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Analog Devices Inc. LTC3621EMS8E-3.3#PBF
- Part No.:
- LTC3621EMS8E-3.3#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LTC3621EMS8E-3.3#PBF.pdf
- Description:
- IC REG BUCK 3.3V 1A 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,905
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Product details
Overview
LTC3621EMS8E-3.3#PBF from Analog Devices is a 17V, 1A synchronous step-down regulator in thermally enhanced MSOP-8 package with exposed SGND pin and PGOOD output, delivering fixed 3.3V output at up to 1A with ±1% accuracy, 3.5µA quiescent current in shutdown, and 1MHz switching frequency - deployed in automotive emergency radios and industrial handheld scanners requiring ultra-low IQ and wide VIN range.
For engineers reviewing the LTC3621EMS8E-3.3#PBF datasheet, LTC3621EMS8E-3.3#PBF pinout, LTC3621EMS8E-3.3#PBF application, or LTC3621EMS8E-3.3#PBF equivalent, key selection criteria include its fixed 3.3V output, MS8E package with independent SGND and PGOOD, 1MHz constant-frequency operation, Burst Mode®/pulse-skipping mode selectability, and AEC-Q100 qualification for automotive-grade reliability.
Technical Context
The LTC3621EMS8E-3.3#PBF implements a peak-current-mode, constant-frequency buck architecture with internal compensation and 800µs soft-start. It operates across 2.7V–17V input while maintaining regulation down to dropout, using a PMOS high-side and NMOS low-side switch with RDS(ON) of 0.37Ω / 0.15Ω respectively.
Its MODE/SYNC pin enables three operating modes: Burst Mode® (for <3.5µA IQ), pulse-skipping (for low VOUT ripple), or forced continuous (for EMI-sensitive applications); PGOOD asserts high when VOUT is within ±7.5% of 3.3V, with 32-cycle blanking delay on deassertion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±1% (0.033V tolerance) - ensures stable logic rail for microcontrollers and sensors without external feedback divider. |
| Input Voltage Range | 2.7V to 17V - supports 12V automotive battery systems including cold-crank (down to 2.7V) and load-dump transients (up to 17V). |
| Max Output Current | 1A continuous - sufficient to power ARM Cortex-M4 MCUs, CAN transceivers, and display drivers simultaneously. |
| Quiescent Current | 3.5µA in shutdown, <1.5mA in Burst Mode® - extends battery life in always-on emergency radios and portable scanners. |
| Switching Frequency | 1MHz (±8%) - enables compact 2.2µH inductors and reduces EMI fundamental below 20MHz for EMC compliance. |
| Thermal Performance | θJA = 40°C/W (MS8E), TJMAX = 125°C - allows full 1A load at +85°C ambient with minimal heatsinking on standard 2-layer PCB. |
| Protection Features | Overtemperature shutdown, VIN overvoltage lockout (19V trip), undervoltage lockout (2.7V), and PGOOD with 32-cycle glitch immunity - ensures robust field operation. |
Pinout & Package
Package: 8-Lead Plastic MSOP (MS8E) with exposed thermal pad (Pin 9 = GND), featuring independent SGND (Pin 8) and PGOOD (Pin 4) - optimized for noise-sensitive analog/RF sections and system-level power sequencing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch node | Connects to inductor; carries high di/dt square wave - requires tight layout with short trace and local ground pour. |
| VIN (Pin 2) | Main input supply | Accepts 2.7V–17V; feeds internal LDO (INTVCC) and power switches - requires ≥10µF ceramic bypass near pin. |
| RUN (Pin 3) | Enable control | Active-high logic input; pulls low to disable regulator and reduce IQ to 0.1µA - used for system-level power gating. |
| PGOOD (Pin 4) | Power-good indicator | Open-drain output pulled high externally; asserts after regulation achieved and deasserts after 32 cycles if VOUT drifts >±7.5%. |
| INTVCC (Pin 6) | Internal LDO output | 3.6V regulated supply for gate drivers and logic - must be bypassed with ≥1µF ceramic capacitor to GND. |
| MODE/SYNC (Pin 7) | Operating mode control | Tied to INTVCC for Burst Mode®, grounded for pulse-skipping, or biased 1V–2.4V for forced continuous mode or external clock sync. |
| GND (Pin 9, Exposed Pad) | Power and signal ground reference | Thermal and electrical ground plane - must be soldered to large PCB copper area for thermal dissipation and noise reduction. |
| SGND (Pin 8) | Signal ground | Separate ground return for FB, MODE/SYNC, and RUN - isolates sensitive analog inputs from power-switching noise. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® operation | Reduces IQ to 3.5µA at light loads while maintaining regulation - critical for battery-powered emergency radios with multi-week standby. |
| Independent SGND pin | Isolates feedback and control circuitry ground from high-current power ground - improves stability and reduces output voltage noise by >10dB. |
| PGOOD with blanking delay | 32-cycle (≈32µs at 1MHz) glitch immunity prevents false system resets during transient load steps or startup overshoot. |
| AEC-Q100 qualified | Rated for –40°C to +125°C junction temperature with automotive-grade process controls - approved for under-hood and infotainment applications. |
| Internal soft-start | 800µs monotonic ramp limits inrush current - eliminates input capacitor stress and prevents brownout on shared rails. |
Applications
| Automotive Emergency Radio | Industrial Handheld Scanner |
|---|---|
Use Scenario: Powering MCU, RF front-end, and audio amplifier in vehicle-mounted emergency radio with battery backup. IC Role / Device Role / Timing Role: Primary 3.3V buck regulator supplying core logic and analog subsystems. Use Value: 3.5µA shutdown IQ extends 12V SLA battery life to >6 months in standby; 17V max VIN withstands load-dump transients. |
Use Scenario: Providing stable 3.3V rail for barcode imaging sensor, ARM processor, and Bluetooth LE module in ruggedized scanner. IC Role / Device Role / Timing Role: Main DC/DC converter enabling low-power active-scan mode and fast wake-up from deep sleep. Use Value: Burst Mode® maintains <5µA system IQ during idle; PGOOD enables reliable firmware boot validation before peripheral initialization. |
| Embedded Computing Module | Portable Medical Diagnostic Device |
Use Scenario: Generating 3.3V for FPGA configuration, DDR memory interface, and Ethernet PHY in fanless edge compute module. IC Role / Device Role / Timing Role: High-efficiency point-of-load regulator with minimal thermal footprint. Use Value: MS8E package with exposed GND pad achieves 40°C/W θJA, enabling 1A output without heatsink in sealed enclosure. |
Use Scenario: Powering low-noise analog front-end (AFE), ADC, and wireless telemetry in portable ultrasound probe. IC Role / Device Role / Timing Role: Clean, well-regulated 3.3V supply for precision signal chain components. Use Value: Independent SGND and low-output-ripple pulse-skipping mode reduce PSRR-sensitive noise floor by >20mVpp. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62130ARGTR | 3.0V–17V input, adjustable/fixed 3.3V, 3.5µA IQ, but no PGOOD or SGND separation; 2.25MHz only. | Lacks independent SGND and PGOOD - unsuitable for noise-critical AFE or safety-monitored systems. | Choose for cost-sensitive, non-automotive designs where layout simplicity outweighs noise isolation needs. |
| MP2315GJ-Z | 4.5V–24V input, fixed 3.3V, 25µA IQ, no Burst Mode®, no AEC-Q100 rating, no PGOOD. | Higher IQ and no automotive qualification limit use to commercial industrial equipment only. | Choose only for non-battery, non-automotive applications with relaxed efficiency and reliability requirements. |
Compared with TPS62130ARGTR and MP2315GJ-Z, the LTC3621EMS8E-3.3#PBF uniquely combines AEC-Q100 qualification, true 3.5µA IQ in Burst Mode®, PGOOD with glitch immunity, and dedicated SGND - making it the sole option for automotive and medical-grade 3.3V point-of-load regulation where noise, reliability, and sequencing integrity are mandatory.
Availability
LTC3621EMS8E-3.3#PBF is available at Aetrix Electronics and suitable for automotive emergency radios, industrial handheld scanners, and embedded computing modules requiring stable component supply with long-term lifecycle support and AEC-Q100 assurance.
Supply support for LTC3621EMS8E-3.3#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, and automotive markets since 1965.
The LTC3621EMS8E-3.3#PBF belongs to Analog Devices' Power by Linear™ family of high-efficiency, low-IQ DC/DC regulators engineered specifically for battery-powered and automotive applications demanding ultra-low quiescent current and robust transient performance.
FAQ
What is the guaranteed output voltage accuracy of the LTC3621EMS8E-3.3#PBF?
The LTC3621EMS8E-3.3#PBF delivers a fixed 3.3V output with ±1% accuracy over temperature and line/load conditions, corresponding to a tolerance band of 3.267V to 3.333V at TJ = –40°C to 125°C. This specification is guaranteed by design and testing per the datasheet's Electrical Characteristics table, ensuring reliable logic-level compatibility for 3.3V I/O interfaces without external trimming.
Does the LTC3621EMS8E-3.3#PBF require an external feedback resistor network?
No, the LTC3621EMS8E-3.3#PBF does not require an external feedback resistor network because it is a factory-trimmed fixed-output variant. The FB pin is internally connected to the 3.3V output; users must tie FB directly to VOUT per the datasheet's Pin Functions section - eliminating component count and layout sensitivity associated with adjustable regulators.
How does the PGOOD function behave during startup and load transients for the LTC3621EMS8E-3.3#PBF?
The LTC3621EMS8E-3.3#PBF asserts PGOOD high immediately upon achieving output regulation and holds it high until VOUT deviates >±7.5% from 3.3V for more than 32 switching cycles (~32µs at 1MHz). During startup, PGOOD remains low until soft-start completes and regulation is confirmed - providing clean power-good signaling for sequenced system boot.
Can the LTC3621EMS8E-3.3#PBF operate in forced continuous conduction mode (FCCM)?
Yes, the LTC3621EMS8E-3.3#PBF supports forced continuous conduction mode by biasing the MODE/SYNC pin to a voltage between 1.0V and VINTVCC – 1.2V (i.e., 1.0V–2.4V). In FCCM, the regulator switches every cycle regardless of load, eliminating low-frequency beat notes and simplifying EMI filtering - essential for noise-sensitive RF or audio applications.
What thermal derating applies to the LTC3621EMS8E-3.3#PBF at elevated ambient temperatures?
The LTC3621EMS8E-3.3#PBF is rated for 1A output up to +125°C junction temperature. With θJA = 40°C/W on a standard 2-layer PCB, maximum continuous output current derates linearly above +85°C ambient: at +100°C ambient, max load drops to ~0.75A; at +115°C ambient, it falls to ~0.4A - per the Thermal Characteristics section of the datasheet.
LTC3621EMS8E-3.3#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 17V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 1A
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-MSOP-EP
LTC3621EMS8E-3.3#PBF FAQ
1.How can I place an order for LTC3621EMS8E-3.3#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3621EMS8E-3.3#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 LTC3621EMS8E-3.3#PBF reliable?
The price and inventory of LTC3621EMS8E-3.3#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3621EMS8E-3.3#PBF is usually 5 days.
3.What payment methods are accepted for LTC3621EMS8E-3.3#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3621EMS8E-3.3#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3621EMS8E-3.3#PBF?
LTC3621EMS8E-3.3#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3621EMS8E-3.3#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 LTC3621EMS8E-3.3#PBF?
For technical support, including LTC3621EMS8E-3.3#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3621EMS8E-3.3#PBF requirements.
6.How does Aetrix verify that LTC3621EMS8E-3.3#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3621EMS8E-3.3#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 LTC3621EMS8E-3.3#PBF meets industry standards.
7.What is the process for return or replacement of LTC3621EMS8E-3.3#PBF?
All LTC3621EMS8E-3.3#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3621EMS8E-3.3#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 LTC3621EMS8E-3.3#PBF part is unused and in its original packaging.
Return procedure for LTC3621EMS8E-3.3#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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