ADM3202/ADM3222/ADM1385

Rev. E | Page 9 of 16

Transmitter (Driver) Section

The drivers convert 3.3 V logic input levels into RS-232 output

voltage swing is typically ±6 V.

Receiver Section

The receivers are inverting level-shifters that accept RS-232

input levels and translate them into 3 V logic output levels. The

inputs have internal 5 kΩ, pull-down resistors to ground and are

protected against overvoltages up to ±30 V. Unconnected inputs

are pulled to 0 V by the internal 5 kΩ, pull-down resistor. This

results in a Logic 1 output level for unconnected inputs or for

inputs connected to GND.

The receivers have Schmitt-trigger inputs with a hysteresis level

of 0.4 V. This ensures error-free reception for both noisy inputs

and for inputs with slow transition times.

HIGH BAUD RATE

The ADM3202/ADM3222 feature high slew rates permitting

data transmission at rates well in excess of the EIA/RS-232E

specifications. RS-232 voltage levels are maintained at data rates

up to 460 kbps even under worst-case loading conditions. This

allows high speed data links between two terminals and is

suitable for the new generation ISDN modem standards that

require data rates of 230 kbps. The slew rate is internally

controlled to less than 30 V/μs to minimize EMI interference.