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Analog Devices Inc. LTC3121EDE#TRPBF
- Part No.:
- LTC3121EDE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 12-WFDFN Exposed Pad
- Datasheet:
-
LTC3121EDE#TRPBF.pdf
- Description:
- IC REG BOOST ADJ 1.5A 12DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,990
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Product details
Overview
LTC3121EDE#TRPBF from Analog Devices (formerly Linear Technology) is a synchronous step-up DC/DC converter with true output disconnect, 1.5A current limit, and programmable output voltage up to 15V. It operates from input voltages as low as 1.8V (start-up) and down to 500mV after regulation, enabling extended battery runtime in low-voltage systems such as piezo actuators and backup-capacitor-powered rails.
For engineers reviewing the LTC3121EDE#TRPBF datasheet, LTC3121EDE#TRPBF pinout, LTC3121EDE#TRPBF application, or LTC3121EDE#TRPBF equivalent, key selection considerations include its 100kHz–3MHz adjustable switching frequency, 25µA Burst Mode quiescent current, output disconnect capability, inrush current limiting, and thermal protection - all integrated in a compact 12-lead 3mm × 4mm DFN package.
Technical Context
The LTC3121EDE#TRPBF employs current-mode PWM control with adaptive slope compensation for stable operation across wide duty cycles and fast transient response. Its dual-MOSFET synchronous rectification architecture uses an N-channel main switch (RDS(ON) = 121mΩ) and P-channel rectifier (RDS(ON) = 188mΩ), enabling up to 95% efficiency at mid-load conditions.
It integrates a 10ms closed-loop soft-start, zero-current detection for light-load efficiency, anti-ringing control above VOUT ≥ VIN + 2V, and overvoltage lockout at ~16.2V. The VCC regulator self-biases from VIN or VOUT, supporting operation even when VIN drops below 3V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.8V to 5.5V (start-up); continues regulation down to 500mV after VOUT ≥ 2.2V - enables deep discharge of single-cell Li-ion or supercapacitors. |
| Output Voltage Range | 2.2V to 15V (programmable via resistor divider on FB pin) - supports 12V analog rails, piezo drive, and PCIe auxiliary power. |
| Switching Frequency | 100kHz to 3MHz (adjustable via RT pin or external SYNC clock) - allows optimization for size (high-freq) or EMI (low-freq/synchronized). |
| Peak Switch Current Limit | 1.5A (min), 1.8A (typ) - sets maximum deliverable output current under boost conditions with VOUT > 1.5V. |
| Quiescent Current (Burst Mode) | 25µA (measured on VIN) - ensures ultra-low standby power for battery-backed systems. |
| Shutdown Current | <1µA - enables true zero-power shutdown with full output disconnect and VOUT discharge. |
| Efficiency (Typical) | Up to 95% at 400mA, VIN = 5V, VOUT = 12V - achieved via synchronous rectification and low RDS(ON) MOSFETs. |
Pinout & Package
The LTC3121EDE#TRPBF is housed in a thermally enhanced 12-lead (3mm × 4mm × 0.75mm) plastic DFN package with exposed PGND pad (Pin 13) requiring soldering to PCB ground plane for rated thermal performance (θJA = 43°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (1) | Power switch node | Connects to inductor; carries high di/dt switching current - requires short, wide trace to minimize EMI and ringing. |
| PGND (2, 13) | Power ground reference | Primary return path for inductor current and output capacitor; exposed pad must be soldered to PCB ground plane. |
| VIN (3) | Main input supply | Accepts 1.8V–5.5V input; powers internal circuitry unless VOUT > VIN and VIN < 3V. |
| PWM/SYNC (4) | Mode control & synchronization | High = fixed-frequency PWM; Low = Burst Mode; external clock = synchronized operation (0.1–3MHz). |
| VCC (5) | Internal LDO output | Regulated ~4.25V rail powering gate drivers; sourced from VIN or VOUT; requires ≥4.7µF ceramic bypass. |
| RT (6) | Oscillator frequency programming | Resistor to SGND sets fOSC = 57.6 / RT (MHz/kΩ); enables precise frequency tuning or sync offset. |
| VC (7) | Error amplifier output | Loop compensation node - connects RC network to stabilize feedback control for varying loads and layouts. |
| FB (8) | Feedback input | Senses resistive divider from VOUT; regulates output using 1.202V internal reference (VOUT = 1.202V × (1 + R1/R2)). |
| SD (9) | Logic shutdown input | Active-high enable: >1.6V = ON; <0.25V = shutdown with <1µA IQ and full output disconnect. |
| SGND (10) | Signal ground reference | Reference for FB, VC, and RT; must connect directly to (–) side of output capacitor to avoid noise coupling. |
| VOUT (11) | Regulated output & rectifier source | Delivers up to 15V; disconnects from VIN during shutdown; supplies gate bias for synchronous P-MOSFET. |
| CAP (12) | Synchronous rectifier gate drive reference | Connects 100nF cap to VOUT to generate ~5.6V below VOUT - enables efficient P-MOSFET drive without external supply. |
Key Features
| Feature | Design Value |
|---|---|
| True output disconnect | Eliminates body-diode conduction during shutdown, allowing VOUT to fully discharge and preventing reverse current into VIN. |
| Inrush current limiting | 10ms closed-loop soft-start limits peak input surge - critical for capacitive loads and low-impedance sources like backup capacitors. |
| Selectably synchronized oscillator | Supports external clock synchronization (0.1–3MHz) to avoid sensitive frequency bands in noise-critical applications like audio or RF systems. |
| Burst Mode operation | Reduces IQ to 25µA while maintaining regulation - extends battery life in always-on sensor nodes and IoT endpoints. |
| Robust fault protection | Integrated short-circuit current foldback, thermal shutdown (>170°C), and output overvoltage lockout (~16.2V) ensure reliable operation under abnormal conditions. |
Applications
| Piezo Actuator Drive | PCI Express Auxiliary Power |
|---|---|
Use Scenario: Driving high-voltage piezoelectric elements requiring 12V–15V from a 3.3V or 5V system rail or single-cell battery. IC Role / Device Role / Timing Role: Synchronous boost converter providing regulated, low-noise, high-efficiency voltage step-up with precise start-up control. Use Value: Enables compact, low-EMI actuator control with minimal external components and no need for discrete high-voltage charge pumps. |
Use Scenario: Generating stable 12V auxiliary power for PCIe add-in cards operating from 3.3V or 5V motherboard rails. IC Role / Device Role / Timing Role: High-current boost regulator delivering up to 400mA at 12V with output disconnect to meet PCIe hot-plug requirements. Use Value: Meets PCIe specification for isolated auxiliary power with zero reverse current and fast transient response during card insertion/removal. |
| Backup Capacitor Power Rail | Small DC Motor Supply |
Use Scenario: Maintaining 12V analog supply during brief AC mains loss using a supercapacitor charged from 5V. IC Role / Device Role / Timing Role: Ultra-low-input-voltage boost converter sustaining regulation down to 500mV input - maximizing energy extraction from decaying capacitor voltage. Use Value: Extends hold-up time by >3× compared to conventional boost ICs, eliminating need for larger, costlier capacitors. |
Use Scenario: Powering miniature 12V DC motors in portable medical devices or robotics from a 3.3V or 4.2V Li-ion cell. IC Role / Device Role / Timing Role: Efficient, compact step-up supply with inrush limiting to prevent motor stall during startup and protect battery voltage sag. Use Value: Delivers consistent torque at low battery voltage while minimizing heat generation and PCB area vs. discrete solutions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61088RHLR | Higher 5.5A switch current limit; fixed 500kHz/1MHz/2.2MHz options; no true output disconnect; 2.7V–12V input range. | Preferred for higher-output-current applications (e.g., >1A at 12V); unsuitable where VIN < 2.7V or output isolation during shutdown is required. | Select TPS61088RHLR when peak load current exceeds 1.5A and input never falls below 2.7V; avoid if deep-discharge operation or true disconnect is needed. |
| MAX17222ETA+ | Lower 0.5A current limit; 0.5V–5.5V input; 2.5V–5.25V output; 1.5µA shutdown current; no SYNC or programmable frequency. | Better suited for ultra-low-power, sub-5V applications (e.g., wearables); lacks high-voltage capability and flexible frequency control. | Choose MAX17222ETA+ only for sub-5V, sub-500mA designs prioritizing minimum quiescent current over voltage range or feature set. |
Compared with TPS61088RHLR and MAX17222ETA+, the LTC3121EDE#TRPBF uniquely combines deep-input-operation (down to 500mV), true output disconnect, and 2.2V–15V programmability - making it the only viable option for 12V rail generation from near-dead batteries or backup capacitors where isolation and inrush control are mandatory.
Availability
LTC3121EDE#TRPBF is available at Aetrix Electronics and suitable for piezo actuator drive, PCIe auxiliary power, and backup capacitor power rail applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LTC3121EDE#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 acquired Linear Technology in 2017 and maintains its precision power management portfolio, emphasizing high-efficiency, robust, and application-optimized DC/DC solutions for industrial, medical, and aerospace markets.
The LTC3121EDE#TRPBF belongs to Linear's high-performance synchronous boost converter family, designed specifically for demanding low-input-voltage, high-output-voltage applications requiring reliability, efficiency, and integrated protection - such as energy harvesting interfaces and battery-extending power architectures.
FAQ
What is the minimum input voltage required to start up the LTC3121EDE#TRPBF?
The LTC3121EDE#TRPBF requires a minimum input voltage of 1.7V (typical) to initiate start-up, with guaranteed operation at 1.8V across temperature. Once regulation is established and VOUT reaches ≥2.2V, the device continues switching down to 500mV input - a key advantage for supercapacitor or deeply discharged battery applications. This behavior is confirmed in the Electrical Characteristics table under "Minimum Start-Up Voltage" and "Input Voltage Range After VOUT ≥ 2.2V".
Does the LTC3121EDE#TRPBF provide true output disconnect during shutdown?
Yes, the LTC3121EDE#TRPBF provides true output disconnect: when the SD pin is pulled low (<0.25V), both internal MOSFETs are turned off and the output is electrically isolated from the input, allowing VOUT to fully discharge through the load. This eliminates reverse current flow and body-diode conduction - a distinguishing feature verified in the Functional Description, Pin Functions (SD pin), and Applications sections of the datasheet.
How is the switching frequency programmed on the LTC3121EDE#TRPBF?
The LTC3121EDE#TRPBF switching frequency is programmed using an external resistor (RT) from the RT pin to SGND, following fOSC(MHz) = 57.6 / RT(kΩ). For example, a 57.6kΩ resistor sets 1MHz operation. The oscillator can also be synchronized to an external clock (0.1–3MHz) applied to the PWM/SYNC pin, with RT adjusted to ~25% below the sync frequency per the alternate formula in the Oscillator section.
What protection features are integrated into the LTC3121EDE#TRPBF?
The LTC3121EDE#TRPBF integrates short-circuit current foldback (reducing peak limit to 1A under overload), thermal shutdown (>170°C), output overvoltage lockout (~16.2V), and input UVLO (via VCC rail monitoring). These protections are documented in the Absolute Maximum Ratings, Electrical Characteristics (e.g., "Overvoltage Lockout"), and Operation sections - ensuring robust operation without external circuitry.
Can the LTC3121EDE#TRPBF operate with an input voltage higher than the output voltage?
Yes, the LTC3121EDE#TRPBF maintains regulation even when VIN > VOUT (e.g., 5V input, 3.3V output), though efficiency and output current capability decrease significantly in this buck-like mode. This behavior is explicitly described in the "VIN > VOUT Operation" subsection of the Operation chapter and reflected in the Typical Performance Characteristics curves showing reduced IOUT capability at high VIN/VOUT ratios.
LTC3121EDE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 12-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 1.8V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 2.2V
- Voltage - Output (Max):
- 15V
- Current - Output:
- 1.5A (Switch)
- Frequency - Switching:
- Up to 3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-DFN (4x3)
LTC3121EDE#TRPBF FAQ
1.How can I place an order for LTC3121EDE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3121EDE#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 LTC3121EDE#TRPBF reliable?
The price and inventory of LTC3121EDE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3121EDE#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3121EDE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3121EDE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3121EDE#TRPBF?
LTC3121EDE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3121EDE#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 LTC3121EDE#TRPBF?
For technical support, including LTC3121EDE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3121EDE#TRPBF requirements.
6.How does Aetrix verify that LTC3121EDE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3121EDE#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 LTC3121EDE#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3121EDE#TRPBF?
All LTC3121EDE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3121EDE#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 LTC3121EDE#TRPBF part is unused and in its original packaging.
Return procedure for LTC3121EDE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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