- Maxim Integrated Products created the MAX232 IC, a voltage logic converter that converts the TTL logic level to TIA or EIA-232-F level. It is essential for communication between the PC and the microcontroller. This IC is utilized in a variety of devices, including modems, computers, battery-powered devices, and terminals.
What is MAX232 IC?
- Microcontrollers and PCs frequently communicate serially using the MAX232 IC. This integrated circuit’s primary job is to convert TTL/CMOS logic values to RS232 during the serial communication process.
- A computer typically functions at RS232 standards like -25 to +25V, but a microcontroller typically operates at TTL of roughly 0 to 5V. Therefore, it is not possible to interface a computer with a microcontroller without a MAX232 IC. For instance, MAX232IC must be included if you want to link a PIC microcontroller to a laptop’s serial connector.
- Here, RS232 voltage logic is used for serial ports on laptops like the 9-pin connector, whereas transistor logic is used for serial ports on microcontrollers such as the Tx and RX pins. RS232 module, MC1488, RS232 adapter cable, and FT232RL are the MAX232’s similar RS232 converters.
Structure of MAX232 IC
- The following diagram illustrates the three primary blocks that make up the MAX232 IC. Since it uses a 5-volt power supply, it may be used with practically any embedded system. The voltage doubler is the initial block in this IC, and to generate the voltage twice as much, a switched capacitor approach is used.
- The following block will change the voltage to +10 & -10 whenever the voltage is doubled. Additionally, the final block has two transmitters and two receivers that convert voltage levels.
Types of MAX232 IC
MAX232 ICs are available in two types MAX232N & MAX232D.
- In MAX232N IC, “N” signifies the package style of PDIP and this package is simple to sell & most extensively used.
- In MAX232D IC, “D” signifies the SOIC package & it is hard to sell but requires a skilled professional to be utilized properly.
MAX232 IC Pin Configuration
MAX232 IC includes 16 pins and each pin is described below. This IC needs four capacitors externally for its proper design. These four capacitors range from 8 to10 up with up to 16 volts.
- Pin-1(C1+): The positive terminal of a capacitor is connected to this pin.
- Pin-2(Vs+): The capacitor’s positive leg is connected to it by grounding the negative leg.
- Pin-3(C1-): The negative pin of the capacitor is connected to this pin and the positive pin is connected to pin1.
- Pin-4(C2+): The positive terminal of a capacitor is connected to this pin.
- Pin-5(C2-): The negative terminal of a capacitor is connected where the positive terminal is connected to Pin4.
- Pin-6(Vs-): The negative terminal of a capacitor is connected to this pin & 5 volts are provided to the positive terminal of the capacitor.
- Pin-7(T2OUT): It provides the converted TTL signal in the form of RS-232. Here TTL signal can be obtained by T2IN Pin from the microcontroller and this pin is connected to Pin2 of the DB-9 port of your computer like RDX.
- Pin-8(R2IN): This Pin gets the signal of RS-232 like an input & provides the changed signal in the form of TTL on the R2OUT pin. This pin is connected to DB9 Port’s Txd pin, which is Pin3.
- Pin-9(R2OUT): It provides the signal changed within TTL form. The signal is received from Pc at R1In Pin. Connect this pin to your module (TTL) RDX pin which receives the signal.
- Pin-10(T2IN): This pin gets the transmitted signal from the microcontroller & gives the changed RS-232 signal over the T2OUT pin. Here, the signal can be transmitted from the microcontroller serial ports and pin. This pin can be connected to your Txd pin of the module.
- Pin-11(T1IN): This pin works like a T2IN.
- Pin-12(R1OUT): This pin works like an R2OUT.
- Pin-13(R1IN): This pin works like an R2IN.
- Pin-14(T1OUT): This pin works like aT2OUT.
- Pin-15(GND): This pin is a GND pin.
- Pin-16(VCC): This pin is a voltage supply pin where 5V is provided to this pin.
Working of MAX232 IC
- We are aware that the principal job of the Max 232 IC is to convert TTL logic level signals into their matching RS-232c level signals and then back to TTL logic level signals.
- This IC is highly helpful when connecting two devices so that data can be sent.
- For instance, the majority of the micro controller’s operations use the TTL logic waveform. These microcontrollers have a UART that can be used to send and receive serial data since they operate at the TTL level, sending and receiving data as composed TTL waves as opposed to the RS-232 waveform used by a normal PC.
- Data must be converted from TTL to Rs 232 level before being sent from the microcontroller to a personal computer. The optimum option for converting this data is therefore the MAX232 IC. This IC has two receivers and two driver channels, and it operates at up to 120 Kbits per second.
- It can transfer data up to a maximum of 12 to 15 meters away. It follows that this IC can be used in terminals, modems, computers, scanners, printers, fax machines, etc.
Features of MAX232 IC
The main features of MAX232 IC include the following.
- It is available in 16-pin SOIC, PDIP & SO packages.
- Simple to Setup & Initialize.
- Operating Speed is120kbit/s.
- Operating Current is 8mA.
- Input Levels ±30V.
- Conversion IC from TTL or CMOS to RS232.
- At a time it supports two conversions like dual drivers & receivers.
- The simple way to change the TIA/ EIA 32 to CMOS/TTL is simply a 5V power supply.
- A 1.0uF capacitor is used to resolve the issue of power decimation.
- The voltage levels of RS232 devices are different in some cases.
- Its highest working temperature is 150o C.
Packages, Dimensions & Ratings
The packages of MAX232 IC include the following.
- The packages of MAX-232 IC are SOIC (16), SOP (16) & PDIP (16).
The package dimensions of MAX 232 IC include the following.
- The dimension of the SOIC (16) package is 9.90 X 3.91 mm.
- The dimension of the PDIP (16) package is 19.03 X 6.35 mm.
- The dimension of the SOP (16) package is 10.03 X 5.3 mm.
- The ratings of MAX232 IC are the current, voltage & power ratings of IC that show its power requirement so that how much current & voltage is used for its operation can be known.
- Input voltage ranges from -0.3 to 6v.
- Output voltage ranges from 0.3 to +0.3.
- The operating temperature is 150oC.
Circuit Diagram of MAX232 IC
- The MAX32IC circuit diagram for RS232-TTL level shifting is displayed below. For use with microcontrollers, use the circuit below. This circuit primarily enables level shifting between RS232 and TTL.
- The MAX232 IC and four external capacitors can be used to construct the circuit, which will internally provide the highest voltage possible. There are other clones of this IC that perform similarly and are often not pricey. They may be switched out without any issues.
- The MAX232 IC must be replaced with the MAX3232 IC if the TTL signal in some contemporary microcontrollers is low voltage. These two chips are similar except that the MAX3232 only operates from about 3V up. If the IC is not available, using a conventional MAX232 through a lower voltage source would be possible, but the output might not be within the parameters specified by the RS232 standard.
- At 115200 bps, the maximum recommended distance is roughly 10 meters. If maximum lengths are necessary, it is possible to use other protocols or standards, such as RS485, that use differential communication, making them less sensitive to noise. This method typically requires more wires.
Applications of MAX232 IC
The applications of MAX232 IC include the following.
- It is used to interface microcontroller through PC.
- Used to convert from TTL or CMOS logic to RS232.
- Utilized within RS232 cables.
- Portable Computing.
- Transactions of Interface.
- RS232 System Powered with a Battery.
- Fewer Power Modes.