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Analog Devices Inc. LTC3127EMSE#PBF
- Part No.:
- LTC3127EMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Management - Specialized
- Package:
- 12-TSSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LTC3127EMSE#PBF.pdf
- Description:
- IC BUCK BOOST SYNC ADJ 12MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,536
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Product details
Overview
LTC3127EMSE#PBF from Analog Devices (formerly Linear Technology) is a wide-input, synchronous buck-boost DC/DC converter with programmable average input current limit (0.2A–1A ±4%), fixed 1.35MHz switching frequency, and continuous conduction across buck, buck-boost, and boost modes. It regulates output voltage (1.8V–5.25V) regardless of whether input is above, below, or equal to output - ideal for USB-powered GSM modems and supercapacitor charging where input power is constrained.
For engineers reviewing the LTC3127EMSE#PBF datasheet, LTC3127EMSE#PBF pinout, LTC3127EMSE#PBF application, or LTC3127EMSE#PBF equivalent, key selection criteria include its input current limit accuracy, seamless mode transition, thermal regulator behavior, Burst Mode quiescent current (35µA), and MSOP-12 package compatibility with high-density layouts.
Technical Context
The LTC3127EMSE#PBF implements an average input current-controlled buck-boost topology using four internal MOSFETs (two P-channel, two N-channel) with RDS(ON) values of 160–190mΩ (P-ch) and 140–170mΩ (N-ch). Its proprietary switching algorithm enables discontinuity-free transitions between operating modes by dynamically varying duty cycles of switch pairs A/C and B/D.
It features dual-loop control: an outer voltage loop (externally compensated via VC pin) and an inner current loop that enforces the PROG-pin-programmed input current limit. Thermal regulation activates at ~130°C to reduce current limit before shutdown occurs at ~150°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.8V to 5.5V - supports single-cell Li-ion, USB 2.0/3.0, and 3.3V/5V rails without external LDO pre-regulation. |
| Output Voltage Range | 1.8V to 5.25V - set via resistor divider on FB pin with 1.195V reference; enables direct generation of common logic/system rails. |
| Switching Frequency | 1.35MHz (±30%) - allows use of compact 2.2–4.7µH inductors and reduces output capacitor size vs lower-frequency converters. |
| Avg Input Current Limit | 0.2A to 1A ±4% - programmed externally with single resistor; critical for compliance with USB 2.0/3.0 current limits and battery charge management. |
| Efficiency | Up to 96% - achieved via synchronous rectification and low RDS(ON) switches; maintains >85% efficiency at 10mA load in Burst Mode. |
| Quiescent Current | 35µA in Burst Mode, <1µA in shutdown - extends battery life in always-on or low-duty-cycle portable instrumentation. |
| Package | 12-lead MSOP (3mm × 4mm × 1.1mm) with exposed PGND pad - thermally enhanced for 40°C/W θJA; requires soldered exposed pad for thermal performance. |
Pinout & Package
Package: 12-lead plastic MSOP (MSE), 3mm × 4mm × 1.1mm, exposed PGND pad (Pin 11) requiring PCB solder connection for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PGND (Pin 11) | Power ground reference for switches and exposed thermal pad | Mandatory solder connection to PCB ground plane; failure causes thermal resistance increase >100°C/W and potential thermal shutdown. |
| SW1 (Pin 1) | Internal node connecting switches A and B | Connects to one end of power inductor; short, low-inductance trace required to minimize EMI and switching losses. |
| VIN (Pin 2) | Main input supply and internal VCC source | Requires ≥10µF ceramic decoupling capacitor placed adjacent to VIN and PGND; powers internal bias circuitry. |
| SHDN (Pin 3) | Logic-controlled enable/disable input | Drives shutdown when <0.3V; enables operation when >1.2V; tolerates voltages up to 6V (beyond VIN/VOUT). |
| MODE (Pin 4) | Burst Mode / PWM mode selection | High = Burst Mode (35µA IQ); Low = forced PWM (400µA IQ, constant frequency, lower noise). |
| PROG (Pin 5) | Input current limit programming node | Resistor to SGND sets average input current limit per RPROG = 54.92·ILIMIT + 4.94 kΩ; accuracy maintained over –40°C to 85°C. |
| SGND (Pin 6) | Signal ground reference for feedback and compensation | Separate from PGND; must be star-connected to PROG, FB, and VC compensation components to avoid noise coupling. |
| FB (Pin 7) | Feedback input for output voltage regulation | Monitors resistive divider; 1.195V reference enables precise output setting from 1.8V to 5.25V. |
| VC (Pin 8) | Error amplifier output for external compensation | Connects to compensation network (R/C) between VC and SGND; supports proportional or integral compensation per output capacitance. |
| VOUT (Pin 9) | Regulated output terminal | Connects to output filter capacitor (≥22µF, low-ESR); supplies load; disconnects from input during shutdown. |
| SW2 (Pin 10) | Internal node connecting switches C and D | Connects to second end of power inductor; same layout rules as SW1 for EMI control. |
Key Features
| Feature | Design Value |
|---|---|
| Seamless buck/buck-boost/boost mode transition | Eliminates output voltage discontinuity and loop instability during VIN crossing VOUT - no external mode-switching circuitry needed. |
| Programmable input current limit with ±4% accuracy | Enables strict adherence to USB port current limits and battery charge profiles without additional current-sense ICs or firmware. |
| Thermal regulation (130°C activation) | Gradually reduces input current limit before thermal shutdown - prevents abrupt system reset during supercap charging or high-pulse-load events. |
| Output disconnect in shutdown | Isolates VOUT from VIN and internal switches - prevents backfeed into input source and protects downstream circuitry. |
| Burst Mode with 35µA quiescent current | Maintains regulation while minimizing light-load power loss - extends runtime in handheld test instruments with intermittent usage. |
Applications
| USB Powered GSM Modems | Supercapacitor Chargers |
|---|---|
Use Scenario: GSM modem draws bursty 1A transmit current from USB 5V port with strict 500mA input limit. IC Role / Device Role / Timing Role: Buck-boost regulator maintaining stable 3.3V rail while enforcing 500mA average input current via PROG pin resistor. Use Value: Prevents USB host overcurrent fault; eliminates need for separate current-limiting circuitry or firmware-based throttling. | Use Scenario: Charging a 10F/2.7V supercapacitor from 3.6V Li-ion battery with controlled current ramp. IC Role / Device Role / Timing Role: Constant-current charger using programmable input limit to regulate charge rate; thermal regulator prevents overheating during bulk charge phase. Use Value: Enables safe, efficient supercap charging without external op-amps or discrete FETs; supports full-capacity energy storage in space-constrained IoT nodes. |
| Handheld Test Instruments | Wireless Terminals |
Use Scenario: Portable multimeter operates from single AA/AAA cell (0.9–1.5V) while powering 3.3V MCU and analog front-end. IC Role / Device Role / Timing Role: Wide-VIN buck-boost delivering regulated 3.3V output down to 1.8V input; Burst Mode extends battery life during standby. Use Value: Eliminates need for multi-rail power architecture; achieves >200-hour battery life on alkaline cells with active measurement intervals. | Use Scenario: Industrial wireless sensor node powered by 3.3V rail but requiring 5V for RF transceiver during transmission bursts. IC Role / Device Role / Timing Role: Step-up converter generating 5V from 3.3V supply; synchronous rectification ensures >92% efficiency at 200mA peak load. Use Value: Reduces heat generation and extends battery life vs diode-based boost; supports reliable 2.4GHz RF link margin in temperature-variable environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3129EMSE#PBF | Higher input range (0.5V–5.5V), integrated soft-start, lower quiescent current (2.5µA), but no programmable input current limit. | Better for ultra-low-power energy harvesting; unsuitable where USB current limiting or precise input current control is required. | Select LTC3129EMSE#PBF only if input can drop below 1.8V and input current regulation is unnecessary. |
| TPS63020DSJR | Fixed 3.3V/5V outputs or adjustable via FB; 2A output capability; no programmable input current limit; 2.5MHz switching. | Higher output current for demanding loads; lacks input current enforcement needed for USB compliance or battery protection. | Choose TPS63020DSJR when peak load exceeds 1A and input current limiting is handled externally or not required. |
Compared with LTC3127EMSE#PBF, LTC3129EMSE#PBF offers deeper input undervoltage support and nanoamp quiescent current but sacrifices programmable input current limiting - making it unfit for USB-limited sources. TPS63020DSJR delivers higher output current and faster switching but lacks the precise input current control essential for battery-fed or port-powered systems.
Availability
LTC3127EMSE#PBF is available at Aetrix Electronics and suitable for USB-powered modems, supercapacitor charging circuits, handheld test instruments, and wireless terminals requiring stable component supply with guaranteed long-term manufacturability.
Supply support for LTC3127EMSE#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 all Linear power products, including robust process control and extended product lifecycles.
The LTC3127 belongs to Linear's high-efficiency buck-boost converter family, designed specifically for power-constrained portable and battery-operated systems requiring seamless VIN-to-VOUT regulation and precise input current management.
FAQ
What is the maximum continuous output current supported by the LTC3127EMSE#PBF?
The LTC3127EMSE#PBF delivers 0.6A continuous output current when VIN > 1.8V, and up to 1A continuous output current when VIN > 3V. Output current capability depends on input voltage, output voltage, ambient temperature, PCB thermal design, and inductor saturation rating - peak inductor current reaches 2.5A, so the inductor must be rated accordingly. Derating is required near thermal limits or at minimum input voltage.
How does the LTC3127EMSE#PBF implement input current limiting, and what is its accuracy?
The LTC3127EMSE#PBF uses an average input current limit circuit controlled by a resistor connected from PROG pin to SGND. The limit is accurate to ±4% over –40°C to 85°C, with typical values of 480–520mA for RPROG = 32.4kΩ. This is distinct from peak current limiting (2.5A typical), which serves as a secondary safety mechanism and is unaffected by the PROG resistor.
Can the LTC3127EMSE#PBF operate with input voltage below 1.8V?
No - the LTC3127EMSE#PBF has a specified minimum input voltage of 1.8V per Absolute Maximum Ratings and Electrical Characteristics tables. Operation below 1.8V may cause malfunction or disable regulation; undervoltage lockout triggers at ~1.7V (typical), shutting down the device. For sub-1.8V operation, consider the pin-compatible LTC3129EMSE#PBF, which supports inputs down to 0.5V.
What is the role of the exposed pad (Pin 11) on the LTC3127EMSE#PBF MSOP package?
The exposed pad (Pin 11) on the LTC3127EMSE#PBF is electrically and thermally connected to PGND. It must be soldered to a dedicated PCB copper area tied to the system power ground plane. Failure to do so increases thermal resistance from 40°C/W to >100°C/W, risking premature thermal shutdown under moderate load and degrading long-term reliability.
Does the LTC3127EMSE#PBF support output voltages above 5.25V?
No - the LTC3127EMSE#PBF is specified for output voltages from 1.8V to 5.25V only. Attempting to set VOUT > 5.25V violates the absolute maximum rating for FB pin voltage (6V) and risks damage or regulation failure. The internal 1.195V feedback reference and resistor-divider equation constrain practical outputs to ≤5.25V; for higher outputs, a different converter such as the LTC3122 or external post-regulation is required.
LTC3127EMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 12-TSSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Applications:
- Energy Harvesting
- Current - Supply:
- 400µA
- Voltage - Supply:
- 1.8V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-MSOP-EP
LTC3127EMSE#PBF FAQ
1.How can I place an order for LTC3127EMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3127EMSE#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 LTC3127EMSE#PBF reliable?
The price and inventory of LTC3127EMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3127EMSE#PBF is usually 5 days.
3.What payment methods are accepted for LTC3127EMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3127EMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3127EMSE#PBF?
LTC3127EMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3127EMSE#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 LTC3127EMSE#PBF?
For technical support, including LTC3127EMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3127EMSE#PBF requirements.
6.How does Aetrix verify that LTC3127EMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3127EMSE#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 LTC3127EMSE#PBF meets industry standards.
7.What is the process for return or replacement of LTC3127EMSE#PBF?
All LTC3127EMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3127EMSE#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 LTC3127EMSE#PBF part is unused and in its original packaging.
Return procedure for LTC3127EMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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