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Analog Devices Inc. LT8620IUDD#PBF
- Part No.:
- LT8620IUDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LT8620IUDD#PBF.pdf
- Description:
- IC REG BUCK ADJ 2A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:797
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Product details
Overview
LT8620IUDD#PBF from Analog Devices (formerly Linear Technology) is a 65V input, 2A synchronous step-down DC/DC regulator in a 24-lead 3mm × 5mm QFN package with exposed GND pad. It delivers up to 2A output current, achieves 94% efficiency at 12VIN to 5VOUT, operates with only 2.5µA quiescent current in Burst Mode®, and supports adjustable switching frequency from 200kHz to 2.2MHz. It is used in automotive infotainment power supplies where wide VIN range and ultralow IQ are critical.
For engineers reviewing the LT8620IUDD#PBF datasheet, LT8620IUDD#PBF pinout, LT8620IUDD#PBF application, or LT8620IUDD#PBF equivalent, key selection criteria include its 65V absolute max input rating, ±9% power-good accuracy, 30ns minimum on-time for high step-down ratios, internal compensation for fast transient response, and BIAS pin support for improved light-load efficiency when VOUT ≥ 3.3V.
Technical Context
The LT8620IUDD#PBF implements peak-current-mode control with internal compensation, enabling stable operation with small external inductors (e.g., 4.7µH) and fast load-transient response. Its architecture integrates top and bottom NMOS power switches (175mΩ / 85mΩ typical RDS(ON)), a 0.970V precision feedback reference, and programmable soft-start via TR/SS pin.
Burst Mode® operation maintains <10mVP-P output ripple while drawing just 2.5µA from VIN at no load; synchronization via SYNC pin allows external clock alignment or pulse-skipping mode. The EN/UV pin provides accurate 1.0V threshold with 40mV hysteresis for VIN undervoltage lockout or shutdown, reducing supply current to 1µA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 65V - supports automotive cold-crank (4.5V) and industrial 48V systems without pre-regulation. |
| Output Current | 2A continuous - sufficient for powering dual-core microcontrollers or FPGA I/O banks. |
| Quiescent Current | 2.5µA at 12VIN/3.3VOUT - enables >10-year battery life in always-on telematics modules. |
| Switching Frequency | 200kHz–2.2MHz (RT-programmable) - allows optimization between EMI filtering size and efficiency. |
| Feedback Reference | 0.970V ±0.006V - enables precise output regulation across temperature with minimal resistor-divider error. |
| Power-Good Accuracy | ±9% of VOUT - ensures reliable system reset sequencing in safety-critical applications. |
| Minimum On-Time | 30ns - supports 12V-to-1.2V conversion at 700kHz without duty-cycle limitation. |
Pinout & Package
LT8620IUDD#PBF is housed in a thermally enhanced 24-lead 3mm × 5mm plastic QFN package (UDD) with exposed GND pad (Pin 25), requiring soldering to PCB for θJC(PAD) = 5°C/W thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1–4, 11–12, 14–16, 20–24 | No Connect (NC) | Internally unconnected; must be left floating or tied to GND per layout guidelines. |
| 5–6, 13 | VIN | Main input power pins - must be shorted together and bypassed locally with low-ESR ceramic capacitor. |
| 7 | GND | Analog ground reference - connects to exposed pad (Pin 25); forms primary thermal path. |
| 8 | FB | Feedback node - regulates voltage by comparing divider output to 0.970V internal reference. |
| 9 | PG | Open-drain power-good flag - asserts high when VOUT is within ±9% of target and no fault exists. |
| 10 | BIAS | Efficiency-boosting bias supply - connect to VOUT ≥ 3.3V to reduce VIN current draw during light loads. |
| 17 | INTVCC | Internal 3.4V regulator output - bypass with ≥1µF ceramic capacitor; not for external loading. |
| 18 | BST | Bootstrap supply for high-side switch - requires 0.1µF ceramic capacitor placed adjacent to IC. |
| 19, 25 | SW | Switch node - connects to inductor and BST capacitor; must be minimized in PCB area for low EMI. |
| 26 | GND (exposed pad) | Thermal and electrical ground - mandatory solder connection to PCB plane for thermal integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow IQ Burst Mode® | 2.5µA input current at no load preserves battery runtime in always-on automotive modules. |
| Synchronous rectification | Integrated 175mΩ/85mΩ NMOS switches eliminate external diode loss, enabling >92% efficiency at 1A. |
| Adjustable frequency (200kHz–2.2MHz) | RT-resistor programming allows EMI compliance tuning and inductor size reduction without loop redesign. |
| Low dropout operation | 250mV dropout at 1A enables stable 5V output from 5.5V input - critical for post-buck LDO replacement. |
| Robust protection suite | Includes overcurrent limiting (top: 4.1A typ, bottom: 3.9A typ), thermal shutdown, and PG fault reporting. |
Applications
| Automotive Infotainment Power | Industrial IoT Sensor Hub |
|---|---|
Use Scenario: Powering display controller, audio codec, and CAN transceiver from 12V vehicle battery with cold-crank tolerance down to 4.5V. IC Role / Device Role / Timing Role: Primary 5V/2A buck regulator supplying core logic rails; PG signal sequences MCU boot after stable VOUT. Use Value: 65V input rating survives load-dump transients; 2.5µA IQ extends backup battery life during ignition-off monitoring. | Use Scenario: Providing regulated 3.3V to ultra-low-power wireless sensor nodes deployed in remote factory environments. IC Role / Device Role / Timing Role: Main system regulator delivering clean 3.3V to ARM Cortex-M0+ MCU and sub-GHz RF transceiver. Use Value: Burst Mode® maintains <10mVP-P ripple at µA-level loads; BIAS pin connection to VOUT cuts IQ by 40% vs VIN sourcing. |
| GSM Base Station Bias Supply | Rail-to-Rail Industrial DAC Power |
Use Scenario: Generating 5V bias for PA driver stages in cellular infrastructure equipment operating from 48V backplane. IC Role / Device Role / Timing Role: Intermediate step-down stage feeding downstream point-of-load converters; SYNC pin synchronized to system clock. Use Value: 30ns min on-time supports 48V-to-5V conversion at 700kHz; low EMI design meets EN55022 Class B limits. | Use Scenario: Powering precision 16-bit DACs and instrumentation amplifiers requiring low-noise, tightly regulated 3.3V rail. IC Role / Device Role / Timing Role: Low-ripple, high-PSRR buck regulator; FB pin accuracy (±0.6%) ensures DAC reference stability. Use Value: Internal compensation eliminates external compensation network; ±9% PG window validates rail integrity before data acquisition. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5164QDRCRQ1 | 4.5V–65V input, 1A output, 1.5µA IQ, but lacks BIAS pin and PG flag. | Lower output current and missing PG limit use in safety-critical automotive domains. | Select when cost sensitivity outweighs need for 2A capability and power-good signaling. |
| MAX20008AATP/V+T | 3.5V–60V input, 2A output, 2.2µA IQ, AEC-Q100 Grade 1, but fixed 2.1MHz frequency. | Higher automotive qualification grade, but no RT-programmability restricts EMI optimization. | Select for ASIL-B systems requiring certified reliability, accepting fixed-frequency trade-offs. |
Compared with LM5164QDRCRQ1 and MAX20008AATP/V+T, the LT8620IUDD#PBF uniquely combines 2A output, programmable frequency, BIAS pin efficiency boost, and ±9% PG accuracy - making it optimal for space-constrained, high-reliability 12V/24V/48V embedded systems demanding both low IQ and robust fault reporting.
Availability
LT8620IUDD#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial IoT sensor hubs, GSM base station bias supplies, and rail-to-rail industrial DAC power applications requiring stable component supply across extended temperature ranges.
Supply support for LT8620IUDD#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 acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for the LT® portfolio.
The LT8620IUDD#PBF belongs to the LT86xx family of high-input-voltage, ultralow-IQ synchronous buck regulators designed specifically for automotive, industrial, and telecom power systems where wide VIN range and standby efficiency are non-negotiable.
FAQ
What is the maximum input voltage rating for the LT8620IUDD#PBF?
The LT8620IUDD#PBF has an absolute maximum input voltage rating of 65V, with guaranteed operation from 3.4V to 65V. This enables direct connection to 48V industrial buses and survival through automotive load-dump transients (ISO 7637-2 Pulse 5a). The LT8620IUDD#PBF incorporates internal protection to prevent damage at 65V, but sustained operation above 60V requires careful thermal design due to increased power dissipation in the integrated MOSFETs.
How does the BIAS pin improve efficiency in the LT8620IUDD#PBF?
The BIAS pin on the LT8620IUDD#PBF allows the internal regulator to draw bias current from VOUT instead of VIN when VBIAS ≥ 3.1V, reducing total input current and improving light-load efficiency. When connected to a 3.3V or 5V output, the LT8620IUDD#PBF draws ~7.2mA from BIAS at 1A load instead of from VIN, lowering overall system power loss. This feature is especially valuable in multi-rail systems where the LT8620IUDD#PBF output powers downstream regulators that can feed back to BIAS.
Can the LT8620IUDD#PBF achieve 5V output from a 5.5V input?
Yes, the LT8620IUDD#PBF supports low-dropout operation with only 250mV dropout at 1A, enabling stable 5V output from a 5.5V input. This is achieved through its low RDS(ON) top switch (175mΩ typ) and ability to operate at very high duty cycles (>95%). In such configurations, the LT8620IUDD#PBF automatically reduces switching frequency via frequency foldback to maintain control, ensuring regulation even under near-dropout conditions without requiring external components.
What is the purpose of the TR/SS pin on the LT8620IUDD#PBF?
The TR/SS (Track/Soft-Start) pin on the LT8620IUDD#PBF serves two functions: it programs output voltage ramp rate during startup via an external capacitor, and enables output voltage tracking for sequencing with other rails. When a capacitor is connected from TR/SS to GND, the internal 2µA current source creates a linear voltage ramp, controlling dVOUT/dt. During normal operation, TR/SS > 0.97V disables tracking and reverts to standard regulation. This dual functionality makes the LT8620IUDD#PBF suitable for complex power-up sequences in FPGAs and multicore processors.
Does the LT8620IUDD#PBF require external compensation components?
No, the LT8620IUDD#PBF features fully internal compensation using peak-current-mode control, eliminating the need for external Type II or Type III compensation networks. This simplifies design, reduces BOM count, and improves consistency across production units. The internal compensation is optimized for stability with standard 4.7µH inductors and ceramic output capacitors, enabling fast transient response (<50µs recovery for 1A load step) without user tuning - a key advantage over voltage-mode controllers requiring manual loop compensation.
LT8620IUDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN 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):
- 3.4V
- Voltage - Input (Max):
- 65V
- Voltage - Output (Min/Fixed):
- 0.97V
- Voltage - Output (Max):
- 64.75V
- Current - Output:
- 2A
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (3x5)
LT8620IUDD#PBF FAQ
1.How can I place an order for LT8620IUDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8620IUDD#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 LT8620IUDD#PBF reliable?
The price and inventory of LT8620IUDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8620IUDD#PBF is usually 5 days.
3.What payment methods are accepted for LT8620IUDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8620IUDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8620IUDD#PBF?
LT8620IUDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8620IUDD#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 LT8620IUDD#PBF?
For technical support, including LT8620IUDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8620IUDD#PBF requirements.
6.How does Aetrix verify that LT8620IUDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT8620IUDD#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 LT8620IUDD#PBF meets industry standards.
7.What is the process for return or replacement of LT8620IUDD#PBF?
All LT8620IUDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8620IUDD#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 LT8620IUDD#PBF part is unused and in its original packaging.
Return procedure for LT8620IUDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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