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Analog Devices Inc. LTC7149IUFD#PBF
- Part No.:
- LTC7149IUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC7149IUFD#PBF.pdf
- Description:
- IC REG BUCK ADJ 4A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:195
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Product details
Overview
LTC7149IUFD#PBF from Analog Devices is a 60V, 4A synchronous monolithic step-down regulator configured for inverting output applications, delivering –28V to 0V output with ±0.8% voltage accuracy, 92% efficiency at 12VIN/–5VOUT, and peak current mode control. It integrates 110mΩ top/50mΩ bottom N-channel MOSFETs and supports programmable switching frequency (300kHz–3MHz) via external RT resistor.
For engineers reviewing the LTC7149IUFD#PBF datasheet, LTC7149IUFD#PBF pinout, LTC7149IUFD#PBF application, or LTC7149IUFD#PBF equivalent, key selection considerations include its board-ground-referenced I/O pins (RUN, PGOOD, MODE/SYNC), single-resistor VOUT programming via ISET, Burst Mode® vs forced continuous mode trade-offs, and thermal management of the exposed SVOUT– pad in the 4mm × 5mm QFN package.
Technical Context
The LTC7149IUFD#PBF employs a peak current mode architecture with internal level-shift circuits enabling all logic-level I/O pins to reference board GND instead of SVOUT–. Its error amplifier compares VOUTSNS (typically tied to GND) against ISET's 50µA bias current to regulate output voltage via RSET: VOUT– = –50µA × RSET.
It features dual LDOs-VIN-powered (3.3V above VOUT–) and EXTVCC-powered (3.1V above VOUT–)-with automatic switchover when EXTVCC exceeds 3.2V above VOUT– and VIN > 5V. Input voltage regulation (VINREG) and overvoltage protection (VOVLO = 64V) provide robustness in high-impedance or transient-prone supplies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 60V; supports wide industrial and telecom input rails without pre-regulation. |
| Output Voltage Range | –28V to 0V; enables negative supply generation for op-amps, ADCs, and RF biasing. |
| Max Output Current | 4A inductor current; sufficient for powering multiple analog or mixed-signal subsystems. |
| Switching Frequency | 300kHz to 3MHz (±50% sync range); allows optimization of size (high fSW) vs efficiency (low fSW). |
| Quiescent Current | 440µA in Burst Mode; extends battery life in low-power standby states. |
| Output Accuracy | ±0.8% over temperature; ensures stable reference and signal chain performance. |
| Package | 28-Lead 4mm × 5mm QFN with exposed SVOUT– pad; requires soldering for thermal and electrical integrity. |
Pinout & Package
Package: 28-Lead (4mm × 5mm) Plastic QFN with exposed thermal pad (Pin 29 = SVOUT–), rated for –40°C to 125°C junction temperature (θJA = 43°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT– (Pins 1, 2, 26–28) | Negative output return | Primary power return path; must be low-impedance connection to output capacitor and load ground. |
| VIN (Pins 3, 4) | Input supply input | Accepts 3.4V–60V; connects to bulk input capacitors and upstream source. |
| RUN (Pin 5) | Enable control input | Logic-high (>1.2V) enables operation; resistor divider from VIN sets precise undervoltage lockout. |
| GND (Pin 6) | Board ground sense | Reference for internal circuitry; must connect directly to PCB ground plane. |
| MODE/SYNC (Pin 7) | Operating mode & clock sync | GND = Burst Mode; floating = forced continuous; external clock = synchronization with ±50% range. |
| PGOOD (Pin 8) | Power-good open-drain output | Pulled low if VPGDFB < 0.555V or > 0.645V relative to VOUT–; 64-cycle blanking prevents transients. |
| RT (Pin 12) | Oscillator frequency set | Resistor to SVOUT– programs fSW; 100kΩ yields ~1MHz; minimum on-time (60ns) constrains max fSW at high VIN. |
| ISET (Pin 14) | Output voltage programming | 50µA current source; RSET to VOUT– sets VOUT– = –50µA × RSET; capacitor adds soft-start. |
| ITH (Pin 15) | Error amp output / compensation | Internal compensation enabled by tying to INTVCC; external components optimize transient response. |
| SW (Pins 19–25) | Switch node | Connects to inductor; high dv/dt node requiring short, low-inductance layout to minimize EMI. |
| SVOUT– (Pins 10, 29) | Exposed thermal pad | Must be soldered to PCB copper pour for thermal dissipation and electrical connection to VOUT–. |
Key Features
| Feature | Design Value |
|---|---|
| Board-ground-referenced I/O | RUN, PGOOD, and MODE/SYNC operate referenced to board GND-not SVOUT–-simplifying level-shifting and control logic. |
| Single-resistor VOUT programming | 50µA ISET current enables precise negative output setting with one external resistor, eliminating feedback dividers. |
| Burst Mode® + forced continuous mode | Automatic light-load efficiency boost (440µA IQ) or user-selectable low-ripple operation via MODE/SYNC pin state. |
| Integrated power MOSFETs | 110mΩ high-side + 50mΩ low-side N-channel switches reduce BOM count and improve thermal performance. |
| Input voltage regulation loop | VINREG pin allows programmable reduction of peak inductor current when input voltage droops below threshold. |
Applications
| Industrial Process Control | Telecom Line Cards |
|---|---|
Use Scenario: Generating –15V and –5V rails for precision analog front-ends in PLC I/O modules operating from 24V or 48V DC distribution buses. IC Role / Device Role / Timing Role: Inverting buck regulator providing isolated negative bias for instrumentation amplifiers and DACs. Use Value: ±0.8% output accuracy and 92% efficiency at 12VIN/–5VOUT ensure stable sensor signal conditioning under varying load conditions. | Use Scenario: Powering line interface ICs (e.g., SLICs) requiring –48V bias in carrier-grade access equipment with strict thermal limits. IC Role / Device Role / Timing Role: High-current inverting regulator delivering up to 4A at –28V from a 60V backplane supply. Use Value: Integrated 110mΩ/50mΩ MOSFETs and exposed SVOUT– pad enable compact, thermally robust design meeting NEBS GR-63-CORE requirements. |
| Distributed Power Systems | Test & Measurement Equipment |
Use Scenario: Local point-of-load conversion in modular rack systems where intermediate bus voltages (e.g., 24V, 36V) feed multiple isolated negative rails. IC Role / Device Role / Timing Role: Synchronous step-down inverter supporting programmable fSW (300kHz–3MHz) to avoid noise coupling into sensitive analog sections. Use Value: ±50% frequency sync range allows synchronization to system clock, eliminating beat frequencies in multi-rail systems. | Use Scenario: Providing clean, adjustable negative supplies for high-resolution ADC drivers and low-noise op-amp stages in portable bench instruments. IC Role / Device Role / Timing Role: Regulator with Burst Mode® operation and 440µA quiescent current enabling battery-powered operation with extended runtime. Use Value: Single-resistor VOUT programming and programmable soft-start (via ISET capacitor) simplify calibration and reduce startup stress on DUTs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar inverting buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC7151SUFD#PBF | Higher 8A output current, 65V rating, integrated compensation; no ISET-based VOUT programming. | Requires external feedback resistors; better suited for high-current, fixed-output designs where layout space permits larger inductors. | Select when >4A output or tighter transient response is required; not drop-in due to different programming method and pinout. |
| TPS543B20RJER | 36V max input, 3A output, PMBus interface; no native inverting topology-requires external inverting configuration. | Needs external inductor and diode for inverting use; adds complexity and reduces efficiency vs monolithic solution. | Choose only if digital telemetry and margining are mandatory; otherwise inferior for dedicated inverting applications. |
Compared with LTC7151SUFD#PBF and TPS543B20RJER, the LTC7149IUFD#PBF uniquely combines single-resistor negative VOUT programming, board-ground-referenced I/O, and 4A capability in a compact QFN-making it optimal for cost-sensitive, space-constrained inverting supplies where analog simplicity and thermal performance are prioritized.
Availability
LTC7149IUFD#PBF is available at Aetrix Electronics and suitable for industrial process control, telecom line cards, and distributed power systems requiring stable component supply across extended temperature ranges (–40°C to 125°C).
Supply support for LTC7149IUFD#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 (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.
The LTC7149IUFD#PBF belongs to ADI's Power by Linear™ family of monolithic DC/DC regulators, designed specifically for high-efficiency, high-voltage inverting and buck applications in space- and thermal-constrained environments.
FAQ
What is the maximum input voltage the LTC7149IUFD#PBF can handle?
The LTC7149IUFD#PBF supports an absolute maximum input voltage of 64V (VIN to VOUT–), with recommended operating range up to 60V. Its VIN overvoltage protection activates at 64V (rising) with 2V hysteresis, suspending switching to protect internal MOSFETs. This makes the LTC7149IUFD#PBF suitable for 48V telecom and industrial bus applications with transient tolerance.
How is the output voltage programmed on the LTC7149IUFD#PBF?
The LTC7149IUFD#PBF uses a precision 50µA current source at the ISET pin: connecting an external resistor RSET from ISET to VOUT– sets VOUT– = –50µA × RSET. For example, a 100kΩ resistor yields –5V. A capacitor from ISET to VOUT– provides programmable soft-start, with tSS ≈ 2.3 × RSET × CSET (0% to 90% ramp).
Does the LTC7149IUFD#PBF require external MOSFETs?
No-the LTC7149IUFD#PBF integrates both high-side (110mΩ) and low-side (50mΩ) N-channel MOSFETs within the monolithic IC. This eliminates external switch selection, gate drive design, and layout complexity while optimizing efficiency and thermal performance in the 4mm × 5mm QFN package.
What are the thermal requirements for the LTC7149IUFD#PBF?
The LTC7149IUFD#PBF requires the exposed SVOUT– pad (Pin 29) to be soldered to a PCB copper pour for thermal conduction. With θJA = 43°C/W, maintaining junction temperature ≤125°C demands adequate copper area and airflow. For high-power operation (e.g., 4A at –12V), thermal vias under the pad and a dedicated ground plane are strongly recommended.
Can the LTC7149IUFD#PBF synchronize to an external clock?
Yes-the MODE/SYNC pin accepts an external clock signal with ±50% frequency capture range around the RT-programmed frequency. For example, if RT sets 1MHz, the external clock must be between 500kHz and 1.5MHz. Synchronization forces forced continuous mode and eliminates beat frequencies in multi-regulator systems.
LTC7149IUFD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Negative
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.4V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 0V
- Voltage - Output (Max):
- -28V
- Current - Output:
- 4A
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LTC7149IUFD#PBF FAQ
1.How can I place an order for LTC7149IUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7149IUFD#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 LTC7149IUFD#PBF reliable?
The price and inventory of LTC7149IUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7149IUFD#PBF is usually 5 days.
3.What payment methods are accepted for LTC7149IUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7149IUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7149IUFD#PBF?
LTC7149IUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7149IUFD#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 LTC7149IUFD#PBF?
For technical support, including LTC7149IUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7149IUFD#PBF requirements.
6.How does Aetrix verify that LTC7149IUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC7149IUFD#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 LTC7149IUFD#PBF meets industry standards.
7.What is the process for return or replacement of LTC7149IUFD#PBF?
All LTC7149IUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7149IUFD#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 LTC7149IUFD#PBF part is unused and in its original packaging.
Return procedure for LTC7149IUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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