LT1791AIS#PBF Analog Devices Integrated Circuit (Small Outline Packages) In Stock
Analog Devices LT1791AIS#PBF is a 60V DC, ±15kV ESD-protected RS-422/RS-485 half-duplex transceiver IC supporting industrial differential serial communication. Features differential Schmitt-trigger receiver inputs with failsafe for open, shorted, or terminated bus conditions. Available in a 14-pin SOIC package for robust multi-node industrial network designs.
- Manufacturer
- Analog Devices
- Package
- Small Outline Packages
- Pin Count
- 14
- Lifecycle
- ACTIVE
- Datasheet
- LT1791AIS#PBF Datasheet PDF
- Category
- Integrated Circuit
- Price
- From $4.4700(MOQ 1)
- Temp Range
- -40.0°C to 85.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- 60V DC bus fault protection tolerating industrial overvoltage and wiring faults up to 60V
- ±15kV ESD protection on RS-485 bus pins for reliable field-side connection without external TVS diodes
- Differential Schmitt-trigger receiver with failsafe ensuring known logic output on open or shorted bus
- Supports EIA-422 and EIA-485 standards enabling multi-drop networks with up to 32 unit loads
- 14-pin SOIC package with half-duplex driver/receiver for compact RS-485 node designs
Applications
The LT1791AIS#PBF targets industrial RS-485 multi-drop networks where long cable runs, ground potential differences, and wiring faults require protection well beyond the standard ±7V RS-485 common-mode range. It is used in PLC communication ports, building automation HVAC controllers, and smart metering bus interfaces where bus lines can be inadvertently shorted to 48V or 60V DC power rails during field installation. The ±15kV ESD rating eliminates the need for external TVS arrays on the bus connector pins, simplifying PCB design and reducing component count in harsh industrial environments.
Specifications
| Pbfree Code | No |
| Manufacturer Package Code | 05-08-1610 (S14) |
| YTEOL | 10 |
| Differential Output | YES |
| Driver Number of Bits | 1 |
| High Level Input Current-Max | 0.000005A |
| Input Characteristics | DIFFERENTIAL SCHMITT TRIGGER |
| Interface IC Type | LINE TRANSCEIVER |
| Interface Standard | EIA-422; EIA-485 |
| JESD-30 Code | R-PDSO-G14 |
| JESD-609 Code | e3 |
| Number of Functions | 1 |
| Out Swing-Min | 1.2V |
| Output Characteristics | DIFFERENTIAL |
| Output Low Current-Max | 0.0016A |
| Output Polarity | TRUE |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | SOP14,.25 |
| Package Shape | RECTANGULAR |
| Package Style | SMALL OUTLINE |
| Peak Reflow Temperature (Cel) | 260 |
| Qualification Status | Not Qualified |
| Receive Delay-Max | 900ns |
| Receiver Number of Bits | 1 |
| Supply Current-Max | 9mA |
| Supply Voltage-Max | 5.25V |
| Supply Voltage-Min | 4.75V |
| Supply Voltage-Nom | 5V |
| Supply Voltage1-Max | 5.25V |
| Supply Voltage1-Min | 4.75V |
| Supply Voltage1-Nom | 5V |
| Surface Mount | YES |
| Technology | BIPOLAR |
| Temperature Grade | INDUSTRIAL |
| Terminal Finish | Matte Tin (Sn) |
| Terminal Form | GULL WING |
| Terminal Pitch | 1.27mm |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | 30 |
| Transmit Delay-Max | 2000ns |
| Package | Small Outline Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| Moisture Sensitivity Level | MSL 1 |
| ECCN | EAR99 |
| HTS Code | 8542.39.00.01 |
| Country of Origin | Malaysia |
Alternate & Equivalent Parts
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
How does the 60V bus fault tolerance of the LT1791AIS#PBF protect against field-wiring mistakes in industrial installations?
The LT1791 tolerates bus line voltages from -60V to +60V DC without damage, far exceeding the ±7V common-mode requirement of standard RS-485 transceivers. In industrial cabinets where 48V or 24V supply rails are wired alongside RS-485 cables, an accidental short from a power line to the bus conductor will not destroy the transceiver. This protection eliminates field failures that would otherwise require board replacement, reducing maintenance downtime in PLCs and drive systems with thousands of deployed units.
What does the failsafe feature of the LT1791AIS#PBF receiver do when the RS-485 bus is open or shorted?
When the differential bus voltage is between -200mV and +200mV—as occurs with an open, shorted, or terminated bus and no active driver—the failsafe circuit forces the receiver output to a logic-high state. This prevents the downstream microcontroller from receiving spurious low or toggling inputs that would trigger false UART frame errors. Without failsafe, a floating receiver input in a standard RS-485 transceiver can produce random outputs, causing software to interpret noise as valid 9600 bps to 115200 bps data frames.
How many nodes can share a single RS-485 network segment when using LT1791AIS#PBF devices?
The LT1791 presents 1 unit load to the RS-485 bus as a receiver, so a standard RS-485 network supports up to 32 unit loads on a single segment, meaning up to 32 LT1791 devices can coexist on one bus without exceeding the driver's fanout specification. For larger networks with more than 32 nodes, repeaters or multipoint transceivers with fractional unit loads such as 0.25 UL allow up to 128 nodes on a single cable segment spanning up to 1200 meters at 100 kbps.
For a MODBUS RTU system running at 115200 bps, is the LT1791AIS#PBF fast enough, and what propagation delay should be budgeted?
Yes, the LT1791 supports data rates up to 10 Mbps, making 115200 bps trivial. Driver propagation delay is typically 15 ns and receiver propagation delay is approximately 25 ns, totalling around 40 ns of transceiver latency per node. At 115200 bps with a bit period of 8.7 µs, the 40 ns transceiver delay represents less than 0.5% of one bit time, well within MODBUS RTU timing margins that allow up to 1.5 character times between bytes in a frame.
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About Analog Devices
Analog Devices (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing integrated circuits used in virtually all types of electronic equipment.
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| Qty. | Unit Price | Ext. Price |
|---|---|---|
| 1+ | $10.4500 | $10.45 |
| 3+ | $6.2600 | $18.78 |
| 10+ | $5.6300 | $56.30 |
| 55+ | $5.2500 | $288.75 |
| 1000+ | $4.4700 | $4470.00 |
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