My Inquiry
My Account
Analog Devices Inc. LTC3355EUF#TRPBF
- Part No.:
- LTC3355EUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LTC3355EUF#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,757
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3355EUF#TRPBF from Analog Devices (formerly Linear Technology) is a monolithic input power interrupt ride-through DC/DC system integrating a 1A buck regulator, 5A boost backup regulator, and 1A CC/CV supercapacitor charger in a single 20-lead 4mm × 4mm QFN package. It delivers regulated 2.7V–5V output from 3V–20V input, charges supercapacitors up to 50F, and sustains VOUT during VIN loss-enabling seamless "dying-gasp" operation in industrial power meters and solid-state drives.
For engineers reviewing the LTC3355EUF#TRPBF datasheet, LTC3355EUF#TRPBF pinout, LTC3355EUF#TRPBF application, or LTC3355EUF#TRPBF equivalent, key selection criteria include its dual-regulator architecture with programmable current limits (VIN, boost, charge), thermal regulation to 110°C, 0.5V minimum VCAP start-up for maximum supercap energy utilization, and integrated PFI/RSTB/CPGOOD status indicators.
Technical Context
The LTC3355EUF#TRPBF implements two independent constant-frequency (1MHz) current-mode switching regulators: a nonsynchronous 1A buck for primary regulation and a nonsynchronous 5A boost for backup, both sharing the same FB error amplifier and 0.8V reference. Its charger uses linear CC/CV topology with 0.8V ICHG and CFB references, programmable via external resistors (RICHG: 60.4kΩ–604kΩ; RIBSTPK: 200kΩ–1MΩ).
Power sequencing is managed by dedicated comparators: PFI monitors VIN dropout (0.775V–0.825V threshold), RSTB asserts reset when VOUT reaches 92.5% of target, and CPGOOD signals VCAP readiness at same threshold. Thermal regulation actively reduces charge current above 110°C, while thermal shutdown disables all functions at 155°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 3V to 20V - supports wide-input industrial supplies and battery-backed systems. |
| VOUT Range | 2.7V to 5V - programmable via FB resistor divider; includes 5.65V overvoltage clamp. |
| Buck Regulator | 1A peak current, 1MHz fixed frequency - enables compact 6.8µH inductor design with <1000µs soft-start. |
| Boost Regulator | 5A peak current, operates down to 0.5V VCAP - extracts >95% of stored supercap energy. |
| Charger | 1A programmable CC/CV linear charger - sets charge current via ICHG pin (0.1A–1A); includes 30mV CFB hysteresis. |
| Thermal Regulation | Junction limit at 110°C - dynamically scales charge current to prevent die overheating without shutdown. |
| Package | 20-lead 4mm × 4mm QFN with exposed pad - θJA = 47°C/W; requires soldered GND pad for thermal conduction. |
Pinout & Package
20-lead 4mm × 4mm plastic QFN (UF package) with exposed thermal pad (Pin 21 = GND). Requires PCB vias under pad for thermal management per datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PFI (1) | VIN dropout monitor input | Compares divided VIN to 0.8V reference; triggers boost enable and buck disable when threshold crossed. |
| FB (2) | Output voltage feedback | 0.8V reference node shared by buck and boost regulators; sets VOUT via resistor divider. |
| MODE (3) | Switching mode control | Logic input selecting PWM (low) or Burst Mode (high) for both buck and boost regulators. |
| VINS (4) | VIN current sense input | Accepts voltage drop across external sense resistor (max 50mV) to program VIN current limit. |
| VIN (5) | Main input power supply | Supplies internal regulator (INTVCC) and buck switch; bypass with ≥10µF ceramic capacitor. |
| VINM5 (6) | VIN–4.65V internal rail filter | Connects 1µF ceramic cap to VIN; stabilizes internal bias rail derived from VIN. |
| SW1 (7) | Buck switch node | Connects to buck inductor and catch diode; high dV/dt node requiring minimized trace area. |
| EN_CHG (8) | Charger enable | Active-high logic input; must be high, VIN > PFI threshold, and VOUT in regulation for charging. |
| CPGOOD (9) | VCAP ready indicator | Open-drain output pulled low until VCAP ≥ 92.5% of programmed voltage (CFB-set). |
| PFOB (10) | Power-fail output | Open-drain output pulled low when PFI detects VIN dropout; enables boost regulator. |
| CFB (11) | VCAP voltage feedback | 0.8V reference node for supercap float voltage; sets VCAP via resistor divider from VCAP pin. |
| ICHG (12) | Charge current programming | 0.8V reference; charge current = 60.4kΩ / RICHG (0.1A–1A range). |
| RSTB (13) | VOUT power-on reset | Open-drain output pulled low until VOUT ≥ 92.5% of FB-set voltage; 250ms delay after release. |
| VCAP (14) | Supercapacitor connection | CC/CV charger output; connects directly to supercap anode; includes 8kΩ bleed resistor for OVP. |
| VOUT (15) | Regulated system output | Delivers load power from buck (VIN present) or boost (VIN lost); shared by both regulators. |
| SW2 (16,17) | Boost switch node | Dual pins connected internally; route to boost inductor and rectifier diode with minimal loop area. |
| INTVCC (18) | Internal bias supply | 2.5V during startup, then tracks VOUT; bypass with 1µF ceramic cap to GND. |
| VCBST (19) | Boost error amplifier output | Compensation node; connect RC network to GND to stabilize boost control loop. |
| IBSTPK (20) | Boost peak current programming | 0.8V reference; boost peak current = 1MΩ / RIBSTPK (1A–5A range). |
| GND (21) | Ground reference & thermal pad | Exposed pad must be soldered to PCB ground plane with multiple vias for thermal and electrical integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated ride-through architecture | Single-chip solution combining buck, boost, and supercap charger eliminates discrete power-path complexity and timing mismatches. |
| 0.5V VCAP start-up capability | Enables use of full supercap voltage range (e.g., 3F–50F), maximizing backup runtime without external boost precharge. |
| Programmable triple current limiting | Independent resistor-programmable limits for VIN input, boost output, and supercap charge current-enabling precise fault protection. |
| Thermal regulation with 110°C clamp | Actively throttles charge current before thermal shutdown, allowing higher average power in constrained thermal environments. |
| Dedicated status outputs (PFOB/RSTB/CPGOOD) | Three open-drain indicators provide deterministic system-level monitoring of power fail, VOUT readiness, and VCAP charge state. |
Applications
| Industrial Power Meters | Solid-State Drives (SSD) |
|---|---|
|
Use Scenario: Maintaining real-time clock, flash wear-leveling metadata, and safe shutdown during AC mains interruption. IC Role / Device Role / Timing Role: LTC3355EUF#TRPBF provides uninterrupted 3.3V VOUT from supercapacitor during <100ms grid dropout. Use Value: Prevents data corruption by sustaining critical SSD controller functions for ≥500ms with 10F supercap at 0.5A load. |
Use Scenario: Preserving DRAM cache contents and completing write operations during sudden power loss. IC Role / Device Role / Timing Role: LTC3355EUF#TRPBF acts as ride-through power source, enabling controlled flush of volatile cache to NAND. Use Value: Achieves JEDEC JESD219 compliance for power-loss protection using single 3F supercap and no external MOSFETs. |
| Industrial Alarms & Sensors | Ride-Through "Dying Gasp" Supplies |
|
Use Scenario: Keeping wireless sensor nodes operational during battery swap or primary supply maintenance. IC Role / Device Role / Timing Role: LTC3355EUF#TRPBF charges supercap from 12V industrial bus and powers 3.3V MCU/RF transceiver during gap. Use Value: Delivers 200ms backup at 150mA from 5F supercap, eliminating need for secondary battery or complex charge management. |
Use Scenario: Providing last-cycle telemetry and fault logging in PLCs and motor drives during brownout events. IC Role / Device Role / Timing Role: LTC3355EUF#TRPBF serves as autonomous backup supply triggered by PFI comparator on main DC rail. Use Value: Guarantees ≥300ms hold-up time at 4V/0.8A with thermal regulation preventing overtemperature during extended backup. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar supercapacitor-based ride-through power supply applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3350IUFD#TRPBF | Lower 3A boost peak current; no VIN current limit; 16-pin 3mm × 4mm QFN. | Targeted at lower-power backup (<500mA) and space-constrained designs; lacks VINS-based input current limiting. | Select when boost load ≤0.5A and board area is premium; verify PFI threshold compatibility with existing resistor dividers. |
| MAX38889ATG+T | 2.7V–5.5V input; 2A boost; integrated 2.5A buck; no separate supercap charger; 20-pin 4mm × 4mm TQFN. | Designed for Li-ion backup instead of supercaps; requires external charger IC or battery management; higher integration but different energy storage paradigm. | Choose for battery-backed systems where cell balancing or fuel gauging is required; not a direct supercap replacement due to missing CC/CV charger. |
Compared with LTC3355EUF#TRPBF, LTC3350IUFD#TRPBF offers smaller footprint and lower cost for light-load ride-through, while MAX38889ATG+T shifts architecture toward battery backup with higher integration but eliminates the dedicated supercap charging path essential for high-cycle-life applications.
Availability
LTC3355EUF#TRPBF is available at Aetrix Electronics and suitable for industrial power meters, solid-state drives, and ride-through "dying-gasp" supplies requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for LTC3355EUF#TRPBF 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 acquired Linear Technology in 2017 and maintains full technical and manufacturing continuity for the LTC portfolio, including precision power management ICs with industry-leading reliability and automotive/industrial qualification.
The LTC3355EUF#TRPBF belongs to Linear's high-integration power backup product line, designed specifically for seamless VIN interruption handling in mission-critical industrial and storage systems using supercapacitors as energy reservoirs.
FAQ
What is the minimum supercapacitor voltage required for LTC3355EUF#TRPBF boost operation?
The LTC3355EUF#TRPBF boost regulator operates down to 0.5V on the VCAP pin, enabling extraction of >95% of stored energy from supercapacitors. This low start-up threshold eliminates the need for external precharge circuits and maximizes usable capacitance in backup applications such as power meters and SSDs.
How does thermal regulation affect the charge current of LTC3355EUF#TRPBF?
The LTC3355EUF#TRPBF incorporates active thermal regulation that begins reducing the supercapacitor charge current when the junction temperature approaches 110°C. This prevents thermal shutdown while maintaining continuous operation, allowing designers to optimize charge rate for typical ambient conditions without risking device damage under worst-case thermal loads.
Can LTC3355EUF#TRPBF support both buck and boost regulation at the same VOUT voltage?
Yes, the LTC3355EUF#TRPBF uses a shared FB pin and 0.8V reference for both buck and boost regulators, ensuring identical VOUT setpoints (2.7V–5V) regardless of operating mode. This eliminates output voltage mismatch during seamless transition from main supply to supercap backup, critical for stable microcontroller and memory operation.
What is the function of the VINS pin on LTC3355EUF#TRPBF?
The VINS pin on LTC3355EUF#TRPBF senses voltage drop across an external resistor between VIN and VINS to implement programmable input current limiting. When the sensed voltage exceeds 50mV, the device reduces charge current first, then buck regulator drive strength-protecting upstream supplies and enabling robust operation in current-limited industrial power rails.
Does LTC3355EUF#TRPBF require external compensation components for the boost regulator?
Yes, the LTC3355EUF#TRPBF requires an external RC network connected from the VCBST pin to ground to compensate the boost control loop. This network stabilizes the error amplifier response and ensures reliable regulation across load and input voltage variations, particularly important when operating near the 0.5V VCAP minimum.
LTC3355EUF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 20V
- Voltage - Output (Min/Fixed):
- 2.7V
- Voltage - Output (Max):
- 5V
- Current - Output:
- 1A
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (4x4)
LTC3355EUF#TRPBF FAQ
1.How can I place an order for LTC3355EUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3355EUF#TRPBF 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 LTC3355EUF#TRPBF reliable?
The price and inventory of LTC3355EUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3355EUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3355EUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3355EUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3355EUF#TRPBF?
LTC3355EUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3355EUF#TRPBF 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 LTC3355EUF#TRPBF?
For technical support, including LTC3355EUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3355EUF#TRPBF requirements.
6.How does Aetrix verify that LTC3355EUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3355EUF#TRPBF 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 LTC3355EUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3355EUF#TRPBF?
All LTC3355EUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3355EUF#TRPBF, 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 LTC3355EUF#TRPBF part is unused and in its original packaging.
Return procedure for LTC3355EUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3355EUF#TRPBF Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
