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Analog Devices Inc. LTC3633AIFE#TRPBF
- Part No.:
- LTC3633AIFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3633AIFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 3A DL 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,846
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Product details
Overview
LTC3633AIFE#TRPBF from Analog Devices (formerly Linear Technology) is a dual-channel monolithic synchronous step-down regulator delivering up to 3A per channel from 3.6V–20V input, featuring current-mode control, 0.6V reference, and selectable Burst Mode® or forced continuous operation. It supports phase-shifted interleaving (0°/180°), external frequency synchronization, and output tracking-used in point-of-load power supplies for FPGA, ASIC, and DSP core rails.
For engineers reviewing the LTC3633AIFE#TRPBF datasheet, LTC3633AIFE#TRPBF pinout, LTC3633AIFE#TRPBF application, or LTC3633AIFE#TRPBF equivalent, key selection criteria include dual 3A output capability, 20V absolute max VIN, 28-lead TSSOP package with exposed PGND pad, and confirmed compatibility with LTC3633A-1 variant for higher-VOUT designs.
Technical Context
The LTC3633AIFE#TRPBF implements a controlled on-time, current-mode architecture with internal phase-locked loop (PLL) servoing of switch on-time to maintain constant frequency across line/load/temperature. Its dual independent channels support interleaved 180° operation to reduce input RMS current and capacitor stress.
Each channel features programmable switching frequency (500kHz–4MHz), adjustable VON-based on-time scaling (0.6V–6V range), and integrated protection including input overvoltage lockout (22.5V trip), overtemperature shutdown, and short-circuit limiting. The device operates with ±8% PGOOD window and 40µs filter time for transient immunity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 20V - supports Li-ion battery stacks and 12V/5V intermediate bus systems. |
| Output Current per Channel | 3A continuous - enables single-chip dual-core rail generation without external MOSFETs. |
| Reference Voltage | 0.6V ±1% - allows precise low-VOUT regulation down to 0.6V with standard resistor dividers. |
| Switching Frequency Range | 500kHz to 4MHz - permits optimization between small magnetics (high-f) and high efficiency (low-f). |
| Efficiency | Up to 95% at full load - achieved via low RDS(ON) (130mΩ top / 65mΩ bottom) and adaptive mode control. |
| Phase Shift Control | Selectable 0° or 180° - reduces input ripple current by interleaving channel switching edges. |
| Protection Features | VIN overvoltage lockout (22.5V), thermal shutdown, short-circuit, and PGOOD status outputs - ensures robust system-level fault handling. |
Pinout & Package
Package: 28-Lead Plastic TSSOP with exposed PGND pad (Pin 29), rated for –40°C to +125°C junction temperature (θJA = 30°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PGOOD1 / PGOOD2 | Open-drain power-good status outputs | Assert low when respective VFB deviates >±8% from 0.6V; release after return to ±5% window with 40µs filtering. |
| RUN1 / RUN2 | Channel enable inputs | Active-high logic: >1.22V enables regulator; <1.01V forces shutdown with µA-level quiescent current. |
| PHMODE | Phase select control | Ground = in-phase operation; INTVCC = 180° interleaved switching to minimize input capacitor RMS current. |
| MODE/SYNC | Mode selection & external clock input | Ground = forced continuous mode; floating/INTVCC = Burst Mode®; driven clock = PLL-synchronized switching. |
| VFB1 / VFB2 | Feedback voltage inputs | Connect to resistor divider to set output voltage; referenced to internal 0.6V bandgap with ±0.6% initial accuracy. |
| TRACKSS1 / TRACKSS2 | Tracking/soft-start control inputs | Apply voltage <0.6V to track external rail; internal 1.4µA pull-up enables soft-start via capacitor-to-SGND. |
| ITH1 / ITH2 | Error amplifier compensation outputs | Interface with RC network for loop stability; connect to INTVCC for factory-tuned internal compensation. |
| VIN1 / VIN2 | Independent input supply pins | Support separate input sources per channel; each rated for 3.6V–20V with 20V absolute max rating. |
| SW1 / SW2 | Switch node connections | Drive external inductors; swing from ~–0.3V (body diode drop) to VIN during operation. |
| BOOST1 / BOOST2 | Floating gate drive supplies | Bootstrap nodes for high-side MOSFET drivers; require ceramic capacitors tied between BOOST and SW. |
| INTVCC | Internal 3.3V regulator output | Powers control circuitry; disabled when both RUN pins are low; requires ≥1µF ceramic bypass to PGND. |
| V2P5 | Dedicated 2.5V LDO output | Supplies 10mA; internally regulated to 2.5V ±0.4%; tie to INTVCC if unused. |
| SGND | Signal ground reference | Low-noise analog ground for feedback dividers, RT resistor, and compensation networks. |
| RT | Frequency programming input | Resistor-to-SGND sets fSW: 80.6kΩ = 4MHz, 162kΩ = 2MHz, 640kΩ = 500kHz (RRT = 3.2×10¹¹/f). |
| PGND | Power ground (exposed pad) | Must be soldered to PCB plane; carries high di/dt currents from input/output capacitors and MOSFETs. |
Key Features
| Feature | Design Value |
|---|---|
| Controlled on-time current-mode architecture | Enables stable high-frequency operation with fast transient response and inherent cycle-by-cycle current limiting. |
| Interleaved 180° phase shift | Reduces input ripple current amplitude by ~70% versus in-phase operation, relaxing input capacitor sizing and EMI filtering. |
| Burst Mode® operation | Extends light-load efficiency to >85% at 10mA while maintaining <20µA quiescent current per channel. |
| External frequency synchronization | Accepts TTL/CMOS clock on MODE/SYNC pin to eliminate beat frequencies in multi-regulator systems. |
| Output voltage tracking and soft-start | Ensures orderly power-up sequencing across multiple rails using single capacitor per TRACKSS pin. |
| Integrated 2.5V and 3.3V auxiliary regulators | Eliminates need for external bias supplies; V2P5 powers external circuitry, INTVCC powers internal logic/drivers. |
Applications
| Point-of-Load Power for FPGA Core Rails | Industrial PLC I/O Module Power |
|---|---|
Use Scenario: Supplying dual 1.2V/1.8V core and I/O rails for Xilinx Artix-7 FPGA in compact industrial controller. IC Role / Device Role / Timing Role: Dual-channel synchronous buck regulator providing tightly regulated, sequenced, low-noise DC power with independent enable and PGOOD monitoring. Use Value: Eliminates discrete DC/DC modules; achieves <1% output deviation under 3A dynamic load steps via current-mode control and 0.6V reference precision. |
Use Scenario: Generating isolated 3.3V and 5V rails for analog sensor front-ends and digital logic in DIN-rail mounted PLC modules. IC Role / Device Role / Timing Role: Dual-output step-down converter operating from 24V DC input bus with input overvoltage protection and thermal derating. Use Value: Reduces board area by 40% vs. two single-channel ICs; 180° phase shift cuts input capacitor count from four to two 10µF ceramics. |
| Battery-Powered Test Equipment | Medical Imaging Sensor Bias Supply |
Use Scenario: Powering 1.5V analog front-end and 3.3V microcontroller in handheld oscilloscope powered by 2-cell Li-ion (6V–8.4V). IC Role / Device Role / Timing Role: High-efficiency dual buck regulator supporting Burst Mode® for standby and forced continuous for active measurement cycles. Use Value: Extends battery life to >12 hours at 100mA avg. load; 95% peak efficiency minimizes thermal rise in sealed enclosure. |
Use Scenario: Providing ultra-low-noise 2.5V bias for CMOS image sensor arrays in portable ultrasound probe head. IC Role / Device Role / Timing Role: Precision dual buck with tracking capability to match reference voltage ramp during sensor initialization. Use Value: Achieves <10µVpp output noise (20Hz–20MHz) via internal compensation and dedicated V2P5 LDO for sensor analog supply. |
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#TRPBF | Same electrical specs but in 4mm × 5mm QFN-28 package with θJA = 43°C/W; no exposed pad on TSSOP equivalent. | Preferred for space-constrained layouts requiring lower profile; QFN offers better thermal performance at high ambient temperatures. | Select when PCB real estate is limited and thermal management via copper pour is feasible. |
| LTC3633AIFE-1#TRPBF | VON sense range extended to 1.5V–12V (vs. 0.6V–6V); identical pinout, package, and protection features. | Suitable for higher-output applications (e.g., 5V/12V rails) where wider VON range improves frequency stability at elevated VOUT. | Choose when designing for >3.3V outputs and requiring guaranteed frequency accuracy across full VOUT range. |
Compared with LTC3633AIFE#TRPBF, the QFN variant offers superior thermal resistance for high-power density designs, while the -1 version extends usable output voltage range without sacrificing pin compatibility-enabling one PCB layout to support multiple output configurations.
Availability
LTC3633AIFE#TRPBF is available at Aetrix Electronics and suitable for point-of-load power supplies, battery-powered instrumentation, and industrial PLC modules requiring stable component supply with full industrial temperature support (–40°C to +125°C).
Supply support for LTC3633AIFE#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 automotive and industrial qualification standards.
The LTC3633A series was designed for high-density, dual-rail DC/DC conversion in space- and thermal-constrained applications such as FPGA, ASIC, and DSP power delivery where efficiency, transient response, and reliability are critical.
FAQ
What is the maximum input voltage rating for the LTC3633AIFE#TRPBF?
The LTC3633AIFE#TRPBF has an absolute maximum input voltage rating of 20V on VIN1 and VIN2 pins. Operation above this level triggers overvoltage lockout at 22.5V (rising) with automatic recovery at 21.5V (falling). This 20V rating distinguishes it from the original LTC3633 (16V max) and confirms pin compatibility within the LTC3633A family.
Does the LTC3633AIFE#TRPBF support output voltage tracking between channels?
Yes, the LTC3633AIFE#TRPBF supports precise output voltage tracking via dedicated TRACKSS1 and TRACKSS2 pins. Applying a voltage below 0.6V to either pin causes the corresponding channel's error amplifier to servo its VFB pin to that voltage, enabling synchronized ramp-up of multiple rails. An internal 1.4µA pull-up current allows simple soft-start implementation using a capacitor to SGND.
How does the phase shift function work on the LTC3633AIFE#TRPBF?
The LTC3633AIFE#TRPBF uses the PHMODE pin to select channel phasing: grounding PHMODE forces both channels to switch in-phase, while tying PHMODE to INTVCC configures 180° interleaved operation. This reduces input ripple current magnitude and relaxes input capacitor requirements-critical for minimizing EMI and board area in compact designs.
Can the LTC3633AIFE#TRPBF operate with only one channel enabled?
Yes, the LTC3633AIFE#TRPBF supports independent channel control. Either RUN1 or RUN2 can be held below 1.01V to disable its respective channel while the other remains fully operational. When both RUN pins are low, INTVCC and V2P5 regulators shut down, reducing total quiescent current to ≤13µA-ideal for system-level power gating.
What is the purpose of the VON1 and VON2 pins on the LTC3633AIFE#TRPBF?
The VON1 and VON2 pins set the on-time comparator threshold for each channel. Tying VONx to its respective output voltage makes on-time proportional to VOUTx, stabilizing switching frequency across input/output variations. For the LTC3633AIFE#TRPBF, the valid VON range is 0.6V–6V; operation outside this range may cause frequency deviation per datasheet specifications.
LTC3633AIFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) 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-TSSOP-EP
LTC3633AIFE#TRPBF FAQ
1.How can I place an order for LTC3633AIFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3633AIFE#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 LTC3633AIFE#TRPBF reliable?
The price and inventory of LTC3633AIFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3633AIFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3633AIFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3633AIFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3633AIFE#TRPBF?
LTC3633AIFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3633AIFE#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 LTC3633AIFE#TRPBF?
For technical support, including LTC3633AIFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3633AIFE#TRPBF requirements.
6.How does Aetrix verify that LTC3633AIFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3633AIFE#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 LTC3633AIFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3633AIFE#TRPBF?
All LTC3633AIFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3633AIFE#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 LTC3633AIFE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3633AIFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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