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Analog Devices Inc. LTC4306CUFD#PBF
- Part No.:
- LTC4306CUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Specialized
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LTC4306CUFD#PBF.pdf
- Description:
- IC INTERFACE SPECIALIZED 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:186
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Product details
Overview
LTC4306CUFD#PBF from Analog Devices (formerly Linear Technology) is a 4-channel, bidirectional I²C/SMBus bus multiplexer with capacitive isolation buffers, programmable stuck-bus timeout, rise time accelerators, and independent downstream pull-up voltage support (2.2V–5.5V). It enables one upstream master to selectively connect to up to four isolated downstream I²C buses while preventing signal corruption during live insertion and supporting nested addressing. Used in modular backplane systems with hot-pluggable SFP modules.
For engineers reviewing the LTC4306CUFD#PBF datasheet, LTC4306CUFD#PBF pinout, LTC4306CUFD#PBF application, or LTC4306CUFD#PBF equivalent, key selection criteria include its 24-lead QFN (4mm × 5mm) package, ±10kV HBM ESD rating, 400kHz maximum SCL frequency, 27-address programmability via ADR0–ADR2, and dual GPIOs with push-pull/open-drain configurable outputs.
Technical Context
The LTC4306CUFD#PBF implements four independent N-channel FET-based bidirectional switches between upstream SDAIN/SCLIN and downstream SDA1–SDA4/SCL1–SCL4, each with integrated buffer offset compensation (VOS,UP-BUF ≤120mV, VOS,DOWN-BUF ≤200mV). Its stuck-low detection uses dual-threshold comparators (0.52V/0.6V) with three programmable timeout modes (7.5ms/15ms/30ms) and automatic disconnection of affected channels.
Rise time acceleration activates when slew rate exceeds 0.8V/µs and pin voltage >0.8V, sourcing 4–5.5mA per active channel to reduce RC-limited rise times. The device supports level translation across mismatched supply domains (e.g., VCC = 3.3V, VCARD1 = 3.3V, VCARD4 = 5V, VBACK = 2.5V) without external level shifters, and includes SMBus Alert Response Address protocol compliance for fault reporting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.7V to 5.5V - powers internal logic and buffers; UVLO threshold at 2.5V nominal with 175mV hysteresis. |
| Max I²C Clock Frequency | 400kHz - supports Fast-mode I²C operation; timing parameters validated per I²C spec (tHD,DATO ≥300ns, tSU,DAT ≥50ns). |
| Downstream Channel Count | 4 - independently controllable via Register 3 Bus x FET State bits; supports 1:4, 2:4, or full 4-channel connection simultaneously. |
| Stuck-Low Timeout Options | 7.5ms / 15ms / 30ms - set by TIMSET1/TIMSET0 bits in Register 2; disables affected channel buffers upon timeout without altering switch state. |
| Rise Time Accelerator Current | 4–5.5mA per active pin - reduces SDA/SCL rise time under high-capacitance loads; regulated to avoid overshoot on light loads. |
| ESD Rating | ±10kV HBM - protects against electrostatic discharge during board handling and live insertion into backplanes. |
| Operating Temperature | 0°C to 70°C - commercial-grade grade confirmed by "C" suffix in LTC4306CUFD#PBF; junction max 125°C with θJA = 43°C/W (QFN exposed pad connected). |
Pinout & Package
Package: 24-lead QFN (4mm × 5mm), exposed pad (Pin 25) - thermal performance requires PCB connection for θJA = 43°C/W; otherwise θJA degrades to 140°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (ALERT) | Fault alert output | Open-drain SMBus-compliant output pulled low on ALERT1–ALERT4 assertion, stuck-bus timeout, or failed connection attempt; requires external 10kΩ pull-up. |
| Pin 2 (SDAIN) | Upstream SDA I/O | Bidirectional data line interface to master-side I²C bus; buffered with offset-compensated circuitry for capacitive isolation. |
| Pin 3 (GND) | Power ground | Reference for all analog and digital circuitry; must be low-impedance connection to system ground plane. |
| Pin 4 (SCLIN) | Upstream SCL input | Master-side clock line input; features slew-rate detection for rise time accelerator activation. |
| Pin 5 (ENABLE) | Interface enable/reset | Active-low control: pulls all registers to default state and disables I²C communication when low; monitors ALERT1–ALERT4 even when disabled. |
| Pin 6 (VCC) | Supply voltage | Primary power rail (2.7–5.5V); bypass capacitor ≥0.01µF required between Pin 6 and Pin 3 for noise suppression. |
| Pins 8–9 (GPIO1, GPIO2) | Configurable I/O | Software-controllable as input, open-drain output, or push-pull output; tolerate 1.5–5.5V pull-up voltages independent of VCC. |
| Pins 10–12 (ADR0–ADR2) | Address inputs | Three-state inputs enabling 27 unique I²C slave addresses (0x10–0x2E); float, tie-high, or tie-low for address selection. |
| Pin 13 (READY) | Connection status indicator | Open-drain output pulled low when no downstream channel is connected; used for system-level bus readiness signaling. |
| Pins 14–17, 19–20, 22–24 (SDA1–SDA4, SCL1–SCL4) | Downstream bus I/O | Four fully isolated SDA/SCL pairs; each pair connects only when corresponding FET switch is enabled via Register 3. |
| Pins 7, 18, 19, 22 (ALERT1–ALERT4) | Fault inputs | Active-low inputs from downstream peripherals; assertion pulls ALERT low and sets corresponding bit in Register 0. |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive bus isolation | Buffers isolate upstream bus capacitance from downstream buses (≤6pF input capacitance per pin), enabling fan-out extension beyond standard I²C limits. |
| Programmable stuck-bus recovery | Three timeout options (7.5/15/30ms) automatically disconnect faulty downstream channels while preserving upstream bus availability. |
| Independent downstream pull-up support | Each downstream channel accepts pull-up voltages from 2.2V to 5.5V - decoupled from VCC - enabling mixed-voltage backplane designs. |
| Nested I²C addressing | 27 unique slave addresses via ADR0–ADR2 allow multiple LTC4306CUFD#PBF devices on same upstream bus without address conflict. |
| Live insertion protection | Prevents SDA/SCL corruption during hot-plug events by blocking signal propagation until downstream bus logic states are verified (default mode). |
Applications
| Modular Telecom Backplanes | Industrial Sensor Hub Aggregation |
|---|---|
Use Scenario: Hot-pluggable SFP+ modules inserted into carrier cards with shared upstream I²C management bus. IC Role / Device Role / Timing Role: I²C bus multiplexer isolating each module's EEPROM, temperature sensor, and laser bias controller from others. Use Value: Prevents bus lockup when a defective module pulls SDA/SCL low; enables individual module reset without disrupting other slots. | Use Scenario: Central microcontroller managing 4 distinct sensor subsystems (pressure, humidity, gas, IMU) with separate I²C addresses and timing requirements. IC Role / Device Role / Timing Role: Bidirectional bus switch enabling time-multiplexed access to each sensor cluster while maintaining electrical isolation. Use Value: Eliminates need for discrete level shifters when sensors operate at 2.5V, 3.3V, and 5V; supports independent pull-up configurations per channel. |
| Server Baseboard Management (BMC) | Automotive Diagnostic Interface Modules |
Use Scenario: BMC monitoring FRUs (Field Replaceable Units) such as DIMMs, fans, and power supplies via dedicated I²C links. IC Role / Device Role / Timing Role: Fault-tolerant bus extender providing ALERT-driven notification of FRU failures and automatic stuck-bus recovery. Use Value: Reduces BMC firmware complexity by offloading fault detection and isolation; READY pin signals bus readiness to host software. | Use Scenario: Diagnostic gateway connecting vehicle ECUs (ABS, airbag, infotainment) to a central OBD-II port via isolated I²C paths. IC Role / Device Role / Timing Role: Robust bus switch with ±10kV HBM ESD protection for harsh automotive environments and reliable fault reporting via ALERT1–ALERT4. Use Value: Ensures diagnostic session continuity despite transient faults on individual ECU buses; GPIOs support custom handshake protocols. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C bus multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TCA9548APWR | 8-channel I²C switch with no rise time accelerators, no stuck-bus timeout, no GPIOs, and fixed 3.3V-only operation; lacks independent downstream pull-up support. | Suitable for low-cost, non-fault-critical fan-out expansion where all downstream buses share same voltage domain. | Select TCA9548APWR only if system does not require hot-swap resilience, mixed-voltage support, or autonomous fault recovery. |
| PCA9548ADH,118 | 8-channel switch with identical feature set to TCA9548APWR but offered in HVQFN package; shares same functional limitations regarding timeout, level translation, and GPIOs. | Preferred where space-constrained PCB layout favors 20-pin HVQFN over TSSOP; still unsuitable for backplane-level fault isolation. | Choose PCA9548ADH,118 when footprint compatibility with existing NXP-based designs is required, but verify absence of stuck-bus recovery needs. |
Compared with TCA9548APWR and PCA9548ADH,118, the LTC4306CUFD#PBF provides superior system robustness through hardware-enforced stuck-bus disconnection, per-channel rise time acceleration, and true mixed-voltage downstream support - critical for modular, hot-pluggable architectures where bus integrity must be maintained across diverse peripheral voltage domains.
Availability
LTC4306CUFD#PBF is available at Aetrix Electronics and suitable for modular telecom backplanes, industrial sensor hub aggregation, server baseboard management (BMC), and automotive diagnostic interface modules requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LTC4306CUFD#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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, formed through the acquisition of Linear Technology in 2017.
The LTC4306CUFD#PBF belongs to ADI's high-reliability interface IC product line, designed specifically for fault-resilient I²C/SMBus infrastructure in modular, hot-pluggable, and multi-voltage electronic systems.
FAQ
What is the operating temperature range of the LTC4306CUFD#PBF?
The LTC4306CUFD#PBF is rated for 0°C to 70°C ambient operation (commercial grade), as indicated by the "C" suffix in the part number. Its absolute maximum junction temperature is 125°C, achievable with proper thermal design - including connection of the exposed pad (Pin 25) to PCB ground for θJA = 43°C/W. Storage temperature range is –65°C to +125°C for the QFN package.
How does the LTC4306CUFD#PBF handle stuck-low bus conditions?
The LTC4306CUFD#PBF continuously monitors downstream SDA/SCL internal node voltages using comparators with 0.52V falling and 0.6V rising thresholds. If either node remains below 0.52V longer than the programmed timeout (7.5ms/15ms/30ms), it asserts ALERT low and disables the upstream-downstream buffers for affected channels - isolating the fault while preserving upstream bus functionality. The Latched Timeout bit in Register 0 indicates occurrence.
Can the LTC4306CUFD#PBF support different pull-up voltages on each downstream channel?
Yes - each downstream channel (SDA1–SDA4, SCL1–SCL4) can be pulled up to an independent supply voltage ranging from 2.2V to 5.5V, regardless of the LTC4306CUFD#PBF's VCC value. This enables true mixed-voltage backplane designs, such as interfacing 2.5V, 3.3V, and 5V peripherals on the same upstream I²C bus without external level shifters.
What is the function of the READY pin on the LTC4306CUFD#PBF?
The READY pin (Pin 13) is an open-drain N-channel MOSFET 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 actively connected. With an external 10kΩ pull-up resistor, it provides a hardware-ready signal to the host controller, indicating bus connectivity status without requiring register reads.
Does the LTC4306CUFD#PBF support SMBus Alert Response Address protocol?
Yes - the LTC4306CUFD#PBF is fully compatible with the SMBus Alert Response Address (ARA) protocol. When ALERT is pulled low due to any fault condition, the host can broadcast the ARA (0x0C), and the LTC4306CUFD#PBF will respond with its configured I²C address on SDAIN, releasing the ALERT line after acknowledgment. This enables standardized, multi-device fault resolution in SMBus systems.
LTC4306CUFD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN 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:
- 24-QFN (4x5)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
LTC4306CUFD#PBF FAQ
1.How can I place an order for LTC4306CUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4306CUFD#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 LTC4306CUFD#PBF reliable?
The price and inventory of LTC4306CUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC4306CUFD#PBF is usually 5 days.
3.What payment methods are accepted for LTC4306CUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4306CUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4306CUFD#PBF?
LTC4306CUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4306CUFD#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 LTC4306CUFD#PBF?
For technical support, including LTC4306CUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4306CUFD#PBF requirements.
6.How does Aetrix verify that LTC4306CUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC4306CUFD#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 LTC4306CUFD#PBF meets industry standards.
7.What is the process for return or replacement of LTC4306CUFD#PBF?
All LTC4306CUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4306CUFD#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 LTC4306CUFD#PBF part is unused and in its original packaging.
Return procedure for LTC4306CUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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