MAX3238ECAI ,+3.0V to +5.5V / 10nA / 250kbps RS-232 Transceivers with 15kV ESD-Protected I/O and Logic PinsELECTRICAL CHARACTERISTICS(V = +3.0V to +5.5V, C1–C4 = 0.1µF (tested at 3.3V ±5%), C1–C4 = 0.22µF ( ..
MAX3238ECAI ,+3.0V to +5.5V / 10nA / 250kbps RS-232 Transceivers with 15kV ESD-Protected I/O and Logic PinsApplicationsR1IN8 21 R1OUTCellular Data Cables PeripheralsR2IN 9 20R2OUTModems Data Cradles1910 T4I ..
MAX3238ECAI ,+3.0V to +5.5V / 10nA / 250kbps RS-232 Transceivers with 15kV ESD-Protected I/O and Logic PinsFeaturesThe MAX3238E/MAX3248E transceivers use Maxim’s Enhanced ESD Protection on RS-232 I/O Pins ..
MAX3238ECAI ,+3.0V to +5.5V / 10nA / 250kbps RS-232 Transceivers with 15kV ESD-Protected I/O and Logic Pinsapplications. A proprietary, high-effi-PART TEMP. RANGE PIN-PACKAGEciency, dual charge-pump power s ..
MAX3238ECAI+ ,+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers with ±15kV ESD-Protected I/O and Logic PinsELECTRICAL CHARACTERISTICS(V = +3.0V to +5.5V, C1–C4 = 0.1µF (tested at 3.3V ±5%), C1–C4 = 0.22µF ( ..
MAX3238ECAI+T ,+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers with ±15kV ESD-Protected I/O and Logic PinsFeaturesThe MAX3238E/MAX3248E transceivers use Maxim’s ♦ Enhanced ESD Protection on RS-232 I/O Pins ..
MAX6760TALTD3+ ,Low-Power, Single/Dual-Voltage Window DetectorsApplicationsMAX6754UK_D_-T -40°C to +125°C 5 SOT23-5MAX6755UK_D_-T -40°C to +125°C 5 SOT23-5● Telec ..
MAX6762TATAD3-T ,Vcc: 3.3 V, Vcc:adj, active timeout period:185 ms, low-power single/dual-voltage window detectorApplications Small SOT23 and TDFN PackagesTelecommunications Power MeteringOrdering InformationNet ..
MAX6763UT+ ,Low-Power, Single/Dual-Voltage Window DetectorsElectrical Characteristics(V = 1.0V to 6.0V, V = 0 to 6.0V (MAX6760–MAX6762), T = -40°C to +125°C, ..
MAX6765TTLD2+ ,Automotive Micropower Linear Regulators with SupervisorELECTRICAL CHARACTERISTICS(V = 14V, C = 0.1µF, C = 10µF, T = T = -40°C to +125°C, unless otherwise ..
MAX6765TTSD2/V+T ,Automotive Micropower Linear Regulators with SupervisorApplicationsEP+Automotive1 23IndustrialTelecomTDFNTypical Application Circuit and Selector Guide a ..
MAX6765TTSD2+ ,Automotive Micropower Linear Regulators with SupervisorFeatures♦ Low 31µA Quiescent CurrentThe MAX6765–MAX6774B are low-quiescent-current,♦ 4V to 72V Wide ..
MAX3238ECAI-MAX3238EEAI
+3.0V to +5.5V / 10nA / 250kbps RS-232 Transceivers with 15kV ESD-Protected I/O and Logic Pins
General DescriptionThe MAX3238E/MAX3248E transceivers use Maxim’s
revolutionary AutoShutdown Plus™ feature to achieve
10nA supply current. These devices shut down the on-
board power supply and drivers when they do not sense
a valid signal transition on either the receiver or transmit-
ter inputs. This occurs if the RS-232 cable is disconnect-
ed or if the transmitters of the connected peripheral are
turned off. The devices turn on again when a valid transi-
tion is applied to any RS-232 receiver or transmitter input.
AutoShutdown Plus automatically achieves this power
savings through its on-board circuitry, as no changes are
required to the existing BIOS or operating system.
All RS-232 inputs and outputs, as well as the logic I/O
pins, have enhanced ESD protection to ±15kV. The addi-
tional ESD protection on the logic I/O pins makes the
MAX3238E/MAX3248E ideal for cell phone data cable
applications because it eliminates the need for costly
external TransZorb™or protection schemes.
The MAX3238E/MAX3248E contain five drivers and three
receivers and are 3V-powered EIA/TIA-232 and V.28/V.24
communication interfaces intended for cell phones, data
cables, and modem applications. A proprietary, high-effi-
ciency, 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 250kbps provides compatibility
with popular software for communicating with personal
computers.
The MAX3238E and the MAX3248E differ only in their
input logic thresholds. The MAX3238E has standard logic
thresholds, while the MAX3248E has low-level logic
thresholds of 0.6V to 1.2V, which are ideal for 1.8V sys-
tems.
The transmitter inputs, FORCEON, and FORCEOFFhave
a 400kΩactive positive feedback resistor. Once driven to
a valid logic level, they will retain this level if the driving
signal is removed or goes high impedance. Unused
transmitter and logic inputs may be left unconnected. The
MAX3238E/MAX3248E can operate with supply voltages
ranging from +3.0V to +5.5V.
Applications
FeaturesEnhanced ESD Protection on RS-232 I/O Pins and
All Logic Pins
±15kV—Human Body Model
±8kV—IEC 1000-4-2 Contact Discharge
±15kV—IEC 1000-4-2 Air-Gap DischargeGuaranteed Data Rate: 250kbps 10nA Low-Power Shutdown with Receivers ActiveSchmitt Triggers on All InputsFlow-Through PinoutMeets EIA/TIA-232 Specifications Down to 3.0VGuaranteed 6V/µs Slew RateLow-Level Logic Thresholds (MAX3248E)RS-232-Compatible Outputs to 2.7V
MAX3238E/MAX3248E
+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers
with ±15kV ESD-Protected I/O and Logic Pins
___________________Pin Configuration19-1632; Rev 1; 6/01
Cellular Data Cables
Modems
Battery-Powered Equipment
Peripherals
Data Cradles
Printers
Typical Operating Circuit appears at end of data sheet.
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.
MAX3238E/MAX3248E
+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers
with ±15kV ESD-Protected I/O and Logic Pins
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VCC= +3.0V to +5.5V, C1–C4 = 0.1µF (tested at 3.3V ±5%), C1–C4 = 0.22µF (tested at 3.3V ±10%), C1 = 0.047µF, and
C2–C4 = 0.33µF (tested at 5.0V ±10%), TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
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..............................-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 (one at a time)............................................Continuous
Continuous Power Dissipation (TA= +70°C)
28-Pin SSOP (derate 9.52mW/°C above +70°C).........762mW
Operating Temperature Ranges
MAX3238ECAI/MAX3248ECAI...........................0°C to +70°C
MAX3238EEAI/MAX3248EEAI.........................-40°C to +85°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................+300°C
Note 1:V+ and V- can have a maximum magnitude of +7V, but their absolute difference can not exceed +13V.
MAX3238E/MAX3248E
+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers
with ±15kV ESD-Protected I/O and Logic Pins
ELECTRICAL CHARACTERISTICS (continued)(VCC= +3.0V to +5.5V, C1–C4 = 0.1µF (tested at 3.3V ±5%), C1–C4 = 0.22µF (tested at 3.3V ±10%), C1 = 0.047µF, and
C2–C4 = 0.33µF (tested at 5.0V ±10%), TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
__________________________________________Typical Operating Characteristics(VCC= +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ, TA= +25°C, unless otherwise noted.)
MAX3238E/MAX3248E
+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers
with ±15kV ESD-Protected I/O and Logic Pins
ELECTRICAL CHARACTERISTICS (continued)(VCC= +3.0V to +5.5V, C1–C4 = 0.1µF (tested at 3.3V ±5%), C1–C4 = 0.22µF (tested at 3.3V ±10%), C1 = 0.047µF, and
C2–C4 = 0.33µF (tested at 5.0V ±10%), TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
Note 2:The transmitter inputs have an active positive feedback resistor. The input current goes to zero when the inputs are at the
supply rails.
Note 3:During AutoShutdown only, a transmitter/receiver edge is defined as a transition through the transmitter/receiver input logic
wake-up thresholds.
MAX3238E/MAX3248E
+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers
with ±15kV ESD-Protected I/O and Logic Pins
Typical Operating Characteristics (continued)(VCC= +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ, TA= +25°C, unless otherwise noted.)
______________________________________________________________Pin Description
MAX3238E/MAX3248E
+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers
with ±15kV ESD-Protected I/O and Logic Pins
_______________Detailed Description
Dual Charge-Pump Voltage ConverterThe MAX3238E/MAX3248Es’ 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 fly-
ing capacitor (C1, C2) and a reservoir capacitor (C3,
C4) to generate the V+ and V- supplies.
RS-232 TransmittersThe MAX3248E transmitters are inverting level translators
that convert a logic low of 0.6V and logic high of 1.2V to
5.0V EIA/TIA-232 levels. The MAX3238E transmitters are
inverting level translators that convert CMOS-logic levels
to 5.0V EIA/TIA-232 levels. The MAX3238E/MAX3248E
transmitters both guarantee a 250kbps data rate with
worst-case loads of 3kΩin parallel with 1000pF, provid-
ing compatibility with PC-to-PC communication software
(such as LapLink™). Transmitters can be paralleled to
drive multiple receivers. Figure 1 shows a complete sys-
tem connection.
When FORCEOFFis driven to ground, the transmitters
and receivers are disabled and the outputs go high
impedance, except for R1OUTB. When the Auto-
Shutdown 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
high-impedance state, but the receivers remain active.
When the power is off, the MAX3238E/MAX3248E per-
mit the outputs to be driven up to ±12V.
The transmitter inputs, FORCEON and FORCEOFF,
havea 400kΩactive positive-feedback resistor. Once
driven to a valid logic level, they will retain this level if
the driving signal is removed or goes high-impedance.
Unused transmitter inputs may be left unconnected.
RS-232 ReceiversThe receivers convert RS-232 signals to CMOS-logic
output levels. All receivers have inverting three-state
outputs and are inactive in shutdown (FORCEOFF)
(Table 1). The MAX3238E/MAX3248Ealso feature an
extra, always-active noninverting output, R1OUTB. This
extra output monitors receiver activity while the other
receivers are high impedance, allowing Ring Indicator
to be monitored without forward biasing other devices
connected to the receiver outputs. This is ideal for sys-
tems where VCCis set to 0 in shutdown to accommo-
date peripherals, such as UARTs (Figure 2).
Table 1. Output Control Truth TableX = Don’t care
*Time since last receiver or transmitter input transition.
MAX3238E/MAX3248E
+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers
with ±15kV ESD-Protected I/O and Logic Pins
AutoShutdown Plus ModeA 10nA supply current is achieved with Maxim’s
AutoShutdown Plus feature, which operates when
FORCEOFFis low and FORCEON is high. When the
MAX3238E/MAX3248E sense no valid signal transitions
on all receiver and transmitter inputs for 30s, the on-
board power supply and drivers are shut off, reducing
supply current to 1µA. If the receiver inputs are in the
invalid range (-0.3V < R_IN < +0.3V) and the transmit-
ter inputs are at GND or VCC, supply current is further
reduced to 10nA. This occurs if the RS-232 cable is
disconnected or if the connected peripheral transmit-
ters are turned off. 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 sys-
tem. The INVALIDoutput is high when the receivers are
active. Since INVALIDindicates the receiver inputs’
condition, it can be used in any mode (Figure 3).
