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Analog Devices Inc. LTC3633AIUFD-2#TRPBF
- Part No.:
- LTC3633AIUFD-2#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3633AIUFD-2#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 3A DL 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,925
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Product details
Overview
LTC3633AIUFD-2#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 selectable 0°/180° phase shift, adjustable 500kHz–4MHz switching frequency, and 0.6V reference enabling low-output-voltage regulation. It serves as a high-efficiency point-of-load power supply in battery-powered instrumentation and distributed power systems.
For engineers reviewing the LTC3633AIUFD-2#TRPBF datasheet, LTC3633AIUFD-2#TRPBF pinout, LTC3633AIUFD-2#TRPBF application, or LTC3633AIUFD-2#TRPBF equivalent, key selection criteria include its dual 3A output capability, controlled on-time current-mode architecture for fast transient response, phase-shifted operation to reduce input/output capacitance requirements, and support for Burst Mode® or forced continuous mode.
Technical Context
The LTC3633AIUFD-2#TRPBF employs a constant-frequency controlled on-time current-mode architecture with internal PLL synchronization, enabling stable operation at high frequencies (up to 4MHz) while maintaining fast load transient response. Its dual channels operate independently with separate PVIN inputs, allowing asymmetric input rail configurations.
Phase alignment is user-selectable via PHMODE pin (0° or 180°), reducing input ripple current by interleaving switch node transitions. The device integrates top and bottom MOSFETs with 130mΩ/65mΩ RDS(ON), supports external frequency synchronization via MODE/SYNC pin, and features independent RUN1/RUN2 enable control with 1.22V rising threshold.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 20V - supports lithium-ion battery stacks and standard 5V/12V intermediate bus rails. |
| Output Current per Channel | 3A continuous - enables compact dual-rail PoL conversion without external MOSFETs. |
| Switching Frequency Range | 500kHz to 4MHz - programmable via RT resistor; allows optimization of inductor size vs. efficiency. |
| Feedback 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 and proper layout. |
| Minimum On-Time | 20ns - supports high step-down ratios (e.g., 12V→1.2V) at 2MHz without pulse-skipping instability. |
| Protection Features | Short-circuit, overvoltage (22.5V PVIN lockout), overtemperature, and PGOOD status - ensures robust system-level reliability. |
Pinout & Package
Package: 28-lead (4mm × 5mm) plastic QFN with exposed PGND pad (Pin 29), rated for –40°C to 125°C junction temperature. Thermal resistance θJA = 43°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PGOOD1 (Pin 1) | Channel 1 power-good status output | Open-drain signal pulled low when VFB1 deviates >±8% from 0.6V reference; used for system sequencing and fault monitoring. |
| PHMODE (Pin 2) | Phase select control input | Logic-high selects 180° out-of-phase operation between channels; reduces input capacitor RMS current and EMI. |
| RUN1 (Pin 3) | Channel 1 enable input | Active-high enable with 1.22V threshold; controls startup/shutdown timing independently per channel. |
| MODE/SYNC (Pin 4) | Mode selection & external clock input | Ground = forced continuous mode; floating/INTVCC = Burst Mode®; driven clock = synchronization source with automatic forced mode. |
| RT (Pin 5) | Oscillator frequency programming | Resistor-to-SGND sets fSW from 500kHz–4MHz; tied to INTVCC defaults to ~2MHz internal oscillator. |
| RUN2 (Pin 6) | Channel 2 enable input | Independent enable control identical to RUN1; enables staggered power-up or fault-isolated shutdown. |
| SGND (Pin 7) | Signal ground reference | Low-noise analog ground for feedback divider, compensation network, and RT resistor-must be isolated from PGND at single-point connection. |
| PGOOD2 (Pin 8) | Channel 2 power-good status output | Dual-channel PGOOD allows independent monitoring of both regulated outputs in safety-critical systems. |
| VFB2 (Pin 9) | Channel 2 feedback input | Connects to resistor divider to set output voltage; referenced to internal 0.6V bandgap for accuracy. |
| TRACKSS2 (Pin 10) | Channel 2 tracking/soft-start input | Enables output voltage ramp-up or coordinated sequencing with other regulators via external capacitor. |
| ITH2 (Pin 11) | Channel 2 error amplifier output | Loop compensation node; connect RC network for stability tuning or tie to INTVCC for internal compensation. |
| VON2 (Pin 12) | Channel 2 on-time voltage input | Sets on-time proportional to VOUT2 when tied to output; supports 0.6V–6V range for LTC3633AIUFD-2#TRPBF. |
| SW2 (Pins 13,14) | Channel 2 switch node | High-current connection to external inductor; swings from ~–0.3V to PVIN2 during operation. |
| PVIN2 (Pins 15,16) | Channel 2 power input | Independent high-side supply for channel 2 MOSFETs; supports different input voltages than PVIN1. |
| BOOST2 (Pin 17) | Channel 2 bootstrap supply | Drives high-side gate; connected to bootstrap capacitor between BOOST2 and SW2 pins. |
| INTVCC (Pin 18) | Internal 3.3V regulator output | Powers internal logic and gate drivers; requires ≥1µF ceramic decoupling to PGND. |
| BOOST1 (Pin 19) | Channel 1 bootstrap supply | Identical function to BOOST2 but for channel 1; must use separate bootstrap capacitor. |
| SVIN (Pin 20) | Signal input supply | Powers control circuitry and internal LDO for INTVCC; can differ from PVIN rails. |
| PVIN1 (Pins 21,22) | Channel 1 power input | Independent high-side supply for channel 1 MOSFETs; enables dual-input architectures. |
| SW1 (Pins 23,24) | Channel 1 switch node | High-current connection to external inductor; same swing behavior as SW2. |
| VON1 (Pin 25) | Channel 1 on-time voltage input | Same function as VON2; ties to VOUT1 to maintain constant on-time proportional to output voltage. |
| ITH1 (Pin 26) | Channel 1 error amplifier output | Identical to ITH2; supports external loop compensation or internal default. |
| TRACKSS1 (Pin 27) | Channel 1 tracking/soft-start input | Enables independent soft-start or voltage tracking for channel 1 output. |
| VFB1 (Pin 28) | Channel 1 feedback input | Primary regulation input for channel 1; connects to resistor divider for precise output setting. |
| PGND (Exposed Pad) | Power ground return | Mandatory solder connection to PCB ground plane for thermal dissipation and low-impedance return path for high di/dt currents. |
Key Features
| Feature | Design Value |
|---|---|
| Controlled on-time current-mode architecture | Delivers fast line/load transient response and stable operation across wide VIN/VOUT ratios without external compensation. |
| Selectably interleaved 180° phase operation | Reduces input capacitor RMS current by up to 30%, lowering required capacitance and EMI filtering complexity. |
| Burst Mode® and forced continuous mode | Enables >90% efficiency at light loads (10mA) while maintaining low output ripple under full load via user-selectable mode. |
| Independent PVIN1/PVIN2 inputs | Supports heterogeneous input sources (e.g., battery + DC/DC) and improves fault isolation between channels. |
| Integrated 130mΩ/65mΩ MOSFETs | Eliminates need for external power switches, reducing BOM count and PCB area while ensuring matched thermal performance. |
| 0.6V ±1% reference with ±0.002%/V line regulation | Ensures <±1% output accuracy across full input range and temperature, critical for FPGA and ASIC core supplies. |
Applications
| Industrial Test Equipment | Medical Portable Diagnostics |
|---|---|
Use Scenario: Dual-rail power for mixed-signal data acquisition modules requiring clean 3.3V analog and 1.8V digital supplies. IC Role / Device Role / Timing Role: Dual-channel synchronous buck regulator providing independent, tightly regulated outputs with synchronized switching to minimize noise coupling. Use Value: 180° phase shift reduces input ripple current by 40%, allowing smaller bulk capacitors and lower EMI emissions in compact handheld enclosures. | Use Scenario: Battery-powered ultrasound probe with real-time DSP and high-resolution ADC requiring low-noise, sequenced power rails. IC Role / Device Role / Timing Role: Primary point-of-load regulator delivering [email protected] and [email protected] with soft-start and tracking for safe FPGA configuration. Use Value: TRACKSS1/2 pins enable monotonic startup and voltage sequencing, preventing latch-up during cold boot from Li-ion battery (3.0V–4.2V). |
| Automotive ADAS Camera Modules | Telecom Remote Radio Units |
Use Scenario: Compact vision processing unit powered from 12V vehicle bus with strict thermal and EMI constraints. IC Role / Device Role / Timing Role: Dual-channel buck converter supplying image sensor (1.2V) and ISP SoC (1.8V) with independent RUN control for dynamic power gating. Use Value: Independent RUN1/RUN2 pins allow selective shutdown of sensor rail during idle periods, cutting quiescent current to 500µA per channel. | Use Scenario: Outdoor small-cell base station requiring reliable dual 3A outputs from 48V intermediate bus via intermediate DC/DC. IC Role / Device Role / Timing Role: Secondary-stage regulator converting 12V intermediate rail to 3.3V and 5V for RF front-end and baseband processors. Use Value: 20V absolute max PVIN rating withstands automotive load-dump transients; PGOOD1/2 signals feed into system watchdog for fault recovery. |
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 |
|---|---|---|---|
| MPQ4436-AEC1 | Automotive-grade (AEC-Q100), 3.5A/channel, fixed 500kHz–3MHz frequency, no phase-shift control. | Lacks 180° phase shift and external frequency sync; limited to automotive environments with stricter qualification. | Choose when AEC-Q100 compliance is mandatory and phase interleaving is not required. |
| TPS544B20 | 4A/channel, 4.5V–18V input, integrated FETs, supports PMBus for telemetry; no Burst Mode®. | Requires external EEPROM for configuration; higher IQ (2.5mA) limits battery life in portable use cases. | Prefer when digital monitoring, margining, or remote fault reporting is needed over ultra-low-light-load efficiency. |
Compared with MPQ4436-AEC1 and TPS544B20, the LTC3633AIUFD-2#TRPBF offers unique phase-shift control and Burst Mode® for lowest light-load IQ (13µA), making it optimal for thermally constrained, battery-sensitive dual-rail applications where analog precision and EMI reduction are prioritized over digital configurability or automotive qualification.
Availability
LTC3633AIUFD-2#TRPBF is available at Aetrix Electronics and suitable for industrial test equipment, medical portable diagnostics, and automotive ADAS camera modules requiring stable component supply with guaranteed long-term availability.
Supply support for LTC3633AIUFD-2#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 high-performance power management portfolio with rigorous process control and application-focused design.
The LTC3633A product line delivers dual-channel monolithic synchronous buck regulators optimized for high-efficiency, low-noise point-of-load conversion in space-constrained systems with demanding transient and thermal requirements.
FAQ
What is the maximum input voltage rating for LTC3633AIUFD-2#TRPBF?
The LTC3633AIUFD-2#TRPBF has an absolute maximum PVIN rating of 20V, with overvoltage lockout triggering at 22.5V (rising) and releasing at 21.5V (falling). This protects internal MOSFETs during transient events while supporting nominal 12V and 19.2V (16-cell Li-ion) input rails. Operation above 20V violates Absolute Maximum Ratings and may cause permanent damage.
Does LTC3633AIUFD-2#TRPBF support output voltage tracking between channels?
Yes, the LTC3633AIUFD-2#TRPBF supports independent output voltage tracking via TRACKSS1 and TRACKSS2 pins. Applying a ramp voltage (e.g., from an external DAC or RC network) to these pins forces the corresponding VFB pin to servo to that voltage during startup, enabling monotonic, sequenced power-up of multiple rails. Tracking range is 0.28V–0.315V at the TRACKSS pin for accurate 0.6V reference scaling.
What is the difference between LTC3633AIUFD-2#TRPBF and LTC3633AIUFD-3#TRPBF?
The LTC3633AIUFD-2#TRPBF and LTC3633AIUFD-3#TRPBF differ in their VON sense range: the -2 version supports 0.6V–6V, while the -3 version supports 1.5V–12V. This affects on-time proportionality and output voltage compatibility-using a -2 part with VOUT >6V causes frequency deviation. Both share identical pinout, package, and all other electrical characteristics.
Can LTC3633AIUFD-2#TRPBF operate with only one channel enabled?
Yes, the LTC3633AIUFD-2#TRPBF supports independent channel operation. Driving RUN1 high and RUN2 low enables only channel 1, while RUN2 high and RUN1 low enables only channel 2. Both channels remain fully functional with independent feedback, compensation, and protection-ideal for partial-power modes or redundancy schemes.
What thermal considerations apply to LTC3633AIUFD-2#TRPBF in QFN-28 package?
The LTC3633AIUFD-2#TRPBF in 4mm×5mm QFN-28 has θJA = 43°C/W. To maintain TJ ≤125°C at full 3A/channel load, ambient temperature must stay below 82°C with adequate copper pour on the exposed PGND pad. Thermal vias (≥6×0.3mm) to inner ground planes are mandatory; insufficient thermal relief increases junction temperature by >20°C under continuous load.
LTC3633AIUFD-2#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):
- 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-QFN (4x5)
LTC3633AIUFD-2#TRPBF FAQ
1.How can I place an order for LTC3633AIUFD-2#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3633AIUFD-2#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 LTC3633AIUFD-2#TRPBF reliable?
The price and inventory of LTC3633AIUFD-2#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3633AIUFD-2#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3633AIUFD-2#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3633AIUFD-2#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3633AIUFD-2#TRPBF?
LTC3633AIUFD-2#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3633AIUFD-2#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 LTC3633AIUFD-2#TRPBF?
For technical support, including LTC3633AIUFD-2#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3633AIUFD-2#TRPBF requirements.
6.How does Aetrix verify that LTC3633AIUFD-2#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3633AIUFD-2#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 LTC3633AIUFD-2#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3633AIUFD-2#TRPBF?
All LTC3633AIUFD-2#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3633AIUFD-2#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 LTC3633AIUFD-2#TRPBF part is unused and in its original packaging.
Return procedure for LTC3633AIUFD-2#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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