MAX3223EUP ,1レA Supply Current, True +3V to +5.5V RS 232 Transceiver with AutoShutdownFeaturesThe MAX3221/MAX3223/MAX3243 achieve 1µA supply 1µA Supply Current Achieved with AutoShutdo ..
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MAX3223EUP+T ,±15kV ESD-Protected, 1µA, 3.0V to 5.5V, 250kbps, RS-232 Transceivers with AutoShutdownELECTRICAL CHARACTERISTICS(V = +3.0V to +5.5V, C1–C4 = 0.1µF (Note 2), T = T to T , unless otherwis ..
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MAX663ESA ,Dual Mode⑩ 5V/Programmable Vicropower Voltage RegulatorsELECTRICAL CHARACTERISTICS, MAX663 AND MAX666 (continued)
(VIN = HN, VOUT = HN, TA = +25''C, unl ..
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includes on-chip ..
MAX663MJA/883B ,Dual Mode™ 5V Programmable Micropower Voltage RegulatorsELECTRICAL CHARACTERISTICS, MAX663 AND MAX666
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MAX6640AEE ,2-Channel Temperature Monitor with Dual Automatic PWM Fan-Speed ControllerELECTRICAL CHARACTERISTICS(V = +3.0V to +5.5V, T = 0°C to +125°C, unless otherwise noted. Typical v ..
MAX6640AEE ,2-Channel Temperature Monitor with Dual Automatic PWM Fan-Speed ControllerApplicationsOrdering InformationDesktop ComputersOPERATING MEASUREMENT PIN-PARTNotebook ComputersRA ..
MAX3223CAP-MAX3223CPP-MAX3223CUP-MAX3223EAP-MAX3223EPP-MAX3223EUP
1レA Supply Current, True +3V to +5.5V RS 232 Transceiver with AutoShutdown
_______________General DescriptionThe MAX3221/MAX3223/MAX3243 achieve 1µA supply
current with Maxim’s revolutionary AutoShutdown™ fea-
ture. When the MAX3221/MAX3223/MAX3243 do not
sense a valid signal level on their receiver inputs, the
on-board power supply and drivers shut down. This
occurs if the RS-232 cable is disconnected or if the
transmitters of the connected peripheral are turned off.
The system turns on again when a valid level is applied
to any RS-232 receiver input. As a result, the system
saves power without changes to the existing BIOS or
operating system.
The MAX3221/MAX3223/MAX3243 transceivers are 3V-
powered EIA/TIA-232 and V.28/V.24 communications
interfaces intended for notebook computer applica-
tions. A proprietary, high-efficiency, dual charge-pump
power supply and a low-dropout transmitter combine to
deliver true RS-232 performance from a single +3.0V to
+5.5V supply. A guaranteed data rate of 120kbps pro-
vides compatibility with popular software for communi-
cating with personal computers.
The MAX3221/MAX3223/MAX3243 require only 0.1µF
capacitors in 3.3V operation, and can operate from input
voltages ranging from +3.0V to +5.5V. They are ideal for
3.3V-only systems, mixed 3.3V and 5.0V systems, or
5.0V-only systems that require true RS-232 performance.
The MAX3221 is a 1-driver/1-receiver 16-pin SSOP ver-
sion of the 20-pin MAX3223 (2-driver/2-receiver). The
MAX3243 3-driver/5-receiver, complete serial port is
ideal for notebook or subnotebook computers. The
MAX3243 includes one complementary always-active
receiver. This receiver can monitor an external device
(such as a modem) in shutdown, without forward bias-
ing the protection diodes in a UART that may have VCC
completely removed.
____________________________Features1µA Supply Current Achieved with AutoShutdownSmall 0.1µF CapacitorsTrue RS-232 Operation from VCC= +3.0V to +5.5VMeets EIA/TIA-562 Specifications Down to 2.7VGuaranteed 120kbps Data Rate6V/µs Min Guaranteed Slew RateSmallest Single-Supply RS-232 Transceiver
(MAX3221)Guaranteed Mouse Driveability (MAX3243)Small TSSOP Package(MAX3223/MAX3243)
________________________ApplicationsNotebook, Subnotebook, and Palmtop Computers
Battery-Powered Equipment
Hand-Held Equipment
Peripherals
Printers
MAX3221/MAX3223/MAX3243*
1µA Supply-Current, True +3V to +5.5V
RS-232 Transceivers with AutoShutdown19-0306; Rev 6; 3/99
* 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; and other patents pending.
†Future product—contact factory for availability.
AutoShutdown is a trademark of Maxim Integrated Products.
Pin Configurations appear at end of data sheet.
Typical Operating Circuits appear at end of data sheet.
_____________________Selector Guide
MAX3221/MAX3223/MAX3243
1µA Supply-Current, True +3V to +5.5V
RS-232 Transceivers with AutoShutdown
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VCC= +3.0V to +5.5V, C1–C4 = 0.1µF (Note 2), TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
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.
VCC...........................................................................-0.3V to +6V
V+ (Note 1)...............................................................-0.3V to +7V
V- (Note 1)...............................................................+0.3V to -7V
V+ + |V-|(Note 1).................................................................+13V
Input Voltages
T_IN, FORCEOFF, FORCEON, EN(MAX3223)......-0.3V to +6V
R_IN...................................................................................±25V
Output Voltages
T_OUT.............................................................................±13.2V
R_OUT, INVALID......................................-0.3V to (VCC+ 0.3V)
Short-Circuit Duration
T_OUT......................................................................Continuous
Continuous Power Dissipation (TA= +70°C)
16-Pin SSOP (derate 7.14mW/°C above +70°C)...........571mW
16-Pin TSSOP (derate 6.70mW/°C above +70°C).........533mW
20-Pin Plastic DIP (derate 11.11mW/°C above +70°C)....889mW
20-Pin SSOP (derate 8.00mW/°C above +70°C)...........640mW
20-Pin TSSOP DIP (derate 7.00mW/°C above +70°C).....559mW
28-Pin Wide SO (derate 12.50mW/°C above +70°C)............1W
28-Pin SSOP (derate 9.52mW/°C above +70°C)...........762mW
28-Pin TSSOP (derate 8.70mW/°C above +70°C).........696mW
Operating Temperature Ranges
MAX32_ _C_ _.......................................................0°C to +70°C
MAX32_ _E_ _....................................................-40°C to +85°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10sec).............................+300°C
Note 1:V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
MAX3221/MAX3223/MAX3243
1µA Supply-Current, True +3V to +5.5V
RS-232 Transceivers with AutoShutdown
ELECTRICAL CHARACTERISTICS (continued)(VCC= +3.0V to +5.5V, C1–C4 = 0.1µF (Note 2), TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
Note 2:C1–C4 = 0.1µF, tested at 3.3V ±10%. C1 = 0.047µF, C2–C4 = 0.33µF, tested at 5.0V ±10%.
MAX3221/MAX3223/MAX3243
1µA Supply-Current, True +3V to +5.5V
RS-232 Transceivers with AutoShutdown
__________________________________________Typical Operating Characteristics(VCC= +3.3V, 235kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ, TA= +25°C, unless otherwise noted.)
MAX3221/MAX3223/MAX3243
1µA Supply-Current, True +3V to +5.5V
RS-232 Transceivers with AutoShutdown
______________________________________________________________Pin Description
_______________Detailed Description
Dual Charge-Pump Voltage ConverterThe MAX3221/MAX3223/MAX3243’s internal power
supply consists of a regulated dual charge pump that
provides output voltages of +5.5V (doubling charge
pump) and -5.5V (inverting charge pump), regardless
of the input voltage (VCC) over the +3.0V to +5.5V
range. The charge pumps operate in a discontinuous
mode: if the output voltages are less than 5.5V, the
charge pumps are enabled; if the output voltages
exceed 5.5V, the charge pumps are disabled. Each
charge pump requires a flying capacitor (C1, C2) and
a reservoir capacitor (C3, C4) to generate the V+ and
V- supplies.
RS-232 TransmittersThe transmitters are inverting level translators that con-
vert CMOS-logic levels to 5.0V EIA/TIA-232 levels. They
guarantee a 120kbps data rate with worst-case loads of
3kΩin parallel with 1000pF, providing compatibility with
PC-to-PC communication software (such as Laplink™).
Typically, the MAX3221/MAX3223/MAX3243 can oper-
ate at data rates of 235kbps. Transmitters can be paral-
leled to drive multiple receivers or mice (MAX3243).
Figure 1 shows a complete system connection.
When FORCEOFFis driven to ground, or the Auto-
Shutdown circuitry senses invalid voltage levels at all
receiver inputs, the transmitters are disabled and the
outputs are forced into a high-impedance state.
MAX3221/MAX3223/MAX3243
1µA Supply-Current, True +3V to +5.5V
RS-232 Transceivers with AutoShutdown
RS-232 ReceiversThe MAX3221/MAX3223/MAX3243’s receivers convert
RS-232 signals to CMOS-logic output levels. All
receivers have one inverting three-state output. In shut-
down (FORCEOFF= low) or in AutoShutdown, the
MAX3221/MAX3223’s receivers are active (Table 1).
Driving ENhigh places the receiver(s) in a high-imped-
ance state. The MAX3243’s receivers are high imped-
ance when the part is shut down.
The MAX3243 has an always-active complementary
output (R2OUTB). R2OUTB is an extra output that mon-
itors receiver activity while the other receivers are high
impedance. This allows Ring Indicator to be monitored
without forward biasing other devices connected to the
receiver outputs. This is ideal for systems where VCCis
set to 0V in shutdown to accommodate peripherals,
such as UARTs (Figure 2).
MAX3221/MAX3223/MAX3243
1µA Supply-Current, True +3V to +5.5V
RS-232 Transceivers with AutoShutdown
AutoShutdownA 1µA supply current is achieved with Maxim’s new
AutoShutdown feature, which operates when
FORCEON is low and FORCEOFFis high. When the
MAX3221/MAX3223/MAX3243 sense no valid signal
levels on all receiver inputs for 30µs, the on-board
power supply and drivers are shut off, reducing supply
current to 1µA. This occurs if the RS-232 cable is dis-
connected or the connected peripheral transmitters are
turned off. The system turns on again when a valid level
is applied to any RS-232 receiver input. As a result, the
system saves power without changes to the existing
BIOS or operating system. When using AutoShutdown,
the INVALIDoutput is high when the device is on and
low when the device is shut down. Because INVALID
indicates the receiver inputs’ condition, it can be used
in any mode (Figure 3).
Table 2 and Figure 3c summarize the MAX3221/
MAX3223/MAX3243operating modes. FORCEON and
FORCEOFFoverride the automatic circuitry and force
the transceiver into its normal operating state or into its
low-power standby state. When neither control is assert-
ed, 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.
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
Figure 3a. MAX32_ _ Entering 1µA Supply Mode via
AutoShutdown
*Note:If the part is in AutoShutdown mode (FORCEOFF= VCC,
FORCEON = GND), it is shut down if no valid RS-232
levels are present on all receiver inputs.
MAX3221/MAX3223/MAX3243
1µA Supply-Current, True +3V to +5.5V
RS-232 Transceivers with AutoShutdownother system to realize that the MAX3221/MAX3223/
MAX3243is awake. If the other system outputs valid
RS-232 signals within that time, the RS-232 ports on
both systems remain enabled.
When shut down, the device’s charge pumps are turned
off, V+ decays to VCC, V- decays to ground, and the
transmitter outputs are disabled (high impedance). The
time required to exit shutdown is typically 100µs (Figure
5b).
Software-Controlled ShutdownIf direct software control is desired, INVALIDcan be
used to indicate DTR or Ring Indicator signal. TieFORCEOFFand FORCEON together to bypass Auto-
Shutdown so the line acts like a SHDNinput.
___________Applications Information
Capacitor SelectionThe capacitor type used for C1–C4 is not critical for
proper operation; either polarized or nonpolarized
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).When using the minimum required capacitor values,
make sure the capacitor value does not degrade
excessively with temperature. If in doubt, use capaci-
tors with a larger nominal value. The capacitor’s equiva-
lent series resistance (ESR) usually rises at
low temperatures and influences the amount of ripple
on V+ and V-.
Table 2. AutoShutdown Logic
