1 Features
1• Extended VCC operating nodes: 1.8 V, 3.3 V, or
5.0 V
– Unique Tripler Charge Pump Architecture
Enables Low VCC of 1.8V While Maintaining
Compatibility with 3.3 V and 5 V Supplies
• Integrated Level-Shifting Functionality Eliminates
the Need for External Power or Additional Level
Shifter While Interfacing with Low-Voltage MCUs
• Enhanced ESD Protection on RIN Inputs and
DOUT Outputs
– ±15 kV IEC 61000-4-2 Air-Gap Discharge
– ±8 kV IEC 61000-4-2 Contact Discharge
– ±15 kV Human-Body Model
• Specified 1000-kbps Data Rate
• Auto Powerdown Plus Feature
• Low 0.5uA Shutdown Supply Current
• Meets or Exceeds Compatibility Requirements of
RS-232 Interface
• For 2.5 V Single Supply Applications, Consider
TRS3318E as an Optimized Solution

2 Applications
• Remote Radio Unit (RRU)
• Base Band Unit (BBU)
• Electronic Point of Sale (EPOS)
• Diagnostics & Data Transmission
• Battery-Powered Equipment

3 Description
The TRS3122E is a two-driver and two-receiver RS-
232 interface device, with split supply pins for mixedvoltage
operation. All RS-232 inputs and outputs are
protected to ±15 kV using the IEC 61000-4-2 Air-Gap
Discharge method, ±8 kV using the IEC 61000-4-2
Contact Discharge method, and ±15 kV using the
Human-Body Model.
The charge pump requires five small 0.1-μF
capacitors for operation from as low as a 1.8-V
supply. The TRS3122E is capable of running at data
rates up to 1000 kbps, while maintaining RS-232-
compatible output levels.
The TRS3122E has a unique VL pin that allows
operation in mixed-logic voltage systems. Both driver
in (DIN) and receiver out (ROUT) logic levels are pin
programmable through the VL pin. This eliminates the
need for additional voltage level shifter while
interfacing with low-voltage microcontrollers or
UARTs.
Auto Powerdown Plus automatically places the
device in a low power mode when the device has not
received or transmitted data for more than 30
seconds. This feature makes this device a very
attractive option for battery powered or other powersensitive
applications.