MAX3385ECAP ,15kV ESD-Protected / 3.0V to 5.5V / Low-Power / up to 250kbps / True RS-232 TransceiverELECTRICAL CHARACTERISTICS(V = +3V to +5.5V, C1–C4 = 0.1µF, tested at 3.3V ±10%; C1 = 0.047µF, C2–C ..
MAX3385ECAP-T ,±15kV ESD-Protected, 3.0 to 5.5V, Low-Power, Up to 250kbps, True RS-232 TransceiverFeaturesThe MAX3385E is a 3V-powered EIA/TIA-232 and♦ ESD Protection for RS-232 I/O PinsV.28/V.24 c ..
MAX3385ECWN ,15kV ESD-Protected / 3.0V to 5.5V / Low-Power / up to 250kbps / True RS-232 Transceiverfeatures a 1µA shutdown mode that reduces power con-PART TEMP. RANGE PIN-PACKAGEsumption and extend ..
MAX3385EEAP ,15kV ESD-Protected / 3.0V to 5.5V / Low-Power / up to 250kbps / True RS-232 TransceiverFeaturesThe MAX3385E is a 3V-powered EIA/TIA-232 and ESD Protection for RS-232 I/O PinsV.28/V.24 c ..
MAX3386ECPW ,RS-232 Transceiver With Split Supply Pin for Logic Side 20-TSSOP 0 to 70FEATURESPW OR DW PACKAGE• V Pin for Compatibility With Mixed-VoltageTOP VIEWLSystems Down to 2.5 V ..
MAX3386ECUP ,3.0V / 15kV ESD-Protected RS-232 Transceiver for PDAs and Cell PhonesFeaturesThe MAX3386E 3V-powered EIA/TIA-232 and V.28/V.24♦ V Pin for Compatibility with Mixed-Volta ..
MAX705CPA ,Low-Cost, uP Supervisory CircuitsMAX705–MAX708/MAX813L19-4334; Rev. 5; 9/95Low-Cost, µP Supervisory Circuits_______________
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MAX705CSA ,Low-Cost, uP Supervisory CircuitsGeneral Description _______
MAX705CSA ,Low-Cost, uP Supervisory CircuitsGeneral Description _______
MAX705CSA ,Low-Cost, uP Supervisory CircuitsApplicationsComputers_________________Pin ConfigurationsControllersIntelligent Instruments TOP VIEW ..
MAX3385ECAP-MAX3385ECWN-MAX3385EEAP
15kV ESD-Protected / 3.0V to 5.5V / Low-Power / up to 250kbps / True RS-232 Transceiver
________________General DescriptionThe MAX3385E is a 3V-powered EIA/TIA-232 and
V.28/V.24 communications interface with low power
requirements, high data-rate capabilities, and en-
hanced 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.
The transceiver has a proprietary low-dropout transmit-
ter 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 capac-
itors 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.
The MAX3385Ehas two receivers and two drivers. It
features a 1µA shutdown mode that reduces power con-
sumption and extends battery life in portable systems.
Its receivers can remain active in shutdown mode,
allowing external devices such as modems to be moni-
tored using only 1µA supply current.
The MAX3385E is available in a space-saving SSOP
package in either the commercial (0°C to +70°C) or
extended-industrial (-40°C to +85°C) temperature range.
________________________ApplicationsHand-Held Equipment Battery-Powered
PeripheralsEquipment
Printers
____________________________FeaturesESD Protection for RS-232 I/O Pins
±15kV—Human Body Model
±8kV—IEC 1000-4-2, Contact Discharge
±15kV—IEC 1000-4-2, Air-Gap DischargeLatchup Free300µA Supply Current1µA Low-Power Shutdown with Receivers Active250kbps Guaranteed Data Rate250µs Time to Exit Shutdown with 3kΩLoad on V+6V/µs Guaranteed Slew RateMeets EIA/TIA-232 Specifications Down to 3.0V
MAX3385E
±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
Pin Configurations19-1437; Rev 1; 10/99
†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.
Typical Operating Circuit
Ordering Information
MAX3385E
±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
ABSOLUTE MAXIMUM RATINGS
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= 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.
VCCto 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, SHDNto GND..............................................-0.3V to +6V
R_IN to GND.....................................................................±25V
Output Voltages
T_OUT to GND...............................................................±13.2V
R_OUT.....................................................-0.3V to (VCC+ 0.3V)
Short-Circuit Duration, T_OUT to GND.......................Continuous
Continuous Power Dissipation (TA= +70°C)
20-Pin SSOP (derate 8.00mW/°C above +70°C)..........640mW
18-Pin SO (derate 9.52mW/°C above +70°C)...............762mW
Operating Temperature Ranges
MAX3385ECAP....................................................0°C to +70°C
MAX3385ECWN...................................................0°C to +70°C
MAX3385EEAP.................................................-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.
MAX3385E
±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
Note 2:Transmitter skew is measured at the transmitter zero cross points.
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= TMINto TMAX,
unless otherwise noted. Typical values are at TA= +25°C.)
TIMING 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= TMINto TMAX,
unless otherwise noted. Typical values are at TA= +25°C.)
MAX3385E
±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
__________________________________________Typical Operating Characteristics(VCC= +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩand CL, TA = +25°C, unless otherwise noted.)
______________________________________________________________Pin Description
MAX3385E
±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
_______________Detailed Description
Dual Charge-Pump Voltage Converter The MAX3385E’s internal power supply consists of a
regulated dual charge pump that provides output volt-
ages of +5.5V (doubling charge pump) and -5.5V
(inverting charge pump), over the 3.0V to 5.5V VCC
range. The charge pump operates in discontinuous
mode; if the output voltages are less than 5.5V, the
charge pump is enabled, and 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 (Figure 1).
RS-232 Transmitters The transmitters are inverting level translators that con-
vert CMOS-logic levels to ±5.0V EIA/TIA-232 levels.
The MAX3385E transmitters guarantee a 250kbps data
rate with worst-case loads of 3kΩin parallel with 1000pF,
providing compatibility with PC-to-PC communication
software (such as LapLink™). Transmitters can be paral-
leled to drive multiple receivers or mice.
The MAX3385E’s transmitters are disabled and the out-
puts are forced into a high-impedance state when the
device is in shutdown (SHDN= GND). The MAX3385E
permits the outputs to be driven up to ±12V in shut-
down.
The transmitter inputs do not have pull-up resistors.
Connect unused inputs to GND or VCC.
RS-232 Receivers The receivers convert RS-232 signals to CMOS-logic
output levels (Table 1).
Shutdown Mode Supply current falls to less than 1µA in shutdown mode
(SHDN= low). When shut down, the device’s charge
pumps are shut off, V+ is pulled down to VCC, V- is
pulled to ground, and the transmitter outputs are dis-
abled (high impedance). The time required to exit shut-
Figure 1. Slew-Rate Test Circuits
Laplink is a trademark of Traveling Software.
down is typically 100µs, as shown in Figure 2. Connect
SHDNto VCCif the shutdown mode is not used.
±15kV ESD Protection As 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
MAX3385E have extra protection against static electric-
ity. 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, shutdown, and
powered down. After an ESD event, Maxim’s “E” ver-
sions keep working without latchup, whereas compet-
ing RS-232 products can latch and must be powered
down to remove latchup.
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:±15kV using the Human Body Model±8kV using the contact-discharge method specified
in IEC 1000-4-2±15kV using IEC 1000-4-2’s air-gap method.
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 3a shows the Human Body Model, and Figure
3b 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,
which is then discharged into the test device through a
1.5kΩresistor.
IEC 1000-4-2 The IEC 1000-4-2 standard covers ESD testing and per-
formanceof finished equipment; it does not specifically
refer to integrated circuits. The MAX3385E helps you
design equipment that meets Level 4 (the highest level) of
IEC 1000-4-2, without the need for additional ESD-pro-
tection 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 with-
stand voltage measured to IEC 1000-4-2 is generally
lower than that measured using the Human Body
Model. Figure 4a shows the IEC 1000-4-2 model, and
Figure 4b shows the current waveform for the 8kV IEC
1000-4-2 Level 4 ESD contact-discharge test.
The air-gap test involves approaching the device with a
charged probe. The contact-discharge method con-
nects the probe to the device before the probe is ener-
gized.
Machine Model The Machine Model for ESD tests all pins using a
200pF storage capacitor and zero discharge resis-
tance. Its objective is to emulate the stress caused by
contact that occurs with handling and assembly during
manufacturing. Of course, all pins require this protec-
tion 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
can be used. The charge pump requires 0.1µF capaci-
tors for 3.3V operation. For other supply voltages, refer
to Table 2 for required capacitor values. Do not use val-
MAX3385E
±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
