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Analog Devices Inc. LTC3351IUFF#PBF
- Part No.:
- LTC3351IUFF#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Management - Specialized
- Package:
- 44-WFQFN Exposed Pad
- Datasheet:
-
LTC3351IUFF#PBF.pdf
- Description:
- HOT SWAPPABLE HIGH CURRENT SUPER
- Quantity:
- Payment:
- Shipping:
Inventory:1,582
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Product details
Overview
LTC3351IUFF#PBF from Analog Devices is a hot-swappable supercapacitor backup power controller that charges, balances, and monitors 1–4 series supercapacitors while delivering >10A bidirectional power via synchronous step-down/step-up conversion. It integrates I²C/SMBus telemetry (16-bit ADC), programmable UV/OV thresholds up to 35V, and all-N-FET power path control for high-availability server and UPS systems.
For engineers reviewing the LTC3351IUFF#PBF datasheet, LTC3351IUFF#PBF pinout, LTC3351IUFF#PBF application, or LTC3351IUFF#PBF equivalent, this page delivers verified functional identity, validated 44-pin QFN package mapping, confirmed 4.5V–35V input range, >10A charge/backup current capability, and two rigorously cross-checked alternative parts with documented technical and application differences.
Technical Context
The LTC3351IUFF#PBF implements a dual-mode synchronous buck-boost controller: in step-down mode it delivers constant-current/constant-voltage charging with programmable input current limit; in step-up mode it reverses power flow to supply VOUT from the supercapacitor stack. Internal shunt balancers eliminate external resistors, and each capacitor node (CAP1–CAP4) features dedicated overvoltage protection via integrated regulators.
Its measurement subsystem includes a 16-bit ADC with ±1.5% full-scale error for VIN, VOUT, VCAP, ISNSP_HS, ISNSP_CHG, ICAP, GPI, and individual capacitor voltages (meas_vcap1–meas_vcap4), all accessible via I²C/SMBus. The hot-swap controller uses N-FETs with programmable current limiting (7–50mV sense threshold) and automatic retry timing controlled by CTIMER.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4.5V to 35V - supports wide-input industrial and server rails without external pre-regulation. |
| Charge/Backup Current | >10A - enables high-power ride-through for 12V UPS and PCIe NVM applications. |
| Supercapacitor Stack | 1–4 series cells, up to 5V per cell - accommodates common 2.7V/3.0V supercapacitor configurations. |
| ADC Resolution | 16-bit - provides precise capacitance and ESR calculation with <±2mV measurement error. |
| Switching Frequency | 200kHz–1MHz (programmable via RT resistor) - allows optimization of efficiency vs. size for 4.7μH–10μH inductors. |
| Package | 44-lead 4mm × 7mm × 0.75mm QFN - thermally enhanced with exposed PGND pad (θJC = 2.6°C/W). |
| I²C/SMBus Interface | 400kHz max clock, SMBALERT interrupt output - enables real-time system monitoring and fault reporting. |
Pinout & Package
Package: 44-lead (4mm × 7mm) plastic QFN with exposed thermal pad (Pin 45 = PGND). Requires soldering of exposed pad to PCB ground plane for thermal compliance (θJA = 36.4°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CAP1–CAP4 | Individual supercapacitor voltage sensing nodes | Enable per-cell voltage monitoring and active shunt balancing without external resistors. |
| ICAP / VCAP | Charge current sense differential inputs | Measure instantaneous charge/discharge current with 32mV full-scale sensitivity for ESR calculation. |
| TGATE / BGATE / SW | Synchronous buck-boost gate drive outputs | Drive external N-channel MOSFETs with 0.6Ω pull-down resistance for low-loss switching. |
| OUTFET | Ideal diode gate driver output | Drives external N-FET between VCAP and VOUT using VCAPP5 charge pump rail for low forward drop. |
| ISNSP_HS / ISNSM | Hot-swap current sense inputs | Set programmable foldback current limit (7–50mV threshold) for inrush and circuit breaker protection. |
| SCL / SDA / SMBALERT | I²C/SMBus interface pins | Provide read/write access to 16-bit telemetry registers including VIN, VOUT, VCAP, capacitance, and ESR. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional synchronous converter | Enables >10A CC/CV charging and step-up backup with >90% efficiency at 5A load (VCAP = 6V → VOUT = 12V). |
| Integrated shunt balancers | Eliminates need for 4× external balancing resistors and associated power loss in 4-cell stacks. |
| 16-bit system monitor ADC | Delivers calibrated measurements of VIN, VOUT, VCAP, ISNSP_HS, ISNSP_CHG, ICAP, GPI, and per-capacitor voltages. |
| Programmable UV/OV thresholds | Configurable up to 35V with 60mV hysteresis to prevent false triggering during line transients. |
| Hot-swap with automatic retry | CTIMER-based fault timing and RETRYB-controlled reconnection ensure safe recovery after overcurrent events. |
Applications
| Server Power Backup | PCIe NVM Card Ride-Through |
|---|---|
Use Scenario: Maintains DRAM retention and NVMe controller state during AC mains interruption in rack-mounted servers. IC Role / Device Role / Timing Role: Backup controller providing seamless transition from main rail to supercapacitor stack within <100µs. Use Value: Enables 10–20ms hold-up time at >10A load using compact 4×10F supercapacitor stack, eliminating bulky batteries. |
Use Scenario: Powers NVMe SSD during hot-plug insertion/removal to prevent data corruption and firmware reset. IC Role / Device Role / Timing Role: Hot-swap controller with programmable inrush limit and ideal diode path for VOUT-to-VCAP isolation. Use Value: Prevents bus droop and ensures clean power sequencing with <5ms recovery from input fault via SMBus-triggered backup enable. |
| Industrial 12V UPS | Mass Storage RAID Controller |
Use Scenario: Provides uninterrupted 12V output for PLC I/O modules during brownouts in factory automation systems. IC Role / Device Role / Timing Role: Step-up mode controller delivering regulated VOUT from decaying VCAP stack with programmable OUTFB feedback. Use Value: Achieves >85% efficiency down to 3.5V VCAP, extending usable energy extraction by 30% versus fixed-threshold solutions. |
Use Scenario: Preserves cache integrity and journaling state in enterprise RAID controllers during unexpected power loss. IC Role / Device Role / Timing Role: System monitor with I²C telemetry reporting real-time VCAP, capacitance decay, and ESR drift to host BMC. Use Value: Enables predictive maintenance by tracking supercapacitor health via periodic SMBus reads of meas_cap and meas_esr registers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar supercapacitor backup controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX34440ETJ+ | 12-bit ADC only; no integrated step-up converter; requires external boost FETs and gate drivers. | Limited to monitoring-only or low-current (<2A) backup; lacks >10A bidirectional power delivery. | Select when system already has discrete boost stage and only needs telemetry + charge control. |
| TPS61088RHLR | Standalone boost converter (no supercapacitor charging, balancing, or monitoring); no I²C interface or hot-swap logic. | Only suitable for unidirectional backup; cannot replace LTC3351IUFF#PBF's integrated charger/monitor/controller functions. | Select only for simple boost-only applications where supercapacitor management is handled externally. |
Compared with MAX34440ETJ+ and TPS61088RHLR, the LTC3351IUFF#PBF uniquely integrates bidirectional power conversion, per-cell balancing, 16-bit telemetry, and hot-swap control in one QFN package-eliminating 12+ external components required by alternatives to achieve equivalent functionality.
Availability
LTC3351IUFF#PBF is available at Aetrix Electronics and suitable for high-availability server power backup, PCIe NVM card ride-through, and industrial 12V UPS applications requiring stable component supply across extended temperature ranges.
Supply support for LTC3351IUFF#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 is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision instrumentation and power management.
The LTC3351 product line delivers integrated supercapacitor backup solutions for mission-critical systems where battery-free, long-life, high-reliability energy storage is essential-targeting datacenter, telecom, and industrial infrastructure.
FAQ
What is the operating temperature range for the LTC3351IUFF#PBF?
The LTC3351IUFF#PBF is specified for operation from –40°C to +125°C junction temperature. Its I-grade qualification guarantees full electrical performance across this range, with thermal design supported by θJC = 2.6°C/W and mandatory soldering of the exposed PGND pad to the PCB ground plane.
Does the LTC3351IUFF#PBF support 4-cell supercapacitor stacks?
Yes, the LTC3351IUFF#PBF explicitly supports 1–4 series supercapacitors via CAP_SLCT0/CAP_SLCT1 pin configuration. Each cell is monitored individually (CAP1–CAP4), actively balanced using internal shunt regulators, and protected against overvoltage up to 5V per cell.
How does the LTC3351IUFF#PBF measure supercapacitor ESR?
The LTC3351IUFF#PBF measures ESR by applying a known test current (programmed via ITST pin resistor) to discharge the stack, then calculating impedance from the resulting voltage decay slope using its 16-bit ADC. Results are reported in the meas_esr register via I²C/SMBus.
Can the LTC3351IUFF#PBF operate without an external microcontroller?
Yes, the LTC3351IUFF#PBF operates autonomously: its internal state machine handles hot-swap startup, CC/CV charging, step-up backup, and shunt balancing without host intervention. I²C is optional for telemetry and configuration; default settings enable full functionality at power-on.
What is the maximum programmable switching frequency of the LTC3351IUFF#PBF?
The LTC3351IUFF#PBF supports a maximum programmable switching frequency of 1MHz, set by connecting a 53.6kΩ resistor from RT to SGND. Minimum frequency is 200kHz (RT = 267kΩ), with typical operation at 500kHz (RT = 107kΩ) for optimal efficiency/size trade-off.
LTC3351IUFF#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 44-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Applications:
- Supercapacitor Backup Controller
- Current - Supply:
- 2.25mA
- Voltage - Supply:
- 4.5V ~ 35V
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 44-QFN (4x7)
LTC3351IUFF#PBF FAQ
1.How can I place an order for LTC3351IUFF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3351IUFF#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 LTC3351IUFF#PBF reliable?
The price and inventory of LTC3351IUFF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3351IUFF#PBF is usually 5 days.
3.What payment methods are accepted for LTC3351IUFF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3351IUFF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3351IUFF#PBF?
LTC3351IUFF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3351IUFF#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 LTC3351IUFF#PBF?
For technical support, including LTC3351IUFF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3351IUFF#PBF requirements.
6.How does Aetrix verify that LTC3351IUFF#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3351IUFF#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 LTC3351IUFF#PBF meets industry standards.
7.What is the process for return or replacement of LTC3351IUFF#PBF?
All LTC3351IUFF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3351IUFF#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 LTC3351IUFF#PBF part is unused and in its original packaging.
Return procedure for LTC3351IUFF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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