Table of Contents
- 1.0 MAX230CWP Datasheet & Specifications
- 1.1 What is the MAX230CWP?
- 1.2 Core Specifications (Voltage, Speed)
- 1.3 How an RS-232 Line Driver Works: The 5V Charge Pump
- 2.0 MAX230CWP Pinout (20-pin SOIC/PDIP)
- 2.1 CWP Package Pin Configuration
- 2.2 Pin Functions Explained (Charge Pump, I/O)
- 3.0 MAX230CWP Applications and Design
- 3.1 Typical Application Circuit Diagram
- 3.2 Common Use Cases & Obsolescence Status
- 3.3 Finding an Equivalent or Replacement
- 4.0 MAX230CWP vs. MAX232: A Key Comparison
- 4.1 Driver/Receiver Count: 5 vs. 2
- 4.2 When to Choose the MAX230CWP
- 5.0 Frequently Asked Questions (FAQ)
In an age of USB-C and 5G, it’s easy to forget the workhorse that built the modern connected world: RS-232. You might be surprised to learn that in 2024, the market for industrial and legacy systems that rely on this rugged serial standard is still massive. This presents a common engineering challenge: how do you get your modern 5V microcontroller to talk to an old-school machine that expects ±10V signals? The answer is a line driver, and for decades, one of the most reliable has been the MAX230CWP RS-232 line driver.
You've probably seen this chip's more famous cousin, the MAX232, but the MAX230 is a different beast for a specific purpose. If you're an engineer maintaining legacy equipment, a designer building a new industrial interface, or a supply chain manager trying to source this mature part, you need a no-fluff technical guide.
This article is your deep dive into the MAX230CWP datasheet. We’ll cover its specifications, pinout, application circuits, and the critical differences between it and the MAX232, so you can make informed design and purchasing decisions.
1.0 MAX230CWP Datasheet & Specifications
The MAX230CWP is a legacy component, originally from Maxim Integrated (now part of Analog Devices). It's an integrated circuit designed to solve one problem perfectly: interfacing 5V logic with the high-voltage world of RS-232.
1.1 What is the MAX230CWP?
At its core, the MAX230CWP is a 5-driver, 0-receiver RS-232 line driver. Let's break that down:
- 5-Driver: It contains five independent transmitter circuits. Each one takes a standard 0V to 5V logic signal (TTL/CMOS) from your microcontroller (like an Arduino or PIC) and converts it into a robust ±10V signal, compliant with the RS-232 standard.
- 0-Receiver: This is the key. Unlike a transceiver, this chip has no receiver circuits. It is for transmit-only applications.
- Single 5V Supply: It achieves this high-voltage magic using only a single +5V power supply.
1.2 Core Specifications (Voltage, Speed)
When you're sourcing this part, these are the datasheet specs that matter. The "CWP" suffix refers to the Commercial temperature range (0°C to 70°C) and the Wide SOIC (W) package.
| Specification | Value |
|---|---|
| Device Function | 5x RS-232 Drivers (Transmitters) |
| Supply Voltage (Vcc) | +5V (±10%) |
| Number of Drivers | 5 |
| Number of Receivers | 0 |
| Data Rate (Typ) | 120 kbps (up to 200 kbps) |
| Logic I/O Level | 5V TTL/CMOS Compatible |
| RS-232 Output Swing (Typ) | ±10V (with 5kΩ load) |
| Supply Current (Typ) | 10 mA (unloaded) |
| Package | 20-Pin SOIC-W (CWP) / PDIP |
| ESD Protection | ±15kV (Human Body Model) |
1.3 How an RS-232 Line Driver Works: The 5V Charge Pump
How does a 5V chip create ±10V? The answer is an internal dual charge pump.
A charge pump is a circuit that uses capacitors to store and transfer energy, effectively "pumping" a voltage up or down. The MAX230CWP uses two of them:
- Voltage Doubler: The first charge pump takes the +5V input and doubles it to approximately +10V, storing it on an external capacitor.
- Voltage Inverter: The second charge pump takes that new +10V and inverts it to approximately -10V, storing it on another external capacitor.
This gives the chip the positive and negative "rails" it needs to generate the RS-232 signals, all from your single 5V supply. This is why the circuit requires four external capacitors to function.
2.0 MAX230CWP Pinout (20-pin SOIC/PDIP)
The MAX230CWP pinout is straightforward. It comes in a 20-pin package, most commonly a Wide SOIC (Small-Outline Integrated Circuit).
2.1 CWP Package Pin Configuration
2.2 Pin Functions Explained (Charge Pump, I/O)
The 20 pins are grouped into power, charge pump, logic inputs, and RS-232 outputs.
| Pin(s) | Name | Type | Function |
|---|---|---|---|
| 1, 6 | C1+, C2+ | Charge Pump | Capacitor 1 Positive Terminal |
| 2, 5 | C1-, C2- | Charge Pump | Capacitor 1 Negative Terminal |
| 3 | C2+ | Charge Pump | Capacitor 2 Positive Terminal |
| 4 | C2- | Charge Pump | Capacitor 2 Negative Terminal |
| 7, 8, 9, 10, 11 | T5IN - T1IN | Logic Input | 5V TTL/CMOS Logic Inputs (from MCU) |
| 12, 13, 14, 19, 20 | T5OUT - T1OUT | RS-232 Output | RS-232 Voltage Level Outputs (to DB-9) |
| 15 | GND | Power | Ground (0V) |
| 16 | VCC | Power | +5V Supply Input |
| 17 | V+ | Charge Pump | Generated +10V Rail |
| 18 | V- | Charge Pump | Generated -10V Rail |
3.0 MAX230CWP Applications and Design
So, you have this chip. How do you actually use it? The application circuit is remarkably simple and is a classic design pattern seen in millions of devices.
3.1 Typical Application Circuit Diagram
The standard application requires the MAX230CWP chip and five capacitors.
- C1, C2, C3, C4: These are the charge pump capacitors. The datasheet typically recommends values between 1.0µF and 10µF.
- C5: This is the power supply bypass capacitor (e.g., 0.1µF to 1.0µF) placed as close to the VCC and GND pins as possible.
3.2 Common Use Cases & Obsolescence Status
You will primarily find the MAX230CWP RS-232 line driver in legacy or industrial equipment.
- Industrial Automation: Driving serial commands to multiple PLCs, HMIs, or motor controllers from a single master.
- Data Loggers: Transmitting data from a 5V microcontroller to a PC or serial printer.
- Point-of-Sale (POS) Systems: Controlling serial printers, barcode scanners, and credit card readers.
- Telecom Equipment: Older serial-based configuration and management ports.
Note on Obsolescence: The MAX230CWP is a mature, legacy component. While it is not recommended for brand new designs (which would likely use USB or Ethernet), it is in high demand for the MRO (Maintenance, Repair, and Operations) market. Millions of devices that use this chip are still in service, and a reliable source of replacements is critical.
3.3 Finding an Equivalent or Replacement
If you're looking for an MAX230CWP equivalent, you must be careful.
- Direct Replacement: The only 100% drop-in replacement is another MAX230CWP.
- Functional Replacement: If you are redesigning a board, you could use a modern 5-driver chip.
- Common Mistake: You cannot use a MAX232 as a direct replacement. The pinout is completely different, and it only has 2 drivers, not 5.
4.0 MAX230CWP vs. MAX232: A Key Comparison
This is the most common point of confusion for engineers. Both are famous 5V RS-232 interface chips from Maxim, but they serve different purposes.
4.1 Driver/Receiver Count: 5 vs. 2
The difference is simple:
- MAX230: 5 Drivers (Transmitters), 0 Receivers.
- MAX232: 2 Drivers (Transmitters), 2 Receivers.
The MAX232 is a transceiver, meaning it can send and receive. The MAX230 is a transmitter (or "driver") only.
| Feature | MAX230CWP | MAX232 (Common variant) |
|---|---|---|
| Function | Line Driver (Transmitter) | Transceiver |
| Drivers (TX) | 5 | 2 |
| Receivers (RX) | 0 | 2 |
| Pins | 20 | 16 |
| Charge Pump Caps | 4 (External) | 4 (External) |
| Use Case | Transmit-only applications | Full-duplex serial port |
4.2 When to Choose the MAX230CWP
You would choose the MAX230CWP over a MAX232 in very specific situations:
- You have a "master" device that only needs to send commands to multiple "slave" devices.
- You need to drive 3, 4, or 5 separate RS-232 lines and don't need to receive data back.
- You are repairing a board that has this exact part number and pinout.
Conclusion: The Specialist for Legacy Communication
The MAX230CWP RS-232 Line Driver is a perfect example of a specialized, legacy component that still holds immense value. It's not a general-purpose transceiver like the MAX232; it's a high-density transmitter designed for applications that need to talk, but not listen, on multiple serial lines.
As we move further into the 2020s, the challenge for industrial and long-life equipment manufacturers is not innovation, but sustainment. Having a reliable supply of legacy parts like the MAX230CWP is what keeps billion-dollar industries running. If you are servicing, repairing, or manufacturing products that rely on this classic workhorse, you need a sourcing partner who understands its role.
For all your legacy and modern interface needs, from the MAX230CWP to the latest transceivers, AichipLink is your trusted partner. Explore our full category of Interface ICs contact us today for a quote on the MAX230CWP and keep your systems communicating.
Written by Jack Elliott from AIChipLink.
AIChipLink, one of the fastest-growing global independent electronic components distributors in the world, offers millions of products from thousands of manufacturers, and many of our in-stock parts is available to ship same day.
We mainly source and distribute integrated circuit (IC) products of brands such as Broadcom, Microchip, Texas Instruments, Infineon, NXP, Analog Devices, Qualcomm, Intel, etc., which are widely used in communication & network, telecom, industrial control, new energy and automotive electronics.
Empowered by AI, Linked to the Future. Get started on AIChipLink.com and submit your RFQ online today!
Frequently Asked Questions
What is the MAX230CWP?
The MAX230CWP is a 5-driver, 0-receiver RS-232 line driver and transmitter IC from Maxim Integrated. It is designed to convert 5V TTL/CMOS logic signals into the ±10V levels required for the RS-232 serial communication standard. It operates from a single +5V supply, using an internal charge pump.
What is the difference between MAX230CWP and MAX232?
The main difference is the driver/receiver count. The MAX230CWP has 5 drivers (transmitters) and 0 receivers. The more common MAX232 has 2 drivers and 2 receivers, making it a full transceiver. You would use the MAX230CWP in a 'transmit-only' application or where you need to drive many serial lines from one chip.
Is the MAX230CWP obsolete?
The MAX230CWP is a mature, legacy component. While not recommended for brand new designs (which often use USB or Ethernet), it is still widely used for maintaining and repairing existing equipment that relies on the RS-232 standard. Many modern equivalents with lower power or smaller packages exist, but the MAX230CWP is a classic part.
What capacitors are needed for the MAX230CWP?
The MAX230CWP requires four external capacitors for its internal charge pump to generate the ±10V. The datasheet typically recommends 1.0µF capacitors for C1, C2, C3, and C4. A fifth bypass capacitor (0.1µF to 1.0µF) on the VCC pin is also standard practice.
Can I use a MAX232 instead of a MAX230CWP?
No, not as a direct drop-in replacement. The pinouts are completely different, and the MAX232 only has two drivers, while the MAX230CWP has five. A board designed for a MAX230CWP will not work with a MAX232.
