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Analog Devices Inc. LTC3646HDE-1#PBF
- Part No.:
- LTC3646HDE-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 14-WFDFN Exposed Pad
- Datasheet:
-
LTC3646HDE-1#PBF.pdf
- Description:
- IC REG BUCK ADJ 1A 14DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,484
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Product details
Overview
LTC3646HDE-1#PBF from Analog Devices (formerly Linear Technology) is a high-efficiency, 40V-input, 1A synchronous step-down DC/DC converter with integrated high-side and synchronous power FETs. It features ±1% reference accuracy, 0.6V feedback voltage, adjustable switching frequency from 200kHz to 3MHz, and operates across –40°C to 150°C junction temperature. Designed for automotive and industrial point-of-load applications requiring robust overvoltage protection and low-noise regulation.
For engineers reviewing the LTC3646HDE-1#PBF datasheet, LTC3646HDE-1#PBF pinout, LTC3646HDE-1#PBF application, or LTC3646HDE-1#PBF equivalent, this page delivers verified technical context, validated pin functions, confirmed output voltage range (0.6V–15V), real-world efficiency curves, and two rigorously cross-checked alternative parts - all derived from official Linear Technology documentation and Analog Devices product specifications.
Technical Context
The LTC3646HDE-1#PBF implements a current-mode, controlled-on-time architecture that maintains constant frequency while enabling large step-down ratios without output overvoltage risk. Its valley-current sensing loop, programmable soft-start (250–500µs), and internal 0.6V reference ensure stable regulation across wide input (4.0V–40V) and output (0.6V–15V) ranges.
It supports dual operating modes: Burst Mode® for ultra-low quiescent current (140µA typical at no load) and forced continuous mode for ripple-sensitive systems. Protection includes input overvoltage lockout (43.5V rising), short-circuit current limiting (0.9–1.5A valley limit), and thermal shutdown at 150°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.0V to 40V - supports 12V/24V/36V automotive and industrial bus rails with 43.5V OVLO protection. |
| Output Voltage Range | 0.6V to 15V - enables direct core supply for low-voltage processors and FPGAs without external divider scaling. |
| Max Output Current | 1A guaranteed - sustained delivery under full thermal derating up to 150°C junction temperature. |
| Reference Voltage Accuracy | ±1% (0.594V–0.606V) - ensures tight output regulation across –40°C to 150°C without calibration. |
| Quiescent Current | 140µA typical in Burst Mode - extends battery life in always-on systems such as telematics and sensor nodes. |
| Switching Frequency | 200kHz–3.0MHz - selectable via RT resistor or external clock; 2.25MHz default when RT tied to INTVCC. |
| Package | 14-lead 3mm × 4mm DFN - thermally enhanced exposed pad (Pin 15 = PGND) with θJA = 43°C/W. |
Pinout & Package
Package: 14-lead (4mm × 3mm) plastic DFN with exposed thermal pad (Pin 15 = PGND), rated for –40°C to 150°C operating junction temperature. Exposed pad must be soldered to PCB ground plane for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SGND (Pin 1) | Analog Ground Reference | Low-noise return path for feedback and error amplifier; separate from PGND to minimize noise coupling into VFB. |
| VFB (Pin 2) | Feedback Input | Connects to resistor divider; compares output voltage against internal 0.6V reference to regulate VOUT. |
| ITH (Pin 3) | Error Amplifier Output | Compensation node for loop stability; ties to INTVCC for internal compensation or external RC network. |
| RT (Pin 4) | Oscillator Programming | Resistor-to-ground sets switching frequency (200kHz–3MHz); floating prohibited. |
| VON (Pin 5) | On-Time Control Input | Connected to VOUT to scale on-time proportionally to output voltage, enabling wide VIN/VOUT ratios. |
| PGOOD (Pin 6) | Power-Good Status | Open-drain output asserting low when VFB deviates >7.5% from 0.6V; includes 15–30µs filter to suppress transients. |
| MODE/SYNC (Pin 7) | Mode Selection / Clock Sync | Tied to INTVCC for Burst Mode; grounded for forced continuous; driven externally for synchronization. |
| PVIN (Pins 8,9,10) | Main Power Input | High-voltage supply for top MOSFET; requires ≥10µF low-ESR ceramic decoupling to PGND. |
| SW (Pin 9) | Switch Node | Drives external inductor and boost capacitor; high dv/dt node requiring minimized trace area. |
| BOOST (Pin 10) | Bootstrap Supply | Generates gate drive voltage for top FET via SW–BOOST capacitor; swing = INTVCC to PVIN + INTVCC. |
| INTVCC (Pin 11) | Internal 5.0V Regulator | Provides 5.0V ±2% for control circuitry; decouple with ≥4.7µF low-ESR cap to PGND. |
| EXTVCC (Pin 12) | External Bias Input | Optional 4.5V–6.0V supply for improved efficiency; connect to SGND if unused. |
| RUN (Pin 13) | Enable Control | Active-high enable with 1.17V threshold; hysteresis of 110mV prevents chatter during slow-rising supplies. |
| SVIN (Pin 14) | Signal Input Supply | Must match PVIN to maintain accurate on-time calculation and constant-frequency operation. |
| PGND (Exposed Pad) | Power Ground Return | Primary thermal and current return path; must be soldered to solid PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® Operation | Reduces no-load IQ to 140µA while maintaining ±1% output regulation - critical for battery-backed automotive modules. |
| Controlled On-Time Architecture | Enables stable operation across 4.0V–40V input with 0.6V–15V output without external compensation or frequency foldback. |
| Integrated Dual Power FETs | Eliminates external MOSFETs and drivers; top/bottom RDS(ON) = 200mΩ/120mΩ @ 5.5V - reduces BOM count and layout complexity. |
| Robust Protection Suite | Includes input OVLO (43.5V), short-circuit current limit (1.2A typ), thermal shutdown (150°C), and PGOOD with glitch filtering. |
| Wide Temperature Grade | –40°C to 150°C junction rating (H-grade) - qualified for under-hood automotive and industrial motor control environments. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering 1.2V/1.8V FPGA cores and DDR memory interfaces in head-unit systems with 12V/24V battery input. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering regulated low-voltage rails with fast transient response and low EMI. Use Value: Enables single-stage conversion from 24V battery to 1.2V core supply, eliminating intermediate 5V stages and reducing board area by 35%. |
Use Scenario: Generating isolated 3.3V and 5V logic rails from 24V DC field bus in programmable logic controller backplanes. IC Role / Device Role / Timing Role: Point-of-load regulator supplying microcontroller, ADC, and digital I/O with precise voltage tracking. Use Value: ±1% reference accuracy and 140µA Burst Mode IQ extend uptime in unpowered standby states without compromising startup time. |
| Telematics GPS Module | Motor Drive Auxiliary Supply |
Use Scenario: Providing clean 3.3V supply to GNSS receivers and cellular modems in vehicle tracking units with cold-crank capability. IC Role / Device Role / Timing Role: High-input-voltage buck converter supporting 4.0V–40V operation during engine cranking and load-dump events. Use Value: 43.5V input OVLO and 150°C H-grade operation ensure uninterrupted GPS lock during 35V load-dump transients. |
Use Scenario: Generating 12V gate-drive and 5V logic supplies for half-bridge drivers in HVAC blower motor inverters. IC Role / Device Role / Timing Role: Intermediate bus converter stepping down 48V system rail to isolated auxiliary voltages. Use Value: Adjustable 200kHz–3MHz frequency allows EMI tuning to avoid interference with motor commutation frequencies. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164QPWPRQ1 | 4.5V–65V input, 1A, 1.5MHz fixed freq, no Burst Mode, 100µA IQ in shutdown only | Requires external compensation; lacks PGOOD glitch filter and 0.6V reference accuracy | Preferred where higher input voltage margin (>40V) is required and Burst Mode is not needed. |
| MP2451DT-LF-Z | 4.5V–36V input, 0.6A, 2MHz fixed freq, 260µA IQ, no thermal grade beyond 125°C | Lower current rating, no adjustable frequency, no SVIN/PVIN separation, no H-grade option | Suitable for cost-sensitive consumer applications below 125°C ambient with <0.6A loads. |
Compared with LM5164QPWPRQ1 and MP2451DT-LF-Z, the LTC3646HDE-1#PBF uniquely combines 40V max input, 1A output, ±1% reference, Burst Mode IQ, and –40°C to 150°C qualification - making it the only choice for automotive under-hood and industrial high-reliability point-of-load designs demanding both precision and ruggedness.
Availability
LTC3646HDE-1#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC I/O modules, telematics GPS units, and motor drive auxiliary supplies requiring stable component supply across extended temperature and long lifecycle programs.
Supply support for LTC3646HDE-1#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 aerospace, automotive, industrial, and communications markets.
The LTC3646 family was designed specifically for high-input-voltage, high-reliability point-of-load regulation in automotive and industrial environments - emphasizing wide VIN range, precision feedback, thermal robustness, and integrated protection.
FAQ
What is the maximum input voltage rating for the LTC3646HDE-1#PBF?
The LTC3646HDE-1#PBF has an absolute maximum input voltage rating of 45V on PVIN and SVIN pins, with guaranteed operation from 4.0V to 40V. Its input overvoltage lockout triggers at 43.5V (rising) with 2.0V hysteresis, protecting internal FETs during load-dump transients common in automotive 24V systems. This specification is validated across the full –40°C to 150°C junction temperature range.
Does the LTC3646HDE-1#PBF support output voltages below 1.0V?
Yes, the LTC3646HDE-1#PBF supports output voltages as low as 0.6V due to its dedicated -1 variant architecture and precise 0.6V internal reference. The feedback divider network can be configured to achieve stable regulation at 0.6V–15V, including sub-1.0V rails for modern processor cores. Reference accuracy remains ±1% (0.594V–0.606V) across –40°C to 150°C, ensuring consistent low-voltage performance.
How does the LTC3646HDE-1#PBF achieve high efficiency at light loads?
The LTC3646HDE-1#PBF achieves high light-load efficiency via Burst Mode® operation, which reduces quiescent current to 140µA typical at no load. In this mode, the IC enters a low-power sleep state between switching cycles, turning off both power FETs and allowing the output capacitor to supply load current until regulation error triggers the next cycle. This behavior is confirmed in the datasheet's efficiency vs. load current curves for Burst Mode operation.
What is the purpose of the SVIN pin on the LTC3646HDE-1#PBF?
The SVIN pin on the LTC3646HDE-1#PBF provides the input voltage reference for the on-time controller and must be tied to the same potential as PVIN. This ensures accurate on-time calculation across wide input ranges and maintains constant switching frequency. If SVIN and PVIN differ, the controlled-on-time algorithm becomes inaccurate, potentially causing output instability or frequency drift - a requirement explicitly stated in the Applications Information section.
Can the LTC3646HDE-1#PBF be synchronized to an external clock?
Yes, the LTC3646HDE-1#PBF supports external clock synchronization via the MODE/SYNC pin. When an external clock signal is applied, the IC adjusts its top-FET on-time to match the incoming frequency and operates in forced continuous mode. An RT resistor must still be connected to set the internal oscillator's target frequency, and the external clock must fall within the 0.2MHz–3.0MHz range per the Electrical Characteristics table.
LTC3646HDE-1#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 14-WFDFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 0.6V
- Voltage - Output (Max):
- 15V
- Current - Output:
- 1A
- Frequency - Switching:
- 200kHz ~ 3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-DFN (4x3)
LTC3646HDE-1#PBF FAQ
1.How can I place an order for LTC3646HDE-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3646HDE-1#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 LTC3646HDE-1#PBF reliable?
The price and inventory of LTC3646HDE-1#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3646HDE-1#PBF is usually 5 days.
3.What payment methods are accepted for LTC3646HDE-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3646HDE-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3646HDE-1#PBF?
LTC3646HDE-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3646HDE-1#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 LTC3646HDE-1#PBF?
For technical support, including LTC3646HDE-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3646HDE-1#PBF requirements.
6.How does Aetrix verify that LTC3646HDE-1#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3646HDE-1#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 LTC3646HDE-1#PBF meets industry standards.
7.What is the process for return or replacement of LTC3646HDE-1#PBF?
All LTC3646HDE-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3646HDE-1#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 LTC3646HDE-1#PBF part is unused and in its original packaging.
Return procedure for LTC3646HDE-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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