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Analog Devices Inc. LTC4305IDHD#PBF
- Part No.:
- LTC4305IDHD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Specialized
- Package:
- 16-WFDFN Exposed Pad
- Datasheet:
-
LTC4305IDHD#PBF.pdf
- Description:
- IC INTERFACE SPECIALIZED 16DFN
- Quantity:
- Payment:
- Shipping:
Inventory:146
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Product details
Overview
LTC4305IDHD#PBF from Analog Devices (formerly Linear Technology) is a 2-channel, bidirectional I²C/SMBus bus multiplexer with capacitive isolation buffers, programmable stuck-bus timeout, and rise time accelerator circuitry. It operates from 2.7V to 5.5V supply, supports independent downstream pull-up voltages (2.2V–5.5V), and delivers ±10kV HBM ESD protection. It enables dynamic channel selection in multi-module systems such as SFP hot-swap backplanes.
For engineers reviewing the LTC4305IDHD#PBF datasheet, LTC4305IDHD#PBF pinout, LTC4305IDHD#PBF application, or LTC4305IDHD#PBF equivalent, key selection criteria include its 16-lead DFN (4mm × 5mm) package, I²C-compatible 400kHz max clock frequency, 30ms/15ms/7.5ms configurable timeout modes, dual ALERT inputs for per-channel fault reporting, and supply-independent bidirectional buffering for fan-out extension.
Technical Context
The LTC4305IDHD#PBF implements upstream-downstream FET-based buffers with 25–200mV offset voltage (dependent on VCC and bus current), enabling transparent I²C protocol preservation-including clock stretching, arbitration, and ACK/NACK-across isolated segments. Its stuck-low detection uses dual internal comparators monitoring 0.52V threshold with 80mV hysteresis and three user-selectable timeout durations.
Rise time acceleration activates only when downstream channels are connected and bus slew rate exceeds 0.8V/µs; it sources up to 5.5mA per pin to reduce rise time without violating I²C edge-rate constraints. Addressing uses three tri-state ADR pins (ADR0–ADR2) supporting 27 unique I²C addresses, with fixed MSBs "10" ensuring compatibility with standard 7-bit addressing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.7V to 5.5V - Enables operation across 3.3V and 5V system rails without level-shifting components. |
| I²C Clock Frequency | Up to 400kHz - Fully compatible with Fast-mode I²C and SMBus 3.0 timing requirements. |
| Stuck-Low Timeout | Configurable 7.5ms / 15ms / 30ms - Prevents bus lockup by auto-disconnecting downstream channels during persistent low states. |
| Rise Time Acceleration | Up to 5.5mA per pin - Actively drives SDA/SCL lines during rising edges to meet rise-time specs under high capacitance loads. |
| Input Capacitance | 6–10pF per SDA/SCL pin - Minimizes added bus loading, preserving signal integrity in multi-drop configurations. |
| ESD Robustness | ±10kV HBM - Ensures reliable operation during live insertion/removal of pluggable modules like SFP transceivers. |
| Operating Temperature | –40°C to +85°C - Qualified for industrial-grade embedded and telecom infrastructure applications. |
Pinout & Package
The LTC4305IDHD#PBF is housed in a 16-lead (4mm × 5mm) plastic DFN package with exposed thermal pad (Pin 17, optional ground connection). Thermal resistance θJA is 43°C/W when the pad is soldered to PCB; otherwise 140°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (ALERT2) | Fault alert input - Channel 2 | Open-drain input tied low by downstream devices to signal faults; monitored independently of bus connection state. |
| 2 (ALERT) | Fault alert output | Open-drain output pulled low on any fault: ALERT1/ALERT2 assertion, stuck bus, or failed connection attempt. |
| 3 (SDAIN) | Upstream SDA bidirectional I/O | Connects to master-side SDA; buffered to downstream SDA1/SDA2; requires external pull-up. |
| 4 (GND) | Device ground reference | Primary return path for all internal circuits and external pull-ups; must be low-impedance. |
| 5 (SCLIN) | Upstream SCL bidirectional I/O | Connects to master-side SCL; buffered to downstream SCL1/SCL2; requires external pull-up. |
| 6 (ENABLE) | Digital enable/reset control | Low disables I²C interface and resets registers; high enables communication and READY output. |
| 7 (VCC) | Power supply input | 2.7V–5.5V supply; bypass capacitor ≥0.01µF required between VCC and GND for stable operation. |
| 8–10 (ADR0–ADR2) | I²C address configuration | Tri-state inputs (float/VCC/GND) setting 27 possible slave addresses; tolerate ±5µA leakage. |
| 11 (READY) | Connection status indicator | N-channel open-drain output pulled low when no downstream channel is connected; high when ≥1 channel active. |
| 12 (SCL1) | Downstream SCL output - Channel 1 | Buffered SCL line for downstream bus 1; requires external pull-up if used; floatable if unused. |
| 13 (SDA1) | Downstream SDA output - Channel 1 | Buffered SDA line for downstream bus 1; requires external pull-up if used; floatable if unused. |
| 14 (ALERT1) | Fault alert input - Channel 1 | Open-drain input tied low by downstream devices on bus 1 to signal faults; independent of connection state. |
| 15 (SDA2) | Downstream SDA output - Channel 2 | Buffered SDA line for downstream bus 2; requires external pull-up if used; floatable if unused. |
| 16 (SCL2) | Downstream SCL output - Channel 2 | Buffered SCL line for downstream bus 2; requires external pull-up if used; floatable if unused. |
| 17 (Exposed Pad) | Thermal pad | Optional ground connection; improves thermal performance (θJA = 43°C/W when soldered). |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive isolation buffering | Isolates upstream bus capacitance from downstream buses, enabling >1000pF total bus load while maintaining I²C timing compliance. |
| Programmable stuck-bus timeout | Three selectable timeout durations (7.5/15/30ms) prevent indefinite bus hang during fault conditions without software intervention. |
| Supply-independent bidirectional buffering | Allows downstream buses to operate at 2.2V–5.5V logic levels regardless of VCC, eliminating need for external level translators. |
| Nested addressing support | 27 unique I²C addresses via ADR0–ADR2 plus mass-write address (1011110b) for simultaneous configuration of multiple units. |
| SMBus Alert Response Protocol | Full compliance with SMBus ARA allows host to identify LTC4305IDHD#PBF as fault source and resolve alerts without polling. |
Applications
| Hot-Swappable SFP Modules | Multi-Sensor I²C Hub |
|---|---|
Use Scenario: Managing I²C communication to multiple pluggable optical transceivers in a telecom line card where modules may be inserted or removed while powered. IC Role / Device Role / Timing Role: LTC4305IDHD#PBF acts as a hot-swap-aware bus switch, isolating each SFP's I²C interface and preventing bus corruption during live insertion/removal. Use Value: Eliminates SDA/SCL glitches during module swap, ensures uninterrupted host monitoring, and enables per-module fault isolation via ALERT1/ALERT2. | Use Scenario: Aggregating I²C sensors (temperature, humidity, pressure) with differing supply voltages onto a single microcontroller bus in an industrial data logger. IC Role / Device Role / Timing Role: LTC4305IDHD#PBF serves as a voltage-level-flexible multiplexer, allowing 3.3V MCU to communicate with 2.5V and 5V sensors on separate downstream buses. Use Value: Removes need for discrete level shifters; preserves I²C timing and protocol integrity across voltage domains; simplifies BOM and layout. |
| Redundant Power Supply Monitoring | Server Baseboard Management (BMC) |
Use Scenario: Monitoring multiple independent DC-DC power supplies in a redundant PSU architecture, where each supply reports telemetry over I²C. IC Role / Device Role / Timing Role: LTC4305IDHD#PBF functions as a fault-tolerant bus extender, connecting BMC to individual PSUs while detecting and isolating faulty units via stuck-bus timeout. Use Value: Prevents single-point failure from disabling entire power monitoring bus; enables rapid identification and quarantine of failing PSUs using ALERT signaling. | Use Scenario: Expanding I²C connectivity on a server motherboard to support diverse FRU (Field Replaceable Unit) devices including DIMMs, fans, and voltage regulators. IC Role / Device Role / Timing Role: LTC4305IDHD#PBF operates as a managed I²C hub, providing channel-selectable access and real-time fault visibility to BMC firmware. Use Value: Supports scalable FRU inventory and health monitoring; reduces BMC GPIO usage; enables per-FRU reset and diagnostics via register-controlled FET switching. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C bus multiplexing applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TCA9548AIPWR | 8-channel I²C switch with no rise time acceleration, no stuck-bus timeout, and no per-channel ALERT inputs; 3.3V-only supply; 16-pin TSSOP package. | Lacks fault reporting and automatic bus recovery; suitable for simple channel expansion without robustness requirements. | Select when cost and channel count outweigh need for fault resilience and mixed-voltage support. |
| PCA9546ADW | 4-channel I²C switch with no buffering, no rise time boost, no ALERT inputs, and no stuck-bus detection; supports 2.3V–5.5V; 20-pin SOIC package. | Provides basic channel routing only; no capacitive isolation or bus integrity features; higher pin count and larger footprint. | Choose for legacy designs requiring pin-compatible upgrade from PCA954x family without advanced protection features. |
Compared with TCA9548AIPWR and PCA9546ADW, the LTC4305IDHD#PBF uniquely integrates capacitive buffering, programmable stuck-bus recovery, per-channel fault inputs, and supply-independent level translation-making it the only option qualified for mission-critical hot-swap and multi-rail I²C systems.
Availability
LTC4305IDHD#PBF is available at Aetrix Electronics and suitable for industrial backplane management, telecom SFP module interfaces, and server baseboard management requiring stable component supply, long-term lifecycle assurance, and guaranteed traceable sourcing.
Supply support for LTC4305IDHD#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. (including former Linear Technology products) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, industrial automation, and communications markets.
The LTC4305IDHD#PBF belongs to the LTC® bus protection and signal integrity product line, designed specifically for robust, fault-resilient I²C/SMBus expansion in demanding environments such as telecom infrastructure and enterprise servers.
FAQ
What is the operating temperature range of the LTC4305IDHD#PBF?
The LTC4305IDHD#PBF is rated for industrial operation from –40°C to +85°C. This specification applies across all electrical parameters in the datasheet's "Electrical Characteristics" table marked with the ● symbol, ensuring guaranteed performance in harsh environments such as base station equipment and industrial controllers.
Does the LTC4305IDHD#PBF require external pull-up resistors on all SDA/SCL lines?
Yes, the LTC4305IDHD#PBF requires external pull-up resistors on SDAIN, SCLIN, SDA1, SCL1, SDA2, and SCL2. The device does not integrate pull-ups; each line must be terminated to its respective supply rail (e.g., VCC for upstream, VCARD1/VCARD2 for downstream) to ensure proper I²C logic levels and rise times.
How does the stuck-low timeout feature work in the LTC4305IDHD#PBF?
The LTC4305IDHD#PBF monitors internal nodes of downstream SDA/SCL switches. If either node remains below 0.52V for a duration set by TIMSET1/TIMSET0 bits (7.5ms, 15ms, or 30ms), it disconnects downstream channels and pulls ALERT low. The timeout is latched in Register 0 until cleared by writing to that register.
Can the LTC4305IDHD#PBF translate between different logic voltage levels?
Yes, the LTC4305IDHD#PBF provides true supply-independent bidirectional level translation: upstream side operates from VCC (2.7V–5.5V), while downstream channels can be pulled up to independent supplies ranging from 2.2V to 5.5V-enabling seamless interfacing between 3.3V MCUs and 2.5V or 5V peripherals without external translators.
What is the function of the READY pin on the LTC4305IDHD#PBF?
The READY pin on the LTC4305IDHD#PBF is an N-channel open-drain output that is pulled low when no downstream channel is connected to the upstream bus, and turns off (high-impedance) when one or more channels are connected. An external 10kΩ pull-up resistor is required to generate a logic-high signal indicating active channel connectivity.
LTC4305IDHD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-WFDFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Applications:
- Multiplexer with Amplifier
- Interface:
- SMBus (2-Wire/I2C)
- Voltage - Supply:
- 2.2V ~ 5.5V
- Supplier Device Package:
- 16-DFN (5x4)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
LTC4305IDHD#PBF FAQ
1.How can I place an order for LTC4305IDHD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4305IDHD#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 LTC4305IDHD#PBF reliable?
The price and inventory of LTC4305IDHD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC4305IDHD#PBF is usually 5 days.
3.What payment methods are accepted for LTC4305IDHD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4305IDHD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4305IDHD#PBF?
LTC4305IDHD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4305IDHD#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 LTC4305IDHD#PBF?
For technical support, including LTC4305IDHD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4305IDHD#PBF requirements.
6.How does Aetrix verify that LTC4305IDHD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC4305IDHD#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 LTC4305IDHD#PBF meets industry standards.
7.What is the process for return or replacement of LTC4305IDHD#PBF?
All LTC4305IDHD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4305IDHD#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 LTC4305IDHD#PBF part is unused and in its original packaging.
Return procedure for LTC4305IDHD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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