The ISL4238E/44E/45E are 2.7V to 5.5V powered RS-232 transmitters/receivers which meet ElA/TIA-232 and V.28/V.24 specifications, even at VCC = 3.0V. Additionally, they provide ±15kV ESD protection (IEC6100-4-2 Air Gap and Human Body Model) on transmitter outputs and receiver inputs (RS-232 pins). Targeted applications are PDAs, Palmtops, and notebook and laptop computers where the low operational, 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 10nA trickle. Tiny 5mm x 5mm Quad Flat No- Lead (QFN) packaging and the use of small, low value capacitors ensure board space savings as well. Data rates greater than 250kbps (ISL4238E/44E)/1Mbps (ISL4245E) are guaranteed at worst case load conditions. The ISL424XE are 3 driver, 5 receiver (DTE) devices that, coupled with the QFN package, provide the industry’s smallest, lowest power complete serial port suitable for PDAs, and laptop or notebook computers. The 5x5 QFN requires 60% less board area than a 28 lead TSSOP, and is nearly 20% thinner. The devices also include a noninverting always-active receiver for “wake-up” capability. The ISL4238E is a 5 driver, 3 receiver device optimized for DCE applications.
The ISL4244E is a low‑power, QFN‑packaged RS‑232 transceiver designed for space‑constrained, battery‑powered devices such as PDAs, notebooks, and handheld equipment. It operates from a single 2.7 V to 5.5 V supply, offers +15 kV ESD protection, and includes an enhanced automatic power‑down function that reduces standby current to a 10 nA trickle.
Key features include three drivers and five receivers, active‑feedback resistors on inputs, non‑inverting always‑active receiver for wake‑up, and a small 5 mm × 5 mm QFN package that saves board space. The datasheet contains pinout diagrams, typical operating circuits, absolute maximum ratings, timing characteristics, and ESD performance data.
| Operating voltage range | 2.7 V to 5.5 V |
|---|---|
| Minimum data rate | 250 kbps |
| Power‑down standby current | 10 nA |
| ESD protection (RS‑232 pins) | +15 kV |
| Drivers / Receivers (ISL4244E) | 3 drivers, 5 receivers |
The device draws only 10 nA in power‑down mode.
The ISL4244E provides three drivers and five receivers.
The RS‑232 pins are protected up to +15 kV according to IEC6100.