Datasheet

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General Description

The MAX3430 fault-protected RS-485 transceiver features

±80V protection from overvoltage signal faults on commu-

nication bus lines. Each device contains one driver and

one receiver, and the output pins can withstand faults,

with respect to ground, of up to ±80V. Even if the faults

occur when the transceiver is active, shut down, or pow-

ered off, the device will not be damaged. The MAX3430

operates from a 3.3V supply and features a slew-rate-lim-

ited driver that minimizes EMI and reduces reflections

caused by improperly terminated cables, allowing error-

free data transmission at data rates up to 250kbps. The

MAX3430 has a 1/4-unit-load receiver input impedance

allowing up to 128 transceivers on a single bus and fea-

tures fail-safe circuitry, which guarantees a logic-high

receiver output when the receiver inputs are open.

Hot-swap circuitry eliminates false transitions on the

data cable during circuit initialization or connection to a

live backplane. Short-circuit current limiting and ther-

mal-shutdown circuitry protect the driver against exces-

sive power dissipation.

The MAX3430 is available in 8-pin SO and 8-pin PDIP

packages, and is specified over commercial and indus-

trial temperature ranges.

Applications

RS-422/RS-485 Communications

Lighting Systems

Industrial-Control Local Area Networks

Profibus Applications

Multimaster RS-485 Networks

Features

♦ ±80V Fault Protection

♦ ±12kV ESD Protection

♦ +3.3V Operation

♦ Internal Slew-Rate Limiting

♦ 250kbps Data Rate

♦ Allows Up to 128 Transceivers on the Bus

♦ -7V to +12V Common-Mode Input Voltage Range

♦ True Fail-Safe Inputs

♦ Hot-Swap Input Structure on DE

♦ Available in 8-Pin SO and PDIP Packages

MAX3430

±80V Fault-Protected, Fail-Safe,

1/4-Unit Load, +3.3V RS-485 Transceiver

________________________________________________________________ Maxim Integrated Products 1

Pin Configuration and Typical Operating Circuit

Ordering Information

CC 0.1µF

GND

MAX3430

19-2756; Rev 1; 4/03

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

PART TEMP RANGE PIN-PACKAGE

MAX3430CPA 0°C to +70°C 8 Plastic DIP

MAX3430CSA 0°C to +70°C 8 SO

MAX3430EPA -40°C to +85°C 8 Plastic DIP

MAX3430ESA -40°C to +85°C 8 SO

TOP VIEW

GND

DIP/SO

Summary of content (13 pages)

PAGE 1
9-2756; Rev 1; 4/03 ±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V RS-485 Transceiver Features ♦ ±80V Fault Protection ♦ ±12kV ESD Protection ♦ +3.
PAGE 2
MAX3430 ±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V RS-485 Transceiver ABSOLUTE MAXIMUM RATINGS (All voltages are referenced to GND.) VCC ........................................................................................+5V RE, DE, DI...................................................-0.3V to (VCC + 0.3V) Driver Output Voltage (A, B) (Note 1) ..................................±80V Receiver Input Voltage (A, B) (Note 1) ................................±80V RO ................................
PAGE 3
±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V RS-485 Transceiver MAX3430 DC ELECTRICAL CHARACTERISTICS (continued) (VCC = +3.3V ±10%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +3.3V and TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS RECEIVER LOGIC VCC 0.6 V RO Output High Voltage VOH IO = -1.6mA RO Output Low Voltage VOL IO = 1mA 0.
PAGE 4
MAX3430 ±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V RS-485 Transceiver DRIVER SWITCHING CHARACTERISTICS (VCC = +3.3V ±10%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +3.3V and TA = +25°C.
PAGE 5
±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V RS-485 Transceiver SHUTDOWN CURRENT vs. TEMPERATURE 175 3 2 150 16 OUTPUT CURRENT (mA) SHUTDOWN CURRENT (µA) 4 20 MAX3430 toc02 RE = 0 DE = VCC SUPPLY CURRENT (mA) 200 MAX3430 toc01 5 OUTPUT CURRENT vs. RECEIVER OUTPUT LOW VOLTAGE 125 100 75 50 MAX3430 toc03 SUPPLY CURRENT vs. TEMPERATURE 12 8 4 1 25 0 0 -40 -20 0 20 40 60 80 0 20 40 60 0 80 1.0 1.5 2.0 2.5 3.0 OUTPUT CURRENT vs.
PAGE 6
±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V RS-485 Transceiver MAX3430 Test Circuits/Timing Diagrams A 3V RL 2 CL DE A DI VOD VO RL B RL CL VOC 2 B Figure 2. Driver Timing Test Circuit Figure 1. Driver DC Test Load VCC RL = 500Ω VCC DI 0 S1 VCC/2 0 OR +3V tDPLH OUT D CL 50pF tDPHL 1/2 VO GENERATOR B 50Ω VO A 1/2 VO VOD = V (A) - V (B) 80% VO 80% 20% VCC 20% tDR DE tDF VCC/2 tDZL, tDZL(SHDN) 0 tDLZ VCC tSKEW = |tDPLH - tDPHL| OUT VOM = (VOL + VCC)/2 0.
PAGE 7
±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V RS-485 Transceiver B VID R A CL 20pF VOH tRPHL tRPLH 1.5V 0 RO VOL Figure 6. Receiver Propagation Delays +1.5V S3 -1.5V VID R S1 R 1kΩ RO VCC S2 CL 20pF GENERATOR 50Ω 3V RE 0 3V S1 OPEN S2 CLOSED S3 = +1.5V RE 1.5V 0 tRZH, tRZH(SHDN) tRZL, tRZL (SHDN) VOH RO VCC RO VOH/2 (VOL + VCC)/2 0 VOL 3V RE 1.5V 0 S1 CLOSED S2 OPEN S3 = -1.5V 3V S1 OPEN S2 CLOSED S3 = +1.5V RE 1.5V 0 S1 CLOSED S2 OPEN S3 = -1.
PAGE 8
±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V RS-485 Transceiver MAX3430 Pin Description PIN NAME 1 RO Receiver Output FUNCTION 2 RE Receiver Output Enable. RO is enabled when RE is low; RO is high impedance when RE is high. The device enters a low-power shutdown mode if RE is high and DE is low. 3 DE Driver Output Enable. Driving DE high enables the driver outputs. Pulling DE low puts the driver outputs in a high-impedance state.
PAGE 9
±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V RS-485 Transceiver Driver The driver accepts a single-ended, logic-level input (DI) and transfers it to a differential, RS-485 level output (A and B). Driving DE high enables the driver, while pulling DE low places the driver outputs (A and B) into a high-impedance state. Receiver The receiver accepts a differential, RS-485 level input (A and B), and transfers it to a single-ended, logic-level output (RO).
PAGE 10
MAX3430 ±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V RS-485 Transceiver stage, provides immediate protection against short circuits over the whole common-mode voltage range. The second, a thermal shutdown circuit, forces the driver outputs into a high-impedance state if the die temperature exceeds +160°C. Normal operation resumes when the die temperature cools by +140°C, resulting in a pulsed output during continuous short-circuit conditions. VCC 15µs TIMER TIMER 5.
PAGE 11
±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V RS-485 Transceiver 128 Transceivers on the Bus The standard RS-485 receiver input impedance is 12kΩ (one-unit load), and a standard driver can drive up to 32-unit loads. The MAX3430 transceiver 1/4-unit-load receiver input impedance (48kΩ) allows up to 128 transceivers connected in parallel on one communication line. Connect any combination of these devices, and/or other RS-485 devices, for a maximum of 32 unit loads to the line.
PAGE 12
Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) DIM A A1 B C e E H L N E H INCHES MILLIMETERS MAX MIN 0.069 0.053 0.010 0.004 0.014 0.019 0.007 0.010 0.050 BSC 0.150 0.157 0.228 0.244 0.016 0.050 MAX MIN 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 1.27 BSC 3.80 4.00 5.80 6.20 0.40 SOICN .EPS MAX3430 ±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.
PAGE 13
±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V RS-485 Transceiver PDIPN.EPS 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.