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Analog Devices Inc. LT1767EMS8#PBF
- Part No.:
- LT1767EMS8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT1767EMS8#PBF.pdf
- Description:
- IC REG BUCK SEPIC ADJ 1.5A 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:581
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Product details
Overview
LT1767EMS8#PBF from Analog Devices (formerly Linear Technology) is a monolithic 1.25MHz, 1.5A step-down switching regulator in an 8-lead MSOP package with exposed pad (MS8E), featuring a 0.22Ω internal NPN switch, 1.2V feedback reference, and fixed 3.3V output. It operates from 3V to 25V input and delivers high efficiency in battery-powered systems, DSL modems, and wall adapters.
For engineers reviewing the LT1767EMS8#PBF datasheet, LT1767EMS8#PBF pinout, LT1767EMS8#PBF application, or LT1767EMS8#PBF equivalent, key selection considerations include its constant-frequency current-mode control, thermal performance in the MS8E package (θJA = 40°C/W), synchronization capability up to 2MHz, and fixed-output configuration eliminating external feedback resistors.
Technical Context
The LT1767EMS8#PBF implements a current-mode buck architecture with cycle-by-cycle peak current limiting and a 1.25MHz internal oscillator. Its BOOST pin enables saturation of the on-chip NPN switch via external capacitor-diode charge pump, reducing conduction loss to ~330mV at –1.5A.
It integrates a 1.2V precision bandgap reference, error amplifier (gm = 850 µMho), slope compensation for stable operation >50% duty cycle, and shutdown logic with 1.33V threshold and 7µA hysteresis - enabling accurate undervoltage lockout without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±2% over temperature and line/load - eliminates need for external feedback divider and ensures tight regulation in point-of-load applications. |
| Switch Current Limit | 1.5A minimum over full temperature range - guarantees consistent maximum load capability without thermal foldback degradation. |
| Switching Frequency | 1.25MHz typical (1.1–1.5MHz over temp) - enables use of small chip inductors (e.g., 4.7µH) and ceramic input/output capacitors, reducing board area and EMI filter size. |
| Input Voltage Range | 3V to 25V - supports wide-range industrial supplies, 12V/24V systems, and single-cell Li-ion (with boost diode tied to VOUT) while maintaining regulation. |
| Feedback Reference | 1.2V ±1.5% - provides stable setpoint for internal error amplifier; fixed 3.3V version internally scales this to match output via integrated resistor network. |
| Shutdown Current | 6µA typical at 25°C - minimizes battery drain in portable systems during standby or deep-sleep modes. |
| Thermal Resistance | θJA = 40°C/W (MS8E package) - requires only moderate PCB copper area for 1.5A continuous operation at ambient ≤85°C. |
Pinout & Package
LT1767EMS8#PBF uses the 8-lead plastic MSOP package with exposed pad (MS8E), where the exposed pad is electrically connected to GND and must be soldered to a large PCB copper area for optimal thermal performance (θJA = 40°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOST | Charge-pump voltage supply for NPN switch driver | Accepts external capacitor-diode network to generate ~VIN + VOUT; enables low VCE(sat) (~330mV) and high efficiency across input range. |
| VIN | Input power and collector of internal NPN switch | Supplies internal bias regulator and switch; requires low-inductance 10µF ceramic bypass close to pin to suppress dI/dt-induced voltage spikes. |
| VSW | Emitter of internal NPN switch | Drives inductor; swings from ~0V to VIN; requires external Schottky catch diode (e.g., UPS120) clamped to ground with VBR < 0.8V. |
| GND | Power and signal reference ground | Directly bonded to exposed pad; must connect to low-impedance ground plane - critical for load regulation, EMI control, and thermal dissipation. |
| SYNC | External clock synchronization input | Logic-compatible (20–80% duty); extends frequency range to 2MHz - allows EMI spreading or matching to system clock domains. |
| VC | Error amplifier output / current limit comparator input | Provides loop compensation node; voltage ranges from 0.35V (light load) to 0.9V (full load); can be driven to ground for forced shutdown. |
| FB | Feedback input (internally tied to 3.3V output) | Fixed 3.3V version connects internal resistor divider to output - no external components required; simplifies layout and improves stability. |
| SHDN | Enable/disable control with UVLO function | 1.33V threshold with 7µA hysteresis - supports programmable undervoltage lockout using external resistor divider (e.g., 4.75V turn-on / 3.75V turn-off). |
Key Features
| Feature | Design Value |
|---|---|
| Constant-frequency current-mode control | Enables predictable EMI profile, fast transient response (<10µs to 50% load step), and stable loop compensation without external slope injection. |
| Integrated 1.5A, 0.22Ω NPN switch | Reduces BOM count and layout complexity vs. external MOSFET solutions; maintains full 1.5A rating across all duty cycles without foldback. |
| MS8E thermally enhanced package | 40°C/W junction-to-ambient thermal resistance enables 1.5A continuous operation with minimal PCB copper - superior to standard MSOP (θJA = 110°C/W). |
| Synchronization to 2MHz | Allows alignment with system clocks or EMI reduction via frequency dithering; preserves constant max current limit and loop stability at higher frequencies. |
| Low 6µA shutdown current | Extends battery life in portable devices; supports clean enable/disable sequencing without auxiliary LDOs or discrete FETs. |
Applications
| DSL Modem Power Supply | Portable Computer Core Logic Rail |
|---|---|
Use Scenario: Provides 3.3V rail for ADSL transceiver PHY and controller ICs in compact, fanless DSL modems operating from 12V wall adapter. IC Role / Device Role / Timing Role: Primary DC/DC converter delivering regulated 3.3V at up to 1.2A with fast load transient response to handle burst data transmission. Use Value: High 1.25MHz switching frequency permits use of 4.7µH chip inductor and 2.2µF ceramic output capacitor - minimizing solution size and eliminating electrolytic components. |
Use Scenario: Generates 3.3V for USB controllers, I/O bridges, and embedded microcontrollers in ultra-thin notebooks powered by Li-ion battery packs (8–12V). IC Role / Device Role / Timing Role: Efficient step-down regulator supporting dynamic voltage scaling and deep-sleep modes via SHDN pin control. Use Value: 6µA shutdown current and wide 3–25V input range extend battery runtime; MS8E package enables placement near load for low-noise, low-impedance power delivery. |
| Industrial Wall Adapter Interface | Distributed Point-of-Load Regulation |
Use Scenario: Converts unregulated 24V DC from DIN-rail power supplies to clean 3.3V for PLC I/O modules and sensor interfaces in factory automation cabinets. IC Role / Device Role / Timing Role: Robust primary regulator handling input transients and reverse polarity protection (with external diode), operating continuously at 85°C ambient. Use Value: 25V absolute max input rating and thermal robustness (TJMAX = 125°C) ensure reliability in harsh environments; SYNC pin allows noise coordination with other converters. |
Use Scenario: Supplies 3.3V to FPGA configuration banks and communication peripherals in multi-rail embedded systems with distributed power architecture. IC Role / Device Role / Timing Role: Local DC/DC converter placed adjacent to load to minimize IR drop and improve PSRR at high frequencies. Use Value: Fixed 3.3V output eliminates feedback resistor tolerance errors; current-mode control provides excellent rejection of upstream rail noise from shared 12V bus. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3605EMS8E#PBF | 3MHz synchronous buck, 1.2A, integrated MOSFETs, 2.5–5.5V input - no BOOST pin required; higher efficiency at light loads due to Burst Mode™. | Requires lower input voltage (≤5.5V); unsuitable for 12V/24V inputs without pre-regulation; better for space-constrained, low-VIN apps like USB-powered devices. | Select LTC3605EMS8E#PBF when input is ≤5.5V and highest light-load efficiency is critical; avoid for direct 12V/24V conversion. |
| TPS54331DR | 3.5A adjustable buck, 500kHz, SOIC-8, external compensation - wider VIN (3.5–28V), but larger package and lower switching frequency increases inductor size. | Supports higher output current and adjustable VOUT, but lacks SYNC and fixed 3.3V option; requires external feedback resistors and compensation network. | Select TPS54331DR when >1.5A output or adjustable voltage is needed; prefer LT1767EMS8#PBF for compact, fixed 3.3V designs with minimal external components. |
Compared with LTC3605EMS8E#PBF and TPS54331DR, the LT1767EMS8#PBF uniquely balances fixed 3.3V simplicity, 1.25MHz operation for small magnetics, and 3–25V input flexibility - making it optimal for cost-sensitive, space-constrained industrial and telecom power rails where external component count and layout area are prioritized.
Availability
LT1767EMS8#PBF is available at Aetrix Electronics and suitable for DSL modems, portable computers, and industrial wall adapters requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT1767EMS8#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 acquired Linear Technology in 2017 and maintains full technical and manufacturing continuity for legacy Linear power products.
The LT1767 series was designed as a high-frequency, thermally optimized monolithic buck regulator family targeting compact, efficient DC/DC conversion in space- and thermal-constrained applications such as networking equipment and portable instrumentation.
FAQ
What is the output voltage of the LT1767EMS8#PBF?
The LT1767EMS8#PBF is the fixed 3.3V output variant of the LT1767 family. Its internal feedback divider sets VOUT = 3.3V ±2% across temperature and line/load conditions, eliminating the need for external resistors. This is confirmed in the Electrical Characteristics table under "Feedback Voltage" for LT1767-3.3, with typical value 3.3V and min/max of 3.234V/3.366V.
Does the LT1767EMS8#PBF require an external catch diode?
Yes, the LT1767EMS8#PBF requires an external Schottky catch diode connected between VSW and ground. The datasheet specifies the UPS120 or MBRM120LTI as recommended parts, rated for ≥2A average forward current and ≥20V reverse voltage. This diode conducts during the switch off-time and clamps negative voltage on VSW to <0.8V to protect parasitic structures.
Can the LT1767EMS8#PBF be synchronized to an external clock?
Yes, the LT1767EMS8#PBF supports external synchronization via its SYNC pin. It accepts logic-level signals (20–80% duty cycle) and locks to frequencies from 1.25MHz up to 2MHz. Synchronization preserves constant maximum switch current and loop stability, and is used for EMI reduction or timing coordination in multi-converter systems.
What is the thermal performance difference between MS8 and MS8E packages for the LT1767EMS8#PBF?
The LT1767EMS8#PBF uses the MS8E (exposed pad) package, which has θJA = 40°C/W - significantly better than the standard MS8 (θJA = 110°C/W). This 64% improvement in thermal resistance allows 1.5A continuous operation at higher ambient temperatures or with less PCB copper area, directly verified in the Pin Configuration section of the datasheet.
How does the BOOST pin function in the LT1767EMS8#PBF?
The BOOST pin in the LT1767EMS8#PBF supplies gate drive voltage to the internal NPN switch via an external capacitor-diode network. By generating ~VIN + VOUT, it ensures deep saturation of the bipolar switch, reducing VCE(sat) to ~330mV and enabling high efficiency. The datasheet specifies a 0.1µF capacitor and CMDSH-3 diode as standard components for this function.
LT1767EMS8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 25V
- Voltage - Output (Min/Fixed):
- 1.2V
- Voltage - Output (Max):
- 22.5V
- Current - Output:
- 1.5A
- Frequency - Switching:
- 1.25MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-MSOP
LT1767EMS8#PBF FAQ
1.How can I place an order for LT1767EMS8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1767EMS8#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 LT1767EMS8#PBF reliable?
The price and inventory of LT1767EMS8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1767EMS8#PBF is usually 5 days.
3.What payment methods are accepted for LT1767EMS8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1767EMS8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1767EMS8#PBF?
LT1767EMS8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1767EMS8#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 LT1767EMS8#PBF?
For technical support, including LT1767EMS8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1767EMS8#PBF requirements.
6.How does Aetrix verify that LT1767EMS8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1767EMS8#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 LT1767EMS8#PBF meets industry standards.
7.What is the process for return or replacement of LT1767EMS8#PBF?
All LT1767EMS8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1767EMS8#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 LT1767EMS8#PBF part is unused and in its original packaging.
Return procedure for LT1767EMS8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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