ایزولاتور ایزولاتور دیجیتال

Product Attributes

Introduction

The ISO7220 and ISO7221 are dual-channel digital isolators. To facilitate PCB layout, the channels are oriented in the same direction in the ISO7220 and in opposite directions in the ISO7221. These devices have a logic input and output buffer separated by TI’s silicon-dioxide (SiO₂) isolation barrier, providing galvanic isolation of up to 4000 V. Used in conjunction with isolated power supplies, these devices block high voltage, isolate grounds, and prevent noise currents on a data bus or other circuits from entering the local ground and interfering with or damaging sensitive circuitry. A binary input signal is conditioned, translated to a balanced signal, then differentiated by the capacitive isolation barrier. Across the isolation barrier, a differential comparator receives the logic transition information, then sets or resets a flip-flop and the output circuit accordingly. A periodic update pulse is sent across the barrier to ensure the proper dc level of the output. If this dc-refresh pulse is not received every 4 μs, the input is assumed to be unpowered or not being actively driven, and the failsafe circuit drives the output to a logic high state. The small capacitance and resulting time constant provide fast operation with signaling rates available from 0 Mbps (dc) to 25 Mbps. The A-option and C-option devices have TTL input thresholds and a noise filter at the input that prevents transient pulses from being passed to the output of the device. These devices require two supply voltages of 3.3 V, 5 V, or any combination. All inputs are 5-V tolerant when supplied from a 3.3-V supply and all outputs are 4-mA CMOS. These devices are characterized for operation over the ambient temperature range of -40°C to 125°C.

Features

• Qualified for Automotive Applications
• 1-Mbps and 25-Mbps Signaling Rate Options
• Low Channel-to-Channel Output Skew: 1 ns (Max)
• Low Pulse-Width Distortion (PWD): 1 ns (Max)
• Low Jitter Content: 1 ns (Typ) at 150 Mbps
• 25-Year (Typ) Life at Rated Voltage
• 4000-Vpeak Isolation, 560 Vpeak VIORM UL 1577, IEC 60747-5-2 (VDE 0884, Rev 2), IEC 61010-1, IEC 60950-1 and CSA Approved
• 50 kV/μs Typical Transient Immunity
• Operates with 3.3-V or 5-V Supplies
• 4 kV ESD Protection
• High Electromagnetic Immunity
• -40°C to 125°C Operating Free-Air Temperature Range