MAX3231EEBV-T ,15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSPFeaturesThe MAX3230E/MAX3231E are +2.5V to +5.5V pow-♦ 6 x 5 Chip-Scale Packaging (UCSP)ered EIA/TI ..
MAX3232 ,3.0V to 5.5V, Low-Power, Up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF External Capacitorsfeatures a 1µA shutdown modethat reduces power consumption and extends batterylife in portable syst ..
MAX3232+CSE ,3.0V to 5.5V / Low-Power / up to 1Mbps / True RS-232 Transceivers Using Four 0.1F External Capacitorsapplications. Both these devices featureMAX3222CUP 0°C to +70°C 20 TSSOPa shutdown mode in which al ..
MAX3232CAE ,3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF External CapacitorsFeatures♦ For Smaller Packaging:The MAX3222/MAX3232/MAX3237/MAX3241 trans-MAX3228E/MAX3229E: +2.5V ..
MAX3232CAE ,3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF External Capacitorsapplications. Both these devices feature+Denotes lead-free package.a shutdown mode in which all rec ..
MAX3232CAE+ ,3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF External Capacitorsapplications. Both these devices feature+Denotes lead-free package.a shutdown mode in which all rec ..
MAX6662MSA+T ,12-Bit + Sign Temperature Sensor with SPI-Compatible Serial InterfaceFeaturesThe MAX6662 is a 12-bit + sign temperature sensor ● 12-Bit + Sign, 0.0625°C Resolutioncombi ..
MAX6662MSA+T ,12-Bit + Sign Temperature Sensor with SPI-Compatible Serial InterfaceElectrical Characteristics(V = +3V to +5.5V, T = -55°C to +125°C, unless otherwise noted. Typical v ..
MAX6665ASA45 ,Fan Controller/Driver with Factory- Programmed Temperature ThresholdsApplications+125°CNotebook and Desktop Computers -40°C toMAX6665ASA55 8 SO-EP* 55°C+125°CServers-40 ..
MAX6665ASA55+T ,Fan Controller/Driver with Factory-Programmed Temperature ThresholdsApplications+125°CNotebook and Desktop Computers -40°C toMAX6665ASA55 8 SO-EP* 55°C+125°CServers-40 ..
MAX666CPA ,Dual Mode⑩ 5V/Programmable Vicropower Voltage RegulatorsFeatures
The MAX663/664/666 CMOS voltage regulators have . Dual Mode Operation: Fixed +5V or Adlus ..
MAX666CSA ,Dual Mode⑩ 5V/Programmable Vicropower Voltage RegulatorsFeatures
The MAX663/664/666 CMOS voltage regulators have . Dual Mode Operation: Fixed +5V or Adlus ..
MAX3231EEBV-T
15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP
General DescriptionThe MAX3230E/MAX3231E are +2.5V to +5.5V pow-
ered EIA/TIA-232 and V.28/V.24 communications inter-
faces with low power requirements, high data-rate
capabilities, and enhanced electrostatic discharge
(ESD) protection, in a chip-scale package (UCSP™).
All transmitter outputs and receiver inputs are protect-
ed 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.
The MAX3230E/MAX3231E achieve a 1µA supply cur-
rent with Maxim’s AutoShutdown™ feature. They save
power without changing the existing BIOS or operating
systems by entering low-power shutdown mode when
the RS-232 cable is disconnected, or when the trans-
mitters of the connected peripherals are off.
The transceivers have a proprietary low-dropout trans-
mitter output stage, delivering RS-232-compliant perfor-
mance from a +3.1V to +5.5V supply, and RS-232-
compatible performance with a supply voltage as low
as +2.5V. The dual charge pump requires only four,
small 0.1µF capacitors for operation from a +3.0V sup-
ply. Each device is guaranteed to run at data rates of
250kbps while maintaining RS-232 output levels.
The MAX3230E/MAX3231E offer a separate power-sup-
ply input for the logic interface, allowing configurable
logic levels on the receiver outputs and transmitter
inputs. Operating over a +1.65V to VCCrange, VLpro-
vides the MAX3230E/MAX3231E compatibility with mul-
tiple logic families.
The MAX3231E contains one receiver and one transmit-
ter. The MAX3230E contains two receivers and two trans-
mitters. The MAX3230E/MAX3231E are available in tiny
chip-scale packaging and are specified across the
extended industrial (-40°C to +85°C) temperature range.
ApplicationsPersonal Digital Assistants
Cell-Phone Data Lump Cables
Set-Top Boxes
Hand-Held Devices
Cell Phones
Features6 x 5 Chip-Scale Packaging (UCSP)ESD Protection for RS-232 I/O Pins
±15kV—IEC 1000-4-2 Air-Gap Discharge
±8kV—IEC 1000-4-2 Contact Discharge
±15kV—Human Body Model1µA Low-Power AutoShutdown250kbps Guaranteed Data RateMeet EIA/TIA-232 Specifications Down to +3.1VRS-232 Compatible to +2.5V Allows Operation
from Single Li+ CellSmall 0.1µF CapacitorsConfigurable Logic Levels
MAX3230E/MAX3231E
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
Typical Operating Circuits19-3250; Rev 0; 5/04
Ordering Information UCSP is a trademark of Maxim Integrated Products, Inc.
AutoShutdown is a trademark of Maxim Integrated Products, Inc.
Typical Operating Circuits continued at end of data sheet.
Pin Configurations appear at end of data sheet.
MAX3230E/MAX3231E
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
ABSOLUTE MAXIMUM RATINGSStresses 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.
VCCto GND...........................................................-0.3V to +6.0V
V+ to GND.............................................................-0.3V to +7.0V
V- to GND..............................................................+0.3V to -7.0V
V+ to |V-| (Note 1)................................................................+13Vto GND..............................................................-0.3V to +6.0V
Input Voltages
T_IN_, FORCEON, FORCEOFFto GND.....-0.3V to (VL+ 0.3V)
R_IN_ to GND...................................................................±25V
Output Voltages
T_OUT to GND...............................................................±13.2V
R_OUT INVALIDto GND............................-0.3V to (VL+ 0.3V)INVALIDto GND.........................................-0.3V to (VCC+ 0.3V)
Short-Circuit Duration T_OUT to GND........................Continuous
Continuous Power Dissipation (TA= +70°C)
6 ✕5 UCSP (derate 10.1mW/°C above +70°C)...........805mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Bump Temperature (soldering)
Infrared (15s)...............................................................+200°C
Vapor Phase (20s).......................................................+215°C
ELECTRICAL CHARACTERISTICS(VCC= +2.5V to +5.5V, VL= +1.65V to +5.5V, C1–C4 = 0.1µF, tested at +3.3V ±10%, TA= TMINto TMAX. Typical values are at TA=
+25°C, unless otherwise noted.) (Note 2)
Note 1:V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
MAX3230E/MAX3231E
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
ELECTRICAL CHARACTERISTICS (continued)(VCC= +2.5V to +5.5V, VL= +1.65V to +5.5V, C1–C4 = 0.1µF, tested at +3.3V ±10%, TA= TMINto TMAX. Typical values are at TA=
+25°C, unless otherwise noted.) (Note 2)
MAX3230E/MAX3231E
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
Note 2:VCCmust be greater than VL.
TIMING CHARACTERISTICS(VCC= +2.5V to +5.5V, VL= +1.65V to +5.5V, C1–C4 = 0.1µF, tested at +3.3V ±10%, TA= TMINto TMAX. Typical values are at TA=
Typical Operating Characteristics(VCC= +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩand CL, TA= +25°C, unless otherwise noted.)
MAX3230E/MAX3231E
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
Typical Operating Characteristics (continued)(VCC= +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩand CL, TA= +25°C, unless otherwise noted.)
MAX3230E/MAX3231E
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
Detailed Description
Dual Mode™ Regulated Charge-Pump
Voltage ConverterThe MAX3230E/MAX3231E internal power supply con-
sists of a dual-mode regulated charge pump. For sup-
ply voltages above +3.7V, the charge pump generates
+5.5V at V+ and -5.5V at V-. The charge pumps oper-
ate 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.
For supply voltages below +2.85V, the charge pump
generates +4.0V at V+ and -4.0V at V-. The charge
pumps operate in a discontinuous mode. If the output
voltages are less than ±4.0V, the charge pumps are
enabled. If the output voltages exceed ±4.0V, 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- supply voltages.
Voltage Generation in the
Switchover RegionThe MAX3230E/MAX3231E include a switchover circuit
between these two modes that have approximately
400mV of hysteresis around the switchover point. The
hysteresis is shown inFigure 1. This large hysteresis
eliminates mode changes due to power-supply bounce.
For example, a three-cell NiMh battery system starts at
VCC= +3.6V, and the charge pump generates an out-
put voltage of ±5.5V. As the battery discharges, the
MAX3230E/MAX3231E maintain the outputs in regula-
tion until the battery voltage drops below +3.1V. The
output regulation points then change to ±4.0V.
When VCCis rising, the charge pump generates an out-
put voltage of ±4.0V, while VCCis between +2.5V and
+3.5V. When VCCrises above the switchover voltage of
+3.5V, the charge pump switches modes to generate
an output of ±5.5V.
Table 1 shows different supply schemes and their oper-
ating voltage ranges.
RS-232 TransmittersThe transmitters are inverting level translators that
convert CMOS logic levels to RS-232 levels. The
MAX3230E/MAX3231E automatically reduce the
RS-232-compliant levels (±5.5V) to RS-232-compatible
levels (±4.0V) when VCCfalls below approximately
+3.1V. The reduced levels also reduce supply-current
requirements, extending battery life. Built-in hysteresis
of approximately 400mV for VCCensures that the RS-
Dual Mode is a trademark of Maxim Integrated Products, Inc.
MAX3230E/MAX3231E
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP232 output levels do not change if VCCis noisy or has a
sudden current draw causing the supply voltage to drop
slightly. The outputs return to RS-232-compliant levels
(±5.5V) when VCCrises above approximately +3.5V.
The MAX3230E/MAX3231E transmitters guarantee a
250kbps data rate with worst-case loads of 3kΩin par-
allel with 1000pF.
When FORCEOFFis driven to ground, the transmitters
and receivers are disabled and the outputs become
high impedance. When the AutoShutdown circuitry
senses that all receiver and transmitter inputs are inac-
tive for more than 30µs, the transmitters are disabled
and the outputs go to a high-impedance state. When
the power is off, the MAX3230E/MAX3231E permit the
transmitter outputs to be driven up to ±12V.
The transmitter inputs do not have pullup resistors.
Connect unused inputs to GND or VL.
RS-232 ReceiversThe MAX3230E/MAX3231E receivers convert RS-232
signals to logic-output levels. All receivers have invert-
ing tri-state outputs and can be active or inactive. In
shutdown (FORCEOFF= low) or in AutoShutdown, the
MAX3230E/MAX3231E receivers are in a high-imped-
ance state (Table 2).
The MAX3230E/MAX3231E feature an INVALIDoutput
that is enabled low when no valid RS-232 signal levels
have been detected on any receiver inputs. INVALIDis
functional in any mode (Figures 2 and 3).
AutoShutdownThe MAX3230E/MAX3231E achieve a 1µA supply cur-
rent with Maxim’s AutoShutdown feature, which oper-
ates when FORCEON is low and FORCEOFFis high.
When these devices sense no valid signal levels on all
receiver inputs for 30µs, the on-board charge pump
and drivers are shut off, reducing VCCsupply current to
1µA. This occurs if the RS-232 cable is disconnected or
the connected peripheral transmitters 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.
Table 2and Figure 2csummarize the MAX3230E/
MAX3231E operating modes. FORCEON and FORCEOFFoverride AutoShutdown. When neither con-
trol is asserted, the IC selects between these states
automatically, based on receiver input levels. Figures
2a, 2b, and3adepict valid and invalid RS-232-receiver
levels. Figures 3a and3bshow the input levels and tim-
ing diagram for AutoShutdown operation.
A system with AutoShutdown can require time to wake
up. Figure 4shows a circuit that forces the transmitters
on for 100ms, allowing enough time for the other sys-
tem to realize that the MAX3230E/MAX3231E are
active. If the other system transmits valid RS-232 sig-
nals within that time, the RS-232 ports on both systems
remain enabled.
When shut down, the device’s charge pumps are off,
V+ is pulled to VCC, V- is pulled to ground, and the
transmitter outputs are high impedance. The time
required to exit shutdown is typically 100µs (Figure 3b).
Logic Supply InputUnlike other RS-232 interface devices, where the receiv-
er outputs swing between 0 and VCC, the MAX3230E/
MAX3231E feature a separate logic supply input (VL)
that sets VOHfor the receiver outputs. The transmitter
inputs (T_IN), FORCEON, and FORCEOFF, are also
referred to VL. This feature allows maximum flexibility in
interfacing to different systems and logic levels. Connectto the system’s logic supply voltage (+1.65V to
+5.5V), and bypass it with a 0.1µF capacitor to GND. If
the logic supply is the same as VCC, connect VLto VCC.
Always enable VCCbefore enabling the VLsupply. VCC
must be greater than or equal to the VLsupply.
Software-Controlled ShutdownIf direct software control is desired, connect FORCEOFF
and FORCEON together to disable AutoShutdown. The
microcontroller (µC) then drives FORCEOFFand
FORCEON like a SHDNinput. INVALIDcan be used to
alert the µC to indicate serial data activity.
±15kV ESD ProtectionAs with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electro-
static discharges encountered during handling and
assembly. The driver outputs and receiver inputs of the
MAX3230E/MAX3231E have extra protection against
static electricity. Maxim’s engineers have developed
state-of-the-art structures to protect these pins against
ESD of ±15kV without damage. The ESD structures
withstand high ESD in all states: normal operation, shut-
down, and power-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.
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:
1) ±15kV using the Human Body Model
2) ±8kV using the Contact Discharge method specified
in IEC 1000-4-2
3) ±15kV using the IEC 1000-4-2 Air-Gap method
ESD Test ConditionsESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents
test setup, test methodology, and test results.
Human Body ModelFigure 5ashows the Human Body Model. Figure 5b
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 interest,
MAX3230E/MAX3231E
±15kV ESD-Protected +2.5V to +5.5V
RS-232 Transceivers in UCSP
