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Analog Devices Inc. LTC3633AIFE#PBF
- Part No.:
- LTC3633AIFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LTC3633AIFE#PBF.pdf
- Description:
- IC REG BUCK ADJ 3A DL 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:150
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Product details
Overview
LTC3633AIFE#PBF from Analog Devices (formerly Linear Technology) is a dual-channel monolithic synchronous step-down regulator delivering 3A per channel across a 3.6V–20V input range. It employs controlled on-time current mode architecture with phase-lockable switching frequency up to 4MHz, enabling high-efficiency point-of-load regulation for battery-powered instruments and distributed power systems.
For engineers reviewing the LTC3633AIFE#PBF datasheet, LTC3633AIFE#PBF pinout, LTC3633AIFE#PBF application, or LTC3633AIFE#PBF equivalent, key selection criteria include its 0.6V reference voltage, selectable Burst Mode®/forced continuous operation, 180° phase-shift capability between channels, and TSSOP-28 package compatibility with thermal performance (θJA = 30°C/W).
Technical Context
The LTC3633AIFE#PBF implements a constant-frequency controlled on-time current mode control loop, where an internal PLL synchronizes the one-shot timer to either an internal oscillator (set by RT resistor) or external clock applied to MODE/SYNC. Its dual independent channels support interleaved 180° out-of-phase operation to reduce RMS input current and relax input capacitor requirements.
Each channel features programmable VON-based on-time scaling (0.6V–6V sense range), internal 0.6V reference with ±1% accuracy over temperature, and integrated protection including input overvoltage lockout (22.5V trip), overtemperature shutdown, and short-circuit robustness via valley current limiting (3.5A typ).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 20V - supports Li-ion stacks and 5V/12V intermediate bus supplies without external pre-regulation. |
| Output Current per Channel | 3A continuous - enables single-chip dual-rail power delivery for FPGA I/O banks or multi-core processors. |
| Switching Frequency Range | 500kHz to 4MHz - adjustable via RT resistor; allows optimization of inductor size vs. efficiency trade-off. |
| Reference Voltage | 0.6V ±1% - enables stable low-output-voltage regulation down to 0.6V with minimal dropout error. |
| Efficiency | Up to 95% - achieved at mid-load in forced continuous mode; Burst Mode® extends light-load efficiency. |
| Phase Shift Control | Selectable 0°/180° - reduces input ripple current by interleaving channel switching edges. |
| Protection Features | Input overvoltage (22.5V), overtemperature, short-circuit, and PGOOD status - ensures system-level fault resilience. |
Pinout & Package
Package: 28-Lead Plastic TSSOP (FE package), 4mm × 5mm footprint, exposed PGND pad (Pin 29) requiring PCB soldering for thermal and electrical integrity. θJA = 30°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 (0.6V reference) | Sense divider output; sets regulated VOUT with ±1% accuracy over temperature. |
| RUN1 / RUN2 | Channel enable (1.22V threshold) | Independent hard-on/off control per channel; supports sequencing and standby modes. |
| PGOOD1 / PGOOD2 | Open-drain power-good status | Asserts low when VOUT deviates >±8%; releases after return within ±5% with 40µs filter. |
| PHMODE | Phase select (0V = in-phase, INTVCC = 180°) | Configures interleaving to halve effective input ripple frequency and reduce capacitor RMS stress. |
| MODE/SYNC | Mode select / external clock input | Ground = forced continuous; float/INTVCC = Burst Mode®; driven clock = synchronization + forced continuous. |
| TRACKSS1 / TRACKSS2 | Tracking/soft-start input | 0.3V bias enables soft-start; sub-0.6V forces output tracking to external rail during power-up. |
| VIN1 / VIN2 | Independent channel input supplies | Allows dual-input operation (e.g., primary + backup rail) with separate overvoltage protection per channel. |
| SW1 / SW2 | Switch node outputs | Drive external inductors; swing from ~–0.3V to VIN; require low-inductance layout for EMI control. |
| BOOST1 / BOOST2 | Floating gate drive supply | Bootstrap nodes for high-side MOSFET drivers; require ceramic capacitors tied to respective SW pins. |
| INTVCC | Internal 3.3V LDO output | Powers control circuitry; disabled when both RUN pins are low; requires ≥1µF ceramic bypass. |
| V2P5 | 2.5V auxiliary regulator | Supplies 10mA; useful for biasing external circuits; tie to INTVCC if unused. |
| RT | Oscillator frequency programming | Resistor to SGND sets fSW = 3.2×10¹¹/RRT; 162kΩ yields ~2MHz typical. |
| SGND | Signal ground reference | Low-noise analog ground for feedback, compensation, and RT networks; separate from PGND. |
| PGND | Power ground (exposed pad) | Return path for input/output capacitors and MOSFET sources; must be soldered to PCB plane. |
Key Features
| Feature | Design Value |
|---|---|
| Controlled on-time current mode | Enables fast transient response and stable operation at high step-down ratios (e.g., 12V→1.2V @ 2MHz). |
| Interleaved 180° phase shift | Reduces input ripple current amplitude by ~70%, allowing smaller bulk input capacitance. |
| Burst Mode® operation | Extends light-load efficiency to >85% at 10mA while maintaining <25µA quiescent current. |
| Programmable VON-based on-time | Maintains constant frequency across output voltage changes (0.6V–6V range) without external compensation. |
| Integrated power-good monitoring | Provides synchronized system reset signaling with built-in 40µs glitch filtering for noise immunity. |
| Independent channel enable & tracking | Supports precise power sequencing and rail-to-rail tracking for multi-voltage SoC applications. |
Applications
| Industrial PLC I/O Modules | Portable Test Equipment |
|---|---|
Use Scenario: Powering isolated analog front-ends and digital logic rails in compact field-mounted controllers. IC Role / Device Role / Timing Role: Dual-rail DC/DC converter generating 3.3V and 5V from 12V backplane with tight sequencing and ripple control. Use Value: Interleaved operation reduces input capacitor count by 30% versus discrete regulators; PGOOD enables safe firmware boot verification. |
Use Scenario: Battery-powered handheld oscilloscopes requiring ultra-low standby power and rapid wake-up. IC Role / Device Role / Timing Role: Primary power management IC supplying FPGA core (1.2V), I/O (3.3V), and analog subsystem (5V) from single Li-ion cell stack. Use Value: Burst Mode® achieves <25µA shutdown current; soft-start prevents inrush into sensitive ADC references during power-up. |
| Medical Imaging Sensors | Automotive ADAS Camera Modules |
Use Scenario: Powering low-noise CMOS image sensors and correlated double sampling circuits in portable ultrasound probes. IC Role / Device Role / Timing Role: Dual-channel buck delivering 1.8V (sensor analog) and 2.5V (reference/ADC) with sub-10mV ripple and precise tracking. Use Value: TRACKSS inputs enable synchronized ramp-up of sensor and reference rails to eliminate settling transients; 0.6V reference ensures stable low-VOUT accuracy. |
Use Scenario: Compact rear-view camera ECU requiring ASIL-B compliant power with fault reporting and thermal margin. IC Role / Device Role / Timing Role: Dual-output regulator providing 3.3V (SoC core) and 1.2V (image processor) from 5V automotive supply with overvoltage/overtemperature protection. Use Value: Input overvoltage lockout (22.5V) withstands load-dump transients; PGOOD signals MCU before video processing starts. |
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 2.2MHz fSW, no phase shift or VON scaling | Requires external sequencing for multi-rail startup; lacks TRACKSS and soft-start flexibility | Preferred for automotive environments needing qualification; less flexible for precision sequencing. |
| LTC3633AEUFD#PBF | Same die in QFN-28 package (θJA = 43°C/W), identical electrical specs, pin-compatible | Higher thermal resistance requires more PCB copper; same functionality and footprint compatibility | Choose for better thermal performance in space-constrained layouts where QFN mounting is feasible. |
Compared with MPQ4436-AEC1, LTC3633AIFE#PBF offers superior design flexibility via programmable frequency, phase control, and tracking-critical for medical and test equipment. Versus LTC3633AEUFD#PBF, the TSSOP variant trades thermal performance for easier hand-soldering and legacy board compatibility.
Availability
LTC3633AIFE#PBF is available at Aetrix Electronics and suitable for industrial PLC I/O modules, portable test equipment, medical imaging sensors, and automotive ADAS camera modules requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LTC3633AIFE#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3633A product line delivers dual-channel monolithic synchronous buck regulation with advanced control features-including phase interleaving, Burst Mode®, and tracking-for high-density, low-noise point-of-load applications in battery-powered and distributed power systems.
FAQ
What is the absolute maximum input voltage rating for LTC3633AIFE#PBF?
The LTC3633AIFE#PBF has an absolute maximum input voltage of 20V on VIN1 and VIN2 pins. Exceeding this risks permanent damage. Its input overvoltage protection activates at 22.5V (rising) and resets at 21.5V (falling), suspending switching until safe conditions return. This safeguard applies independently per channel, making LTC3633AIFE#PBF suitable for 12V systems with transient tolerance.
Does LTC3633AIFE#PBF support output voltage tracking between its two channels?
Yes, LTC3633AIFE#PBF supports precise output voltage tracking via dedicated TRACKSS1 and TRACKSS2 pins. Applying a common ramp voltage below 0.6V to both pins forces each channel's feedback loop to servo its VOUT to that reference, enabling synchronized startup and rail matching. An internal 1.4µA pull-up current allows simple soft-start implementation using a single capacitor to SGND on either TRACKSS pin.
How does the PHMODE pin affect system-level EMI in LTC3633AIFE#PBF designs?
The PHMODE pin configures LTC3633AIFE#PBF for in-phase (0V) or 180° out-of-phase (INTVCC) operation. Selecting 180° interleaving reduces input ripple current amplitude and shifts harmonic content, lowering conducted EMI at the fundamental switching frequency. This allows smaller input bulk capacitors and eases compliance with CISPR-22/32 Class B limits-particularly critical in compact portable equipment where LTC3633AIFE#PBF is commonly deployed.
Can LTC3633AIFE#PBF operate with only one channel enabled?
Yes, LTC3633AIFE#PBF supports independent channel operation. Driving RUN1 high while holding RUN2 low enables only Channel 1, and vice versa. The disabled channel draws <13µA quiescent current and disconnects its internal LDO (INTVCC remains active if Channel 1 is on). This capability allows dynamic power partitioning in systems like multi-sensor nodes where LTC3633AIFE#PBF powers active and standby subsystems separately.
What is the minimum on-time specification for LTC3633AIFE#PBF and why does it matter?
LTC3633AIFE#PBF has a minimum on-time of 20ns (typical) at VON = 0.6V and VIN = 4V. This parameter determines the lowest achievable duty cycle and thus the maximum practical step-down ratio at high frequencies-for example, enabling 12V→1.2V conversion at 2MHz (10% duty cycle). Shorter minimum on-time preserves regulation stability in high-frequency, high-ratio applications where LTC3633AIFE#PBF is often selected.
LTC3633AIFE#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
LTC3633AIFE#PBF FAQ
1.How can I place an order for LTC3633AIFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3633AIFE#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#PBF reliable?
The price and inventory of LTC3633AIFE#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#PBF is usually 5 days.
3.What payment methods are accepted for LTC3633AIFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3633AIFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3633AIFE#PBF?
LTC3633AIFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3633AIFE#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#PBF?
For technical support, including LTC3633AIFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3633AIFE#PBF requirements.
6.How does Aetrix verify that LTC3633AIFE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3633AIFE#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#PBF meets industry standards.
7.What is the process for return or replacement of LTC3633AIFE#PBF?
All LTC3633AIFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3633AIFE#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#PBF part is unused and in its original packaging.
Return procedure for LTC3633AIFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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