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Analog Devices Inc. LTC3728LIGN-1#TRPBF
- Part No.:
- LTC3728LIGN-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC3728LIGN-1#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,455
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Product details
Overview
LTC3728LIGN-1#TRPBF from Analog Devices (formerly Linear Technology) is a dual-phase, 180° out-of-phase, synchronous step-down controller driving all-N-channel MOSFET stages for high-efficiency DC/DC conversion. It operates at a phase-lockable constant frequency up to 550 kHz, features ±1.5% output voltage accuracy, 0.8 V reference, and power-good indication. It is used in notebook computers and telecom systems requiring tightly regulated dual outputs with minimized input ripple.
For engineers reviewing the LTC3728LIGN-1#TRPBF datasheet, LTC3728LIGN-1#TRPBF pinout, LTC3728LIGN-1#TRPBF application, or LTC3728LIGN-1#TRPBF equivalent, key selection criteria include its dual-channel current-mode architecture, absence of overcurrent latchoff, OPTI-LOOP® compensation, 4.5 V–28 V input range, and compatibility with 5 mm × 5 mm QFN or 28-lead SSOP packages.
Technical Context
The LTC3728LIGN-1#TRPBF implements two independent current-mode control loops with 180° phase interleaving to reduce RMS input current and EMI. Each channel uses a transconductance error amplifier (gm = 1.3 mmho, GBW = 3 MHz) and a precision 0.8 V reference with ±1.5% accuracy over temperature.
Its oscillator supports phase-locking via PLLIN and frequency tuning via PLLFLTR (260–550 kHz), while FCB pin selects among Burst Mode®, constant-frequency discontinuous conduction, or forced continuous PWM operation. The device lacks overcurrent latchoff-unlike the standard LTC3728L-and includes foldback current limiting and output overvoltage protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Dual synchronous buck controller with 180° phase interleaving - reduces input capacitor RMS current by ~39% vs. in-phase dual controllers. |
| Input Voltage Range | 4.5 V to 28 V (30 V absolute max) - supports wide battery chemistries including 3-cell Li-ion and 24 V industrial rails. |
| Output Accuracy | ±1.5% over temperature - ensures stable regulation for microprocessor core and I/O supplies. |
| Switching Frequency | 250 kHz to 550 kHz, phase-lockable - enables EMI reduction via synchronization to system clock or noise-sensitive bands. |
| Reference Voltage | 0.800 V ±1.2 mV - low-drift reference compatible with future low-voltage microprocessors and ASICs. |
| Power Good Threshold | ±7.5% window on both VOSENSE pins - provides reliable system enable/disable signaling for sequenced power-up. |
| Shutdown IQ | 20 μA - enables ultra-low quiescent operation during standby in battery-powered devices. |
Pinout & Package
Package: 28-Lead Narrow Plastic SSOP (GN package), exposed pad not present - suitable for cost-sensitive, thermally moderate applications with standard reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS1, RUN/SS2 | Soft-start and enable control per channel | Capacitor-to-ground sets ramp time; <1.0 V forces shutdown of respective controller - enables independent sequencing. |
| VOSENSE1, VOSENSE2 | Feedback input for error amplifiers | Accepts remote-sense voltage from resistive divider - maintains ±1.5% regulation despite PCB trace IR drop. |
| SENSE1+, SENSE1−, SENSE2+, SENSE2− | Differential current sense inputs | Measure voltage across external RSENSE to set peak inductor current limit - supports accurate foldback and OCP. |
| TG1, TG2, BG1, BG2 | High-current gate drivers | TG drives top N-MOSFETs with floating bootstrap supply; BG drives bottom N-MOSFETs referenced to PGND - enables full-synchronous rectification. |
| PGOOD | Open-drain status indicator | Pulled low if either output deviates >±7.5% - used for system-level fault reporting and power sequencing logic. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 180° phased controllers | Reduces required input capacitance by ~50% and lowers conducted EMI - critical for compact portable designs. |
| OPTI-LOOP® compensation | Enables stable loop response across wide COUT/ESR variations - eliminates need for custom compensation per output capacitor type. |
| No overcurrent latchoff | Prevents permanent shutdown during transient overload - allows automatic recovery after short-circuit removal without reset. |
| Adjustable soft-start | Independent RUN/SS pins with 1.2 μA charge current - supports staggered startup of dual rails to limit inrush. |
| Three operating modes | Burst Mode® (high efficiency at light load), constant frequency (low-noise), and forced PWM (continuous conduction) - selectable via FCB pin voltage. |
Applications
| High-Efficiency Notebook Power | Telecom DC Distribution |
|---|---|
Use Scenario: Dual-output (5 V/3.3 V) VRM for CPU and chipset in thin-and-light notebooks with strict thermal and ripple constraints. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing interleaved switching to minimize input ripple and maximize efficiency at 5 A per rail. Use Value: 180° phase shift cuts RMS input current by 39%, enabling smaller ceramic input capacitors and reducing board area by >20%. | Use Scenario: Intermediate bus converter in 48 V telecom shelf supplying multiple point-of-load regulators. IC Role / Device Role / Timing Role: High-input-voltage dual controller delivering stable 12 V and 5 V outputs with precise sequencing and PGOOD monitoring. Use Value: 4.5 V–28 V input range accommodates wide-range front-end converters; ±1.5% accuracy ensures downstream POL stability. |
| Portable Instrumentation | Battery-Operated Digital Systems |
Use Scenario: Power management for handheld test equipment requiring low-noise analog supplies and fast transient response. IC Role / Device Role / Timing Role: Dual-channel controller with Burst Mode® operation to extend battery life while maintaining clean 3.3 V and 1.8 V rails. Use Value: 20 μA shutdown IQ and programmable light-load mode reduce no-load power to <100 μW - extends runtime in sleep states. | Use Scenario: Power subsystem for ruggedized PDAs or medical handhelds using Li-ion batteries with variable discharge curves. IC Role / Device Role / Timing Role: Dual buck controller supporting dynamic input voltage (7–24 V) and foldback current limiting during battery sag or short events. Use Value: Foldback current limiting reduces MOSFET dissipation during shorts; 99% duty cycle enables operation down to VIN ≈ VOUT + 0.1 V. |
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 |
|---|---|---|---|
| LTC3728LEGN-1#TRPBF | Identical functionality and pinout, but in 28-lead SSOP with exposed pad not connected - same thermal resistance (θJA = 95°C/W). | Same use cases; preferred where GN package footprint is already established and thermal margin is sufficient. | Select when board layout rework is undesirable and junction temperature remains <115°C under worst-case load. |
| LTC3728LIUH-1#TRPBF | Same die, but rated for –40°C to 85°C with guaranteed full-spec performance over temperature - higher VIN absolute max (35 V). | Required for industrial environments with extended ambient or higher input transients (e.g., 24 V automotive systems). | Choose when operating beyond commercial temperature range or needing 35 V input surge tolerance. |
Compared with LTC3728LIGN-1#TRPBF, the LTC3728LEGN-1#TRPBF offers identical electrical behavior in a legacy SSOP package, while the LTC3728LIUH-1#TRPBF adds guaranteed industrial-grade specs and higher input voltage robustness - neither is pin-compatible with the GN variant due to different pin counts and layouts.
Availability
LTC3728LIGN-1#TRPBF is available at Aetrix Electronics and suitable for notebook computers, telecom DC distribution systems, and portable instrumentation requiring stable component supply with guaranteed long-term manufacturability.
Supply support for LTC3728LIGN-1#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 full product support, documentation, and manufacturing continuity for the LTC portfolio.
The LTC3728L family targets high-efficiency, multi-rail DC/DC conversion in space-constrained portable and telecom applications - emphasizing phase interleaving, low IQ, and flexible light-load operation.
FAQ
What is the key functional difference between LTC3728LIGN-1#TRPBF and the standard LTC3728L?
The LTC3728LIGN-1#TRPBF lacks the overcurrent latchoff feature present in the standard LTC3728L. This means that under short-circuit conditions, LTC3728LIGN-1#TRPBF enters foldback current limiting and recovers automatically once the fault clears, rather than latching off permanently until reset. This behavior improves system resilience in transient-fault environments.
Does LTC3728LIGN-1#TRPBF support phase synchronization with an external clock?
Yes, LTC3728LIGN-1#TRPBF supports full phase synchronization via the PLLIN pin, which accepts an external clock signal. The internal phase-locked loop aligns the rising edge of TG1 with the rising edge of the PLLIN signal. When PLLIN is left open, the oscillator defaults to minimum frequency (≈260 kHz) via internal pull-down.
What are the supported operating modes of LTC3728LIGN-1#TRPBF and how are they selected?
LTC3728LIGN-1#TRPBF supports three modes via the FCB pin: Burst Mode® (FCB < 0.8 V), constant-frequency discontinuous conduction (FCB tied to INTVCC), and forced continuous PWM (FCB grounded). Each mode trades off light-load efficiency, output ripple, and EMI profile - enabling optimization for specific system requirements.
Can LTC3728LIGN-1#TRPBF drive MOSFETs directly without external gate drivers?
Yes, LTC3728LIGN-1#TRPBF integrates high-current gate drivers: TG1/TG2 (top-side, floating) and BG1/BG2 (bottom-side, ground-referenced), each capable of 3 A peak current. These drivers directly interface with N-channel MOSFETs - no external drivers needed - provided proper bootstrap capacitor sizing and Schottky diode selection per the datasheet guidelines.
What is the purpose of the 3.3VOUT pin on LTC3728LIGN-1#TRPBF?
The 3.3VOUT pin on LTC3728LIGN-1#TRPBF is an integrated linear regulator output providing up to 10 mA DC (50 mA peak) at 3.3 V ±3%. It is commonly used to power auxiliary circuitry such as level shifters, bias networks, or monitoring ICs - eliminating the need for a separate LDO in many dual-rail designs.
LTC3728LIGN-1#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-SSOP (0.154", 3.90mm 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):
- 4.5V ~ 35V
- 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
LTC3728LIGN-1#TRPBF FAQ
1.How can I place an order for LTC3728LIGN-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3728LIGN-1#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 LTC3728LIGN-1#TRPBF reliable?
The price and inventory of LTC3728LIGN-1#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3728LIGN-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3728LIGN-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3728LIGN-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3728LIGN-1#TRPBF?
LTC3728LIGN-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3728LIGN-1#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 LTC3728LIGN-1#TRPBF?
For technical support, including LTC3728LIGN-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3728LIGN-1#TRPBF requirements.
6.How does Aetrix verify that LTC3728LIGN-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3728LIGN-1#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 LTC3728LIGN-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3728LIGN-1#TRPBF?
All LTC3728LIGN-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3728LIGN-1#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 LTC3728LIGN-1#TRPBF part is unused and in its original packaging.
Return procedure for LTC3728LIGN-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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