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Analog Devices Inc. LTC3633AEUFD-3#TRPBF
- Part No.:
- LTC3633AEUFD-3#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3633AEUFD-3#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 3A DL 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,086
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Product details
Overview
LTC3633AEUFD-3#TRPBF 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 fixed 1.5V–12V VON sense range and 0.6V internal reference enabling precise low-voltage regulation. It supports phase-shifted operation, external frequency synchronization, and Burst Mode® for high efficiency in battery-powered instrumentation and distributed power systems.
For engineers reviewing the LTC3633AEUFD-3#TRPBF datasheet, LTC3633AEUFD-3#TRPBF pinout, LTC3633AEUFD-3#TRPBF application, or LTC3633AEUFD-3#TRPBF equivalent, key selection criteria include its 1.5V–12V VON sensing capability (distinguishing it from LTC3633A-2), 28-pin QFN-4mm×5mm package with exposed PGND pad, dual-channel independent enable/control, and integrated overvoltage/overtemperature protection.
Technical Context
The LTC3633AEUFD-3#TRPBF uses a controlled on-time, current-mode architecture with internal PLL to lock switching frequency to an internal oscillator or external clock applied at MODE/SYNC. Its dual channels operate independently with selectable 0°/180° phase shift, reducing input/output capacitor stress through interleaved operation.
Each channel features separate RUN, VFB, TRACKSS, ITH, VON, and PGOOD pins, supporting independent soft-start, output tracking, loop compensation, and power-good monitoring. The device implements valley-current limiting (2.6A–4.5A), ±8% PGOOD windowing with 40µs filtering, and PVIN overvoltage lockout at 22.5V rising / 21.5V falling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 20V - supports Li-ion stacks and 5V/12V point-of-load rails without external pre-regulation. |
| Output Current per Channel | 3A continuous - enables dual-rail supplies for FPGAs, ASICs, or multi-core processors. |
| VON Sense Range | 1.5V to 12V - defines valid output voltage programming range for stable constant-frequency operation. |
| Switching Frequency | 500kHz to 4MHz - adjustable via RT resistor or external sync signal; default 2MHz when RT = INTVCC. |
| Feedback Reference | 0.6V ±1% - allows accurate low-VOUT regulation (e.g., 1.2V, 1.8V) using standard resistor dividers. |
| Efficiency | Up to 95% - achieved in forced continuous mode at mid-load; Burst Mode® extends light-load efficiency. |
| Protection Features | Short-circuit, PVIN overvoltage (22.5V trip), overtemperature, and PGOOD status - ensures robust system-level fault handling. |
Pinout & Package
Package: 28-lead (4mm × 5mm) plastic QFN with exposed PGND pad (Pin 29), rated for –40°C to 125°C junction temperature. Exposed pad must be soldered to PCB for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PGOOD1 (Pin 1) | Channel 1 power-good status | Open-drain output pulled low if VFB1 deviates >±8% from 0.6V; releases at ±5% with 40µs filter. |
| PHMODE (Pin 2) | Phase select control | Logic-high (INTVCC) forces 180° out-of-phase switching between channels; ground forces in-phase operation. |
| RUN1 (Pin 3) | Channel 1 enable | Active-high enable: >1.22V enables regulation; <1.01V disables channel with shutdown current <13µA. |
| MODE/SYNC (Pin 4) | Mode control / sync input | Ground = forced continuous mode; float/INTVCC = Burst Mode®; external clock = sync + forced continuous. |
| RT (Pin 5) | Oscillator frequency set | Resistor to SGND programs fSW = 500kHz–4MHz; tied to INTVCC defaults to ~2MHz. |
| RUN2 (Pin 6) | Channel 2 enable | Independent enable pin identical in function and threshold to RUN1. |
| SGND (Pin 7) | Signal ground reference | Low-noise analog ground for feedback divider, RT, and compensation networks. |
| PGOOD2 (Pin 8) | Channel 2 power-good status | Functionally identical to PGOOD1, referenced to VFB2. |
| VFB2 (Pin 9) | Channel 2 feedback input | Connects to resistor divider; error amplifier compares to 0.6V reference to regulate VOUT2. |
| TRACKSS2 (Pin 10) | Channel 2 tracking/soft-start | Voltage <0.6V forces FB servo to TRACK value; internal 1.4µA pull-up enables soft-start with external capacitor. |
| ITH2 (Pin 11) | Channel 2 error amp output | Compensation node: connect RC network for stability; tie to INTVCC for internal compensation. |
| VON2 (Pin 12) | Channel 2 on-time setpoint | Sets comparator threshold for controlled on-time; tied to VOUT2 for VOUT-proportional timing (1.5V–12V range). |
| SW2 (Pins 13,14) | Channel 2 switch node | Connects to inductor; swings from ~–0.3V to PVIN2 during operation. |
| PVIN2 (Pins 15,16) | Channel 2 power input | Independent high-side MOSFET supply; supports different input voltages per channel. |
| BOOST2 (Pin 17) | Channel 2 bootstrap supply | Drives high-side gate; connects to (+) of bootstrap cap; swings up to PVIN2 + INTVCC. |
| INTVCC (Pin 18) | Internal 3.3V regulator output | Powers internal logic/drivers; requires ≥1µF ceramic decoupling to PGND. |
| BOOST1 (Pin 19) | Channel 1 bootstrap supply | Identical function to BOOST2, referenced to PVIN1. |
| SVIN (Pin 20) | Signal input supply | Powers internal LDO for INTVCC; accepts 3.6V–20V, same as PVIN range. |
| PVIN1 (Pins 21,22) | Channel 1 power input | Independent high-side MOSFET supply; electrically isolated from PVIN2. |
| SW1 (Pins 23,24) | Channel 1 switch node | Identical function to SW2, referenced to PVIN1. |
| VON1 (Pin 25) | Channel 1 on-time setpoint | Identical function to VON2, supports 1.5V–12V VOUT1 sensing. |
| ITH1 (Pin 26) | Channel 1 error amp output | Identical function to ITH2, supports external or internal compensation. |
| TRACKSS1 (Pin 27) | Channel 1 tracking/soft-start | Identical function to TRACKSS2, enables independent soft-start per channel. |
| VFB1 (Pin 28) | Channel 1 feedback input | Identical function to VFB2, regulates VOUT1 via resistor divider to 0.6V reference. |
| PGND (Pin 29) | Power ground | Exposed pad; mandatory low-impedance connection to PCB ground plane for thermal dissipation and noise control. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 3A buck regulators | Enables compact dual-rail power delivery with separate enable, feedback, and soft-start per channel. |
| 180° phase-shifted operation | Reduces RMS input/output capacitor ripple current by ~30%, allowing smaller bulk capacitance. |
| Burst Mode® with <13µA shutdown current | Extends battery life in portable instruments by minimizing quiescent power at light loads. |
| External frequency synchronization | Eliminates beat frequencies in multi-regulator systems and enables deterministic EMI shaping. |
| Integrated 0.6V reference and valley-current limit | Ensures tight output regulation accuracy and repeatable current-limit threshold across temperature. |
| 1.5V–12V VON sensing range | Differentiates LTC3633AEUFD-3#TRPBF from -2 variants and enables stable high-VOUT designs (e.g., 5V, 12V rails). |
Applications
| Point-of-Load Power Supply | Battery-Powered Instrumentation |
|---|---|
Use Scenario: Providing tightly regulated 3.3V and 1.8V rails to FPGA I/O banks and core logic from a 12V intermediate bus. IC Role / Device Role / Timing Role: Dual-channel synchronous buck regulator delivering independent, phase-controlled outputs with fast transient response. Use Value: Reduces total solution size by integrating two 3A regulators in one QFN; 180° phasing cuts input capacitor requirements by 40%. | Use Scenario: Powering handheld test equipment with dual ADC/DAC signal chains requiring isolated 5V analog and 1.2V digital supplies. IC Role / Device Role / Timing Role: High-efficiency dual buck controller managing battery discharge profile via Burst Mode® and independent RUN control. Use Value: Achieves >90% efficiency at 100mA load per rail, extending runtime; PGOOD signals enable safe system sequencing. |
| Distributed Power System | Industrial Control Module |
Use Scenario: Generating 5V and 3.3V auxiliary rails in a modular PLC backplane powered from 24V DC. IC Role / Device Role / Timing Role: Robust dual buck IC with PVIN overvoltage protection (22.5V) and overtemperature shutdown. Use Value: Withstands industrial transients without latch-up; exposed PGND pad ensures reliable thermal performance at 125°C ambient. | Use Scenario: Supplying isolated 12V and 5V rails to microcontroller, CAN transceiver, and sensor interface in a DIN-rail mounted controller. IC Role / Device Role / Timing Role: Dual-channel regulator with independent TRACKSS inputs enabling coordinated power-up sequencing. Use Value: Eliminates need for external sequencing ICs; soft-start prevents inrush current on cold start. |
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-2#TRPBF | VON sense range 0.6V–6V vs. 1.5V–12V; otherwise pin- and function-compatible. | Optimized for sub-6V outputs (e.g., 1.2V, 3.3V); unsuitable for 12V VOUT without external scaling. | Select -2 for low-VOUT designs; -3 for 5V/12V rails where VON must track full output range. |
| TPS544B20RJRR | Single-channel 4A buck with PMBus interface; no dual-channel or phase-shift capability. | Requires two devices for dual-rail; adds digital control overhead but enables telemetry and margining. | Choose when telemetry, dynamic voltage scaling, or higher single-rail current (>3A) is required. |
Compared with LTC3633AEUFD-2#TRPBF, the LTC3633AEUFD-3#TRPBF supports higher output voltages without external resistive scaling of VON, while both share identical package, pinout, and control architecture. Against TPS544B20RJRR, the LTC3633AEUFD-3#TRPBF offers integrated dual-channel operation and analog simplicity at the cost of digital configurability.
Availability
LTC3633AEUFD-3#TRPBF is available at Aetrix Electronics and suitable for point-of-load power supplies, battery-powered instrumentation, and distributed power systems requiring stable component supply, extended temperature support (–40°C to 125°C), and dual-rail integration in minimal footprint.
Supply support for LTC3633AEUFD-3#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 its precision power product portfolio with rigorous automotive and industrial qualification standards.
The LTC3633A family is designed for high-density, high-efficiency dual-output DC/DC conversion in space-constrained applications where independent regulation, phase control, and robust protection are critical.
FAQ
What is the VON sense range of the LTC3633AEUFD-3#TRPBF?
The LTC3633AEUFD-3#TRPBF has a confirmed VON sense range of 1.5V to 12V, as specified in the Electrical Characteristics table and Operation section of the datasheet. This distinguishes it from the LTC3633A-2 variant (0.6V–6V) and enables stable constant-frequency operation when regulating higher output voltages such as 5V or 12V without external voltage scaling circuitry. The VON pin directly senses the output voltage within this range to maintain accurate on-time control.
Does the LTC3633AEUFD-3#TRPBF support external frequency synchronization?
Yes, the LTC3633AEUFD-3#TRPBF supports external frequency synchronization via the MODE/SYNC pin (Pin 4). When driven with a clean CMOS clock signal, the internal PLL locks the switching frequency to the external source, forcing forced continuous mode operation. This capability eliminates beat frequencies in multi-regulator systems and enables deterministic EMI reduction - a feature confirmed in the Features list, Typical Application schematic, and PIN FUNCTIONS description.
What package type and thermal characteristics does the LTC3633AEUFD-3#TRPBF use?
The LTC3633AEUFD-3#TRPBF uses a 28-lead (4mm × 5mm) plastic QFN package with exposed PGND pad (Pin 29), as documented in the ORDER INFORMATION and PIN CONFIGURATION sections. Its thermal resistance is θJA = 43°C/W, and the maximum junction temperature is 125°C. The exposed pad must be soldered to the PCB for effective thermal dissipation and low-impedance grounding - a requirement explicitly stated in both the Absolute Maximum Ratings and Top View diagrams.
How does the LTC3633AEUFD-3#TRPBF implement power-good signaling?
The LTC3633AEUFD-3#TRPBF provides independent open-drain PGOOD1 (Pin 1) and PGOOD2 (Pin 8) outputs. Each pulls low when its respective VFB pin deviates more than ±8% from the 0.6V reference and releases when regulation returns within ±5%. A built-in 40µs filter prevents false triggering during transients. These signals are confirmed in the Electrical Characteristics table (PGOOD thresholds), PIN FUNCTIONS description, and Typical Application schematic showing pull-up resistors to INTVCC.
Can the LTC3633AEUFD-3#TRPBF operate with independent input voltages per channel?
Yes, the LTC3633AEUFD-3#TRPBF supports independent input supplies via separate PVIN1 (Pins 21,22) and PVIN2 (Pins 15,16) pins, each rated for 1.5V to 20V. This allows channel-specific input sources - for example, one channel powered from a 12V rail and the other from a 5V rail - as verified in the ELECTRICAL CHARACTERISTICS table (PVIN1/PVIN2 Supply Range) and PIN FUNCTIONS description. SVIN (Pin 20) remains shared for signal circuitry.
LTC3633AEUFD-3#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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-QFN (4x5)
LTC3633AEUFD-3#TRPBF FAQ
1.How can I place an order for LTC3633AEUFD-3#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3633AEUFD-3#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 LTC3633AEUFD-3#TRPBF reliable?
The price and inventory of LTC3633AEUFD-3#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3633AEUFD-3#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3633AEUFD-3#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3633AEUFD-3#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3633AEUFD-3#TRPBF?
LTC3633AEUFD-3#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3633AEUFD-3#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 LTC3633AEUFD-3#TRPBF?
For technical support, including LTC3633AEUFD-3#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3633AEUFD-3#TRPBF requirements.
6.How does Aetrix verify that LTC3633AEUFD-3#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3633AEUFD-3#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 LTC3633AEUFD-3#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3633AEUFD-3#TRPBF?
All LTC3633AEUFD-3#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3633AEUFD-3#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 LTC3633AEUFD-3#TRPBF part is unused and in its original packaging.
Return procedure for LTC3633AEUFD-3#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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