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Analog Devices Inc. LTC3728LIGN#TRPBF
- Part No.:
- LTC3728LIGN#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC3728LIGN#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,102
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Product details
Overview
LTC3728LIGN#TRPBF from Analog Devices (formerly Linear Technology) is a dual-phase, synchronous step-down controller IC driving two independent N-channel MOSFET stages in 180° out-of-phase operation. It delivers up to 5A per channel at 5V and 3.3V outputs, supports 4.5V–28V input, features 0.8V ±1% reference accuracy, and operates at phase-lockable frequencies from 250kHz to 550kHz. It is used in high-efficiency notebook DC/DC power supplies where input capacitor stress reduction and low-noise regulation are critical.
For engineers reviewing the LTC3728LIGN#TRPBF datasheet, LTC3728LIGN#TRPBF pinout, LTC3728LIGN#TRPBF application, or LTC3728LIGN#TRPBF equivalent, key selection considerations include its dual-channel current-mode architecture, OPTI-LOOP™ compensation for wide output capacitance tolerance, integrated 3.3V linear regulator, and FCB-selectable operating modes (Burst Mode®, constant-frequency PWM, forced continuous).
Technical Context
The LTC3728LIGN#TRPBF implements a constant-frequency, peak-current-mode control architecture with two fully independent channels synchronized 180° out of phase. Each channel uses a transconductance error amplifier (gm = 1.3 mmho, GBW = 3 MHz), precision 0.8V reference (±1% over temp), and dedicated ITH pins for loop compensation and current limit setting. The 180° phasing reduces input ripple current by ~70%, directly lowering required input capacitance and EMI.
It integrates dual high-current gate drivers (TG/BG) with 55ns/45ns typical rise/fall times, a phase-locked loop (PLLIN/PLLFLTR) supporting external sync or programmable frequency (260–550 kHz), and robust protection including output overvoltage latching, foldback current limiting, and short-circuit latchoff via RUN/SS timing. Its INTVCC/EXTVCC dual-supply architecture enables efficient self-biasing from regulated outputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 28V - supports all common battery chemistries (Li-ion, LiPo, 12V lead-acid) and industrial DC rails. |
| Output Voltage Accuracy | ±1% over temperature - ensures stable core voltage delivery for microprocessors and FPGAs without recalibration. |
| Switching Frequency | 250kHz to 550kHz, phase-lockable - enables EMI reduction via synchronization and optimal trade-off between efficiency and component size. |
| Peak Gate Drive Current | 3A per TG/BG driver - drives large N-channel MOSFETs with fast switching (55ns TG rise time) to minimize conduction and switching losses. |
| Feedback Reference Voltage | 0.800V ±0.008V - low-voltage reference compatible with modern sub-1V logic and high-precision point-of-load regulation. |
| Shutdown Quiescent Current | 20µA - enables ultra-low-power standby in battery-operated systems without compromising startup responsiveness. |
| Power Good Threshold | ±7.5% on both VOSENSE1/VOSENSE2 - provides reliable system-level power sequencing and fault detection for dual-rail supplies. |
Pinout & Package
Package: 28-Lead Narrow Plastic SSOP (GN), –40°C to +85°C operating range. Exposed pad not present; SGND is internal signal ground referenced to pin 9.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS1, RUN/SS2 | Soft-start & short-circuit timer control | Capacitor-based ramp controls inrush current; falling below 1.0V shuts down respective channel; discharge current triggers latchoff during sustained overcurrent. |
| SENSE1+/SENSE1–, SENSE2+/SENSE2– | Differential current sense inputs | Measure voltage across RSENSE to set peak inductor current limit; total source current ≤ –60µA ensures minimal offset error. |
| VOSENSE1, VOSENSE2 | Remote feedback inputs | Connect to resistor divider at output; ±1% 0.8V reference enables precise regulation even with PCB trace resistance. |
| TG1, TG2 | Top N-MOSFET gate drivers | Floating drivers with 55ns rise time; swing = INTVCC – 0.5V above SW node - supports high-side drive in buck topology. |
| BG1, BG2 | Bottom N-MOSFET gate drivers | Ground-referenced drivers with 45ns rise time; swing = 0V to INTVCC - enables synchronous rectification for >95% efficiency. |
| PGOOD | Open-drain power-good indicator | Pulled low if either output deviates >±7.5%; enables safe processor reset or system enable sequencing. |
| FCB | Operating mode selector | Voltage <0.8V forces continuous PWM; 0.8V–(INTVCC–2V) enables Burst Mode®; tied to INTVCC disables burst for constant-frequency operation. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP™ Compensation | Minimizes output capacitor ESR dependency - allows stable operation with ceramic, polymer, or mixed-capacitor banks without redesign. |
| 180° Dual-Phase Operation | Reduces RMS input ripple current by ~70% - cuts required input capacitance and lowers EMI filter size/cost in compact layouts. |
| Integrated 3.3V Linear Regulator | 10mA DC / 50mA peak output - powers auxiliary circuitry (e.g., ADC references, level shifters) without external LDO. |
| Programmable Frequency via PLLFLTR | DC voltage (0–2.4V) sets oscillator from 260kHz to 550kHz - enables fine-tuning for efficiency vs. size vs. noise trade-offs. |
| Dropout Detection & Recovery | Forces 400ns top-FET off every 10th cycle when VIN ≈ VOUT - maintains bootstrap capacitor charge and prevents loss of regulation near dropout. |
| Output Overvoltage Protection | Latches bottom MOSFET on until VOSENSE returns within ±7.5% - protects downstream loads from transient overshoot or feedback failure. |
Applications
| Notebook Computer Power Supply | Telecom Line Card DC/DC |
|---|---|
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 two independent output rails with coordinated phasing. Use Value: 180° phasing cuts input capacitor count by 50% and reduces conducted EMI, enabling thinner chassis designs. |
Use Scenario: Point-of-load regulation for FPGA, DSP, and SerDes on telecom line cards with strict thermal limits. IC Role / Device Role / Timing Role: High-efficiency, thermally optimized dual-channel controller delivering [email protected] and [email protected] from 48V intermediate bus. Use Value: OPTI-LOOP™ ensures stability across wide temperature and load transients; PGOOD enables hot-swap sequencing. |
| Portable Test Instrumentation | Battery-Powered Industrial Controller |
Use Scenario: Precision analog supply generation (±5V, +3.3V) in handheld multimeters and oscilloscopes. IC Role / Device Role / Timing Role: Dual-output controller with low-noise Burst Mode® operation for extended battery life during idle periods. Use Value: 20µA shutdown IQ and programmable low-power modes extend runtime; 0.8V reference supports accurate DAC/ADC biasing. |
Use Scenario: Robust 5V/3.3V power for ARM Cortex-M7 MCU, CAN transceivers, and isolated I/O in field-deployed controllers. IC Role / Device Role / Timing Role: Fault-tolerant dual-controller with overvoltage latching, short-circuit latchoff, and –40°C to +85°C operation. Use Value: Integrated protection eliminates need for external supervisors; wide VIN handles automotive cold-crank (4.5V) and load-dump (28V) events. |
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 |
|---|---|---|---|
| MP2918GL-Z | Single-chip dual-phase controller with integrated MOSFET drivers only; no 3.3V LDO; max fSW = 1MHz; requires external current sense resistors. | Lacks integrated 3.3V regulator and PLL sync capability; better suited for space-constrained, high-frequency designs where auxiliary rail is externally supplied. | Select MP2918GL-Z when board area is critical and 3.3V rail is available elsewhere; verify external sense resistor layout for accuracy. |
| ISL95836IRZ-T7A | Intel VR12.5-compliant dual-phase controller; supports DVID, SVID interface; no integrated 3.3V LDO; higher pin count (40-QFN); wider temp grade (–40°C to +125°C). | Designed for CPU VR applications with dynamic voltage identification; lacks Burst Mode® and OPTI-LOOP™; requires PMBus host. | Choose ISL95836IRZ-T7A only for Intel-compatible CPU power delivery; not suitable for generic dual-rail embedded use. |
Compared with MP2918GL-Z and ISL95836IRZ-T7A, the LTC3728LIGN#TRPBF uniquely combines dual-phase control, integrated 3.3V LDO, PLL synchronization, and Burst Mode® in a compact SSOP package - making it optimal for cost-sensitive, thermally constrained, and multi-rail embedded systems without CPU-specific protocols.
Availability
LTC3728LIGN#TRPBF is available at Aetrix Electronics and suitable for notebook computers, telecom line cards, portable instrumentation, and battery-powered industrial controllers requiring stable component supply, long-term lifecycle support, and guaranteed −40°C to +85°C operation.
Supply support for LTC3728LIGN#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, acquired Linear Technology in 2017 to strengthen its power management portfolio.
The LTC3728LIGN#TRPBF belongs to ADI's legacy Linear Technology high-efficiency DC/DC controller family, designed specifically for dual-phase, low-noise, high-current point-of-load regulation in space- and thermal-constrained portable and industrial systems.
FAQ
What is the operating temperature range for the LTC3728LIGN#TRPBF?
The LTC3728LIGN#TRPBF is rated for –40°C to +85°C ambient operation, as confirmed by its "I" grade suffix and GN package specification. This makes it suitable for industrial and automotive under-hood applications where extended temperature performance is required. The device's thermal shutdown and current-limiting protections remain fully functional across this full range.
Does the LTC3728LIGN#TRPBF support external frequency synchronization?
Yes, the LTC3728LIGN#TRPBF supports external synchronization via the PLLIN pin, which accepts a TTL/CMOS clock input. The internal phase-locked loop aligns the rising edge of TG1 to the rising edge of the PLLIN signal. When PLLIN is left open, the oscillator defaults to minimum frequency (≈260kHz) via internal pull-down on PLLFLTR.
How does the FCB pin affect operating mode selection in the LTC3728LIGN#TRPBF?
The FCB pin selects among three distinct operating modes: (1) <0.8V → forced continuous PWM, (2) 0.8V to (INTVCC – 2V) → Burst Mode®, (3) tied to INTVCC → constant-frequency discontinuous mode. This single-pin control enables dynamic efficiency optimization without firmware or external logic, directly influencing light-load efficiency and output ripple.
Can the LTC3728LIGN#TRPBF drive both high-side and low-side N-channel MOSFETs?
Yes, the LTC3728LIGN#TRPBF integrates dual high-current floating drivers (TG1/TG2) for high-side N-MOSFETs and ground-referenced drivers (BG1/BG2) for low-side N-MOSFETs. Each TG driver delivers 3A peak current with 55ns rise time, while each BG driver provides 3A peak with 45ns rise time - enabling fully synchronous buck operation with minimal dead-time loss.
What protection features are built into the LTC3728LIGN#TRPBF?
The LTC3728LIGN#TRPBF includes output overvoltage latching (via OV comparator), foldback current limiting during short-circuit conditions, RUN/SS-based timed short-circuit latchoff, undervoltage lockout (UVLO = 3.5V), and thermal shutdown. Its PGOOD pin provides system-level fault indication when either output deviates >±7.5% - enabling robust, autonomous power system supervision.
LTC3728LIGN#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 ~ 28V
- 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#TRPBF FAQ
1.How can I place an order for LTC3728LIGN#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3728LIGN#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#TRPBF reliable?
The price and inventory of LTC3728LIGN#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#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3728LIGN#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3728LIGN#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3728LIGN#TRPBF?
LTC3728LIGN#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3728LIGN#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#TRPBF?
For technical support, including LTC3728LIGN#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3728LIGN#TRPBF requirements.
6.How does Aetrix verify that LTC3728LIGN#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3728LIGN#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#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3728LIGN#TRPBF?
All LTC3728LIGN#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3728LIGN#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#TRPBF part is unused and in its original packaging.
Return procedure for LTC3728LIGN#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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