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Analog Devices Inc. LT8640AJUDCM#TRPBF
- Part No.:
- LT8640AJUDCM#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-WFQFN Exposed Pad, 18 Leads
- Datasheet:
-
LT8640AJUDCM#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 5A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,947
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Product details
Overview
LT8640AJUDCM#TRPBF from Analog Devices is a 42V input, 5A continuous/8A peak synchronous step-down regulator featuring Silent Switcher architecture, 2.5µA quiescent current in regulation, 30ns minimum on-time, and AEC-Q100 qualification for automotive applications. It delivers high efficiency up to 96% at 1MHz (12VIN→5VOUT) and supports fixed or adjustable output configurations.
For engineers reviewing the LT8640AJUDCM#TRPBF datasheet, LT8640AJUDCM#TRPBF pinout, LT8640AJUDCM#TRPBF application, or LT8640AJUDCM#TRPBF equivalent, this page provides verified technical context, package mapping, validated pin functions, confirmed EMI performance data, and real-world design implications for automotive power systems, industrial DC-DC conversion, and low-IQ battery-powered subsystems.
Technical Context
The LT8640AJUDCM#TRPBF implements peak current mode control with internal compensation, enabling stable operation across 200kHz–3MHz via RT resistor programming. Its dual-input/dual-ground pin structure (VIN1/VIN2, GND1/GND2) minimizes high-di/dt loop area to suppress conducted EMI-validated by CISPR25 Class 5 peak limits in both fixed-frequency and spread-spectrum modes.
It integrates synchronous NMOS switches (67mΩ top / 28mΩ bottom), supports four operating modes via SYNC/MODE pin (Burst Mode, FCM, spread spectrum, external sync), and features ultralow dropout (100mV @1A) with safe reverse-current tolerance-critical for automotive cold-crank and load-dump resilience.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.4V to 42V - supports automotive battery transients including cold-crank (down to ~3.4V) and ISO 7637-2 pulse 5a (up to 42V). |
| Output Current | 5A continuous / 8A peak - enables single-chip 5V/5A rail for ADAS camera modules or infotainment processors without external current boosting. |
| Quiescent Current | 2.5µA @ full regulation - sustains >10-year battery life in always-on vehicle telematics or remote keyless entry receivers. |
| Switching Frequency | 200kHz to 3MHz - allows compact magnetics (e.g., 1µH at 3MHz); frequency foldback prevents inductor saturation during start-up or overcurrent. |
| EMI Performance | CISPR25 Class 5 compliant - meets stringent automotive radiated/conducted emission limits without external ferrite beads or shielding cans. |
| Thermal Rating | –40°C to +150°C junction - qualified per AEC-Q100 Grade 1; exposed SW pad improves thermal resistance (θJA = 29°C/W on demo board). |
| Feedback Reference | 0.970V ±0.006V - enables precise output regulation; line/load regulation <±0.02%/V and <±0.15% over full load range. |
Pinout & Package
LT8640AJUDCM#TRPBF uses an 18-lead 3mm × 4mm side-solderable QFN (UDCM package) with exposed SW pad (Pin 21) requiring PCB solder connection for thermal and electrical integrity. Pins 5 and 12 are omitted; corner pins serve mechanical support only.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BIAS (1) | Internal regulator bias supply | Reduces VIN current draw when tied to VOUT ≥3.1V; enables >95% efficiency at light loads in automotive 12V systems. |
| INTVCC (2) | Internal 3.4V regulator bypass | Must be decoupled with ≥1µF ceramic capacitor; powers control logic and gate drivers-no external loading permitted. |
| BST (3) | Bootstrap voltage supply | Drives top NMOS gate above VIN; requires 0.1µF ceramic capacitor placed adjacent to IC for reliable high-side switching. |
| VIN1 (4), VIN2 (13) | Dual input power inputs | Split inputs reduce high-frequency input ripple; each requires dedicated 1µF local bypass to respective GND1/GND2 for EMI suppression. |
| GND1 (6,7), GND2 (10,11) | Power switch return paths | Independent ground returns isolate high-di/dt currents; must be tied together and connected to solid ground plane under IC. |
| SW (8,9,21) | Switch node outputs | Pins 8/9 are internal switch outputs; Pin 21 is exposed pad tied to SW-must be soldered to PCB for thermal conduction and low-inductance path. |
| EN/UV (14) | Enable and undervoltage lockout | Hysteretic threshold (1.00V rise / 0.96V fall) enables programmable input UVLO using external resistor divider from VIN. |
| RT (15) | Frequency setting resistor | Resistor to GND sets fSW: 221kΩ → 210kHz, 60.4kΩ → 700kHz, 18.2kΩ → 1.95MHz-enables optimization for size vs. efficiency. |
| TR/SS (16) | Soft-start and tracking control | 1.9µA internal pull-up enables capacitor-programmed slew rate; supports output voltage tracking in multi-rail systems. |
| SYNC/MODE (17) | Operating mode selection | Ground = Burst Mode (2.5µA IQ); float = FCM; INTVCC-high = spread spectrum; external clock = sync-no external components needed. |
| GND (18) | System ground reference | Connects to system ground plane; separates signal ground from power grounds (GND1/GND2) to minimize noise coupling. |
| PG (19) | Power good open-drain output | Asserts high when FB/VOUT is within ±8% of target and no fault exists; valid above 3.4V VIN regardless of EN/UV state. |
| FB (20) | Feedback voltage sense | Regulates to 0.970V; connects to resistor divider tap-requires 4.7–22pF phase-lead capacitor between FB and VOUT for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher architecture | Minimizes EMI through symmetrical layout, split VIN/GND paths, and integrated bootstrap capacitor-reduces need for external EMI filters in automotive ECUs. |
| Ultralow 2.5µA quiescent current | Enables >10-year battery standby in always-on vehicle modules without compromising regulation accuracy or transient response. |
| 30ns minimum on-time | Supports high VIN-to-low VOUT conversion (e.g., 42V→3.3V) at 2MHz, enabling ultra-compact 3.3V auxiliary rails in space-constrained ADAS sensors. |
| AEC-Q100 Grade 1 qualification | Validated for –40°C to +150°C operation with lifetime derating above 125°C-meets reliability requirements for engine bay and transmission control units. |
| Spread spectrum modulation | ±22% triangular frequency dither reduces peak EMI by >10dB across 150kHz–108MHz-passes CISPR25 Class 5 without layout changes. |
| Safe reverse-current tolerance | Withstands negative output current without latch-up or damage-essential for regenerative braking interfaces and bidirectional power domains. |
Applications
| Automotive Camera Power Supply | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powers 5V image sensor and ISP in rear-view camera module exposed to engine bay temperatures and battery transients. IC Role / Device Role / Timing Role: Primary 42V-to-5V buck converter delivering regulated 5V/3A with fast load-step response and cold-crank hold-up. Use Value: Silent Switcher EMI compliance eliminates shielded enclosures; 2.5µA IQ extends vehicle-off battery life beyond 10 years. |
Use Scenario: Generates isolated 5V rail for digital I/O circuitry in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: High-efficiency, wide-input DC-DC stage converting 24VDC field bus to clean 5V logic supply. Use Value: 42V max input withstands industrial surge events; spread spectrum mode ensures EMC certification without redesign. |
| Telematics Control Unit (TCU) | EV Battery Management System (BMS) |
Use Scenario: Supplies 3.3V core voltage to LTE modem and GNSS receiver in always-connected vehicle telematics unit. IC Role / Device Role / Timing Role: Low-noise, low-IQ buck converter maintaining regulation during stop-start cycles and deep sleep states. Use Value: Burst Mode operation achieves 2.5µA IQ; 30ns on-time supports 12V→3.3V conversion at 2MHz for minimal footprint. |
Use Scenario: Powers isolated CAN transceivers and microcontroller in high-voltage battery pack monitoring circuits. IC Role / Device Role / Timing Role: Robust 42V-input buck supplying 5V/1A to safety-critical communication interface with reverse-current protection. Use Value: AEC-Q100 qualification ensures reliability; safe reverse-current tolerance prevents damage during cell balancing events. |
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 |
|---|---|---|---|
| LT8645S | 6A continuous / 9A peak output; LQFN package; external compensation; no internal caps. | Higher current capability and improved thermal performance (θJA = 22°C/W); suited for 5V/6A ADAS domain controllers. | Select LT8645S when >5A continuous current or enhanced thermal margin is required; not pin-compatible due to different package and compensation scheme. |
| MPQ4420AGL-A | 42V/2A; 17-lead QFN; 17µA IQ; no spread spectrum; non-AEC-Q100. | Limited to 2A output; higher quiescent current degrades battery life; lacks automotive qualification and EMI features. | Consider MPQ4420AGL-A only for cost-sensitive, non-automotive industrial applications where 2A output and relaxed EMI requirements apply. |
Compared with LT8640AJUDCM#TRPBF, LT8645S offers higher current and better thermal performance but requires external compensation and layout changes, while MPQ4420AGL-A sacrifices automotive qualification, EMI robustness, and ultra-low IQ for lower cost in non-safety-critical designs.
Availability
LT8640AJUDCM#TRPBF is available at Aetrix Electronics and suitable for automotive camera power supplies, industrial PLC I/O modules, and telematics control units requiring stable component supply, AEC-Q100 compliance, and long-term lifecycle support.
Supply support for LT8640AJUDCM#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 automotive, industrial, communications, and healthcare markets.
The LT8640A product line delivers high-efficiency, low-EMI synchronous buck regulators optimized for automotive and harsh-environment applications demanding AEC-Q100 qualification, wide input range, and ultralow quiescent current.
FAQ
What is the maximum input voltage rating for the LT8640AJUDCM#TRPBF?
The LT8640AJUDCM#TRPBF has an absolute maximum input voltage rating of 42V across VIN1 and VIN2 pins. This rating enables direct connection to 24V and 48V industrial buses and automotive battery systems-including transient conditions defined in ISO 7637-2 Pulse 5a. Operation above 3.4V is required for startup, and the device maintains regulation down to 2.9V minimum input under specific conditions.
Does the LT8640AJUDCM#TRPBF support fixed-output voltage configurations?
Yes, the LT8640AJUDCM#TRPBF itself is the adjustable version, but its family includes the LT8640AJUDCM-3.3#TRPBF variant with a factory-trimmed 3.3V fixed output. The LT8640AJUDCM#TRPBF uses the FB pin and external resistor divider to set output voltage; its feedback reference is precisely 0.970V with ±0.006V tolerance over temperature.
How does the SYNC/MODE pin configure operating modes on the LT8640AJUDCM#TRPBF?
The SYNC/MODE pin on the LT8640AJUDCM#TRPBF selects four distinct modes: grounded for Burst Mode (2.5µA IQ), floating for Forced Continuous Mode (FCM), tied to INTVCC (~3.4V) for spread spectrum FCM, or driven by external clock for synchronization. Each mode alters switching behavior without external components-enabling dynamic trade-offs between efficiency, EMI, and transient response.
What thermal performance can be expected from the LT8640AJUDCM#TRPBF in a typical layout?
On the DC3099A demo board, the LT8640AJUDCM#TRPBF achieves θJA = 29°C/W and ψJT = 0.5°C/W. With proper PCB design-including soldering the exposed SW pad (Pin 21) to a thermal plane-the device sustains 5A continuous output at +85°C ambient. Derating begins above 125°C junction temperature per AEC-Q100 lifetime requirements.
Is the LT8640AJUDCM#TRPBF compatible with spread spectrum EMI reduction?
Yes, the LT8640AJUDCM#TRPBF supports spread spectrum modulation with ±22% triangular frequency dither when the SYNC/MODE pin is tied to INTVCC (~3.4V) or a 3V–4V external supply. This feature reduces peak radiated emissions by >10dB across 150kHz–108MHz and is validated to meet CISPR25 Class 5 limits without additional filtering components.
LT8640AJUDCM#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- Silent Switcher®1
- Package/Case:
- 20-WFQFN Exposed Pad, 18 Leads
- 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):
- 2.9V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 0.97V
- Voltage - Output (Max):
- 41.58V
- Current - Output:
- 5A
- Frequency - Switching:
- 200kHz ~ 3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 20-QFN (3x4)
LT8640AJUDCM#TRPBF FAQ
1.How can I place an order for LT8640AJUDCM#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8640AJUDCM#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 LT8640AJUDCM#TRPBF reliable?
The price and inventory of LT8640AJUDCM#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8640AJUDCM#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8640AJUDCM#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8640AJUDCM#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8640AJUDCM#TRPBF?
LT8640AJUDCM#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8640AJUDCM#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 LT8640AJUDCM#TRPBF?
For technical support, including LT8640AJUDCM#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8640AJUDCM#TRPBF requirements.
6.How does Aetrix verify that LT8640AJUDCM#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8640AJUDCM#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 LT8640AJUDCM#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8640AJUDCM#TRPBF?
All LT8640AJUDCM#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8640AJUDCM#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 LT8640AJUDCM#TRPBF part is unused and in its original packaging.
Return procedure for LT8640AJUDCM#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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