The ISO1500 device is a galvanically-isolated differential line transceiver for TIA/EIA RS-485 and RS-422 applications. This device has a 3-channel digital isolator and an RS-485 transceiver in an ultra-small 16-pin SSOP package. The bus pins of this transceiver are protected against IEC ESD contact discharge and IEC EFT events. The receiver output has a failsafe for bus open, short, and idle conditions. The small solution size of ISO1500 greatly reduces the board space required compared to other integrated isolated RS-485 solutions or discrete implementation with optocouplers and non-isolated RS-485 transceiver.
The device is used for long distance communications. Isolation breaks the ground loop between the communicating nodes, allowing for a much larger common mode voltage range. The symmetrical isolation barrier of each device is tested to provide 3000 VRMS of isolation for 1 minute per UL 1577 between the bus-line transceiver and the logic-level interface.
The ISO1500 device can operate from 1.71 V to 5.5 V on side 1 which lets the devices interface with low-voltage FPGAs and ASICs. The supply voltage on side 2 is from 4.5 V to 5.5 V. This device supports a wide operating ambient temperature range from –40°C to +125°C.
PART NUMBER | PACKAGE | BODY SIZE (NOM) |
---|---|---|
ISO1500 | SSOP (16) | 4.90 mm × 3.90 mm |
Changes from C Revision (September 2019) to D Revision
Changes from B Revision (May 2019) to C Revision
Changes from A Revision (December 2018) to B Revision
Changes from * Revision (September 2018) to A Revision
PIN | I/O | DESCRIPTION | |
---|---|---|---|
NAME | NO. | ||
A | 12 | I/O | Transceiver noninverting input or output (I/O) on the bus side |
B | 13 | I/O | Transceiver inverting input or output (I/O) on the bus side |
D | 6 | I | Driver input |
DE | 5 | I | Driver enable. This pin enables the driver output when high and disables the driver output when low or open. |
GND1 | 2 | — | Ground connection for VCC1 |
8 | |||
GND2 | 9 | — | Ground connection for VCC2 |
15 | |||
NC(1) | 7 | — | No internal connection |
11 | |||
14 | |||
R | 3 | O | Receiver output |
RE | 4 | I | Receiver enable. This pin disables the receiver output when high or open and enables the receiver output when low. |
VCC1 | 1 | — | Logic-side power supply |
VCC2 | 10 | — | Transceiver-side power supply. These pins are not connected internally and must be shorted externally on PCB. |
16 |