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Analog Devices Inc. LT8640HUDC-1#TRPBF
- Part No.:
- LT8640HUDC-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN, 18 Leads, Exposed Pad
- Datasheet:
-
LT8640HUDC-1#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,944
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Product details
Overview
LT8640HUDC-1#TRPBF from Analog Devices is a 42V, 5A synchronous step-down Silent Switcher regulator with forced continuous mode (FCM), 2.5µA quiescent current in regulation, 30ns minimum on-time, and AEC-Q100 H-grade (–40°C to 150°C junction) qualification for automotive power supplies.
For engineers reviewing the LT8640HUDC-1#TRPBF datasheet, LT8640HUDC-1#TRPBF pinout, LT8640HUDC-1#TRPBF application, or LT8640HUDC-1#TRPBF equivalent, key selection criteria include ultralow EMI performance, FCM transient response, input voltage range (3.4V–42V), thermal robustness at 150°C, and compatibility with 3mm × 4mm QFN PCB layouts.
Technical Context
The LT8640HUDC-1#TRPBF implements peak current mode control with internal 0.97V reference and programmable oscillator (200kHz–3MHz via RT resistor). Its Silent Switcher architecture uses symmetrical layout and integrated bypass capacitors to suppress EMI without external filters.
Unlike the LT8640, the LT8640-1 variant (including LT8640HUDC-1#TRPBF) supports forced continuous mode-enabling negative inductor current, improved load-step response, and stable operation down to zero load-activated by floating the SYNC/MODE pin or applying spread spectrum modulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports wide automotive battery transients including cold-crank (4.5V) and load-dump (40V+). |
| Output Current | 5A continuous, 7A peak - sustains high-current loads like ADAS sensors or infotainment processors without derating at 125°C ambient. |
| Quiescent Current | 2.5µA at 12VIN → 3.3VOUT in regulation - enables always-on systems (e.g., telematics wake-up logic) with multi-year battery life. |
| Minimum On-Time | 30ns - enables high-frequency (up to 3MHz), high-VIN-to-low-VOUT conversion (e.g., 24V → 1.2V) with small inductors. |
| Switching Frequency | Programmable 200kHz–3MHz via RT pin - allows optimization of size (high-freq) vs. efficiency (low-freq) and EMI band placement. |
| Thermal Grade | AEC-Q100 H-grade (–40°C to 150°C TJ) - qualified for under-hood automotive applications with guaranteed parametric performance at full junction temperature. |
| EMI Performance | Meets CISPR 25 Class 5 radiated/ conducted limits - eliminates need for external EMI filters in automotive ECU designs. |
Pinout & Package
LT8640HUDC-1#TRPBF uses an 18-lead 3mm × 4mm plastic QFN package with exposed SW pads (pins 21, 22) for thermal management. The package is side-wettable capable but this variant (UDC) uses standard QFN leads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BIAS (1) | Internal regulator bias supply | Connect to VOUT (≥3.3V) to reduce VIN current draw and improve light-load efficiency. |
| INTVCC (2) | Internal 3.4V LDO output | Bypass with ≥1µF ceramic capacitor; powers control circuitry-do not load externally. |
| BST (3) | Bootstrap capacitor connection | Requires 0.1µF ceramic cap between BST and SW to drive high-side NMOS gate above VIN. |
| VIN1 (4), VIN2 (13) | Dual input power inputs | Each requires dedicated 1µF local ceramic bypass; reduces high-frequency input ripple and EMI. |
| GND1 (6,7), GND2 (10,11), GND (18) | Power and signal ground returns | Must be tied together and connected to low-impedance ground plane; critical for EMI and thermal performance. |
| SW (8,9,21,22) | Switch node outputs | Exposed pads (21,22) must be soldered to SW trace for thermal conduction; keep SW node area minimal on PCB. |
| EN/UV (14) | Enable and undervoltage lockout | Hysteresis of 40mV; rising threshold = 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 charges external capacitor to control VOUT ramp rate; also enables VOUT tracking during sequencing. |
| SYNC/MODE (17) | Operating mode selection | Float = Forced Continuous Mode (FCM); tie to GND = Burst Mode; tie to INTVCC = FCM + spread spectrum. |
| FB (20) | Feedback voltage sense | Regulates to 0.970V ±0.6%; connect resistive divider tap here; add 4.7pF–22pF phase-lead cap from FB to VOUT. |
| PG (19) | Power good open-drain flag | Active-high when VOUT is within ±8% of target and no fault - used for system power sequencing and monitoring. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® architecture | Integrated dual-input/dual-GND paths and symmetrical layout minimize magnetic field loop area, reducing radiated EMI by >30dB vs conventional buck regulators. |
| Forced Continuous Mode (FCM) | Enables negative inductor current and fast load-step response (<10µs recovery for 1A step) - essential for CPU/GPU core rails with dynamic current demands. |
| Ultralow 2.5µA quiescent current | Maintains regulation at microamp loads without pulse-skipping artifacts - preserves low-noise output for RF and sensor bias supplies. |
| 30ns minimum on-time | Supports direct 24V→1.2V or 48V→3.3V conversion at 2MHz, eliminating intermediate stages and saving board space in distributed power architectures. |
| AEC-Q100 H-grade qualification | Validated for 150°C junction operation with lifetime reliability data - suitable for engine control, transmission, and ADAS modules requiring extended temperature capability. |
| Spread spectrum modulation | +20% triangular frequency dithering reduces peak EMI amplitude by spreading energy across bandwidth - simplifies EMC certification for automotive Tier-1 suppliers. |
Applications
| Automotive Engine Control Unit (ECU) | Industrial PLC I/O Power Supply |
|---|---|
Use Scenario: Powers microcontroller, CAN transceiver, and analog front-end in under-hood ECU exposed to 125°C ambient and 40V load-dump transients. IC Role / Device Role / Timing Role: Primary 5V/3.3V point-of-load regulator delivering clean, low-EMI power with AEC-Q100 H-grade reliability. Use Value: Eliminates external EMI filter components while maintaining <10mVP-P ripple and surviving 150°C junction temperature during sustained high-load operation. |
Use Scenario: Supplies isolated I/O modules in factory automation PLCs requiring stable 5V/3.3V rails across –40°C to 85°C ambient with immunity to 24V industrial bus noise. IC Role / Device Role / Timing Role: High-efficiency, low-noise DC/DC converter with programmable frequency to avoid interference with 4–20mA loop frequencies. Use Value: 2.5µA IQ enables always-on diagnostics; 30ns on-time supports 24V→5V conversion at 2MHz, minimizing inductor size in space-constrained DIN-rail enclosures. |
| ADAS Camera Module Power | GSM Base Station RF Bias Supply |
Use Scenario: Powers image sensor and ISP in automotive surround-view camera operating near exhaust manifold with rapid thermal cycling. IC Role / Device Role / Timing Role: Silent Switcher buck regulator providing ultra-low EMI power to prevent RF interference with 77GHz radar co-location. Use Value: Meets CISPR 25 Class 5 radiated limits without ferrite beads or shielding cans - reduces BOM cost and assembly complexity. |
Use Scenario: Generates low-noise 5V bias for GSM PA driver stages in macrocell base stations where switching noise must not degrade adjacent channel power ratio (ACPR). IC Role / Device Role / Timing Role: High PSRR, low-ripple DC/DC converter with programmable spread spectrum to suppress switching harmonics near 900MHz/1800MHz bands. Use Value: Output ripple <10mVP-P and <–65dBc switching noise at 1MHz ensure ACPR compliance without post-regulation LDOs. |
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 |
|---|---|---|---|
| LT8640HUDC#TRPBF | Pulse-skipping mode instead of FCM; lacks forced continuous operation and negative inductor current capability. | Suitable for lower-transient applications where Burst Mode efficiency is prioritized over load-step response. | Select only if FCM is unnecessary and pulse-skipping behavior is acceptable for the load profile. |
| MPQ4433AGL-A-Z | 40V input, 3.5A output, 17µA IQ, no spread spectrum, non-AEC-Q100, 20-pin 4mm × 4mm QFN. | Targeted at industrial/commercial use; lacks automotive qualification and EMI suppression features. | Consider for cost-sensitive non-automotive designs where AEC-Q100 and CISPR 25 compliance are not required. |
Compared with LT8640HUDC#TRPBF, the LT8640HUDC-1#TRPBF delivers superior transient response and zero-load stability via FCM, while MPQ4433AGL-A-Z offers lower cost and smaller footprint but sacrifices automotive qualification, EMI performance, and ultralow IQ.
Availability
LT8640HUDC-1#TRPBF is available at Aetrix Electronics and suitable for automotive ECU power supplies, industrial PLCs, ADAS camera modules, and GSM RF bias circuits requiring stable component supply with AEC-Q100 H-grade assurance and long-term production continuity.
Supply support for LT8640HUDC-1#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 semiconductors, serving precision instrumentation, industrial automation, communications, and automotive markets.
The LT8640/LT8640-1 product line was designed specifically for automotive and industrial applications demanding ultralow EMI, high efficiency at light loads, and robust operation across extreme temperature ranges.
FAQ
What is the maximum junction temperature rating for the LT8640HUDC-1#TRPBF?
The LT8640HUDC-1#TRPBF is AEC-Q100 H-grade qualified with a guaranteed operating junction temperature range of –40°C to 150°C. This rating is validated across all electrical parameters in the datasheet, enabling deployment in under-hood automotive environments where ambient temperatures exceed 125°C.
How does the SYNC/MODE pin configure forced continuous mode on the LT8640HUDC-1#TRPBF?
On the LT8640HUDC-1#TRPBF, forced continuous mode (FCM) is activated by leaving the SYNC/MODE pin floating (with leakage <1µA). In FCM, the LT8640HUDC-1#TRPBF maintains continuous switching across all load conditions-including zero load-and allows negative inductor current to improve transient response.
Can the LT8640HUDC-1#TRPBF operate with a 24V input and 3.3V output at 2MHz switching frequency?
Yes. The LT8640HUDC-1#TRPBF supports 24V→3.3V conversion at 2MHz using a 60.4kΩ RT resistor. Its 30ns minimum on-time ensures stable operation, and its Silent Switcher architecture maintains <10mVP-P output ripple and meets CISPR 25 Class 5 EMI limits without external filtering.
What is the purpose of the BIAS pin on the LT8640HUDC-1#TRPBF, and how should it be connected?
The BIAS pin on the LT8640HUDC-1#TRPBF supplies the internal regulator when biased ≥3.1V, reducing VIN current draw and improving light-load efficiency. For 3.3V–25V output voltages, connect BIAS directly to VOUT; otherwise, bypass with 1µF capacitor if using an external supply.
Does the LT8640HUDC-1#TRPBF require external compensation components?
No. The LT8640HUDC-1#TRPBF uses internal compensation and requires only a 4.7pF–22pF phase-lead capacitor between FB and VOUT for stability. No external RC network or type-II/type-III compensator is needed, simplifying design and reducing bill-of-materials count.
LT8640HUDC-1#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 ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-QFN (3x4)
LT8640HUDC-1#TRPBF FAQ
1.How can I place an order for LT8640HUDC-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8640HUDC-1#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 LT8640HUDC-1#TRPBF reliable?
The price and inventory of LT8640HUDC-1#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8640HUDC-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8640HUDC-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8640HUDC-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8640HUDC-1#TRPBF?
LT8640HUDC-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8640HUDC-1#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 LT8640HUDC-1#TRPBF?
For technical support, including LT8640HUDC-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8640HUDC-1#TRPBF requirements.
6.How does Aetrix verify that LT8640HUDC-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8640HUDC-1#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 LT8640HUDC-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8640HUDC-1#TRPBF?
All LT8640HUDC-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8640HUDC-1#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 LT8640HUDC-1#TRPBF part is unused and in its original packaging.
Return procedure for LT8640HUDC-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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