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Analog Devices Inc. LT8631HFE#TRPBF
- Part No.:
- LT8631HFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-TSSOP (0.173", 4.40mm Width), 16 Leads, Exposed Pad
- Datasheet:
-
LT8631HFE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1A 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,852
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Product details
Overview
LT8631HFE#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. It delivers regulated output from 0.8V to 60V across a 3V–100V input range, supports programmable 100kHz–1MHz switching frequency, and maintains <10mVP-P output ripple at light loads-ideal for telecom power supplies and industrial distributed regulation.
For engineers reviewing the LT8631HFE#TRPBF datasheet, LT8631HFE#TRPBF pinout, LT8631HFE#TRPBF application, or LT8631HFE#TRPBF equivalent, key selection criteria include its –40°C to 150°C junction temperature rating, 7µA quiescent current at 48VIN/5VOUT, programmable undervoltage lockout via EN/UV, power good flag with ±7.5% threshold, and thermal-enhanced 20-lead TSSOP package with exposed GND pad.
Technical Context
The LT8631HFE#TRPBF implements constant-frequency peak current mode control with internal top (775 mΩ) and bottom (550 mΩ) synchronous switches. Its VC node regulates peak inductor current up to 2.1 A typical, while minimum on-time (120 ns) and off-time (190 ns) enable stable operation across wide input/output ratios.
Burst Mode operation activates below ~100 mA load, reducing IQ to 7 µA at 48VIN/5VOUT while maintaining <10 mVP-P ripple; pulse-skipping or external synchronization (100–1000 kHz) is selectable via SYNC/MODE pin. Power good flag asserts when VFB deviates >±7.5% from 0.808 V reference, with 1.9% hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 100V - supports automotive cold-crank, 48V industrial, and telecom 72V backplanes without external pre-regulation. |
| Output Voltage Range | 0.8V to 60V - set by external resistor divider; feedback reference is 0.808 V with ±0.3% line/load regulation. |
| Max Output Current | 1.35 A at 7.5VIN/5VOUT; 1.8 A at 50VIN/5VOUT - limited by internal VC clamp and thermal design with exposed pad. |
| Quiescent Current | 7 µA at 48VIN/5VOUT in Burst Mode - enables >10-year battery life in always-on industrial sensors. |
| Switching Frequency | 100 kHz to 1 MHz - set by RT resistor (8.66kΩ–187kΩ); supports synchronization to external clock. |
| Operating Temperature | –40°C to +150°C junction - qualified for under-hood automotive and high-temp industrial environments. |
| Package Thermal Resistance | θJA = 40°C/W, θJC(PAD) = 10°C/W - requires soldered exposed pad to PCB copper for reliable 150°C operation. |
Pinout & Package
LT8631HFE#TRPBF is housed in a thermally enhanced 20-lead plastic TSSOP (FE package) with exposed GND pad (Pin 21), rated for high-voltage lead spacing and 100V absolute max VIN rating. The exposed pad must be soldered to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (1) | Main power input & switch drain | Supplies internal bias and powers top switch; must be decoupled locally to GND; withstands 100V transient. |
| EN/UV (3) | Enable & UVLO programming | Active-high enable with 1.19 V threshold; external resistor divider sets UVLO point; <5 µA shutdown current. |
| PG (5) | Open-drain power good flag | Sinks current when VFB deviates >±7.5% from 0.808 V; 1.9% hysteresis prevents chatter during transients. |
| SYNC/MODE (7) | Mode selection & sync input | GND = Burst Mode; >1.5 V = pulse-skipping; external 100–1000 kHz clock forces sync operation. |
| RT (8) | Frequency programming | Resistor to GND sets fSW from 100 kHz (187 kΩ) to 1 MHz (8.66 kΩ); no floating allowed. |
| TR/SS (10) | Soft-start & tracking control | Capacitor to GND controls VOUT ramp rate; also accepts external voltage for output tracking. |
| FB (11) | Feedback input | Inverting input of error amp; regulated to 0.808 V; bias current <25 nA minimizes divider loading. |
| VOUT (12) | Output sense & current return | Connects to output capacitor; carries full load current and serves as current-sense return path. |
| IND (14) | Inductor current sense | Input to internal current-sense resistor; connects directly to inductor terminal for accurate peak-current detection. |
| INTVCC (16) | Internal LDO bypass | Bypass pin for internal 3 V regulator; requires 2.2 µF ceramic cap to GND; no external load permitted. |
| BST (18) | Bootstrap supply | Drives top switch gate above VIN; 0.1 µF capacitor between BST and SW required for proper gate drive. |
| SW (20) | Switch node | Connection point for external inductor and BST capacitor; high dI/dt node requiring short, low-inductance PCB trace. |
| GND (21) | Power & signal ground | Exposed pad is sole ground connection; must be soldered to large copper area for thermal management and noise control. |
Key Features
| Feature | Design Value |
|---|---|
| Low-Ripple Burst Mode | 7 µA IQ at 48VIN/5VOUT with <10 mVP-P output ripple - extends battery life without compromising noise-sensitive analog circuitry. |
| Ultrawide Input Range | 3V to 100V operation - eliminates need for front-end pre-regulators in 24V/48V/72V systems and automotive applications with load dump. |
| Integrated Synchronous Switches | 775 mΩ top / 550 mΩ bottom MOSFETs - reduces external component count and improves efficiency over discrete solutions. |
| Programmable UVLO & Soft-Start | EN/UV pin sets custom undervoltage lockout; TR/SS capacitor controls monotonic VOUT ramp and enables output voltage tracking. |
| Robust Fault Protection | Short-circuit protection, thermal shutdown, and tolerance to pin open/short faults - ensures field reliability in unattended industrial equipment. |
Applications
| Telecom Power Supply | Distributed Industrial Regulation |
|---|---|
Use Scenario: Regulating 48V or 72V telecom backplane to 5V/3.3V for line cards and baseband processors. IC Role / Device Role / Timing Role: Primary non-isolated buck converter delivering 1A at high efficiency across wide line and load variations. Use Value: 92% peak efficiency at 48VIN/5VOUT and 7µA quiescent current reduce heat buildup and extend system uptime in dense chassis. | Use Scenario: Local point-of-load conversion in PLC modules, motor drives, or sensor hubs operating from 24V–100V DC bus. IC Role / Device Role / Timing Role: High-reliability step-down regulator supporting –40°C to +150°C ambient with fault-tolerant pin behavior. Use Value: 150°C junction rating and exposed-pad thermal design enable convection-cooled operation without heatsinks in sealed enclosures. |
| Automotive Subsystem Power | High-Voltage IoT Sensor Node |
Use Scenario: Powering infotainment displays, ADAS cameras, or telematics units from 12V battery with cold-crank (3V) and load-dump (100V) immunity. IC Role / Device Role / Timing Role: Input-robust buck regulator with programmable UVLO and soft-start to prevent inrush during ignition cycles. Use Value: 100V absolute max VIN and 99% duty cycle capability maintain regulation during 3V cold-crank events without brownout. | Use Scenario: Battery-powered environmental monitor deployed in remote infrastructure with 10+ year lifetime requirement. IC Role / Device Role / Timing Role: Ultra-low-IQ DC/DC converter powering MCU, RF transceiver, and analog sensors from LiSOCl₂ or primary lithium cells. Use Value: 7µA IQ in Burst Mode enables multi-year operation on a single 2.5Ah cell, validated across full –40°C to +85°C operating range. |
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 |
|---|---|---|---|
| LTC3639EMSE#PBF | 60V max input, 1.5A output, 3mm × 4mm MSOP; lower IQ (4µA) but narrower VIN range. | Best suited for 12V/24V systems where 100V tolerance is unnecessary and board space is constrained. | Select when input never exceeds 60V and footprint reduction outweighs ultrawide-VIN capability. |
| LM5164QPWPRQ1 | 100V input, 0.6A output, 1.5MHz max fSW, automotive AEC-Q100 Grade 1 (–40°C to +125°C). | Targeted at automotive ECUs requiring AEC-Q100 qualification but not extended 150°C operation. | Choose for automotive production where AEC-Q100 compliance is mandatory and 1A output is sufficient. |
Compared with LTC3639EMSE#PBF and LM5164QPWPRQ1, LT8631HFE#TRPBF uniquely combines 100V input, 1A output, –40°C to +150°C operation, and 7µA Burst Mode IQ-making it the only option for high-temp industrial or extended-range automotive subsystems demanding full 100V tolerance and 1A continuous delivery.
Availability
LT8631HFE#TRPBF is available at Aetrix Electronics and suitable for telecom power supplies, distributed industrial regulation, and automotive subsystem power requiring stable component supply across extended temperature and high-reliability environments.
Supply support for LT8631HFE#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 power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT8631 product line delivers ultrawide-input, high-efficiency synchronous buck regulators optimized for harsh environments-including telecom rectified lines, industrial 48V/72V buses, and automotive battery systems with load dump.
FAQ
What is the maximum junction temperature rating for LT8631HFE#TRPBF?
The LT8631HFE#TRPBF is guaranteed over the full –40°C to +150°C junction temperature range, with thermal shutdown activation above 150°C. This rating is validated per Analog Devices' characterization and statistical process controls, distinguishing it from the EFE (125°C) and IFE (125°C) variants. Proper PCB layout with soldered exposed pad is required to sustain continuous 150°C operation.
How does LT8631HFE#TRPBF achieve 7µA quiescent current at 48VIN/5VOUT?
LT8631HFE#TRPBF achieves 7µA quiescent current in Burst Mode by disabling all non-essential circuitry between energy pulses-including oscillator, gate drivers, and error amplifier-while maintaining regulation via periodic small charge bursts to the output capacitor. This behavior is confirmed in the Electrical Characteristics table (Rev. D, p.3) and Typical Performance plots (G06, G12), measured at 48VIN/5VOUT with no load.
Can LT8631HFE#TRPBF operate with an input voltage as low as 3V?
Yes, LT8631HFE#TRPBF supports 3V to 100V input. At 3V input, it maintains regulation down to 0.8V output using 99% maximum duty cycle, as specified in the Features list and Absolute Maximum Ratings. This enables cold-crank operation in automotive systems where battery voltage dips to 3V during engine start.
What is the purpose of the TR/SS pin on LT8631HFE#TRPBF?
The TR/SS (Track/Soft-Start) pin on LT8631HFE#TRPBF controls output voltage ramp rate during startup and enables output voltage tracking. A capacitor to GND sets soft-start time; an external voltage applied to TR/SS allows one LT8631HFE#TRPBF output to track another rail. The pin sources/sinks current (–4.5 µA typical sink, 3.0 V VOH) and has defined offset tolerances per Electrical Characteristics (p.3).
Does LT8631HFE#TRPBF require external MOSFETs?
No, LT8631HFE#TRPBF integrates both high-side and low-side synchronous power MOSFETs (775 mΩ and 550 mΩ respectively), eliminating the need for external switches. This is explicitly stated in the Features section ("Internal Synchronous Switches") and Block Diagram (p.10), and confirmed by the absence of external gate drive requirements in the Applications Information.
LT8631HFE#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 ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP-EP
LT8631HFE#TRPBF FAQ
1.How can I place an order for LT8631HFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8631HFE#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 LT8631HFE#TRPBF reliable?
The price and inventory of LT8631HFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8631HFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8631HFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8631HFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8631HFE#TRPBF?
LT8631HFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8631HFE#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 LT8631HFE#TRPBF?
For technical support, including LT8631HFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8631HFE#TRPBF requirements.
6.How does Aetrix verify that LT8631HFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8631HFE#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 LT8631HFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8631HFE#TRPBF?
All LT8631HFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8631HFE#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 LT8631HFE#TRPBF part is unused and in its original packaging.
Return procedure for LT8631HFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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