My Inquiry
My Account
Analog Devices Inc. LT8631IFE#PBF
- Part No.:
- LT8631IFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 20-TSSOP (0.173", 4.40mm Width), 16 Leads, Exposed Pad
- Datasheet:
-
LT8631IFE#PBF.pdf
- Description:
- IC REG BUCK ADJ 1A 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,848
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT8631IFE#PBF from Analog Devices is a 100V, 1A synchronous step-down DC/DC regulator with internal MOSFETs, peak current mode control, and low-ripple Burst Mode operation. It supports input voltages from 3V to 100V and delivers regulated output from 0.8V to 60V, enabling use in automotive, telecom (36–72V), and industrial power systems where wide VIN and micropower efficiency are critical.
For engineers reviewing the LT8631IFE#PBF datasheet, LT8631IFE#PBF pinout, LT8631IFE#PBF application, or LT8631IFE#PBF equivalent, key selection factors include its 16µA quiescent current at 12VIN/5VOUT, ±7.5% power-good flag accuracy, programmable 100kHz–1MHz switching frequency via RT resistor, and thermal-enhanced 20-lead TSSOP package with exposed GND pad.
Technical Context
The LT8631IFE#PBF 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) support high-VIN, low-duty-cycle operation down to 0.8VOUT.
Burst Mode activation is controlled by the SYNC/MODE pin: grounded for low-ripple (<10 mVP-P) micropower operation at light loads, or pulled high for pulse-skipping mode. The TR/SS pin provides soft-start ramp control and flexible output voltage tracking, while EN/UV enables programmable undervoltage lockout and shutdown with <5 µA total quiescent current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 100V - supports direct regulation from unregulated automotive battery (cold-crank), telecom -48V/-72V supplies, and industrial HV rails without pre-regulation. |
| Output Current | 1.0 A continuous - verified at VIN = 7.5V/50V, L = 15 µH, ensuring stable delivery under full load across operating temperature range. |
| Quiescent Current | 16 µA at 12VIN/5VOUT - enables >10-year battery life in always-on IoT sensors and remote monitoring devices. |
| Feedback Reference | 0.808 V ±12 mV - precision reference enables accurate output regulation with minimal drift over –40°C to +125°C junction temperature. |
| Switching Frequency | 100 kHz to 1 MHz - set by external RT resistor (e.g., 25.5 kΩ → 400 kHz), balancing efficiency, EMI, and external component size. |
| Power Good Flag | ±7.5% threshold with 1.9% hysteresis - provides reliable system-level power sequencing and fault detection without external comparators. |
| Package | 20-lead TSSOP with exposed GND pad - θJA = 40°C/W, θJC(PAD) = 10°C/W, enabling high-power density in thermally constrained PCB layouts. |
Pinout & Package
LT8631IFE#PBF is housed in a thermally enhanced 20-lead plastic TSSOP package (FE20 variant) with exposed GND pad (Pin 21) requiring soldering to PCB for optimal thermal performance and high-voltage lead spacing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (1) | Main power input and switch drain | Accepts 3–100V; connects directly to top MOSFET drain and internal bias circuitry - requires local high-dI/dt decoupling to GND. |
| EN/UV (3) | Enable and UVLO programming | Active-high enable with 1.19 V threshold; external resistor divider sets UVLO point - pulls <100 nA, enabling precise brown-in/out control. |
| PG (5) | Open-drain power-good flag | Sinks current when VFB deviates >±7.5% from 0.808 V - used for system reset, sequencing, or fault logging with 1.9% hysteresis. |
| SYNC/MODE (7) | Mode selection and clock sync | GND = Burst Mode; >1.5 V = pulse-skipping; external clock (100–1000 kHz, 20–80% duty) forces synchronization - no external components needed. |
| RT (8) | Frequency programming | Resistor to GND sets fSW (100–1000 kHz); values from 8.66 kΩ to 187 kΩ - determines trade-off between efficiency, size, and EMI. |
| TR/SS (10) | Soft-start and tracking | Capacitor to GND controls VOUT ramp rate; also accepts external voltage for output tracking - 4.5 µA internal current source ensures monotonic start-up. |
| FB (11) | Feedback input | Inverting input of error amplifier referenced to 0.808 V - connects to resistor divider from VOUT; bias current <25 nA minimizes divider loading. |
| VOUT (12) | Output sense and current sensing | Connects to output capacitor and internal current-sense resistor - not the power output node; actual output is taken from IND pin. |
| IND (14) | Inductor connection and power output | Main power output path; connects to inductor and output capacitor - carries full load current and switch-node transients. |
| BST (18) | Bootstrap supply | Drives top MOSFET gate above VIN; requires 0.1 µF ceramic cap to SW - ensures sufficient gate drive during high-duty-cycle operation. |
| SW (20) | Switch node | Internal connection between top and bottom MOSFETs - high dV/dt node; must be routed short and away from sensitive analog traces. |
| GND (21) | Ground reference and thermal pad | Only ground connection; exposed pad must be soldered to large copper area - serves as both signal and thermal ground; all small-signal returns tie here. |
Key Features
| Feature | Design Value |
|---|---|
| Low-Ripple Burst Mode | 16 µA IQ at 12VIN/5VOUT with <10 mVP-P output ripple - eliminates need for external LDO post-regulation in battery-powered systems. |
| Ultrawide Input Range | 3V to 100V operation - supports single-supply designs across automotive (6–16V nominal, 40V transients), telecom (-36V to -72V), and industrial HV rails. |
| Programmable UVLO | EN/UV pin allows resistor-based undervoltage lockout setting - enables custom brown-out protection without external supervisor ICs. |
| Flexible Soft-Start & Tracking | TR/SS pin supports both monotonic soft-start and precise output voltage tracking - simplifies multi-rail power sequencing in FPGAs and processors. |
| Robust Fault Protection | Short-circuit protection, thermal shutdown, and tolerance to pin open/short faults - reduces need for external current limiting or fuse circuits. |
| High-Voltage Lead Spacing | TSSOP package meets creepage/clearance requirements for 100V operation - eliminates need for slotting or isolation gaps on PCB. |
Applications
| Automotive Infotainment Power Supply | Industrial PLC I/O Module |
|---|---|
Use Scenario: Regulating 12V battery (up to 40V transient) to 5V/1A for display controller, audio codec, and CAN interface in vehicle head units. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering stable 5V rail with Burst Mode enabling <16 µA sleep current during ignition-off state. Use Value: Eliminates need for discrete high-side switch and external UVLO, reducing BOM count by 3–4 components while maintaining ASIL-B compatible power integrity. | Use Scenario: Generating isolated 3.3V/1A from 24V DC field bus for microcontroller, ADC, and digital I/O in programmable logic controllers. IC Role / Device Role / Timing Role: Non-isolated step-down converter providing clean, low-noise 3.3V supply with ±7.5% PG flag for watchdog-triggered safe shutdown. Use Value: Enables direct regulation from 24V without intermediate 12V stage, improving overall system efficiency by 8–12% versus two-stage conversion. |
| Telecom Distributed Power | Remote Sensor Node Power |
Use Scenario: Point-of-load regulation from -48V telecom supply to 3.3V/1A for baseband processor and RF front-end in remote radio units. IC Role / Device Role / Timing Role: High-input-voltage buck converter operating in pulse-skipping mode (SYNC/MODE tied high) to maintain tight regulation under dynamic RF load bursts. Use Value: Achieves >90% efficiency at 500 mA load while tolerating -48V input reversals and 100V surges per GR-1089, reducing heatsink requirements. | Use Scenario: Micropower 3.3V/1A supply for LoRaWAN edge sensor powered by primary lithium thionyl chloride (LiSOCl₂) cell with 3.6V nominal and 20-year shelf life. IC Role / Device Role / Timing Role: Always-on buck regulator using Burst Mode to sustain 16 µA IQ, enabling >15-year runtime on 19 Ah cell at 10 µA average system load. Use Value: Delivers regulated 3.3V across full battery discharge curve (4.2V → 2.0V) without external boost converter, cutting solution size by 40%. |
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, fixed 2MHz fSW, no SYNC/MODE pin, higher IQ (25 µA) | Targeted at space-constrained DC/DC modules; lacks ultrawide VIN and programmable frequency | Select when board area is critical and input stays ≤60V; avoid for automotive cold-crank or telecom -48V applications. |
| MAX20004AATP+T | 42V max input, 1A output, integrated compensation, 2.2MHz fSW, no Burst Mode, IQ = 28 µA | Designed for ADAS camera modules; includes spread-spectrum and AEC-Q100 Grade 1 qualification | Choose only for automotive vision systems requiring AEC-Q100 compliance; not suitable for >42V inputs or micropower standby. |
Compared with LTC3639EMSE#PBF and MAX20004AATP+T, the LT8631IFE#PBF uniquely combines 100V input capability, 16 µA Burst Mode quiescent current, and programmable 100kHz–1MHz switching - making it the only option for high-reliability, ultralow-power, wide-VIN industrial and telecom point-of-load designs.
Availability
LT8631IFE#PBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLC I/O modules, and telecom distributed power supplies requiring stable component supply, long-term lifecycle support, and guaranteed –40°C to +125°C operation.
Supply support for LT8631IFE#PBF 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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT8631IFE#PBF belongs to Analog Devices' Power by Linear™ family of high-voltage monolithic DC/DC regulators, engineered specifically for robust, efficient, and compact power conversion in harsh environments with wide input ranges and stringent micropower requirements.
FAQ
What is the maximum input voltage rating for the LT8631IFE#PBF?
The LT8631IFE#PBF has an absolute maximum input voltage rating of 100V on the VIN pin, with guaranteed operation across 3V to 100V. This enables direct regulation from automotive battery (including 40V load dump), telecom -48V/-72V supplies, and industrial HV rails without external pre-regulators or clamping circuits.
How does the LT8631IFE#PBF achieve 16 µA quiescent current?
The LT8631IFE#PBF achieves 16 µA quiescent current at 12VIN/5VOUT through low-ripple Burst Mode operation: during light loads, it delivers brief current pulses to the output capacitor followed by extended sleep periods where most internal circuitry is disabled. The EN/UV pin must be held above 1.19V, and SYNC/MODE grounded for this mode.
Can the LT8631IFE#PBF be synchronized to an external clock?
Yes, the LT8631IFE#PBF can be synchronized to an external clock applied to the SYNC/MODE pin. The external signal must be within 100kHz–1000kHz, have 20–80% duty cycle, and be referenced to GND. When synchronized, the LT8631IFE#PBF operates in pulse-skipping mode and locks its switching edges to the external clock's rising edge.
What is the purpose of the TR/SS pin on the LT8631IFE#PBF?
The TR/SS pin on the LT8631IFE#PBF serves dual functions: (1) soft-start control - a capacitor to GND sets the VOUT ramp rate via a 4.5 µA internal current source; (2) output voltage tracking - an external voltage applied to TR/SS forces VOUT to follow that reference, enabling precise power sequencing in multi-rail systems.
Does the LT8631IFE#PBF require external MOSFETs or diodes?
No, the LT8631IFE#PBF integrates both high-side and low-side synchronous power MOSFETs (775 mΩ and 550 mΩ typical RDS(on)), eliminating the need for external switches or catch diodes. Only passive components - input/output capacitors, inductor, RT resistor, BST capacitor, and FB divider - are required for full operation.
LT8631IFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width), 16 Leads, Exposed Pad
- Packaging:
- Tube
- 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
LT8631IFE#PBF FAQ
1.How can I place an order for LT8631IFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8631IFE#PBF 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 LT8631IFE#PBF reliable?
The price and inventory of LT8631IFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8631IFE#PBF is usually 5 days.
3.What payment methods are accepted for LT8631IFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8631IFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8631IFE#PBF?
LT8631IFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8631IFE#PBF 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 LT8631IFE#PBF?
For technical support, including LT8631IFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8631IFE#PBF requirements.
6.How does Aetrix verify that LT8631IFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT8631IFE#PBF 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 LT8631IFE#PBF meets industry standards.
7.What is the process for return or replacement of LT8631IFE#PBF?
All LT8631IFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8631IFE#PBF, 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 LT8631IFE#PBF part is unused and in its original packaging.
Return procedure for LT8631IFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT8631IFE#PBF Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
