The ISL4270E is a 3.0V to 5.5V powered RS-232 transceiver that meets ElA/TIA-232 and V.28/V.24 specifications, even at VCC = 3.0V. It provides ±15kV ESD protection (IEC61000-4-2 Air Gap and Human Body Model) on transmitter outputs and receiver inputs (RS-232 pins). Targeted applications are notebook and laptop computers where the low operational power consumption and even lower standby power consumption is critical. Efficient on-chip charge-pumps coupled with manual and enhanced automatic powerdown functions reduce the standby supply current to a 300nA trickle. The 5mmx5mm Quad Flat No-Lead (QFN) packaging and the use of small, low value capacitors ensure board space savings. Data rates greater than 250kbps are ensured at worst case load conditions.
The ISL4270E features a VL pin that adjusts the logic pin output levels and input thresholds to values compatible with the VCC powering the external logic (for example, a UART).
This device includes an enhanced automatic powerdown function that powers down the on-chip power-supply and driver circuits. Automatic powerdown occurs when all receiver and transmitter inputs detect no signal transitions for a period of 30 seconds. The ISL4270E automatically powers back up whenever it senses a transition on any transmitter or receiver input.
Application Note AN9863 summarizes the features of each device comprising the 3V RS-232 family.
- Available in near chip scale QFN (5mmx5mm) package
- VL supply pin for compatibility with mixed voltage systems
- ESD protection for RS-232 I/O pins to ±15kV (IEC61000)
- Manual and enhanced automatic powerdown features
- Meets EIA/TIA-232 and V.28/V.24 specifications at 3V
- On-chip charge pumps require only four external 0.1µF capacitors
- Receivers stay active in powerdown
- Very low supply current: 300µA
- Guaranteed minimum data rate: 50kbps
- Wide power supply range: single +3V to +5.5V
- Low supply current in powerdown state: 300nA
- Pb-free (RoHS compliant)