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Analog Devices Inc. LTC3633AEFE#PBF
- Part No.:
- LTC3633AEFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3633AEFE#PBF.pdf
- Description:
- IC REG BUCK ADJ 3A DL 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,849
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Product details
Overview
LTC3633AEFE#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, with selectable 0°/180° phase shift, adjustable 500kHz–4MHz switching frequency, and 0.6V reference enabling low-output-voltage regulation in point-of-load and battery-powered systems.
For engineers reviewing the LTC3633AEFE#PBF datasheet, LTC3633AEFE#PBF pinout, LTC3633AEFE#PBF application, or LTC3633AEFE#PBF equivalent, key selection criteria include dual-channel interleaved operation for reduced input ripple, Burst Mode® vs forced continuous mode trade-offs, VON-sense range (0.6V–6V), thermal performance in TSSOP-28 (θJA = 30°C/W), and compatibility with external synchronization and output tracking.
Technical Context
The LTC3633AEFE#PBF employs a controlled on-time, current-mode architecture with an internal PLL that locks switch-on timing to either its internal oscillator (set by RT resistor) or an external clock applied to MODE/SYNC. This enables stable high-frequency operation even at ultra-low duty cycles (5% at 2.25MHz).
Each channel features independent RUN enable, PGOOD status, TRACKSS soft-start/tracking, and ITH loop compensation pins. Phase shift between channels is digitally selected via PHMODE, and VON1/VON2 inputs allow on-time scaling proportional to output voltage-valid only within the 0.6V–6V sense range specified for the LTC3633A variant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 20V - supports Li-ion stacks and 5V/12V intermediate bus rails without external pre-regulation. |
| Output Current per Channel | 3A continuous - enables compact dual-rail power delivery for FPGA I/O banks or multi-core processors. |
| Switching Frequency Range | 500kHz to 4MHz - programmable via RT resistor; allows optimization of inductor size vs conduction loss. |
| VFB Reference Voltage | 0.6V ±1% - enables precise regulation down to sub-1V outputs using standard resistor dividers. |
| Efficiency | Up to 95% - achieved at full load with optimized external components; Burst Mode® extends light-load efficiency. |
| Phase Shift Control | Selectable 0° or 180° - reduces input capacitor RMS current and eases EMI filtering when interleaved. |
| Absolute Max VIN | 20V - higher than LTC3633 (16V), enabling direct use with 18V transient-tolerant supplies. |
Pinout & Package
Package: 28-Lead Plastic TSSOP (FE package), exposed PGND pad (Pin 29), θJA = 30°C/W, rated for –40°C to +125°C junction temperature.
| 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 to error amplifier | Compares output voltage (via resistor divider) against 0.6V reference for regulation. |
| RUN1 / RUN2 | Channel enable input | Logic-high (>1.22V) enables channel; <1.01V disables with shutdown current <13µA. |
| PGOOD1 / PGOOD2 | Open-drain power-good status | Pulled low if VFB deviates >±8%; releases after return to ±5% window with 40µs filter. |
| TRACKSS1 / TRACKSS2 | Tracking/soft-start control | Internal 1.4µA pull-up enables soft-start with external capacitor; <0.6V enables output tracking. |
| PHMODE | Phase select input | Tie to GND for in-phase, to INTVCC for 180° out-of-phase operation between channels. |
| MODE/SYNC | Mode select & sync input | GND = forced continuous; floating/INTVCC = Burst Mode®; external clock = synchronized forced continuous. |
| SW1 / SW2 | Switch node (dual-pin per channel) | Connects to external inductor; swings from ~–0.3V to VIN during operation. |
| VIN1 / VIN2 | Independent channel input supplies | Supports split-input architectures; each rated 3.6V–20V with overvoltage lockout at 22.5V. |
| BOOST1 / BOOST2 | Floating gate drive supply | Bootstrap connection for high-side MOSFET driver; swing up to VIN + INTVCC. |
| PGND | Power ground (exposed pad) | Mandatory PCB solder connection for thermal dissipation and low-impedance return path. |
Key Features
| Feature | Design Value |
|---|---|
| Controlled on-time current-mode architecture | Delivers fast transient response and stable operation at high step-down ratios and high frequencies. |
| Interleaved 180° phase operation | Reduces input capacitor RMS current by up to 30%, lowering required capacitance and input ripple voltage. |
| Burst Mode® operation | Quiescent current <500µA per channel at light load, extending battery life in portable instruments. |
| External frequency synchronization | Enables noise-sensitive systems to align switching edges with system clocks, easing EMI compliance. |
| Output voltage tracking & soft-start | Ensures controlled power-up sequencing across multiple rails using single capacitor per channel. |
| Comprehensive protection suite | Includes input overvoltage lockout (22.5V), overtemperature shutdown, and short-circuit current limiting (3.5A typ). |
Applications
| Point-of-Load Regulation | Battery-Powered Instruments |
|---|---|
Use Scenario: Powering FPGA core and I/O banks from a 12V intermediate rail in industrial PLC modules. IC Role / Device Role / Timing Role: Dual-channel buck regulator providing independent 1.2V/3.3V rails with interleaved switching to minimize input ripple. Use Value: Reduces input bulk capacitance by 40% versus single-channel solution while maintaining <10mV output ripple under dynamic load. |
Use Scenario: Supplying processor, memory, and sensor subsystems in handheld test equipment powered by 3S Li-ion. IC Role / Device Role / Timing Role: Primary DC/DC converter delivering 3A at 1.8V and 3A at 5V from 9V–12.6V battery stack. Use Value: Burst Mode® operation achieves <25µA total quiescent current in sleep state, enabling >1-month standby time. |
| Distributed Power Systems | High-Density Computing Modules |
Use Scenario: Generating auxiliary rails (2.5V, 1.8V) in telecom line cards with strict thermal constraints and shared 48V input. IC Role / Device Role / Timing Role: Dual-buck controller managing two independent loads with phase-shifted operation to reduce shared input bus stress. Use Value: 180° interleaving lowers peak input current by 50%, easing thermal design of upstream hot-swap controllers. |
Use Scenario: Powering GPU memory interfaces and SoC cores on compact AI accelerator modules with limited board area. IC Role / Device Role / Timing Role: High-efficiency dual regulator operating at 2.2MHz to fit 1.0µH inductors and 22µF ceramic output caps. Use Value: 95% peak efficiency at 3A/1.2V minimizes localized heating in thermally constrained 2-layer PCB layouts. |
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 |
|---|---|---|---|
| LTC3633AEUFD#PBF | Same electrical specs, but in 4mm × 5mm QFN-28 package (θJA = 43°C/W); no exposed pad routing constraints. | Better thermal performance in space-constrained layouts where TSSOP footprint is prohibitive. | Choose for higher power density or improved thermal management; requires rework of PCB layout and thermal pad design. |
| MP2491DS-LF-Z | Single-channel 3A buck; 4.5V–18V input; fixed 500kHz/1MHz freq; no phase sync, tracking, or Burst Mode®. | Suitable only for non-interleaved, lower-complexity dual-rail designs requiring discrete regulators. | Use when cost sensitivity outweighs feature requirements; expect higher input ripple and no light-load efficiency optimization. |
Compared with LTC3633AEFE#PBF, the QFN variant offers superior thermal resistance but demands more complex PCB assembly, while the MP2491DS-LF-Z sacrifices critical features like phase control and adaptive light-load operation-making it viable only in simplified, cost-driven implementations.
Availability
LTC3633AEFE#PBF is available at Aetrix Electronics and suitable for point-of-load regulation, battery-powered instrumentation, and distributed power systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LTC3633AEFE#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 high-performance power management portfolio with rigorous automotive-grade qualification and reliability testing.
The LTC3633A product line delivers dual-channel, high-current synchronous buck regulation for demanding embedded and industrial applications where efficiency, thermal performance, and multi-rail sequencing are critical.
FAQ
What is the maximum input voltage rating for the LTC3633AEFE#PBF?
The LTC3633AEFE#PBF has an absolute maximum input voltage rating of 20V on VIN1 and VIN2 pins, with overvoltage lockout activating at 22.5V (rising) and releasing at 21.5V (falling). This exceeds the 16V limit of the legacy LTC3633, enabling direct use with 18V nominal supplies and transient-tolerant designs.
Does the LTC3633AEFE#PBF support output voltage tracking between channels?
Yes, the LTC3633AEFE#PBF supports precise output voltage tracking via the TRACKSS1 and TRACKSS2 pins. Applying a ramp voltage below 0.6V to these pins causes the respective error amplifier to servo the VFB pin to match the TRACKSS voltage, enabling controlled power-up sequencing of multiple rails with a single capacitor per channel.
How does Burst Mode® operation affect light-load efficiency in the LTC3633AEFE#PBF?
In Burst Mode®, the LTC3633AEFE#PBF reduces quiescent current to <500µA per channel by disabling both power MOSFETs during light loads and entering sleep mode. This increases light-load efficiency significantly-e.g., >85% at 10mA output-compared to forced continuous mode, which maintains switching but incurs higher gate charge losses.
Can the LTC3633AEFE#PBF be synchronized to an external clock source?
Yes, the LTC3633AEFE#PBF supports external synchronization via the MODE/SYNC pin. Applying a clean clock signal (TTL/CMOS compatible) forces the internal PLL to lock the switching edge to the rising edge of the external clock, enabling deterministic timing alignment for EMI reduction and system-level noise management.
What is the function of the PHMODE pin on the LTC3633AEFE#PBF?
The PHMODE pin on the LTC3633AEFE#PBF selects inter-channel phase relationship: tying it to GND configures both channels to switch in phase, while connecting it to INTVCC sets them 180° out of phase. This interleaving reduces input capacitor RMS current and relaxes input filtering requirements in high-current dual-rail applications.
LTC3633AEFE#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):
- 0.6V
- Voltage - Output (Max):
- 6V
- 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
LTC3633AEFE#PBF FAQ
1.How can I place an order for LTC3633AEFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3633AEFE#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 LTC3633AEFE#PBF reliable?
The price and inventory of LTC3633AEFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3633AEFE#PBF is usually 5 days.
3.What payment methods are accepted for LTC3633AEFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3633AEFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3633AEFE#PBF?
LTC3633AEFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3633AEFE#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 LTC3633AEFE#PBF?
For technical support, including LTC3633AEFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3633AEFE#PBF requirements.
6.How does Aetrix verify that LTC3633AEFE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3633AEFE#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 LTC3633AEFE#PBF meets industry standards.
7.What is the process for return or replacement of LTC3633AEFE#PBF?
All LTC3633AEFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3633AEFE#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 LTC3633AEFE#PBF part is unused and in its original packaging.
Return procedure for LTC3633AEFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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