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Analog Devices Inc. LTC7149IUFD#TRPBF
- Part No.:
- LTC7149IUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC7149IUFD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 4A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,812
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Product details
Overview
LTC7149IUFD#TRPBF 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 industrial telecom power supplies requiring negative rail generation.
For engineers reviewing the LTC7149IUFD#TRPBF datasheet, LTC7149IUFD#TRPBF pinout, LTC7149IUFD#TRPBF application, or LTC7149IUFD#TRPBF equivalent, key selection considerations include its single-resistor VOUT programming, board-ground-referenced I/O (RUN, PGOOD, MODE/SYNC), programmable soft-start, and ±50% frequency sync range - all critical for stable negative-bias supply design in distributed systems.
Technical Context
The LTC7149IUFD#TRPBF implements a peak current mode architecture with inherent cycle-by-cycle current limiting and fast transient response. Its internal level-shift circuits enable all control pins (RUN, MODE/SYNC, PGOOD) to reference board GND rather than SVOUT–, simplifying PCB layout and system grounding.
It supports dual operating modes via the MODE/SYNC pin: Burst Mode® for ultra-low quiescent current (440µA) at light loads, and forced continuous conduction mode for low-output-ripple operation. Frequency is resistor-programmable from 300kHz to 3MHz with ±50% external clock synchronization capability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 3.4V to 60V - supports wide-input industrial and telecom rails without pre-regulation. |
| VOUT Range | –28V to 0V - enables true negative output generation from positive input sources. |
| Output Current | Up to 4A inductor current - sufficient for powering op-amp bias rails, ADC/DAC references, and RF front-end stages. |
| Efficiency | 92% at 12VIN/–5VOUT - minimizes thermal load in space-constrained modules. |
| Output Accuracy | ±0.8% - ensures precise negative voltage regulation for sensitive analog circuitry. |
| IQ (Burst Mode) | 440µA - extends battery life in always-on monitoring systems with negative bias requirements. |
| fSW Range | 300kHz–3MHz (resistor-programmable) - allows optimization of size vs. EMI in compact designs. |
Pinout & Package
Package: 28-Lead (4mm × 5mm) Plastic QFN with exposed pad (Pin 29 = SVOUT–), rated for –40°C to 125°C junction temperature. Exposed pad must be soldered to PCB plane for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT– (Pins 1,2,26–28) | Negative output return | Primary output node; multiple pins reduce IR drop and improve current handling for –28V/4A operation. |
| VIN (Pins 3,4) | Input supply | High-voltage input path; dual pins minimize trace resistance and thermal stress under 60V max. |
| RUN (Pin 5) | Enable control | GND-referenced logic input; 1.2V rising threshold enables accurate VIN undervoltage lockout via resistor divider. |
| GND (Pin 6) | Board ground sense | Reference for internal LDOs and level-shifted I/O; must connect directly to PCB ground plane. |
| MODE/SYNC (Pin 7) | Mode select & sync input | GND = Burst Mode; floating = forced continuous; external clock = synchronized switching with ±50% capture range. |
| PGOOD (Pin 8) | Power-good indicator | Open-drain output pulled low when VPGDFB < 0.555V or > 0.645V relative to VOUT–; includes 64-cycle blanking delay. |
| RT (Pin 12) | Frequency programming | Resistor-to-SVOUT– sets fSW; 100kΩ yields ~1MHz; supports external clock sync within ±50% of programmed frequency. |
| ISET (Pin 14) | Output voltage programming | 50µA precision current source; RSET from ISET to VOUT– sets VOUT– = –50µA × RSET. |
| ITH (Pin 15) | Error amplifier output | Compensation node; tie to INTVCC for internal compensation or use external network for OPTI-LOOP® optimization. |
| SW (Pins 19–25) | Switch node | High-current connection to external inductor; multiple pins reduce parasitic inductance and EMI. |
| SVOUT– (Pins 10,29) | Exposed pad / thermal & electrical return | Mandatory solder connection to PCB copper; serves as primary return for high-side MOSFET and thermal path. |
Key Features
| Feature | Design Value |
|---|---|
| Single-resistor VOUT programming | Enables precise negative output setting (e.g., –5V, –12V, –15V) with one external resistor - eliminates trimming and reduces BOM count. |
| Board-GND-referenced I/O | RUN, MODE/SYNC, and PGOOD operate referenced to board GND instead of SVOUT–, eliminating need for isolated level-shifting circuitry. |
| Programmable soft-start | Capacitor from ISET to VOUT– controls ramp rate (tSS ≈ 2.3 × RSET × CSET), preventing inrush current into pre-biased loads. |
| Integrated 110mΩ/50mΩ MOSFETs | Monolithic power stage eliminates external FETs and gate drivers - reduces footprint and improves reliability in harsh environments. |
| Overtemperature protection | Thermal shutdown activates above 125°C junction temperature, protecting device during overload or poor heatsinking conditions. |
Applications
| Industrial Process Control | Telecom Line Card Power |
|---|---|
Use Scenario: Generating –15V bias for analog sensor signal conditioning in PLC I/O modules operating from 24VDC field bus. IC Role / Device Role / Timing Role: Inverting buck regulator providing stable negative rail with ±0.8% accuracy and 440µA quiescent current in standby. Use Value: Enables direct interface with legacy bipolar op-amps and precision ADCs without external charge pumps or discrete inverter stages. | Use Scenario: Supplying –5V to RF transceiver ICs on 48V-powered telecom line cards with strict EMI limits. IC Role / Device Role / Timing Role: High-efficiency (92%) inverting regulator with programmable 1MHz switching and ±50% sync range for EMI reduction via clock dithering. Use Value: Eliminates need for separate isolated DC/DC converter while meeting EN55022 Class B conducted emissions with minimal filtering. |
| Distributed Power Systems | Test & Measurement Equipment |
Use Scenario: Local –12V generation for high-speed comparators and DAC buffers in modular instrumentation backplanes. IC Role / Device Role / Timing Role: Wide-VIN (3.4–60V) inverting regulator supporting hot-swap input with programmable soft-start and overvoltage lockout. Use Value: Ensures clean, sequenced negative rail startup across varying input voltages and prevents latch-up during live insertion. | Use Scenario: Precision –2.5V reference supply for 16-bit SAR ADCs in portable benchtop analyzers powered by Li-ion batteries. IC Role / Device Role / Timing Role: Low-noise inverting regulator with Burst Mode® operation and 440µA IQ extending battery runtime between calibrations. Use Value: Maintains ADC full-scale accuracy without drift from load-dependent VREF variation, even at microampere loads. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar inverting buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC7150SIV#TRPBF | Higher 60V/5A rating, integrated MOSFETs with lower RDS(ON) (75mΩ/35mΩ), supports 300kHz–3MHz fSW, but requires external VOUT feedback resistors. | Designed for higher-current applications (>4A) and tighter load regulation; lacks single-resistor VOUT programming. | Select when >4A output or lower dropout is required; avoid if simplicity of ISET-based programming is critical. |
| TPS63710DSCR | 3.5V–20V input, –12V/1.5A output, fixed –12V option only, no ISET programming, uses external feedback resistors, lower efficiency (87% @ 12VIN/–12VOUT). | Targeted at low-power portable applications; lacks wide-VIN support, programmable frequency, and Burst Mode®. | Select for cost-sensitive, low-current designs where 60V input and 4A output are unnecessary. |
Compared with LTC7149IUFD#TRPBF, LTC7150SIV#TRPBF offers higher current capability and lower conduction loss but sacrifices single-resistor VOUT simplicity; TPS63710DSCR provides a lower-cost, lower-performance alternative for fixed-output, low-power negative rails without wide-VIN or high-efficiency requirements.
Availability
LTC7149IUFD#TRPBF is available at Aetrix Electronics and suitable for industrial process control, telecom line card power, and distributed power systems requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across –40°C to 125°C.
Supply support for LTC7149IUFD#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 (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#TRPBF belongs to ADI's Power by Linear™ family of monolithic DC/DC regulators, engineered specifically for high-efficiency, wide-input-range negative rail generation in space- and thermally-constrained systems.
FAQ
What is the maximum output current capability of the LTC7149IUFD#TRPBF?
The LTC7149IUFD#TRPBF delivers up to 4A of inductor current in continuous conduction mode. This rating assumes proper thermal management via the exposed SVOUT– pad soldered to a PCB copper plane, ambient temperature ≤85°C, and appropriate input/output capacitor selection per the datasheet guidelines. Peak current limit is internally set to 5.4–6.6A.
How is the output voltage programmed on the LTC7149IUFD#TRPBF?
The LTC7149IUFD#TRPBF uses a precision 50µA current source on the ISET pin. Connecting an external resistor RSET from ISET to VOUT– sets VOUT– = –50µA × RSET. For example, a 100kΩ resistor yields –5.0V output. This single-resistor method eliminates feedback dividers and ensures ±0.8% accuracy over temperature and line.
Does the LTC7149IUFD#TRPBF support external clock synchronization?
Yes, the LTC7149IUFD#TRPBF supports external clock synchronization via the MODE/SYNC pin. When driven by an external clock signal, the internal oscillator locks within ±50% of its RT-resistor-programmed frequency. The part automatically enters forced continuous mode during sync operation, ensuring deterministic timing for EMI reduction in noise-sensitive systems.
What is the purpose of the SVOUT– pin on the LTC7149IUFD#TRPBF?
The SVOUT– pin (Pins 10 and 29) is the exposed thermal pad of the QFN package and serves as the electrical return for the high-side MOSFET and internal level-shift circuits. It must be soldered to a PCB copper plane tied to VOUT– to ensure rated thermal performance (θJA = 43°C/W) and proper operation of the internal level-shifted I/O pins.
Can the LTC7149IUFD#TRPBF operate with a 3.3V input to generate –3.3V output?
No - the LTC7149IUFD#TRPBF requires minimum 3.4V input, and generating –3.3V from 3.3V violates the minimum on-time constraint (tON(MIN) = 60ns). At such low |VOUT|/VIN ratios, the duty cycle approaches 100%, and the internal controller cannot reliably sense peak current. Operation is supported down to VIN ≥ 4.5V for –3.3V output per design guidelines.
LTC7149IUFD#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:
- 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#TRPBF FAQ
1.How can I place an order for LTC7149IUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7149IUFD#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 LTC7149IUFD#TRPBF reliable?
The price and inventory of LTC7149IUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7149IUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC7149IUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7149IUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7149IUFD#TRPBF?
LTC7149IUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7149IUFD#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 LTC7149IUFD#TRPBF?
For technical support, including LTC7149IUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7149IUFD#TRPBF requirements.
6.How does Aetrix verify that LTC7149IUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC7149IUFD#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 LTC7149IUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC7149IUFD#TRPBF?
All LTC7149IUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7149IUFD#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 LTC7149IUFD#TRPBF part is unused and in its original packaging.
Return procedure for LTC7149IUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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