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Analog Devices Inc. LTC3728EG#TRPBF
- Part No.:
- LTC3728EG#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC3728EG#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,267
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Product details
Overview
LTC3728EG#TRPBF from Analog Devices (formerly Linear Technology) is a dual-phase, constant-frequency current-mode synchronous step-down controller driving two independent N-channel MOSFET stages. It operates at 250–550 kHz with 180° phase shift, supports 3.5V–36V input, delivers ±1% output voltage accuracy at 0.8V reference, and integrates OPTI-LOOP compensation for wide output capacitance/ESR optimization - used in high-efficiency dual-rail DC/DC converters for notebook computers and telecom systems.
For engineers reviewing the LTC3728EG#TRPBF datasheet, LTC3728EG#TRPBF pinout, LTC3728EG#TRPBF application, or LTC3728EG#TRPBF equivalent, key selection criteria include dual-phase interleaving for reduced input ripple, programmable operating modes (Burst Mode®, constant-frequency PWM, forced continuous), remote sense capability, and integrated 3.3V LDO output - all critical for low-noise, high-density power delivery in battery-powered and industrial embedded systems.
Technical Context
The LTC3728EG#TRPBF implements a dual-channel, 180° out-of-phase, current-mode control architecture with independent ITH error amplifier outputs and differential current sensing per channel. Its phase-locked loop accepts external synchronization via PLLIN and allows frequency tuning from 250 kHz to 550 kHz using a DC voltage on PLLFLTR.
It features three selectable operating modes via the FCB pin: Burst Mode® for light-load efficiency, constant-frequency discontinuous conduction mode (with burst inhibit), and forced continuous PWM. Output overvoltage protection latches the bottom MOSFET until recovery, while foldback current limiting activates when VOSENSE drops below 70% of setpoint - enabling robust short-circuit handling without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 36V - supports wide battery chemistries (12V, 24V, Li-ion stacks) and industrial DC rails. |
| Output Voltage Accuracy | ±1% at 0.8V reference - ensures tight regulation for modern microprocessor core supplies. |
| Switching Frequency | 250 kHz to 550 kHz, phase-lockable - enables EMI reduction via synchronization and layout optimization. |
| Dual-Phase Operation | 180° interleaved channels - cuts input RMS current by ~30%, reducing required input capacitance and EMI filtering cost. |
| Integrated 3.3V LDO | 10mA DC / 50mA peak output - powers auxiliary circuitry (e.g., level shifters, sensors) without external regulator. |
| Shutdown Quiescent Current | 20μA - enables ultra-low power standby in portable and always-on systems. |
| Power Good Threshold | ±7.5% window on both outputs - provides reliable system-level power sequencing and fault detection. |
Pinout & Package
Package: 28-pin plastic SSOP (0.300" wide), exposed pad soldered to SGND for thermal and electrical performance. Pin pitch: 0.025", body dimensions: 9.9mm × 3.9mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS1, RUN/SS2 (Pins 1, 15) | Soft-start & latchoff control | Capacitor-based ramp sets startup time; falling below 1.0V shuts down respective channel; used for timed short-circuit shutdown. |
| SENSE1+/SENSE2+, SENSE1−/SENSE2− (Pins 2,14,13,12) | Differential current sense inputs | Measure RSENSE voltage drop to regulate peak inductor current; supports accurate current limiting and foldback. |
| VOSENSE1, VOSENSE2 (Pins 4, 12) | Remote feedback inputs | Accept resistive divider output from load point - enables precise regulation despite PCB IR drop. |
| ITH1, ITH2 (Pins 8, 11) | Error amplifier output & compensation node | Controls current limit threshold and loop stability; connects to OPTI-LOOP network for wide COUT/ESR tolerance. |
| TG1, TG2 / BG1, BG2 (Pins 27,16,23,19) | Top/bottom gate drivers | Drive N-MOSFET gates with 3A peak current; TG swing = INTVCC − 0.5V referenced to SW; BG swing = 0V to INTVCC. |
| PGOOD (Pin 28) | Open-drain power-good indicator | Pulls low if either output deviates >±7.5% - enables safe system enable/disable sequencing with external pull-up. |
Key Features
| Feature | Design Value |
|---|---|
| 180° Dual-Phase Interleaving | Reduces input capacitor RMS current by ~30%, enabling smaller, lower-cost bulk capacitors and easing EMI compliance. |
| OPTI-LOOP Compensation | Allows stable operation across wide range of output capacitor types (ceramic, polymer, electrolytic) and ESR values without redesign. |
| Three-Mode FCB Control | Selects Burst Mode® (high efficiency at light load), constant-frequency (low noise), or forced continuous (output sink capability). |
| Integrated 3.3V Linear Regulator | Delivers 10mA DC with 50mA peak - powers bias circuits, references, or logic without external LDO or charge pump. |
| Output Overvoltage Protection | Latches bottom MOSFET on during >7.5% overvoltage - prevents damage to downstream ICs during transient events or feedback faults. |
| Programmable Short-Circuit Shutdown | Uses RUN/SS capacitor discharge timing to initiate latchoff after sustained overcurrent - configurable without external timers. |
Applications
| High-Efficiency Notebook Power | Telecom DC Distribution |
|---|---|
|
Use Scenario: Dual-rail 5V/3.3V conversion from 12V or 19V adapter in ultraportable notebooks. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing independent 5A outputs with interleaved switching to minimize input ripple and heat. Use Value: Reduces input capacitor count by 40% vs single-phase design and improves full-load efficiency to >92% at 5V/5A. |
Use Scenario: Point-of-load regulation in 48V telecom shelf systems powering FPGA, DSP, and interface ICs. IC Role / Device Role / Timing Role: High-voltage input controller generating tightly regulated 1.2V, 1.8V, or 3.3V rails with remote sense and PGOOD sequencing. Use Value: ±1% accuracy and ±7.5% PGOOD window ensure reliable startup and fault reporting in redundant power architectures. |
| Battery-Powered Test Equipment | Industrial Embedded DC/DC Module |
|
Use Scenario: Portable oscilloscope or multimeter requiring isolated 5V and 3.3V rails from Li-ion battery pack (8–28V). IC Role / Device Role / Timing Role: Dual-output controller with wide VIN range and Burst Mode® for <100μA quiescent operation during sleep. Use Value: Achieves >85% efficiency at 10mA load via Burst Mode®, extending battery runtime by 3.2× vs constant-frequency mode. |
Use Scenario: DIN-rail mounted PLC I/O module needing robust, field-replaceable 5V/3.3V power with overvoltage and short-circuit protection. IC Role / Device Role / Timing Role: Controller with latchoff-enabled RUN/SS pins and OVP that sustains operation during line transients up to 36V. Use Value: Integrated foldback limiting and 99% duty cycle dropout operation maintain regulation during brownouts without external supervision. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-phase synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3855EUH#TRPBF | Single-channel, 3–36V input, 2-phase capable via external clock sync; no integrated 3.3V LDO; higher max fSW (850kHz). | Requires external 3.3V supply; better suited for higher-frequency, space-constrained designs where dual independent controllers are not needed. | Choose when board area is critical and auxiliary 3.3V rail is already available; verify external sync timing compatibility. |
| MP8765GL-Z | Monolithic dual 3A buck (integrated MOSFETs); 4.5–30V input; fixed 500kHz; no PLL sync or FCB mode selection. | No external MOSFET flexibility; lacks remote sense, PGOOD window adjustability, and multi-mode light-load control. | Choose for cost-sensitive, low-complexity applications where 3A per channel suffices and efficiency at light load is secondary. |
Compared with LTC3728EG#TRPBF, LTC3855EUH#TRPBF offers higher frequency and sync flexibility but requires external biasing, while MP8765GL-Z simplifies BOM with integrated FETs but sacrifices precision regulation, protection granularity, and adaptive light-load behavior.
Availability
LTC3728EG#TRPBF is available at Aetrix Electronics and suitable for notebook computing, telecom power distribution, portable instrumentation, battery-operated digital devices, and industrial DC power systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LTC3728EG#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 high-performance analog and power management portfolio with rigorous qualification and long-term product support.
The LTC3728EG#TRPBF belongs to Linear's high-efficiency synchronous controller family, designed specifically for dual-rail, interleaved DC/DC conversion in space- and thermally-constrained applications demanding precision regulation and robust fault protection.
FAQ
What is the maximum input voltage rating for the LTC3728EG#TRPBF?
The LTC3728EG#TRPBF has an absolute maximum input supply voltage (VIN) rating of 36V. Continuous operation is specified from 3.5V to 30V, with transient tolerance up to 36V. Exceeding 36V may cause permanent damage. The device also supports 36V on SW1/SW2 pins and 42V on BOOST1/BOOST2 pins under defined conditions per the Absolute Maximum Ratings table.
Does the LTC3728EG#TRPBF support remote voltage sensing?
Yes, the LTC3728EG#TRPBF supports remote voltage sensing via dedicated VOSENSE1 and VOSENSE2 pins. These inputs accept feedback from a resistive divider placed directly at the load, compensating for PCB trace resistance and ensuring ±1% output accuracy regardless of voltage drop between converter and load - a critical feature for high-current, low-voltage rails.
How does the FCB pin configure operating modes on the LTC3728EG#TRPBF?
The FCB pin on the LTC3728EG#TRPBF selects among three modes: <0.8V enables forced continuous PWM; 0.8V–(INTVCC−1V) enables Burst Mode®; ≥4.3V (tied to INTVCC) disables Burst Mode® for constant-frequency operation. This pin controls both channels simultaneously and can also regulate a secondary winding when used with auxiliary transformer feedback.
What protection features are integrated into the LTC3728EG#TRPBF?
The LTC3728EG#TRPBF integrates output overvoltage protection (latching bottom MOSFET on if VOSENSE exceeds ±7.5%), foldback current limiting (activates when output drops below 70% of setpoint), programmable short-circuit latchoff (via RUN/SS capacitor timing), undervoltage lockout (3.5V turn-on threshold), and thermal shutdown (125°C junction limit). All operate autonomously without external components.
Is the 3.3V output on the LTC3728EG#TRPBF regulated and load-capable?
Yes, the LTC3728EG#TRPBF includes an internal 3.3V linear regulator (pin 10, 3.3VOUT) with ±2% accuracy over temperature and load. It delivers 10mA DC continuously and supports 50mA peak current - sufficient for powering level shifters, ADC references, or small logic circuits. In shutdown, leakage is ≤50μA, preserving system standby power.
LTC3728EG#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 2
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 3.5V ~ 30V
- Frequency - Switching:
- 260kHz ~ 550kHz
- Duty Cycle (Max):
- 99.4%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SSOP
LTC3728EG#TRPBF FAQ
1.How can I place an order for LTC3728EG#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3728EG#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 LTC3728EG#TRPBF reliable?
The price and inventory of LTC3728EG#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3728EG#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3728EG#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3728EG#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3728EG#TRPBF?
LTC3728EG#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3728EG#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 LTC3728EG#TRPBF?
For technical support, including LTC3728EG#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3728EG#TRPBF requirements.
6.How does Aetrix verify that LTC3728EG#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3728EG#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 LTC3728EG#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3728EG#TRPBF?
All LTC3728EG#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3728EG#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 LTC3728EG#TRPBF part is unused and in its original packaging.
Return procedure for LTC3728EG#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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