MAX232D - 5V Dual RS-232 Transceiver, 120kbps, SOIC-16 | TI
Référence : MAX232D ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $1.32 | $1,32 |
| 10 | $1.13 | $11,30 |
| 100 | $0.92 | $92,00 |
| 500 | $0.81 | $405,00 |
| 1 000 | $0.74 | $740,00 |
| 3 000 | $0.62 | $1 860,00 |
MAX232D Présentation
A dual EIA-232 (RS-232) line driver/receiver is an interface IC that bridges TTL/CMOS logic levels (0-5V) and the much higher bipolar voltage swings (+/-5V to +/-15V) required by legacy serial-port standards. By generating these higher rails internally from a single low-voltage supply, dual RS-232 transceivers eliminate the need for a separate negative or high-voltage power rail, simplifying board design and reducing BOM cost. In the broader product hierarchy, the MAX232D belongs to the EIA-232 transceiver family (RS-232 transceiver), then to the Interface ICs category, then to Integrated Circuits, ultimately serving as an enabler of UART-to-DB9 connectivity in microcontroller- and FPGA-based systems.
Key features of the MAX232D include TIA/EIA-232-F and ITU V.28 compliance, +/-30V receiver input tolerance that survives mis-wired cables and transients, an integrated 5V-to-+/-10V charge pump with four external 1 uF capacitors (charge-pump flying capacitors), two drivers and two receivers in a single 16-pin SOIC package, and ESD protection on the RS-232 bus pins (per the family spec). The 120 kbps data rate is more than adequate for serial console, modem, and industrial telemetry traffic, while the wide 4.5V to 5.5V supply range accommodates standard 5V regulated rails and battery-powered designs with headroom.
Architecturally, the charge pump uses a voltage-doubler plus an inverting charge pump clocked from an internal oscillator (typically 125 kHz to 250 kHz range), which provides the +10V and -10V rails that drive the RS-232 output stages. The receivers use Schmitt-trigger inputs with hysteresis for noise immunity on long cables. Compared to using a discrete transistor-based level shifter or a +-12V linear supply, the MAX232D solution occupies roughly 30 mm x 6 mm of board area and removes one power supply from the design.
Typical applications include microcontroller UART-to-RS-232 conversion on serial ports of industrial PLCs, point-of-sale (POS) terminals, embedded debug consoles for firmware development, and legacy PC RS-232 COM ports. The MAX232D is also commonly deployed in factory automation where 5V microcontrollers need to drive RS-232-controlled motor drives or sensors. Other uses include test and measurement equipment (scopes and analyzers with serial ports), legacy networking gear with DB-9 management ports, and education/development boards (Arduino shield, FPGA dev kit UART bridges).
When designing with the MAX232D, observe charge-pump capacitor polarity: TI recommends 1 uF (or larger) low-ESR ceramic capacitors on each of the four charge-pump pins (C1+, C1-, C2+, C2-, V+, V-). Place the capacitors as close to the IC as possible to minimize parasitic resistance and ringing. Avoid long cable stubs on T1OUT/T2OUT pins, and add TVS diodes for additional ESD protection if the application involves frequent cable mating/unmating.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Alternatives de remplacement direct pour MAX232D — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec MAX232D (même facteur de forme et même empreinte) — différant par Operating Temperature, Package, Function.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
MAX232ECD
✅ Remplacement direct✓ En stock
$0.65 / unité
Voir la fiche technique →MAX232DR
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX3232CD
✅ Remplacement direct✓ En stock
$0.7831 / unité
Voir la fiche technique →ST232CDR
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
SP232ACN-L
✅ Remplacement direct✓ En stock
Contactez-nous pour le prix
Voir la fiche technique →ADM232AARNZ
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX232IN
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX232D Spécifications
| Fonction | Dual RS-232 line driver/receiver (2/2 transceiver, full) |
| Débit de données | 120 kbps |
| Supply Voltage (Vcc) | 4.5 V to 5.5 V |
| Courant d'alimentation | 8 mA typical |
| Receiver Input Levels | +/-30 V tolerant |
| Number of Drivers | 2 |
| Number of Receivers | 2 |
| Charge Pump Capacitors Required | 4 external (typically 1 uF) |
| Generated RS-232 Rails | Approx. +/-9 V to +/-10 V from internal charge pump |
| Compliance | TIA/EIA-232-F, ITU V.28 |
| Température de fonctionnement | 0 C to +70 C (commercial grade) |
| Boîtier | SOIC-16 (D) |
| Type de montage | Surface Mount |
| Statut RoHS | Compliant |
| Interchangeable With | Maxim MAX232 (industry-standard die) |
Configuration des broches de MAX232D
| Broche 1 | C1+ — Charge-pump flying capacitor 1, positive terminal |
| Broche 2 | V+ — Charge-pump +9V (approximately) output |
| Broche 3 | C2+ — Charge-pump flying capacitor 2, positive terminal |
| Broche 4 | C2- — Charge-pump flying capacitor 2, negative terminal |
| Broche 5 | V- — Charge-pump -9V (approximately) output |
| Broche 6 | T1OUT — Driver 1 RS-232 output |
| Broche 7 | T2OUT — Driver 2 RS-232 output |
| Broche 8 | R2IN — Receiver 2 RS-232 input (+/-30V tolerant) |
| Broche 9 | R2OUT — Receiver 2 TTL/CMOS output |
| Broche 10 | T2IN — Driver 2 TTL/CMOS input |
| Broche 11 | T1IN — Driver 1 TTL/CMOS input |
| Broche 12 | R1OUT — Receiver 1 TTL/CMOS output |
| Broche 13 | R1IN — Receiver 1 RS-232 input (+/-30V tolerant) |
| Broche 14 | GND — Ground |
| Broche 15 | Vcc — +5V supply (4.5V-5.5V) |
| Broche 16 | C1- — Charge-pump flying capacitor 1, negative terminal |
Applications typiques
MAX232D convient pour 6 applications: Microcontroller UART-to-RS-232 Console, Industrial PLC and Factory Automation Ports, Point-of-Sale (POS) Terminal Interface, Embedded Debug and Development Boards, Legacy Networking and Telecom Gear, Test and Measurement Front Panels.
Microcontroller UART-to-RS-232 Console
The MAX232D bridges a 5V microcontroller's UART (TX/RX at 0-5V CMOS levels) to a TIA/EIA-232-F RS-232 port at +/-9V. With a 120 kbps data rate, it exceeds the 115200 baud commonly used by serial debug consoles, and the +/-30V receiver input tolerance protects the MCU from mis-wired or short-cabled conditions. The integrated charge pump removes the need for a separate negative or high-voltage rail, collapsing the BOM to one IC plus four 1 uF caps and 100 nF decoupling.
Recommandé
Industrial PLC and Factory Automation Ports
In factory PLC backplanes and machine controllers, the MAX232D serves as the on-board RS-232 transceiver for legacy COM-port connectivity to motor drives, HMIs, and bar-code scanners. Its TIA/EIA-232-F compliance guarantees interoperability with third-party industrial equipment, while the integrated charge pump simplifies the 24V-to-5V power architecture (one local 5V rail per PLC island). Operating at 5V supply and 8 mA typical quiescent current, it adds little thermal load to sealed control cabinets.
Recommandé
Point-of-Sale (POS) Terminal Interface
POS terminals and electronic cash registers still rely on RS-232 for receipt printers, cash-drawer kickers, and legacy barcode scanners. The MAX232D's 5V single-supply operation matches the POS mainboard's logic rail, its 120 kbps capacity handles even fast receipt-print streams, and its commercial temperature grade suits indoor retail environments. The SOIC-16 package keeps the BOM small enough to fit inside the cramped POS mainboard alongside the printer port and Ethernet stack.
Recommandé
Embedded Debug and Development Boards
FPGA development boards (e.g., Altera/Intel, Xilinx) and Arduino-class microcontroller shields use the MAX232D to expose a legacy DB-9 serial port to host PCs for firmware downloads and printf-style debug logs. At 115200 baud (the typical debug rate) the MAX232D's 120 kbps ceiling is non-binding, and the SOIC-16 footprint is small enough to fit on even the most space-constrained FPGA carrier boards. Two drivers and two receivers also enable simultaneous hardware-flow-control if needed.
Recommandé
Legacy Networking and Telecom Gear
RS-232 remains the debug/management interface on routers, switches, base stations, and other networking gear with DB-9 console ports. The MAX232D, with its +/-30V receiver input tolerance, tolerates the surges that occur when field engineers hot-plug cables into live equipment. The integrated charge-pump eliminates a costly inverting DC-DC converter from the BOM, and the 5V supply aligns directly with the system's auxiliary 5V rail.
Recommandé
Test and Measurement Front Panels
Benchtop oscilloscopes, spectrum analyzers, and signal generators use the MAX232D for SCPI-command control over RS-232 from a host PC. Because test instruments often use long cable runs (>1.5 m), the +/-30V receiver input tolerance prevents latch-up, and the 120 kbps data rate handles even dense waveform transfers. The 5V supply is easily derived from the instrument's internal logic rail, simplifying mechanical packaging and thermal management.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour MAX232D — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | MAX232ECD | MAX232DR | MAX3232CD | ST232CDR | SP232ACN-L | ADM232AARNZ |
|---|---|---|---|---|---|---|---|
| Package | SOIC-16 (D) | SOIC-16 (D) - same | SOIC-16 (D) - same | SOIC-16 (D) - same | SOIC-16 (D) - same | SOIC-16 (N) - same footprint | SOIC-16 (N) - same footprint |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | STMicroelectronics | MaxLinear (Sipex) | Analog Devices (Maxim) |
| Supply Voltage | 4.5V - 5.5V | 4.5V - 5.5V | 4.5V - 5.5V | 3.0V - 5.5V (wider) | 4.5V - 5.5V | 4.5V - 5.5V | 4.5V - 5.5V |
| Data Rate | 120 kbps | 120 kbps | 120 kbps | 120 kbps | 120 kbps | 120 kbps | 120 kbps |
| Drivers / Receivers | 2 / 2 | 2 / 2 | 2 / 2 | 2 / 2 | 2 / 2 | 2 / 2 | 2 / 2 |
| Receiver Input Levels | +/-30V | +/-30V | +/-30V | +/-30V | +/-30V | +/-30V | +/-30V |
| Operating Temperature | 0 C to +70 C | -40 C to +85 C (industrial) | 0 C to +70 C | 0 C to +70 C | 0 C to +70 C | 0 C to +70 C | -40 C to +85 C (industrial) |
| Charge-Pump Capacitors | 4 x 1 uF external | 4 x 1 uF external | 4 x 0.1 uF external | 4 x 1 uF external | 4 x 1 uF external | 4 x 1 uF external | |
| Approx. Unit Price (qty 100) | ~$0.92 | ~$1.15 | ~$0.92 | ~$1.05 | ~$0.45 | ~$0.55 | ~$1.85 |
Principaux différenciateurs
- Industry-standard MAX232 die reference (vs MAX232IN (PDIP-16))
- Better cross-brand second-sourcing than competitors (vs ST232CDR)
- 5V-optimized charge pump vs. wide-range MAX3232 (vs MAX3232CD)
Notes de conception
Place the four charge-pump capacitors (C1, C2 between C1+/C1- and C2+/C2-; reservoir caps on V+ and V-) within 2-3 mm of their respective IC pins using the shortest possible traces. Use X5R or X7R ceramic with 1 uF nominal (10V rating recommended for V+/V- reservoirs). Long traces increase parasitic inductance, which causes the charge pump to ring and degrade the +/-9V rail regulation, leading to sluggish RS-232 driver edges at 120 kbps.
The MAX232D dissipates roughly 200-400 mW in normal operation depending on load and switching activity, well within the SOIC-16 package's thermal limits. No heatsink is required even in sealed industrial enclosures at ambient temperatures up to 70 C. Ensure that the GND pin (14) and Vcc pin (15) each have a 100 nF decoupling capacitor placed within 5 mm to suppress supply-rail ringing from the charge pump's switching currents.
The MAX232D's RS-232 outputs are designed to drive cables of up to 3-5 meters at 120 kbps. For longer cable runs (10 m+), insert a series 50-100 ohm resistor at each T1OUT/T2OUT pin to damp reflections, or add a TVS diode (e.g. PESD5V0S1BA) at the DB-9 connector for additional ESD protection. The receivers have built-in hysteresis for noise immunity on marginal signals; adding external filtering is rarely necessary for legitimate RS-232 voltages.
Do not connect the MAX232D to a 3.3V-only supply without level-shifting the MCU's UART lines to 5V CMOS first - the input thresholds assume TTL/5V CMOS logic, and 3.3V signals may not cross the receiver's positive-going threshold reliably. Use the MAX3232 (3.0V-5.5V) for 3.3V-only systems. Estimated: V_IH_min for the MAX232D driver inputs is around 2.0V per the family datasheet, so 3.3V signals typically pass, but 1.8V signals do not.
Informations de conformité
RoHS and REACH compliant per TI product page. Not AEC-Q100 qualified - use MAX232E variant or industrial-grade equivalents for automotive. Halogen-free status not explicitly stated in retrieved web data.
