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Analog Devices Inc. LTC3633AIFE-3#PBF
- Part No.:
- LTC3633AIFE-3#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3633AIFE-3#PBF.pdf
- Description:
- IC REG BUCK ADJ 3A DL 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,121
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Product details
Overview
LTC3633AIFE-3#PBF from Analog Devices (formerly Linear Technology) is a dual-channel monolithic synchronous step-down regulator delivering 3A per channel across 3.6V–20V input, supporting independent 1.5V–12V output ranges with 0.6V reference and current-mode control. It enables high-efficiency point-of-load power for battery-powered instruments and distributed systems using phase-shifted operation and external frequency synchronization.
For engineers reviewing the LTC3633AIFE-3#PBF datasheet, LTC3633AIFE-3#PBF pinout, LTC3633AIFE-3#PBF application, or LTC3633AIFE-3#PBF equivalent, key selection criteria include its 1.5V–12V VON sense range (distinguishing it from LTC3633A-2), 28-pin TSSOP package with exposed PGND pad, Burst Mode® vs forced continuous mode selection, and dual-channel 180° phase shift capability for reduced input ripple.
Technical Context
The LTC3633AIFE-3#PBF implements a controlled on-time, current-mode architecture with internal phase-locked loop (PLL) servoing to maintain constant switching frequency from 500kHz to 4MHz. Its dual channels support selectable 0°/180° phase alignment via PHMODE pin, enabling interleaved operation that halves input capacitor RMS current.
Each channel features independent RUN enable inputs, dedicated TRACKSS/ITH/VON/VFB pins, and separate PVIN supplies-allowing asymmetric input sourcing. Overvoltage lockout triggers at 22.5V PVIN rising edge, and thermal shutdown activates above 125°C junction temperature with automatic recovery.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 20V - supports Li-ion stacks and 12V/5V intermediate bus systems |
| Output Voltage Sense Range | 1.5V to 12V - defines minimum/maximum programmable output when VON tied to VOUT |
| Max Output Current | 3A per channel - sustained DC load capability with thermal derating above 85°C ambient |
| Switching Frequency | 500kHz to 4MHz - set by RT resistor or synchronized externally via MODE/SYNC pin |
| Feedback Reference | 0.6V ±1% - enables low-output designs (e.g., 1.5V) with standard resistor dividers |
| Efficiency | Up to 95% - achieved at mid-load in forced continuous mode with optimized inductor/capacitor selection |
| Phase Shift Control | Selectable 0° or 180° - reduces input capacitance requirement by interleaving channel currents |
Pinout & Package
Package: 28-Lead Plastic TSSOP with exposed PGND pad (pin 29), rated for –40°C to 125°C operating junction temperature (θJA = 25°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ITH1 / ITH2 | Error amplifier output & compensation node | Connects to RC network for loop stability; tie to INTVCC for internal compensation |
| VFB1 / VFB2 | Feedback input for channel 1/2 | Compares divided output voltage to 0.6V reference; sets regulation point |
| RUN1 / RUN2 | Channel enable inputs | Logic-high (>1.22V) enables regulation; <1.0V forces shutdown with µA quiescent current |
| TRACKSS1 / TRACKSS2 | Tracking/soft-start control | Below 0.6V enables output tracking; internal 1.4µA pull-up enables soft-start with external capacitor |
| PHMODE | Phase alignment select | Ground = in-phase; INTVCC = 180° out-of-phase interleaving for lower input ripple |
| MODE/SYNC | Operation mode & sync input | Ground = forced continuous; floating/INTVCC = Burst Mode®; driven clock = sync + forced continuous |
| PGOOD1 / PGOOD2 | Open-drain power-good status | Pulled low if VFB outside ±8%; releases at ±5% with 40µs filter to suppress transient glitches |
| SW1 / SW2 | Switch node outputs | Connect to external inductors; swing from ~–0.3V to PVIN; require low-inductance layout |
| PVIN1 / PVIN2 | Power MOSFET supply inputs | Independent inputs per channel; each rated 1.5V–20V; enable asymmetric input sourcing |
| BOOST1 / BOOST2 | Floating gate driver supplies | Bootstrap capacitor connections; swing up to PVIN + INTVCC for high-side NMOS drive |
| INTVCC | Internal 3.3V regulator output | Powers control circuitry; requires ≥1µF ceramic decoupling to PGND; disabled when both RUN pins low |
| SVIN | Signal input supply | Powers internal LDO for INTVCC; accepts 3.6V–20V; separates signal integrity from power paths |
| RT | Oscillator frequency programming | Resistor to SGND sets fSW = 3.2E11/RRT Hz; tie to INTVCC for ~2MHz default |
| PGND | Power ground (exposed pad) | Must be soldered to PCB plane for thermal dissipation and low-impedance return path |
Key Features
| Feature | Design Value |
|---|---|
| Dual-channel 3A synchronous buck | Integrates two complete 3A regulators in single 28-pin TSSOP, reducing board area vs discrete solutions |
| 180° phase-shifted operation | Halves input capacitor RMS current and eases EMI filtering requirements in multi-rail systems |
| Burst Mode® with 500µA quiescent current | Extends battery life in portable instruments by disabling switching during light loads |
| External frequency synchronization | Enables deterministic timing in noise-sensitive systems and eliminates beat frequencies between rails |
| Independent tracking & soft-start | Allows coordinated power-up sequencing across multiple voltages using shared TRACKSS biasing |
| Overvoltage and overtemperature protection | Auto-recovering fault responses prevent damage during transients without system-level intervention |
Applications
| Portable Test Equipment | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Handheld multimeters and oscilloscope probes requiring isolated 3.3V and 5V rails from single Li-ion cell stack. IC Role / Device Role / Timing Role: Dual-channel step-down regulator providing independently regulated, phase-shifted outputs with soft-start sequencing. Use Value: Enables compact form factor via integrated dual 3A channels and reduces input capacitance by 50% using 180° interleaving. | Use Scenario: Fieldbus interface modules needing 1.8V FPGA core, 3.3V I/O, and 5V analog supply from 12V backplane. IC Role / Device Role / Timing Role: Point-of-load regulator delivering three stable outputs with tracking capability and independent enable control. Use Value: Simplifies power tree design with single IC replacing three discrete converters while maintaining tight cross-regulation. |
| Medical Wearables | Automotive Infotainment ECUs |
Use Scenario: ECG patch monitors powered by coin-cell or thin-film battery requiring ultra-low quiescent current and precise voltage sequencing. IC Role / Device Role / Timing Role: Low-noise, high-efficiency dual regulator operating in Burst Mode® with programmable soft-start timing. Use Value: Achieves >200-hour runtime on CR2032 via 500µA sleep current and eliminates cold-start failures with controlled ramp-up. | Use Scenario: Head-unit display controllers needing 1.1V SoC core, 1.8V memory, and 3.3V interface rails from automotive 12V supply with load dump immunity. IC Role / Device Role / Timing Role: Robust dual-channel buck converter with 22.5V PVIN overvoltage lockout and thermal shutdown. Use Value: Survives ISO 7637-2 pulse 5a (25V/100ms) without latch-up, eliminating need for upstream TVS clamping. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3633AEFE-3#PBF | Same electrical specs and pinout; differs only in QFN-28 vs TSSOP-28 package | QFN offers lower θJA (43°C/W) and better thermal performance in space-constrained layouts | Select for higher power density or improved thermal management; requires rework of land pattern |
| TPS543B20RGLT | Single-channel 3A buck with PMBus interface; no phase shift or dual independent outputs | Requires two devices for dual-rail designs; adds digital configuration overhead but enables real-time telemetry | Choose when telemetry, margining, or dynamic voltage scaling are required over analog simplicity |
Compared with LTC3633AEFE-3#PBF, the LTC3633AIFE-3#PBF trades thermal performance for easier hand-soldering and legacy PCB compatibility; versus TPS543B20RGLT, it provides true dual-channel integration without communication bus dependencies or firmware integration effort.
Availability
LTC3633AIFE-3#PBF is available at Aetrix Electronics and suitable for portable test equipment, industrial PLC I/O modules, medical wearables, and automotive infotainment ECUs requiring stable component supply with long-term lifecycle assurance.
Supply support for LTC3633AIFE-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 acquired Linear Technology in 2017 and maintains its precision power management portfolio with rigorous qualification standards for industrial and automotive applications.
The LTC3633A series targets high-density, high-efficiency point-of-load conversion where dual independent rails, phase interleaving, and low-quiescent-current operation are critical-especially in battery-powered and thermally constrained systems.
FAQ
What is the VON sense range for LTC3633AIFE-3#PBF, and why does it matter?
The LTC3633AIFE-3#PBF has a VON sense range of 1.5V to 12V, meaning it accurately regulates outputs within that span when VON pins are tied to their respective VOUTs. This distinguishes it from the LTC3633A-2 (0.6V–6V range) and ensures stable operation for higher-voltage rails like 5V or 12V without frequency deviation. Using an output outside this range risks switching frequency instability and degraded regulation accuracy in the LTC3633AIFE-3#PBF.
How does the PHMODE pin affect system-level input capacitance requirements?
When PHMODE is tied to INTVCC, the LTC3633AIFE-3#PBF configures its two channels to switch 180° out of phase, causing input current pulses to alternate rather than coincide. This interleaving reduces peak-to-peak input ripple current by approximately 50%, allowing smaller bulk input capacitors and easing EMI filter design. Grounding PHMODE forces in-phase operation, doubling input ripple amplitude and increasing RMS stress on the input capacitor in the LTC3633AIFE-3#PBF.
Can LTC3633AIFE-3#PBF operate with different input voltages on PVIN1 and PVIN2?
Yes, the LTC3633AIFE-3#PBF supports independent input supplies: PVIN1 and PVIN2 each accept 1.5V to 20V and may be driven from separate sources. This enables asymmetric configurations-for example, powering Channel 1 from a 12V bus and Channel 2 from a 5V auxiliary rail-without cross-coupling or efficiency penalty. The SVIN pin remains common and must be supplied within 3.6V–20V to power internal logic in the LTC3633AIFE-3#PBF.
What protection features are built into LTC3633AIFE-3#PBF, and how do they behave?
The LTC3633AIFE-3#PBF integrates PVIN overvoltage lockout (trip at 22.5V, resume at 21.5V), overtemperature shutdown (>125°C junction), short-circuit protection, and PGOOD monitoring with 40µs glitch filtering. All protections are auto-recovering: after fault removal, the device resumes regulation without reset. Input overvoltage suspension halts switching immediately, preserving MOSFET integrity, and triggers internal soft-start upon recovery-ensuring clean re-entry into regulation for the LTC3633AIFE-3#PBF.
Is LTC3633AIFE-3#PBF pin-compatible with other variants in the LTC3633A family?
No, the LTC3633AIFE-3#PBF is not pin-compatible with LTC3633A-2 variants due to differing VON sense ranges and associated internal reference configurations. While physical pin count and layout match across TSSOP-28 versions (e.g., LTC3633AIFE-2#PBF and LTC3633AIFE-3#PBF), substituting them without adjusting feedback and VON networks will cause regulation failure. Always verify VON range alignment and update resistor dividers before interchanging LTC3633AIFE-3#PBF with other family members.
LTC3633AIFE-3#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 3.6V
- Voltage - Input (Max):
- 20V
- Voltage - Output (Min/Fixed):
- 1.5V
- Voltage - Output (Max):
- 12V
- Current - Output:
- 3A
- Frequency - Switching:
- 500kHz ~ 4MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LTC3633AIFE-3#PBF FAQ
1.How can I place an order for LTC3633AIFE-3#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3633AIFE-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 LTC3633AIFE-3#PBF reliable?
The price and inventory of LTC3633AIFE-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 LTC3633AIFE-3#PBF is usually 5 days.
3.What payment methods are accepted for LTC3633AIFE-3#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3633AIFE-3#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3633AIFE-3#PBF?
LTC3633AIFE-3#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3633AIFE-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 LTC3633AIFE-3#PBF?
For technical support, including LTC3633AIFE-3#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3633AIFE-3#PBF requirements.
6.How does Aetrix verify that LTC3633AIFE-3#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3633AIFE-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 LTC3633AIFE-3#PBF meets industry standards.
7.What is the process for return or replacement of LTC3633AIFE-3#PBF?
All LTC3633AIFE-3#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3633AIFE-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 LTC3633AIFE-3#PBF part is unused and in its original packaging.
Return procedure for LTC3633AIFE-3#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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