MAX232ECDR - Dual RS-232 Driver/Receiver, ESD-Protected | TI
MPN: MAX232ECDR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.62 | $1.62 |
| 10 | $1.42 | $14.20 |
| 100 | $1.18 | $118.00 |
| 500 | $0.96 | $480.00 |
| 1,000 | $0.82 | $820.00 |
MAX232ECDR Overview
What is an RS-232 transceiver? An RS-232 transceiver is a type of serial interface IC that translates logic-level (0 V/5 V or 0 V/3.3 V) signals on the TTL/CMOS side to bipolar RS-232 voltage levels (typically ±5 V to ±15 V) required by the TIA/EIA-232-F standard. RS-232 transceivers sit inside the interface ICs family, between UART/SCI controllers and external DB9/DB25 connectors, enabling legacy PC and industrial serial communication. The MAX232 family historically integrated charge-pump doublers/inverters to generate ±10 V from a single +5 V rail, eliminating the need for a dual supply.
Key features of the MAX232ECDR include on-chip ±10 V generation from a single 5 V supply via four external 1.0 µF charge-pump capacitors, ±30 V receiver input tolerance that exceeds the TIA/RS-232-F specification, low supply current (typically 8 mA), and TTL/CMOS-compatible logic I/O. The integrated IEC 61000-4-2 ESD protection on the RS-232 lines eliminates external TVS arrays in most designs, reducing BOM cost and PCB area. The device operates across the commercial 0 °C to 70 °C temperature range.
The MAX232ECDR uses a CMOS charge-pump voltage doubler/inverter architecture: an internal oscillator drives an external capacitor network that produces V+ (≈ +10 V) and V− (≈ −10 V) rails from the +5 V supply. Drivers translate TTL inputs to RS-232 levels (5 V → +10 V for a mark, 0 V → −10 V for a space); receivers invert and level-shift incoming RS-232 signals back to TTL. The 120 kbit/s data rate supports standard serial links including legacy modems, point-of-sale terminals, and industrial PLC links.
Typical applications include factory automation PLCs and industrial control RS-232 ports, point-of-sale (POS) terminals, legacy PC COM ports and peripherals (mice, barcode scanners), embedded microcontroller UART bridges, and instrumentation serial links. The integrated ESD protection makes it especially suitable for handheld and field-exposed equipment where IEC 61000-4-2 air-discharge events are routine.
When designing with this part, place the four 1.0 µF charge-pump capacitors as close as possible to the C1+, C1−, C2+, C2− pins to minimize ripple and EMI. Note that VCC must rise monotonically and quickly to ensure proper charge-pump startup; an RC delay on VCC is not recommended. Receiver inputs tolerate ±30 V even when VCC = 0 V (true fail-safe), simplifying hot-plug and powered-down interfaces.
This page synthesizes distributor stock and pricing, drop-in same-package alternatives, IEC 61000-4-2 design guidance, and comparator pinout notes not consolidated on the manufacturer datasheet front page.
Drop-in alternatives for MAX232ECDR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MAX232ECDR (same form factor and footprint) — differing in Function, RS-232 Output Voltage Swing.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX232EIDR
✅ Drop-In📋 Reference alternative (not in catalog)
MAX232ECDRG4
✅ Drop-In📋 Reference alternative (not in catalog)
MAX232ECD
✅ Drop-In✓ In Stock
$0.65 / Unit
View Datasheet →MAX3232ECDR
✅ Drop-In📋 Reference alternative (not in catalog)
SP232EEN-L
✅ Drop-In📋 Reference alternative (not in catalog)
MAX232ECDR Specifications
| Function | Dual RS-232 Driver/Receiver |
| Number of Drivers | 2 |
| Number of Receivers | 2 |
| Data Rate | 120 kbit/s |
| Supply Voltage (VCC) | 4.5 V to 5.5 V |
| Supply Current | 8 mA (typ) |
| Receiver Input Voltage Range | ±30 V |
| RS-232 Output Voltage Swing | ±5 V min, ±10 V typ (from charge pump) |
| ESD Protection (HBM) | ±15 kV (per datasheet) |
| ESD Protection (IEC 61000-4-2) | Contact ±8 kV, Air ±15 kV |
| Charge-Pump Capacitors | 4 x 1.0 µF external |
| Operating Temperature Range | 0 °C to 70 °C (commercial) |
| Package | 16-pin SOIC (D) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Standards Compliance | TIA/EIA-232-F, ITU-T V.28 |
MAX232ECDR Pin Configuration
| Pin 1 | C1+ — Charge-pump flying capacitor 1 positive terminal |
| Pin 2 | V+ — Charge-pump generated +10 V supply (driver VCC) |
| Pin 3 | C1- — Charge-pump flying capacitor 1 negative terminal |
| Pin 4 | C2+ — Charge-pump flying capacitor 2 positive terminal |
| Pin 5 | C2- — Charge-pump flying capacitor 2 negative terminal |
| Pin 6 | V- — Charge-pump generated -10 V supply (driver VEE) |
| Pin 7 | T2OUT — RS-232 driver 2 output (to DB-9) |
| Pin 8 | R2IN — RS-232 receiver 2 input (from DB-9) |
| Pin 9 | R2OUT — TTL/CMOS receiver 2 output (to UART) |
| Pin 10 | T2IN — TTL/CMOS driver 2 input (from UART) |
| Pin 11 | T1IN — TTL/CMOS driver 1 input (from UART) |
| Pin 12 | R1OUT — TTL/CMOS receiver 1 output (to UART) |
| Pin 13 | R1IN — RS-232 receiver 1 input (from DB-9) |
| Pin 14 | T1OUT — RS-232 driver 1 output (to DB-9) |
| Pin 15 | GND — Ground |
| Pin 16 | VCC — +5 V supply input |
Typical Applications
MAX232ECDR is suitable for 6 applications: Industrial PLC RS-232 Communication Ports, Point-of-Sale (POS) Terminal Serial Ports, Legacy PC COM Port / Peripheral Interface, Embedded Microcontroller UART-to-RS-232 Bridge, Industrial Instrumentation & Test Equipment Serial Links, Consumer Electronics Service / Debug Ports.
Industrial PLC RS-232 Communication Ports
The MAX232ECDR fits industrial PLC RS-232 ports because it integrates IEC 61000-4-2 ±8 kV contact / ±15 kV air ESD protection on the RS-232 pins, eliminating external TVS arrays in factory environments where air-discharge events are routine. Operating from a single 5 V rail with 1.0 µF charge-pump caps and supporting 120 kbit/s, it bridges the PLC's TTL UART to legacy HMI panels, motor drives, and bar-code scanners. The ±30 V receiver input tolerance handles mis-wired field cabling without latching. Compared to a discrete op-amp + TVS design, the MAX232ECDR cuts BOM cost roughly 40% and shrinks PCB area while meeting IEC 61000-4-2 levels common to EN 61131-2 industrial control equipment.
Recommended
Point-of-Sale (POS) Terminal Serial Ports
POS terminals need robust RS-232 ports for cash drawers, receipt printers, and PIN pads, where cables are repeatedly plugged by staff and exposed to static discharge. The MAX232ECDR's ±15 kV IEC 61000-4-2 air-discharge rating protects against routine customer handling, while its 120 kbit/s speed covers all standard peripheral baud rates. With only four 1.0 µF caps needed and no external charge-pump circuitry, the BOM stays lean for cost-sensitive POS designs. The 16-pin SOIC footprint is drop-in compatible with the MAX232 family for legacy firmware upgrade paths.
Recommended
Legacy PC COM Port / Peripheral Interface
The MAX232ECDR was designed for legacy PC DB-9 COM ports connecting peripherals like serial mice, barcode scanners, and GPS receivers. With ±30 V receiver input tolerance exceeding the TIA/EIA-232-F specification, it survives line transients on hot-plug events. The single 5 V supply matches the PC mainboard 5 VSB rail, and 120 kbit/s data rate supports 115.2 kbaud standard COM-port operation. Integrated ESD protection (HBM ±15 kV) eliminates the need for external TVS diodes on the DB-9 connector footprint, simplifying motherboard design and reducing component count by ~30% versus discrete designs.
Recommended
Embedded Microcontroller UART-to-RS-232 Bridge
Most 5 V microcontrollers (8051, PIC16, ATmega, MSP430 with 5 V I/O) lack native RS-232 levels, requiring an external transceiver. The MAX232ECDR is the industry standard bridge: connect the MCU's UART TX/RX pins to T1IN/R1OUT, and the DB-9 TXD/RXD lines to T1OUT/R1IN. With 120 kbit/s throughput it handles all standard baud rates up to 115.2 k. The single 5 V supply matches the MCU rail and the IEC 61000-4-2 ESD rating protects against bench-test mishaps. Designers can swap directly to the MAX3232ECDR if migrating to a 3.3 V MCU without PCB changes.
Recommended
Industrial Instrumentation & Test Equipment Serial Links
Bench instruments like digital multimeters, oscilloscopes, and spectrum analyzers traditionally offer RS-232 for SCPI command interfaces. The MAX232ECDR's ±15 kV HBM and IEC 61000-4-2 ESD protection on the rear-panel DB-9 port prevents field failures from operator-induced discharge. The ±30 V receiver tolerance handles ground-loop transients common in lab setups, and the 120 kbit/s rate covers SCPI over RS-232. The 0 °C to 70 °C commercial temperature range suits controlled-lab environments; for outdoor test gear choose the MAX232EIDR industrial variant.
Recommended
Consumer Electronics Service / Debug Ports
Many consumer electronics (set-top boxes, A/V receivers, smart-home hubs) expose RS-232 debug ports for factory programming and field service. The MAX232ECDR provides a small-footprint single-chip solution: 5 V from the main supply, four 1.0 µF caps, and a 16-pin SOIC that fits behind the rear panel. The integrated IEC 61000-4-2 ESD rating protects against technician mishandling during service. With 120 kbit/s bandwidth, it accommodates all common firmware-update baud rates. Compared to building the charge pump from discretes, the integrated solution cuts PCB area by ~50% and BOM cost by ~60%.
Recommended
Recommended Products Summary
Engineering reference data for MAX232ECDR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX232EIDR | MAX232ECDRG4 | MAX232ECD | MAX3232ECDR | SP232EEN-L |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | MaxLinear |
| Package | SOIC-16 | SOIC-16 (same) | SOIC-16 (same) | SOIC-16 (same) | SOIC-16 (same) | SOIC-16 (same) |
| Supply Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 3.0 V to 5.5 V | 4.5 V to 5.5 V |
| Data Rate | 120 kbit/s | 120 kbit/s | 120 kbit/s | 120 kbit/s | 250 kbit/s | 120 kbit/s |
| IEC 61000-4-2 ESD | ±8 kV contact, ±15 kV air | ±8 kV contact, ±15 kV air | ±8 kV contact, ±15 kV air | ±8 kV contact, ±15 kV air | ±8 kV contact, ±15 kV air | ±15 kV HBM (IEC rating not specified) |
| Operating Temperature | 0 °C to 70 °C | -40 °C to 85 °C | 0 °C to 70 °C | 0 °C to 70 °C | 0 °C to 70 °C | 0 °C to 70 °C |
| Charge-Pump Capacitors | 4 x 1.0 µF | 4 x 1.0 µF | 4 x 1.0 µF | 4 x 1.0 µF | 4 x 0.1 µF | 4 x 1.0 µF |
| Lifecycle Status | Active | Active | Active | Active | Active | Active |
Key Differentiators
- Integrated IEC 61000-4-2 ESD protection on RS-232 pins (vs MAX232CDR (non-E))
- Wide supply voltage range with 3.3 V to 5 V compatibility (vs MAX232ECDR vs MAX3232ECDR)
- Cross-brand second-source availability from MaxLinear (vs SP232EEN-L (MaxLinear))
Design Notes
Place the four charge-pump capacitors (C1, C2, C3, C4) within 5 mm of the C1+, C1−, C2+, C2− pins and use a wide ground pour under the SOIC to minimize charge-pump ripple. According to TI layout guidelines, lead inductance above ~20 nH per capacitor leg degrades the ±10 V rail regulation and increases EMI. Keep the VCC decoupling capacitor (0.1 µF) within 3 mm of pin 16. Use a ground island around the charge-pump area to prevent switching noise coupling into the receiver sections.
Do not exceed 5.5 V on VCC; the absolute-maximum is 6 V and overvoltage will damage the charge-pump oscillator. Do not omit the four 1.0 µF capacitors - the charge pump cannot generate ±10 V without them. VCC must rise monotonically from 0 V to 4.5 V within 1 ms to ensure proper charge-pump startup; if your upstream rail ramps slowly, add a power-on-reset supervisor or pull-up to keep drivers in high-Z. Receiver inputs are ±30 V tolerant but the drivers' T1OUT/T2OUT pins must NEVER be driven externally above ±15 V or absolute damage will occur.
The MAX232ECDR's internal charge-pump oscillator operates around 250 kHz to 400 kHz and is a common source of EMI near sensitive analog circuits. To minimize radiated emissions: (1) place the four charge-pump capacitors on the same PCB layer with short traces; (2) use a ground guard ring around the charge-pump section; (3) add a 10 µF tantalum bypass on VCC if long cables share the supply; (4) keep T1OUT/T2OUT traces short and routed away from receiver inputs. According to TI, the IC's integrated charge-pump typically produces ~20 mVpp ripple on V+ and V−, which is well below the 5 V receiver threshold hysteresis.
Compliance Information
RoHS and REACH compliant per TI product page; the MAX232ECDR is not AEC-Q100 qualified (it is a commercial-grade part). For automotive RS-232 applications choose MAX3232EIDR-Q1 or equivalent.
