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Analog Devices Inc. LT8631EFE#TRPBF
- Part No.:
- LT8631EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-TSSOP (0.173", 4.40mm Width), 16 Leads, Exposed Pad
- Datasheet:
-
LT8631EFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1A 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,465
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Product details
Overview
LT8631EFE#TRPBF from Analog Devices is a 100V input, 1A synchronous step-down DC/DC regulator with internal MOSFETs, peak current mode control, and low-ripple Burst Mode operation delivering 16µA quiescent current at 12VIN→5VOUT. It supports 3V–100V input, 0.8V–60V output, and operates up to 1MHz with programmable frequency via RT resistor. Used in automotive front-end power supplies where wide VIN and ultra-low IQ are critical.
For engineers reviewing the LT8631EFE#TRPBF datasheet, LT8631EFE#TRPBF pinout, LT8631EFE#TRPBF application, or LT8631EFE#TRPBF equivalent, key selection criteria include its 100V absolute max VIN rating, ±7.5% power-good flag accuracy, 99% max duty cycle for high-VIN dropout, thermal-enhanced 20-lead TSSOP package with exposed GND pad, and compatibility with ultralow-IQ system-level sleep modes.
Technical Context
The LT8631EFE#TRPBF implements constant-frequency peak current mode control with internal top (775mΩ) and bottom (550mΩ) synchronous switches. Its VC node regulates peak inductor current, while the error amplifier compares FB voltage against either the internal 0.808V reference or TR/SS voltage for tracking.
Burst Mode operation activates below ~10mA load, reducing IQ to 16µA (12VIN) or 7µA (48VIN) while maintaining <10mVP-P output ripple. Synchronization capability allows external clocking from 100kHz to 1MHz, and EN/UV pin enables programmable undervoltage lockout with 1.19V threshold and 17mV hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 100V - supports direct connection to 24V/48V/72V telecom rails and 12V/24V/48V automotive batteries without pre-regulation. |
| Output Current | 1A continuous - verified at 7.5VIN→5VOUT with 15µH inductor; derates to 1.35A at 50VIN due to thermal limits in TSSOP package. |
| Quiescent Current (IQ) | 16µA at 12VIN→5VOUT - enables >1-year battery life in always-on automotive telematics with 100µAh coin cell. |
| Feedback Reference | 0.808V ±12mV - sets output accuracy; used with resistor divider to program VOUT from 0.8V to 60V. |
| Switching Frequency | 100kHz to 1MHz - set by RT resistor (8.66kΩ–187kΩ); 400kHz typical for balanced efficiency and EMI performance. |
| Power Good Flag | ±7.5% VFBREF window with 1.9% hysteresis - provides reliable system reset signaling without external monitoring circuitry. |
| Max Duty Cycle | 99% - enables regulation down to VOUT = VIN − 0.775V (top switch drop), critical for high-input, low-output applications like 48V→5V conversion. |
Pinout & Package
LT8631EFE#TRPBF is housed in a thermally enhanced 20-lead plastic TSSOP (FE package) with exposed GND pad (Pin 21) requiring PCB soldering for optimal thermal resistance (θJA = 40°C/W, θJC = 10°C/W). High-voltage lead spacing meets reinforced isolation requirements for 100V systems.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (1) | Main power input & top switch drain | Accepts 3V–100V; must be decoupled directly to GND with low-ESR capacitor; high dI/dt node requiring short PCB trace. |
| EN/UV (3) | Enable input & UVLO programming node | Active-high enable; 1.19V threshold with 17mV hysteresis; tied to VIN for always-on operation or resistor-divider for custom UVLO. |
| PG (5) | Open-drain power-good flag | Sinks current when VOUT deviates >±7.5% from regulation; 1.9% hysteresis prevents chatter during transient recovery. |
| SYNC/MODE (7) | Mode selection & synchronization input | GND = Burst Mode; >1.5V = pulse-skipping; external 100–1000kHz clock = synchronized operation with 20–80% duty cycle. |
| RT (8) | Frequency programming resistor node | Connects to GND via 8.66kΩ–187kΩ resistor to set fSW from 100kHz to 1MHz; floating prohibited. |
| TR/SS (10) | Soft-start & output tracking control | Capacitor-connected node; 4.5µA internal current source ramps VOUT; also accepts external ramp for sequencing with other rails. |
| FB (11) | Error amplifier inverting input | Regulated to 0.808V; connects to resistor divider from VOUT; feedback current ≤25nA minimizes load error. |
| VOUT (12) | Output sense & current-sense return | Internal current-sense resistor return; connect output capacitor directly between VOUT and GND for accurate sensing and stability. |
| IND (14) | Inductor current-sense input | Connects to inductor's SW-side terminal; senses peak current for cycle-by-cycle limiting and regulation. |
| INTVCC (16) | Internal 3V LDO bypass | Requires 2.2µF ceramic capacitor to GND; powers internal bias circuits; no external loading permitted. |
| BST (18) | Bootstrap supply for top switch gate drive | Connect 0.1µF capacitor between BST and SW; ensures sufficient gate overdrive for top FET across full VIN range. |
| SW (20) | Switch node | High dI/dt switching output; connect inductor and BST cap as close as possible; minimal trace length required. |
| GND (21) | Exposed thermal pad / signal ground | Only ground connection; must be soldered to large copper pour for thermal management and low-noise small-signal reference. |
Key Features
| Feature | Design Value |
|---|---|
| Low-Ripple Burst Mode | 16µA IQ at 12VIN→5VOUT with <10mVP-P output ripple - eliminates need for secondary LDO in always-on subsystems. |
| Ultrawide Input Range | 3V to 100V operation - supports direct integration into 12V/24V/48V automotive, industrial, and telecom power architectures. |
| Internal Synchronous Switches | 775mΩ top / 550mΩ bottom MOSFETs - removes external FETs and drivers, reducing BOM count and layout complexity. |
| Programmable Power-Good Flag | ±7.5% VFBREF threshold with 1.9% hysteresis - enables precise system power sequencing without external comparators. |
| Flexible Soft-Start & Tracking | TR/SS pin supports both controlled VOUT ramp-up and rail-to-rail voltage tracking - simplifies multi-rail power sequencing. |
| Robust Fault Protection | Short-circuit protection, thermal shutdown, and tolerance to pin open/short faults - enhances reliability in harsh environments. |
Applications
| Automotive Front-End Supply | Industrial 48V Distribution |
|---|---|
|
Use Scenario: Powering infotainment head units and ADAS sensors from vehicle battery (9V–16V cold crank, up to 45V load dump). IC Role / Device Role / Timing Role: Primary buck regulator providing stable 5V/3.3V rails with 100V abs-max rating to survive transients. Use Value: Eliminates need for external TVS or pre-regulator; 16µA IQ extends battery runtime during vehicle sleep mode. |
Use Scenario: Local point-of-load conversion in factory automation PLCs powered from 48V DC bus. IC Role / Device Role / Timing Role: Step-down regulator delivering 12V/5V to I/O modules and communication interfaces. Use Value: 99% max duty cycle maintains regulation during brownouts; thermal TSSOP package supports convection-cooled enclosures. |
| Telecom Intermediate Bus | High-Voltage IoT Gateway |
|
Use Scenario: Converting 36V–72V telecom rectified output to 12V intermediate bus for downstream DC/DC stages. IC Role / Device Role / Timing Role: Efficient, low-noise intermediate regulator with synchronization capability for EMI reduction. Use Value: 400kHz fixed-frequency operation balances size and efficiency; SYNC/MODE pin enables phase alignment with other converters. |
Use Scenario: Powering cellular modem, MCU, and sensor interface in outdoor smart meter or grid-edge device. IC Role / Device Role / Timing Role: Single-chip solution converting 60V solar or PoE++ input to 3.3V logic rail. Use Value: 0.8V–60V programmable output covers diverse battery and energy-harvesting sources; PG flag enables firmware health monitoring. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8640S | Higher 4A output, 42V max VIN, integrated compensation, lower 2.5µA IQ in Silent Switcher mode | Not rated for >42V input; lacks 100V robustness; better for noise-sensitive RF applications | Select LT8640S only if input stays ≤42V and EMI is critical; LT8631EFE#TRPBF remains preferred for true 100V survivability. |
| LM5164QPWPRQ1 | 65V max VIN, 1A output, 14µA IQ, automotive AEC-Q100 qualified, no internal BST capacitor requirement | Lower voltage rating excludes 72V telecom and 48V+ automotive transients; different pinout and compensation scheme | Choose LM5164QPWPRQ1 for AEC-Q100-compliant designs under 65V; LT8631EFE#TRPBF offers broader voltage margin and tighter PG accuracy. |
Compared with LT8640S and LM5164QPWPRQ1, the LT8631EFE#TRPBF uniquely combines 100V absolute maximum input, ±7.5% power-good accuracy, and 16µA Burst Mode IQ in a single TSSOP package-making it the only option for high-reliability 72V telecom or 48V automotive front-end regulation where input transients exceed 65V.
Availability
LT8631EFE#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial 48V distribution, and telecom intermediate bus applications requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across –40°C to 125°C.
Supply support for LT8631EFE#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 LT8631EFE#TRPBF belongs to Analog Devices' µModule® and monolithic DC/DC regulator product line, designed specifically for ultrawide-input, low-quiescent-current power conversion in harsh environments where reliability and transient robustness are non-negotiable.
FAQ
What is the maximum input voltage rating for the LT8631EFE#TRPBF?
The LT8631EFE#TRPBF has an absolute maximum input voltage rating of 100V on the VIN pin, with guaranteed operation from 3V to 100V. This enables direct connection to 72V telecom supplies and survival of automotive load-dump transients up to 100V. The device enters dropout mode below minimum operating voltage but maintains regulation until VIN drops below VOUT + top switch drop (~0.775V).
How does the LT8631EFE#TRPBF achieve 16µA quiescent current?
The LT8631EFE#TRPBF achieves 16µA quiescent current through low-ripple Burst Mode operation: during light loads, it delivers brief current pulses to the output capacitor and then enters deep sleep, disabling most internal circuitry. This mode is active by default when SYNC/MODE is grounded, and the 16µA value is measured at 12VIN→5VOUT with no load.
Can the LT8631EFE#TRPBF be synchronized to an external clock?
Yes, the LT8631EFE#TRPBF can be synchronized to an external clock applied to the SYNC/MODE pin. The device accepts frequencies from 100kHz to 1MHz with 20–80% duty cycle. When synchronized, it operates in pulse-skipping mode and locks its switching edge to the rising edge of the external clock signal-enabling EMI reduction in noise-sensitive systems.
What is the purpose of the TR/SS pin on the LT8631EFE#TRPBF?
The TR/SS pin on the LT8631EFE#TRPBF serves dual functions: soft-start control and output voltage tracking. A capacitor connected to this pin sets the VOUT ramp rate during startup, preventing inrush current. It also accepts an external voltage ramp to coordinate sequencing with other power rails-ensuring proper power-up order in multi-rail systems.
Does the LT8631EFE#TRPBF require external MOSFETs?
No, the LT8631EFE#TRPBF integrates both high-side and low-side synchronous power MOSFETs (775mΩ and 550mΩ respectively), eliminating the need for external switches, gate drivers, or associated discrete components. This integration reduces solution size, simplifies layout, and improves efficiency across the full load range compared to controller-based solutions.
LT8631EFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width), 16 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):
- 3V
- Voltage - Input (Max):
- 100V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 60V
- Current - Output:
- 1A
- Frequency - Switching:
- 100kHz ~ 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP-EP
LT8631EFE#TRPBF FAQ
1.How can I place an order for LT8631EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8631EFE#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 LT8631EFE#TRPBF reliable?
The price and inventory of LT8631EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8631EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8631EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8631EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8631EFE#TRPBF?
LT8631EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8631EFE#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 LT8631EFE#TRPBF?
For technical support, including LT8631EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8631EFE#TRPBF requirements.
6.How does Aetrix verify that LT8631EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8631EFE#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 LT8631EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8631EFE#TRPBF?
All LT8631EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8631EFE#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 LT8631EFE#TRPBF part is unused and in its original packaging.
Return procedure for LT8631EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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