My Inquiry
My Account
Analog Devices Inc. LT3686AHMSE#TRPBF
- Part No.:
- LT3686AHMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 12-TSSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3686AHMSE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1.2A 12MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,849
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3686AHMSE#TRPBF from Analog Devices (formerly Linear Technology) is a 3.6V–37V input, 1.2A synchronous step-down DC/DC converter in thermally enhanced 12-lead MSOP package with exposed pad. It delivers regulated 3.3V or adjustable output up to 1.2A, supports 300kHz–2.5MHz switching frequency, features internal compensation, boost diode, and active load control via BD pin for fixed-frequency operation at light loads - used in automotive power rails and industrial 24V-to-3.3V conversion.
For engineers reviewing the LT3686AHMSE#TRPBF datasheet, LT3686AHMSE#TRPBF pinout, LT3686AHMSE#TRPBF application, or LT3686AHMSE#TRPBF equivalent, key selection factors include its –40°C to 150°C guaranteed junction temperature rating, 100ns minimum on-time enabling high VIN-to-VOUT ratios at 2MHz, cycle-by-cycle current limit, and SYNC/MODE pin dual functionality for external clock synchronization and BD active load enable/disable.
Technical Context
The LT3686AHMSE#TRPBF employs current-mode PWM control with internal bipolar NPN power switch and integrated boost diode. Its oscillator is resistor-programmable (RT pin) and supports external synchronization via SYNC/MODE pin, which also controls BD pin active load regulation to maintain constant frequency down to zero load.
Protection architecture includes cycle-by-cycle current limiting (1.9A typ), thermal shutdown, overvoltage lockout (37V typ), and precision UVLO (3.6V threshold). Soft-start and frequency foldback suppress inrush current, while DA pin monitors catch diode valley current to reduce switching frequency under overload or short-circuit conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 37V continuous; withstands 60V transients - supports direct connection to automotive batteries and 24V industrial supplies. |
| Output Current | 1.2A maximum continuous - sufficient for powering microcontrollers, sensors, and interface ICs in embedded systems. |
| Switching Frequency | 300kHz to 2.5MHz, RT-programmable - enables compact magnetics and avoids AM band interference (≥1.8MHz). |
| Feedback Reference | 0.790V to 0.815V (±1.9% over temp) - sets output voltage accuracy for stable 3.3V or adjustable rail regulation. |
| Min On-Time | 100ns typical - allows 16VIN→3.3VOUT conversion at 2MHz without pulse-skipping. |
| Quiescent Current | <1µA in shutdown (VEN/UVLO < 0.4V) - preserves battery life in always-on systems. |
| Junction Temp Range | –40°C to +150°C (guaranteed) - qualified for under-hood automotive and high-temp industrial environments. |
Pinout & Package
LT3686AHMSE#TRPBF uses a 12-lead plastic MSOP package with exposed thermal pad (Pin 13 = GND), JEDEC MO-187AC compliant, θJA = 40°C/W, θJC = 10°C/W. The exposed pad must be soldered to PCB copper for thermal performance and electrical grounding.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1, Exposed Pad 13) | Power and signal ground reference | Primary thermal path and return for all internal circuits; exposed pad must be soldered to large copper area. |
| VIN (Pin 2) | Main input supply connection | Supplies internal regulator and power switch; requires local 2.2µF ceramic bypass near pin. |
| BD (Pin 3) | Active load control terminal | Regulated current sink (≤40mA) when SYNC/MODE > 0.8V - maintains full switching frequency at light loads. |
| FB (Pin 4) | Feedback voltage sensing node | Regulated to 0.8V reference; connects to resistor divider to set VOUT; R2 = 10kΩ recommended. |
| SS (Pin 5) | Soft-start and tracking control | Internal 2µA current source charges external capacitor; ramps FB and frequency during startup. |
| RT (Pin 6) | Oscillator frequency programming | Resistor to GND sets fSW (300kHz–2.5MHz); e.g., 15.4kΩ → 2.1MHz. |
| EN/UVLO (Pin 7) | Enable and programmable UVLO input | Pull <0.4V to shut down; 1.28V threshold enables precise input undervoltage protection. |
| SYNC/MODE (Pin 8) | External sync clock input / BD mode select | Accepts square wave ≥200ns pulse width; high state (>0.8V) enables BD active load, low (<0.4V) disables it. |
| BOOST (Pin 9) | Bootstrap drive voltage supply | Charged via internal diode and external capacitor; provides >VIN gate drive for NPN switch saturation. |
| DA (Pin 10) | Catch diode anode monitor | Detects valley current in external Schottky diode; triggers frequency foldback if >1.7A to limit fault current. |
| SW (Pin 11) | Switch node output | Connects to inductor, catch diode cathode, and BOOST capacitor; carries high dI/dt switching waveform. |
| - (Pin 12) | No connect (NC) | Not internally bonded; left floating or tied to GND per layout best practice. |
Key Features
| Feature | Design Value |
|---|---|
| Thermally enhanced MSOP-12 with exposed pad | Enables 1.2A operation at 150°C junction temperature without derating - eliminates need for heatsinks in space-constrained designs. |
| Internal boost diode and compensation | Reduces BOM count by two components (external boost diode + compensation network) and simplifies layout. |
| Constant frequency at light loads via BD active load | Eliminates audible noise and unpredictable output ripple in discontinuous mode - critical for EMI-sensitive automotive infotainment. |
| Synchronization capability with mode-select dual function | Allows system-level clock alignment across multiple regulators while reusing same pin for BD control - saves GPIO resources. |
| Robust fault protection suite | Combines cycle-by-cycle current limit, DA valley-current foldback, thermal shutdown, OVLO (37V), and UVLO - survives load dumps and cold-crank events. |
Applications
| Automotive Infotainment Power Supply | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Regulating 24V vehicle battery to clean 3.3V for DSP, display controller, and CAN transceiver. IC Role / Device Role / Timing Role: Primary buck converter providing isolated, low-noise 3.3V rail with AM-band avoidance and load-dump immunity. Use Value: 150°C rating ensures reliability under hood; BD active load prevents audio-band ripple during idle states. |
Use Scenario: Converting 24V field bus supply to 3.3V for microcontroller, ADC, and digital isolators in modular I/O cards. IC Role / Device Role / Timing Role: High-efficiency point-of-load regulator with precise UVLO to prevent brownout resets during line fluctuations. Use Value: 100ns min on-time supports wide input range without pulse-skipping; internal compensation accelerates design cycle. |
| Medical Portable Diagnostic Device | Ruggedized Edge Gateway |
|
Use Scenario: Battery-powered ultrasound or patient monitor requiring ultra-low shutdown IQ and stable 3.3V for FPGA and analog front-end. IC Role / Device Role / Timing Role: Always-on power manager with <1µA shutdown current and soft-start to avoid sensor initialization glitches. Use Value: EN/UVLO programmability enables custom brownout thresholds; thermal shutdown protects Li-ion battery charging circuitry. |
Use Scenario: Outdoor telecom gateway converting 48V PoE++ or solar input to 3.3V for wireless SoC and security MCU. IC Role / Device Role / Timing Role: Wide-input buck regulator with overvoltage lockout (37V) and transient tolerance (60V) for unregulated renewable sources. Use Value: SYNC capability allows deterministic timing across multi-rail power tree; exposed pad ensures conduction cooling in sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8610EMSE#PBF | 42V input, 1.2A, Silent Switcher architecture, 2.2MHz max, 2.5µA quiescent current in Burst Mode | Better EMI performance and lower IQ in light-load modes; no BD pin or active load control | Choose LT8610EMSE#PBF for noise-sensitive RF or medical applications where EMI compliance is critical; not drop-in due to different pinout and control scheme. |
| TPS54202DRCT | 6V–36V input, 2A, 2.2MHz max, integrated FETs, 1.5µA shutdown IQ, no BD pin or active load | Higher output current, lower cost, but only rated to 125°C junction and lacks light-load fixed-frequency capability | Choose TPS54202DRCT for cost-sensitive industrial applications below 125°C ambient; requires redesign for BD-based ripple control. |
Compared with LT3686AHMSE#TRPBF, LT8610EMSE#PBF offers superior EMI suppression but sacrifices BD-controlled fixed-frequency light-load operation, while TPS54202DRCT provides higher current and lower cost but lacks 150°C qualification and active load functionality - making LT3686AHMSE#TRPBF uniquely suited for high-temp automotive and precision ripple-sensitive designs.
Availability
LT3686AHMSE#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLC modules, portable medical diagnostics, ruggedized edge gateways, and battery-powered instrumentation requiring stable component supply across extended temperature ranges.
Supply support for LT3686AHMSE#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving aerospace, automotive, industrial, and communications markets.
The LT3686A product line delivers robust, wide-input buck regulators optimized for harsh environments - designed specifically for automotive under-hood, industrial automation, and high-reliability portable equipment where thermal resilience and transient immunity are mandatory.
FAQ
What is the guaranteed operating junction temperature range for LT3686AHMSE#TRPBF?
The LT3686AHMSE#TRPBF is fully specified and guaranteed over –40°C to +150°C junction temperature. This H-grade rating distinguishes it from E-grade (–40°C to 125°C) and I-grade (–40°C to 125°C) variants, making LT3686AHMSE#TRPBF suitable for under-hood automotive and high-ambient industrial deployments where sustained 150°C operation is required.
How does the BD pin function in LT3686AHMSE#TRPBF, and what is its design impact?
The BD pin in LT3686AHMSE#TRPBF serves as a regulated current sink (up to 40mA) that activates when SYNC/MODE is held above 0.8V. It maintains constant switching frequency down to zero load, eliminating pulse-skipping artifacts and associated audio-band output ripple. This behavior is critical for noise-sensitive applications like automotive infotainment displays and precision analog signal chains powered by LT3686AHMSE#TRPBF.
Can LT3686AHMSE#TRPBF synchronize to an external clock, and what are the timing requirements?
Yes, LT3686AHMSE#TRPBF supports external synchronization via the SYNC/MODE pin. The input clock must have ≥200ns high and low pulse widths, logic high >0.8V, logic low <0.4V, and frequency higher than the RT-set free-running frequency (e.g., >2.1MHz for 15.4kΩ). Synchronization enables deterministic timing across multi-regulator systems without requiring additional clock distribution circuitry.
What is the minimum on-time specification of LT3686AHMSE#TRPBF, and why does it matter for high-input-voltage applications?
The LT3686AHMSE#TRPBF has a typical minimum on-time of 100ns. This parameter directly determines the highest input voltage at which the device can maintain continuous conduction mode at a given output voltage and switching frequency - for example, enabling 16VIN→3.3VOUT conversion at 2MHz. Below this limit, pulse-skipping occurs, increasing output ripple unless mitigated by the BD active load.
Does LT3686AHMSE#TRPBF require an external catch diode, and what are the key selection criteria?
Yes, LT3686AHMSE#TRPBF requires an external Schottky catch diode connected between SW and GND (anode to DA pin). Recommended devices include MBRM140 (40V, 1A) or equivalents with ≤0.4V forward drop, ≥60V reverse rating, and low capacitance. Diode selection directly impacts efficiency, thermal performance, and DA-pin-based fault protection responsiveness in LT3686AHMSE#TRPBF designs.
LT3686AHMSE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 12-TSSOP (0.118", 3.00mm Width) 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):
- 3.6V
- Voltage - Input (Max):
- 37V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 37V
- Current - Output:
- 1.2A
- Frequency - Switching:
- 300kHz ~ 2.5MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-MSOP-EP
LT3686AHMSE#TRPBF FAQ
1.How can I place an order for LT3686AHMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3686AHMSE#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 LT3686AHMSE#TRPBF reliable?
The price and inventory of LT3686AHMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3686AHMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3686AHMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3686AHMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3686AHMSE#TRPBF?
LT3686AHMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3686AHMSE#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 LT3686AHMSE#TRPBF?
For technical support, including LT3686AHMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3686AHMSE#TRPBF requirements.
6.How does Aetrix verify that LT3686AHMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3686AHMSE#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 LT3686AHMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3686AHMSE#TRPBF?
All LT3686AHMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3686AHMSE#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 LT3686AHMSE#TRPBF part is unused and in its original packaging.
Return procedure for LT3686AHMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3686AHMSE#TRPBF 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…
