特性
- ESD Protection for RS-232 Bus Pins
- ±15-kV Human-Body Model (HBM)
- ±8-kV IEC 61000-4-2, Contact Discharge
- ±15-kV IEC 61000-4-2, Air-Gap Discharge
- Meets or Exceeds the Requirements of TIA/EIA-232-F and ITU v.28 Standards
- Operates With 3-V to 5.5-V VCC Supply
- Operates up to 1000 kbit/s
- Two Drivers and Two Receivers
- Low Standby Current . . . 1 µA Typ
- External Capacitors . . . 4 × 0.1 µF
- Accepts 5-V Logic Input With 3.3-V Supply
- APPLICATIONS
- Battery-Powered Systems
- PDAs
- Notebooks
- Laptops
- Palmtop PCs
- Hand-Held Equipment
DESCRIPTION/
ORDERING INFORMATION
The TRSF3222E consists of two line drivers, two line receivers, and a dual charge-pump circuit with ±15-kV ESD protection pin to pin (serial-port connection pins, including GND).
The TRSF3222E meets the requirements of TIA/EIA-232-F and provides the electrical interface between an asynchronous communication controller and the serial-port connector. The charge pump and four small external capacitors allow operation from a single 3-V to 5.5-V supply. The TRSF3222E operates at typical data signaling rates up to 1000 kbit/s and is an improved drop-in replacement for industry-popular '3222 two-driver, two-receiver functions.
The TRSF3222E can be placed in the power-down mode by setting the power-down (PWRDOWN) input low, which draws only 1 µA from the power supply. When the device is powered down, the receivers remain active while the drivers are placed in the high-impedance state. Also, during power down, the onboard charge pump is disabled; V+ is lowered to VCC, and V- is raised toward GND. Receiver outputs also can be placed in the high-impedance state by setting enable (EN) high.
