC
GND
14
R2OUTB
R1OUT
20
19
R1IN
4
5
+3.3V
0.1µF
19
5k
C
BYPASS
V
CC
R2OUT
R3OUT
R4OUT
R2IN
R3IN
R4IN
R5IN
3
2
18
17
16
C1+
V+
V-
C1
0.1µF
C3
0.1µF
5k
5k
4
5
6
C1-
LOGIC
OUTPUTS
MAX3223E
E
7
6
7
8
RS-232
INPUTS
C2+
C4
0.1µF
C2
0.1µF
C2-
13
12
T1IN
T1OUT 17
TTL/CMOS
INPUTS
RS-232
OUTPUTS
5k
5k
8
T2IN
T2OUT
R5OUT
15
23
16
15 R1OUT
10 R2OUT
R1IN
FORCEON
FORCEOFF
INVALID
TTL/CMOS
OUTPUTS
RS-232
INPUTS
22
21
5k
V
CC
R2IN
9
TO POWER-
MANAGEMENT UNIT
GND
25
5k
TO POWER-
MANAGEMENT
UNIT
EN
INVALID 11
1
FORCEOFF
FORCEON
20
14
V
CC
GND
18
______________________________________________________________________________________ 15
±15kV ESD-Prote c te d, 1µA, 3.0V to 5.5V, 250kbps ,
RS -2 3 2 Tra n s c e ive rs w it h Au t o S h u t d o w n
P in Co n fig u ra t io n s
E
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
MAX3223E
C2+
C2-
5
C1-
C2+
C2-
V-
13 T1OUT
MAX3221E
R1OUT
FORCEON
T1IN
6
FORCEON
12
V-
7
11 T1IN
10 INVALID
T2OUT
8
R2IN
T2IN
9
9
R1IN
R1OUT
R2OUT
INVALID
10
SSOP
DIP/SSOP
C2+
C2-
C1+
V+
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
V-
V
CC
3
R1IN
R2IN
R3IN
R4IN
R5IN
T1OUT
T2OUT
T3OUT
T3IN
T2IN
T1IN
GND
C1-
4
5
1E/MAX243
MAX3243E
FORCEON
FORCEOFF
INVALID
R2OUTB
R1OUT
6
7
8
9
10
11
12
13
14
R2OUT
R3OUT
R4OUT
R5OUT
SO/SSOP
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
16 ____________________Ma x im In t e g ra t e d P ro d u c t s , 1 2 0 S a n Ga b rie l Drive , S u n n yva le , CA 9 4 0 8 6 4 0 8 -7 3 7 -7 6 0 0
© 1998 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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