MAX3250:±50V Isolated, 3.0V to 5.5V, 250kbps, 2 Tx/2 Rx, RS-232 Transceiver

The MAX3250 is a 3.0V to 5.5V powered, ±50V isolated EIA/TIA-232 and V.28/V.24 communications interface with high data-rate capabilities. The MAX3250 is a dual die part that operates with up to ±50V difference between the RS-232 side and the logic side (ISOCOM to GND). This makes the device ideal for operation in noisy conditions with high common-mode voltages. This feature prevents damage to the device if RS-232 lines are inadvertently short-circuited to a +24V or ±48V power bus. The MAX3250 is powered by a single 3V to 5.5V supply on the logic side. Power is transferred from the logic side to the isolated side by ±100V external capacitors. The MAX3250 has two receivers (Rx) and two drivers (Tx) and is guaranteed to run at data rates of 250kbps while maintaining RS-232 output levels. The transceivers have a proprietary low-dropout transmitter output stage, delivering true RS-232 performance from a 3V to 5.5V supply with a dual charge pump. The device features an active-low FAULT open-drain output to signal an excessive isolated-side voltage condition on any of the RS-232 inputs. This output can drive an alarm LED or can be monitored by the processor to prevent operation under these conditions. The receiver outputs are high impedance in shutdown, allowing multiple interfaces (IrDA, RS-232, RS-485) to be connected to the same UART. The MAX3250 is available in a space-saving 28-pin SSOP package.

Key Features
  • Isolation Breaks Ground Loops Due to High Common-Mode Voltages While Maintaining Data Rate
    • ±50V Isolation
    • 250kbps Guaranteed Data Rate
    • Active-Low FAULT Output Signals Excessive Isolated-Side Voltage
  • Integration of Isolation and RS-232 Saves Space
    • SSOP Package
  • Shutdown Allows Multiple Interfaces (IrDA, RS-232, RS-485) to be Connected to the Same UART
    • High-Impedance Transmitter and Receiver Outputs in Shutdown
    • 20µA Supply Current in Shutdown
  • Inductorless/Transformerless Design Simplifies EMI Compliance
  • Low-Cost Replacement for Opto-Isolated Transceivers
  • Meets EIA/TIA-232 Specifications Down to 3.0V
MAX3250: Typical Operating Circuit
MAX3250: Typical Operating Circuit
Applications/Uses
  • Diagnostic Ports
  • Industrial Control
  • PC-to-Router Connections
  • Point-of-Sale Equipment
  • Programmable Logic Controllers
  • Telecom Equipment
DataSheet
titleDownload file
MAX3250 Data SheetMAX3250.pdf
Parametrics
Part NumberVSUPPLY
(V)
TxRxData Rate
(kbps)
ICC
(mA)
Internal Charge PumpExt. CapsCap. Value
(µF)
Rx Active in ShutdnPackage/PinsBudgetary
Price
mintypnomSee Notes
MAX32503
3.3
5
2225015Yes90.470SSOP/28$3.82 @1k
Quality and Environmental Data
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX3250CAINo Longer AvailableMAX3250CAI+SSOP,;28 pin;81.6 mm²0°C to +70°CNo
MAX3250CAI+ActiveSSOP,;28 pin;81.6 mm²0°C to +70°CLead Free
MAX3250CAI+TActiveSSOP,;28 pin;81.6 mm²0°C to +70°CLead Free
MAX3250CAI-TNo Longer AvailableMAX3250CAI+TSSOP,;28 pin;81.6 mm²0°C to +70°CNo
MAX3250EAINo Longer AvailableMAX3250EAI+SSOP,;28 pin;81.6 mm²-40°C to +85°CNo
MAX3250EAI+ActiveSSOP,;28 pin;81.6 mm²-40°C to +85°CLead Free
MAX3250EAI+TActiveSSOP,;28 pin;81.6 mm²-40°C to +85°CLead Free
MAX3250EAI-TNo Longer AvailableMAX3250EAI+TSSOP,;28 pin;81.6 mm²-40°C to +85°CNo
MAX3250.pdf MAX3250
MAX3250.pdf MAX3250
MAX3250.pdf MAX3250
Understanding Common-Mode Signals MAX3157
Using the MAX3250 ±50V-Isolated RS-232 Transceivers MAX3250
MAX3250.pdf MAX3250
MAX3250.pdf MAX3250