MAX3232 IC : Pin Configuration & Its Applications

MAX3232 IC is extensively used for serial communication in between Microcontroller and a computer for changing the TTL/CMOS logic levels to RS232. So, if we want to interface any microcontroller with the Computer, first we have to convert the logic of TTL/CMOS to RS232.


Alternate names of this IC are; RS232 to TTL Converter IC, MAX3232IDBRE4, AX3232CAE, MAX232CSE,  MAX3232 SMD IC, MAX3232 IC, Surface Mount Device RS-232 Transceivers IC, SMD IC, RS-232 Transceivers SMD & SMD IC. This article discusses an overview of a MAX3232 IC, pin configuration, specifications, and its applications.

What is MAX3232 IC?

MAX3232 IC is a converter IC, used to convert RD232 to TTL. This IC includes line drivers-2, line receivers-2 & a circuit for dual charge-pump including ESD protection from terminal to terminal with 15 kV. The requirements of TIA/EIA-232-F can be attained by this IC to provide an interface in between the serial-port connector & an asynchronous communication controller.

MAX3232 IC
MAX3232 IC

Transceivers like MAX3222 & MAX3232 use fewer dropout transmitter output phases and also dual charge pumps for achieving the right RS232 performance once powered through the supply like 3V-5.5V. The supply voltage of max3232 is 5volts or 3.3 volts, which uses 0.3mA of power which is connected externally through 4 0.1uF capacitors.

Pin Configuration:

The pin configuration of MAX3232 IC includes 16- pins where each pin and its functionality is shown below:

MAX3232 IC Pin Configuration
MAX3232 IC Pin Configuration
  • Pin1 (C1+): This pin is the positive terminal of capacitor ‘C1’.
  • Pin2 (V+): Positive charge pump o/p for storage capacitor only.
  • Pin3 (C1-): This pin is a negative terminal of capacitor ‘C1’.
  • Pin4 (C2+): This is a positive terminal of the ‘C2’ capacitor.
  • Pin5 (C2-): This is a negative terminal of the ‘C2’ capacitor.
  • Pin6 (V-): Negative charge pump o/p for storage capacitor only.
  • Pin7 (DOUT2): The output of RS232 line data.
  • Pin8 (RIN2): The input of RS232 line data.
  • Pin9 (ROUT2): Logic data o/p to UART.
  • Pin10 (DIN2): Logic data i/p from UART).
  • Pin11 (DIN1): Logic data i/p from UART.
  • Pin12 (ROUT1): Logic data o/p to UART).
  • Pin13 (RIN1): The input of RS232 line data from the remote RS232 system.
  • Pin14 (DOUT1): The output of RS232 line data to remote RS232 system.
  • Pin15 (Ground): Ground pin.
  • Pin16 (Vcc): Voltage supply pin.

Features & Specifications:

The features and specifications of MAX3232 IC include the following.

  • It can work with 5V & 3.3V logic devices.
  • TTL to RS232 Converter IC.
  • It supports two conversions like Dual drivers & Receivers.
  • Simple to set up & initialize.
  • The operating speed is 120kbit/s.
  • The operating current is 8mA.
  • It is accessible in 16-pin SO, PDIP & SOIC packages.
  • Manufacturer by Texas Instruments.
  • TR Packaging (Tape and Reel).
  • The receiver of hysteresis is 300mV.
  • Status of part is Active.
  • Package or Case is 16-SOIC.
  • Transceiver type.
  • The type of mounting is surface mount.
  • RS232 Protocol.
  • Operating temperature ranges from 0°C to 70°C.
  • The number of drivers is 2.
  • Voltage supply ranges from 3Volts to 5.5V.
  • The number of receivers is 2.
  • 250kbps data rate.
  • Full duplex.

The equivalent MAX3232 IC is MAX232 IC and Alternative MAX3232 IC is FT232RL, RS232 adapter cable, RS232 module & RS232 converters.

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MAX3232 vs MAX232:

The main difference between MAX3232 & MAX232 is discussed below.

Both ICs like MAX3232 & MAX232 have a similar pin configuration & package style. The MAX3232 IC supports both 3.3V & 5V based systems, whereas the MAX232 IC supports 5V based systems thus, MAX3232 IC is a better choice as compared to MAX232 if you are working through a 3.3V based system, as it avoids the issue while converting logic level. Here, MAX232 IC is the most commonly used TTL to RS232 converter IC.

How to use MAX3232 IC/Circuit Diagram:

The circuit diagram of MAX3232 IC is shown below. In this circuit, MAX3232 IC is interfaced with a microcontroller. This circuit is very simple to design due to the simple setup of the IC and it works with 3.3V or +5V. So the Vcc pin is powered with the required voltage whereas the GND pin of this IC is given to circuit ground.

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In this circuit, the IC which is used needs four capacitors to work, and its value range from 1uF – 22uF. The main function of this IC is to change the logic level by using a microcontroller. Here the microcontroller is connected to a PC. In the following circuit, we can notice that pins in the IC like T2 in, T2 out, R2 in & R2 out are not connected because we are not using the second module.

MAX3232 Converter IC with Microcontroller
MAX3232 Converter IC with Microcontroller

Every microcontroller has the capability of serial communication that includes a transmitter (Tx) pin & a Receiver (Rx) pin. The connection of these two pins can be done to the Pin 11 (T1 in) & Pin 12 (R1 out) respectively. Here, pin 12 and pin 11 are TTL/CMOS logic inputs, and the logic signals of the RS232 converter can be obtained using pin 13 (R1 in) & pin 14 (T1 out).


Here when the IC is powered with 3.3V or 5V, a 3.3V/5V signal is converted into a +25V signal through a technique known as a charge pump, which includes a capacitor that gets charged to supply 25V.

Where to use/Applications:

The applications of MAX3232 IC include the following.

  • MAX3232 IC is used in converting TTL or CMOS to RS232.
  • The different Microcontrollers like ARM or PIC or Atmel uses TTL or CMOS logic which works through either 0V (or) +5V, however, our computers work through RS232 at -24V or +24V.
  • As a result, if we want to interface a microcontroller with the computer then we need to change the logic from TTL or CMOS to RS232.
  • So, if you are seeking an integrated circuit to achieve this conversion & also to interface any microcontroller through your computer, then this IC is the correct choice for you.
  • Used to convert TTL or CMOS logic to RS232.
  • Hand-Held device.
  • Utilized in RS232 cables.
  • Palmtop personal computers.
  • Battery-operated systems.
  • Notebooks.
  • PDAs.
  • Laptops.

Please refer to this link to know more about MAX3232 IC Datasheet.

Thus, MAX3232 IC with SO-16 Package & RS232 Interface is used for interfacing a microcontroller with a computer, used within RS232 cables & also for converting TTL/CMOS logic to RS232. Here is a question for you, what are the different serial communication is available in the market?

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