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Analog Devices Inc. LT8640IUDC#TRPBF
- Part No.:
- LT8640IUDC#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN, 18 Leads, Exposed Pad
- Datasheet:
-
LT8640IUDC#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,967
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Product details
Overview
LT8640IUDC#TRPBF from Analog Devices is a 42V, 5A synchronous step-down Silent Switcher regulator with 2.5µA quiescent current in regulation, 30ns minimum on-time, and integrated power MOSFETs. It delivers up to 96% efficiency at 1MHz (12VIN→5VOUT), supports 200kHz–3MHz programmable switching frequency, and operates across –40°C to 125°C junction temperature for automotive and industrial power supplies.
For engineers reviewing the LT8640IUDC#TRPBF datasheet, LT8640IUDC#TRPBF pinout, LT8640IUDC#TRPBF application, or LT8640IUDC#TRPBF equivalent, key selection criteria include ultralow IQ in Burst Mode, EMI-optimized Silent Switcher architecture, forced continuous mode capability (via LT8640-1 variant), thermal performance in 3mm × 4mm QFN, and AEC-Q100 qualification for automotive systems.
Technical Context
The LT8640IUDC#TRPBF employs peak current-mode control with an internal 0.97V reference and adjustable oscillator (RT-pin programmable). Its Silent Switcher architecture uses symmetrical layout and integrated input capacitors to suppress EMI emissions, achieving CISPR 25 Class 5 compliance without external filters.
It features dual input rails (VIN1/VIN2), side-wettable QFN package with exposed SW pads, and configurable operation modes via SYNC/MODE pin - including Burst Mode (2.5µA IQ), pulse-skipping (LT8640), or forced continuous mode (LT8640-1). The BIAS pin enables efficiency optimization by sourcing INTVCC from VOUT when ≥3.3V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports wide-range industrial and automotive battery inputs, including cold-crank and load-dump conditions. |
| Output Current | 5A continuous, 7A peak - enables single-chip 5V/5A or 3.3V/5A conversion without external current sharing. |
| Quiescent Current | 2.5µA at full regulation - sustains >10-year battery life in always-on IoT sensors and telematics modules. |
| Switching Frequency | 200kHz to 3MHz (RT-programmable) - allows compact magnetics (e.g., 1µH at 3MHz) and avoids AM radio band interference. |
| Minimum On-Time | 30ns - enables high VIN-to-low VOUT conversion (e.g., 42V→3.3V at 2MHz) without pulse skipping. |
| Feedback Reference | 0.970V ±0.006V - provides precise output regulation with <±0.5% line/load regulation over temperature. |
| EMI Performance | CISPR 25 Class 5 compliant (radiated & conducted) - eliminates need for external EMI filters in automotive infotainment and ADAS designs. |
Pinout & Package
LT8640IUDC#TRPBF is housed in an 18-lead, 3mm × 4mm plastic QFN (UDC) package with side-wettable leads and exposed SW pads (pins 21, 22) for enhanced thermal dissipation (θJC = 12°C/W). Pins 5 and 12 are omitted; top-side marking "LGNJ" identifies the I-grade variant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BIAS (1) | Internal regulator bias supply | Accepts 3.3V–25V input to reduce VIN current draw; must be bypassed with 1µF if not tied to VOUT. |
| INTVCC (2) | Internal 3.4V LDO output | Powers control circuitry; requires ≥1µF low-ESR ceramic bypass to GND; no external loading permitted. |
| BST (3) | Bootstrap capacitor connection | Drives high-side MOSFET gate; requires 0.1µF ceramic capacitor placed adjacent to IC. |
| VIN1 (4), VIN2 (13) | Dual input power rails | Each requires dedicated 1µF local ceramic bypass; shared bulk input capacitor connects to both. |
| GND1 (6,7), GND2 (10,11) | Power switch return paths | Must be shorted together and connected to low-impedance ground plane near input capacitors. |
| SW (8,9,21,22) | Switch node outputs | Exposed pads (21,22) must be soldered to SW trace for thermal integrity; SW routing must be minimized for EMI control. |
| EN/UV (14) | Enable and undervoltage lockout | Hysteretic threshold (0.96V/1.00V) enables programmable input UVLO using resistor divider from VIN. |
| RT (15) | Oscillator frequency programming | Resistor to GND sets fSW: 221kΩ → 210kHz, 60.4kΩ → 700kHz, 18.2kΩ → 2.0MHz. |
| TR/SS (16) | Soft-start and output tracking | 1.9µA internal current source enables voltage ramp control; pulled low during fault/shutdown. |
| SYNC/MODE (17) | Operating mode selection | Ground = Burst Mode; float = FCM (LT8640-1); INTVCC-high = spread spectrum; clock input = sync mode. |
| GND (18) | System ground reference | Connects to system ground plane; separates signal ground from power ground paths. |
| PG (19) | Power good open-drain output | Asserts high when FB is within ±8% of 0.97V and VIN > 3.4V; pulls down with 2kΩ typical resistance. |
| FB (20) | Feedback voltage sense | Regulates to 0.970V; requires RC network (e.g., 4.7pF + resistor divider) for stability and phase margin. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® architecture | Integrated input capacitors and symmetrical layout reduce radiated EMI by >30dB vs conventional buck regulators. |
| Ultralow 2.5µA quiescent current | Enables >10-year battery runtime in always-on applications like vehicle event data recorders and smart sensors. |
| 30ns minimum on-time | Supports direct 42V→3.3V conversion at 2MHz, eliminating intermediate stages and reducing BOM count. |
| AEC-Q100 Grade I qualification | Guaranteed operation from –40°C to +125°C junction temperature for under-hood automotive use. |
| Forced Continuous Mode (FCM) | Available on LT8640-1 variant; enables fast load-transient response (<50µs recovery) and negative inductor current. |
| Spread spectrum modulation | ±20% frequency dithering reduces peak EMI amplitude by 10–15dB, easing EMC certification. |
Applications
| Automotive Infotainment Power | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering SoC, DDR memory, and display interfaces in head units with 12V/24V battery input and strict CISPR 25 EMI limits. IC Role / Device Role / Timing Role: Primary 5V/5A DC/DC converter delivering low-noise, ripple-free power with Silent Switcher EMI suppression. Use Value: Eliminates external EMI filters, reduces PCB area by 30%, and meets Class 5 radiated emission limits without shielding. |
Use Scenario: Generating isolated 3.3V logic rail from 24V field bus in programmable logic controllers with high ambient temperature. IC Role / Device Role / Timing Role: High-efficiency, thermally robust buck regulator operating continuously at 85°C ambient. Use Value: Maintains >92% efficiency at full load and 125°C junction, enabling convection-cooled enclosure design. |
| GSM Base Station RF Power | Medical Patient Monitor |
Use Scenario: Supplying PA bias and analog front-end circuits in cellular base stations requiring ultra-low noise and fast transient response. IC Role / Device Role / Timing Role: Secondary 3.3V/5A regulator with FCM mode enabled for sub-100µs load-step recovery. Use Value: Delivers <10mV output deviation during 1A–5A load steps, preserving RF signal integrity and spectral purity. |
Use Scenario: Battery-backed 5V/3.3V power for portable diagnostic devices requiring >5-year shelf life and FDA-compliant reliability. IC Role / Device Role / Timing Role: Always-on standby regulator with 2.5µA IQ, soft-start sequencing, and PG monitoring for system health. Use Value: Extends primary Li-ion battery life to >120 months in sleep mode while ensuring safe power-up sequencing. |
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 |
|---|---|---|---|
| LT8640-1IUDC#TRPBF | Forced Continuous Mode (FCM) instead of pulse-skipping; higher light-load IQ (~100µA vs 2.5µA); identical pinout and package. | Preferred for fast transient loads (e.g., RF PAs, FPGA core rails) where output voltage droop must be minimized. | Select LT8640-1IUDC#TRPBF when FCM operation is required; otherwise, LT8640IUDC#TRPBF offers superior light-load efficiency. |
| MPQ4433AGL-AEC1-P | 40V input, 3.5A output, 17µA IQ; AEC-Q100 qualified; no spread spectrum or Silent Switcher; 3mm × 4mm QFN. | Lacks CISPR 25 compliance; requires external EMI filtering; lower output current limits use cases to ≤3.5A. | Choose MPQ4433AGL-AEC1-P only if cost sensitivity outweighs EMI performance and 5A capability requirements. |
Compared with LT8640-1IUDC#TRPBF, the LT8640IUDC#TRPBF trades higher light-load efficiency for pulse-skipping behavior, while MPQ4433AGL-AEC1-P lacks integrated EMI mitigation and current capability - making LT8640IUDC#TRPBF optimal for high-reliability, EMI-constrained 5A automotive and industrial designs.
Availability
LT8640IUDC#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLCs, and medical diagnostics equipment requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant performance.
Supply support for LT8640IUDC#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.
The LT8640/LT8640-1 belongs to Analog Devices' Silent Switcher family of high-efficiency, low-EMI DC/DC regulators, engineered specifically for automotive and industrial applications demanding robustness, precision, and regulatory compliance.
FAQ
What is the maximum junction temperature rating for LT8640IUDC#TRPBF?
The LT8640IUDC#TRPBF is rated for operation from –40°C to +125°C junction temperature and is guaranteed across this full range. Its thermal design supports θJA = 40°C/W on standard 2-layer PCBs, and the exposed SW pads (pins 21, 22) must be soldered to maximize heat transfer. Derating is recommended above 125°C to ensure long-term reliability.
Does LT8640IUDC#TRPBF support synchronization to an external clock?
Yes, the LT8640IUDC#TRPBF supports external clock synchronization via the SYNC/MODE pin (pin 17). When driven with a clean CMOS clock signal between 200kHz and 3MHz, the device locks its internal oscillator and operates in pulse-skipping mode, maintaining tight frequency alignment for noise-sensitive systems like audio amplifiers or ADC reference supplies.
How does the BIAS pin improve efficiency in LT8640IUDC#TRPBF?
The BIAS pin (pin 1) allows the LT8640IUDC#TRPBF to power its internal circuitry from VOUT instead of VIN when VOUT ≥ 3.3V. This reduces total input current by ~11mA (typical BIAS pin current at 2MHz), improving full-load efficiency by up to 1.2% - especially valuable in high-current, high-input-voltage applications like 42V→5V conversion.
Can LT8640IUDC#TRPBF operate with a 1µH inductor at 3MHz?
Yes, the LT8640IUDC#TRPBF supports 3MHz operation with a 1µH inductor, enabled by its 30ns minimum on-time. At 12VIN→5VOUT, this configuration delivers >90% efficiency with minimal output ripple (<10mVP-P), allowing ultra-compact designs ideal for space-constrained automotive ECUs and portable test equipment.
Is LT8640IUDC#TRPBF pin-compatible with LT8640-1IUDC#TRPBF?
Yes, the LT8640IUDC#TRPBF and LT8640-1IUDC#TRPBF share identical pinout, package (18-lead 3mm × 4mm QFN), and footprint. The only functional difference lies in the SYNC/MODE pin behavior: LT8640IUDC#TRPBF defaults to pulse-skipping when floating, while LT8640-1IUDC#TRPBF defaults to Forced Continuous Mode - requiring no PCB changes for migration.
LT8640IUDC#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- Silent Switcher®1
- Package/Case:
- 20-WFQFN, 18 Leads, Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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):
- 42V
- Voltage - Output (Min/Fixed):
- 0.97V
- Voltage - Output (Max):
- 42V
- Current - Output:
- 5A
- Frequency - Switching:
- 210kHz ~ 2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (3x4)
LT8640IUDC#TRPBF FAQ
1.How can I place an order for LT8640IUDC#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8640IUDC#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 LT8640IUDC#TRPBF reliable?
The price and inventory of LT8640IUDC#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8640IUDC#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8640IUDC#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8640IUDC#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8640IUDC#TRPBF?
LT8640IUDC#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8640IUDC#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 LT8640IUDC#TRPBF?
For technical support, including LT8640IUDC#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8640IUDC#TRPBF requirements.
6.How does Aetrix verify that LT8640IUDC#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8640IUDC#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 LT8640IUDC#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8640IUDC#TRPBF?
All LT8640IUDC#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8640IUDC#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 LT8640IUDC#TRPBF part is unused and in its original packaging.
Return procedure for LT8640IUDC#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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