The ISOW77xx family of devices are galvanically-isolated quad-channel digital isolator with an integrated high-efficiency power converter with low emissions. The integrated DC-DC converter provides up to 550 mW of isolated power, eliminating the need for a separate isolated power supply in space-constrained isolated designs.
FEATURE |
ISOW774x ISOW774xF |
ISOW774xB ISOW774xFB |
---|---|---|
Protection Level | Reinforced | Basic |
Surge Test Voltage | 10 kVPK | 7.8 kVPK |
Isolation Rating | 5000 VRMS | 5000 VRMS |
Working Voltage | 1000 VRMS/1500VPK | 1000 VRMS/1500VPK |
Package | DFM (20) | DFM (20) |
Body Size (Nom) | 12.83 mm × 7.5 mm | 12.83 mm × 7.5 mm |
Changes from Revision B (January 2022) to Revision C (April 2022)
Changes from Revision A (October 2021) to Revision B (January 2022)
Changes from Revision * (September 2021) to Revision A (October 2021)
The high-efficiency of the power converter allows for operation at a wide operating ambient temperature range of –40°C to +125°C. This device provides improved emissions performance, allowing for simplified board design and has provisions for ferrite beads to further attenuate emissions. The ISOW774x has been designed with enhanced protection features in mind, including soft-start to limit inrush current, over-voltage and under-voltage lock out, fault detection on the EN/FLT pin, overload and short-circuit protection, and thermal shutdown.
The ISOW77xx family of devices provide high electromagnetic immunity while isolating CMOS or LVCMOS digital I/Os. The signal-isolation channel has a logic input and output buffer separated by a double capacitive silicon dioxide (SiO2) insulation barrier, whereas, power isolation uses on-chip transformers separated by thin film polymer as insulating material. There are five orderable configurations of four channel ISOW77xx flavor using the last part number digit to note the number of reverse channels. For example, the ISOW7740 has 4 forward channels and 0 reverse channels, while the ISOW7743 would have 1 forward channel and 3 reverse channels. If the input signal is lost, the default output is high for the ISOW77xx devices without the F suffix and low for the ISOW77xx devices with the F suffix. The ISOW774x can operate from a single supply voltage of 3 V to 5.5 V by connecting VIO and VDD together on PCB. If lower logic levels are required, these devices support 1.71 V to 5.5 V logic supply (VIO) that can be independent from the power converter supply (VDD) of 3 V to 5.5 V. VISOIN and VISOOUT needs to be connected on board with either a ferrite bead or fed through a LDO.
These devices help prevent noise currents on data buses, such as UART, SPI, RS-485, RS-232, and CAN, or other circuits from entering the local ground and interfering with or damaging sensitive circuitry. Through innovative chip design and layout techniques, electromagnetic compatibility of the device has been significantly enhanced to ease system-level ESD, EFT, surge and emissions compliance. The device is available in a 20-pin SOIC wide-body (SOIC-WB) DFM package.
PIN | I/O | DESCRIPTION | |||||
---|---|---|---|---|---|---|---|
NAME | NO. | ||||||
ISOW7740 | ISOW7741 | ISOW7742 | ISOW7743 | ISOW7744 | |||
GNDIO | 6 | 6 | 6 | 6 | 6 | — | Ground connection for VIO. GND1 and GNDIO needs to be shorted on board. |
GND1 | 10 | 10 | 10 | 10 | 10 | — | Ground connection for VDD. GND1 and GNDIO needs to be shorted on board. |
GND2 | 11 | 11 | 11 | 11 | 11 | — | Ground connection for VISOOUT. GND2 and GISOIN pins can be shorted on board or connected through a ferrite bead. See the Layout Section for more information. |
GISOIN | 15 | 15 | 15 | 15 | 15 | — | Ground connection for VISOIN. GND2 and GISOIN pins can be shorted on board or connected through a ferrite bead. See the Layout Section for more information. |
INA | 2 | 2 | 2 | 2 | 19 | I | Input channel A |
INB |
3 |
3 |
3 |
18 | 18 | I | Input channel B |
INC |
4 |
4 |
17 |
17 |
17 |
I | Input channel C |
IND |
5 |
16 |
16 |
16 |
16 |
I | Input channel D |
OUTA | 19 | 19 | 19 | 19 | 2 | O | Output channel A |
OUTB | 18 | 18 |
18 |
3 |
3 |
O | Output channel B |
OUTC | 17 |
17 |
4 |
4 |
4 |
O | Output channel C |
OUTD | 16 | 5 | 5 | 5 | 5 | O | Output channel D |
EN_IO1 |
7 |
7 |
7 |
7 |
7 |
I |
Output Enable 1: When EN_IO1 is high or open then the channel output pins on side 1 are enabled. When EN_IO1 is low then the channel output pins on side 1 are in a high impedance state and the transmitter of the channel input pins on side 1 are disabled. |
EN_IO2 |
14 |
14 | 14 | 14 | 14 |
I |
Output Enable 2: When EN_IO2 is high or open then the channel output pins on side 2 are enabled. When EN_IO2 is low then the channel output pins on side 2 are in a high impedance state and the transmitter of the channel input pins on side 2 are disabled. |
EN/FLT |
8 |
8 |
8 |
8 |
8 |
I/O |
Multi-function power converter enable input pin or
fault output pin. Can only be used as either an input pin or an
output pin. Power converter enable input pin: enables and disables the integrated DC-DC power converter. Connect directly to microcontroller or through a series current limiting resistor to use as an enable input pin. DC-DC power converted is enabled when EN/FLT is high to the VIO voltage level and disabled when low at GND1 voltage level. Fault output pin: Alert signal if power converter is not operating properly. This pin is active low. Connect to microcontroller through a 5 kΩ or greater pull-up resistor in order to use as a fault outpin pin. See Section 9.3.3 for more information |
VSEL |
13 |
13 |
13 |
13 |
13 |
I |
VISOOUT selection pin. VISOOUT = 5 V when VSEL shorted to VISOOUT. VISOOUT = 3.3 V, when VSEL shorted to GND2. For more information see the Device Functional Modes. |
VIO | 1 | 1 | 1 | 1 | 1 | — | Side 1 logic supply. |
VDD |
9 |
9 |
9 |
9 |
9 |
— | Side 1 DC-DC converter power supply. |
VISOIN |
20 |
20 | 20 | 20 |
20 |
— | Side 2 supply voltage for isolation channels. VISOIN and VISOOUT pins can be shorted on board or connected through a ferrite bead. See Application and Implementation for more information. |
VISOOUT |
12 |
12 |
12 |
12 |
12 |
— |
Isolated power converter output voltage. VISOIN and VISOOUT pins can be shorted on board or connected through a ferrite bead. See Application and Implementation for more information. |