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Analog Devices Inc. LTM2881CY-3#PBF
- Part No.:
- LTM2881CY-3#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Digital Isolators
- Package:
- 32-BBGA Module
- Datasheet:
-
LTM2881CY-3#PBF.pdf
- Description:
- DGTL ISO 2.5KV RS422/RS485 32BGA
- Quantity:
- Payment:
- Shipping:
Inventory:3,538
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Product details
Overview
LTM2881CY-3#PBF from Analog Devices (formerly Linear Technology) is a galvanically isolated RS485/RS422 µModule transceiver with integrated 5V isolated DC/DC converter, designed for ground-loop-free industrial communication. It delivers 100mA isolated output current at 5V, supports 20Mbps full-duplex data rate or 250kbps slew-limited mode, and provides 2500VRMS isolation with ±30kV/μs common-mode transient immunity. It is used in PROFIBUS-DP networks and industrial fieldbus systems requiring robust noise immunity.
For engineers reviewing the LTM2881CY-3#PBF datasheet, LTM2881CY-3#PBF pinout, LTM2881CY-3#PBF application, or LTM2881CY-3#PBF equivalent, key selection criteria include its 3.3V logic-side supply range (3.0–3.6V), 1.62–5.5V flexible VL interface, integrated 120Ω switchable termination, high-impedance failsafe receiver (96kΩ), and BGA package with 32-pin 15mm × 11.25mm footprint.
Technical Context
The LTM2881CY-3#PBF implements coreless transformer-based µModule isolation to transfer both power and bidirectional data across a reinforced barrier. Its isolated DC/DC converter operates at ~2MHz, uses a full-wave voltage doubler rectifier, and feeds a low-noise LDO to regulate VCC2 at 5V with up to 100mA output under load.
Signal isolation employs pulse encoding with error checking and fail-safe shutdown. The transceiver supports TIA/EIA-485-A and PROFIBUS compliance, features event-driven low-jitter DI/RO processing, and includes SLO-controlled slew-rate limiting to reduce EMI while maintaining signal integrity on mismatched or stubbed cables.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Supply Range | 3.0V to 3.6V - powers logic side; matches standard 3.3V systems with ±10% margin |
| VCC2 Output | 5.0V ±2.5%, 100mA max - powers isolated transceiver and external circuitry without external regulators |
| Data Rate | 20Mbps (full-speed) or 250kbps (SLO mode) - selectable via SLO pin to balance speed vs. EMI |
| Isolation Rating | 2500VRMS for 1 minute - meets UL-CSA E151738 recognition and enables safe operation in 560VPEAK working environments |
| Common-Mode Immunity | ±30kV/μs - ensures uninterrupted communication during fast transients in noisy industrial settings |
| Receiver Input Impedance | >96kΩ - supports up to 256 nodes per RS485 bus without violating unit-load limits |
| Logic Interface Voltage | VL = 1.62V to 5.5V - enables direct connection to 1.8V, 2.5V, 3.3V, or 5V microcontrollers without level shifters |
Pinout & Package
Package: 32-pin BGA, 15mm × 11.25mm × 3.42mm, MSL Level 3, RoHS-compliant SAC305 finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1 (DOUT) | Isolated logic output | Reflects DIN state across barrier; enters high-impedance on isolation fault |
| A2 (TE) | Terminator enable | Logic high activates internal 120Ω A–B termination resistor |
| A3 (DI) | Driver input | Controls Y/Z outputs when DE = high; referenced to VL |
| A4 (DE) | Driver enable | Logic high enables driver; low places Y/Z in high-Z state (<10µA leakage) |
| A5 (RE) | Receiver enable | Logic low enables RO; high forces RO into high-Z with <±1µA leakage |
| A6 (RO) | Receiver output | Active-high logic output reflecting A–B polarity; failsafe-high when idle/open/shorted |
| A7 (VL) | Logic supply | Provides interface voltage for DI, DE, RE, TE, DOUT, RO, ON; bypassed internally with 2.2µF |
| A8 (ON) | Global enable | High enables VCC2 generation and data transfer; low resets logic side and disables isolation |
| B1–B5 (GND) | Logic ground | Reference for VCC, VL, and logic-side pins; must be connected to system logic ground |
| B6–B8 (VCC) | Logic supply input | 3.0–3.6V input; internally bypassed with 2.2µF to GND |
| L1 (DIN) | Isolated logic input | Drives DOUT across barrier; referenced to VCC2/GND2 |
| L2 (SLO) | Slew rate control | Low = 250kbps slew-limited mode; high = full 20Mbps operation |
| L3 (Y) | Non-inverting driver output | RS485/RS422 differential output; high-Z when DE = low |
| L4 (Z) | Inverting driver output | Complementary to Y; high-Z when DE = low |
| L5 (B) | Inverting receiver input | RS485/RS422 differential input; >96kΩ impedance, failsafe-enabled |
| L6 (A) | Non-inverting receiver input | RS485/RS422 differential input; symmetric threshold (±200mV) with 25mV hysteresis |
| L7–L8 (VCC2) | Isolated 5V output | Regulated 5V supply for transceiver and external loads; 100mA max at 3.3V input |
| K1–K8 (GND2) | Isolated ground | Reference for VCC2, DIN, SLO, Y, Z, A, B; connects to cable shield or isolated system ground |
Key Features
| Feature | Design Value |
|---|---|
| Integrated isolated DC/DC converter | Eliminates need for external isolated power supplies or transformers; delivers regulated 5V/100mA from 3.3V input |
| Switchable 120Ω termination | Reduces external component count and PCB area; enables dynamic bus topology reconfiguration via TE pin |
| Failsafe RS485 receiver | Guarantees RO = high during bus idle, open, or shorted conditions-no external biasing resistors required |
| ±15kV HBM ESD protection | Protects transceiver pins against electrostatic discharge without latch-up or damage, improving field reliability |
| Thermal shutdown & current limiting | Prevents permanent damage during sustained overloads or short circuits on Y/Z outputs |
Applications
| Industrial Fieldbus Networks | PROFIBUS-DP Isolation |
|---|---|
Use Scenario: Connecting PLCs and remote I/O modules over long RS485 daisy chains in factory automation where ground potentials differ by hundreds of volts. IC Role / Device Role / Timing Role: Galvanic isolator and transceiver - breaks ground loops, suppresses CM noise, and maintains signal integrity at up to 20Mbps. Use Value: Enables reliable multi-node communication without ground-referenced interference or data corruption from 30kV/μs transients. | Use Scenario: Isolating PROFIBUS-DP slave devices in hazardous-area instrumentation where intrinsic safety and voltage separation are mandated. IC Role / Device Role / Timing Role: Certified isolated transceiver compliant with TIA/EIA-485-A and PROFIBUS physical layer requirements. Use Value: Meets UL-CSA E151738 recognition and supports 560VPEAK continuous working voltage for certified system design. |
| RS485 Ground Loop Elimination | Isolated Sensor Interface |
Use Scenario: Interfacing distributed temperature or pressure sensors across electrically noisy plant floors with varying earth references. IC Role / Device Role / Timing Role: Full-duplex isolated transceiver with high-impedance receiver - prevents circulating ground currents and preserves signal fidelity. Use Value: Supports up to 256 nodes per bus and eliminates need for external termination or biasing components. | Use Scenario: Powering and communicating with isolated analog front-end modules (e.g., ADCs, signal conditioners) using the same device's VCC2 output. IC Role / Device Role / Timing Role: Dual-function IC - provides isolated 5V/100mA power + RS485 data channel in one BGA package. Use Value: Reduces bill-of-materials and board space versus discrete isolator + transceiver + DC/DC solution. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar isolated RS485 transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADM2483BRWZ | SOIC-16, 2.5kVRMS isolation, no integrated DC/DC; requires external isolated 5V supply | Lower integration; suitable for space-constrained designs where external isolated power already exists | Select when board layout allows separate isolated power and lower cost outweighs integration benefits |
| ISO1540DR | I²C isolator only; no RS485 transceiver or DC/DC - functionally distinct | Not applicable for RS485 bus interfaces; limited to digital control signal isolation | Exclude for RS485 applications; consider only for non-RS485 digital isolation needs |
Compared with ADM2483BRWZ, LTM2881CY-3#PBF reduces system complexity by integrating power and data isolation, while offering higher isolation rating (2500VRMS vs. 2500VRMS) and built-in termination. Unlike ISO1540DR, it delivers full RS485 functionality-not just signal isolation-making it a complete subsystem replacement.
Availability
LTM2881CY-3#PBF is available at Aetrix Electronics and suitable for industrial fieldbus networks, PROFIBUS-DP systems, RS485 ground loop elimination, and isolated sensor interfaces requiring stable component supply and long-term manufacturability.
Supply support for LTM2881CY-3#PBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LTM2881CY-3#PBF belongs to the µModule isolated transceiver product line, engineered to simplify robust industrial communication by combining signal isolation, power conversion, and RS485/RS422 transceivers in a single certified package.
FAQ
What is the maximum continuous working voltage supported by the LTM2881CY-3#PBF?
The LTM2881CY-3#PBF supports a maximum continuous working insulation voltage of 560VPEAK, verified per IEC 60664-1 and reflected in its VIORM rating of 400VRMS. This enables safe deployment in industrial AC mains-connected equipment and high-voltage motor drives where reinforced isolation is required.
Does the LTM2881CY-3#PBF require external components for basic operation?
No - the LTM2881CY-3#PBF requires zero external components for full operation. All decoupling capacitors (2.2µF on VCC, VL, and VCC2) are integrated internally. Only PCB layout adherence to recommended creepage/clearance (9.48mm) and grounding (separate GND/GND2 planes) is needed.
How does the SLO pin affect data rate and EMI performance in the LTM2881CY-3#PBF?
When SLO is pulled low to GND2, the LTM2881CY-3#PBF enters slew-limited mode, capping data rate at 250kbps but reducing high-frequency harmonics significantly - demonstrated by >20dB suppression above 5MHz in spectral analysis. This mitigates radiated emissions from cables and improves EMC compliance in Class A/B environments.
Can the LTM2881CY-3#PBF power external circuitry using its VCC2 output?
Yes - the LTM2881CY-3#PBF delivers up to 100mA at 5V on VCC2 when powered from 3.3V VCC. After supplying the internal transceiver (~40mA typical), ~60mA remains available for external loads such as isolated ADCs, DACs, or level translators - confirmed in the "VCC2 Surplus Current vs Temperature" graph (Figure G11).
What happens to RO and DOUT during an isolation barrier failure in the LTM2881CY-3#PBF?
During an isolation communication failure, both RO and DOUT enter a high-impedance state with leakage current <±1µA - a fail-safe behavior explicitly documented in the Pin Functions section. This prevents erroneous logic states from propagating to downstream controllers and avoids bus contention in multi-drop configurations.
LTM2881CY-3#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- µModule®
- Package/Case:
- 32-BBGA Module
- Packaging:
- Tray
- Product Status:
- Active
- Technology:
- Magnetic Coupling
- Type:
- RS422, RS485
- Isolated Power:
- Yes
- Number of Channels:
- 2
- Inputs - Side 1/Side 2:
- 1/1
- Channel Type:
- Unidirectional
- Voltage - Isolation:
- 2500Vrms
- Common Mode Transient Immunity (Min):
- 30kV/µs
- Data Rate:
- 20Mbps
- Propagation Delay tpLH / tpHL (Max):
- -
- Pulse Width Distortion (Max):
- -
- Rise / Fall Time (Typ):
- -
- Voltage - Supply:
- 3V ~ 3.6V
- Grade:
- -
- Qualification:
- -
- Operating Temperature:
- 0°C ~ 70°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-BGA (15x11.25)
LTM2881CY-3#PBF FAQ
1.How can I place an order for LTM2881CY-3#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTM2881CY-3#PBF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LTM2881CY-3#PBF reliable?
The price and inventory of LTM2881CY-3#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTM2881CY-3#PBF is usually 5 days.
3.What payment methods are accepted for LTM2881CY-3#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTM2881CY-3#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTM2881CY-3#PBF?
LTM2881CY-3#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTM2881CY-3#PBF order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LTM2881CY-3#PBF?
For technical support, including LTM2881CY-3#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTM2881CY-3#PBF requirements.
6.How does Aetrix verify that LTM2881CY-3#PBF is sourced from the original manufacturer or authorized distributors?
All LTM2881CY-3#PBF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LTM2881CY-3#PBF meets industry standards.
7.What is the process for return or replacement of LTM2881CY-3#PBF?
All LTM2881CY-3#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTM2881CY-3#PBF, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LTM2881CY-3#PBF part is unused and in its original packaging.
Return procedure for LTM2881CY-3#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTM2881CY-3#PBF Tags
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