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Analog Devices Inc. LTC3728LCUH#TRPBF
- Part No.:
- LTC3728LCUH#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC3728LCUH#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,063
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Product details
Overview
LTC3728LCUH#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 offset, delivers ±1% output voltage accuracy at 0.8 V reference, supports 4.5–28 V input, and integrates 5 V/3.3 V auxiliary regulators - used in high-efficiency notebook CPU core power supplies.
For engineers reviewing the LTC3728LCUH#TRPBF datasheet, LTC3728LCUH#TRPBF pinout, LTC3728LCUH#TRPBF application, or LTC3728LCUH#TRPBF equivalent, key selection criteria include dual-phase interleaving for reduced input ripple, OPTI-LOOP compensation adaptability to diverse output capacitors, FCB-selectable operating modes (Burst Mode®, constant-frequency PWM, forced continuous), and integrated overvoltage/short-circuit protection with latchoff.
Technical Context
The LTC3728LCUH#TRPBF implements a dual-channel, current-mode control architecture with independent error amplifiers (ITH1/ITH2), differential current sense inputs (SENSE1±/SENSE2±), and phase-locked oscillator enabling synchronization across channels or to external clocks via PLLIN. Each channel features dedicated RUN/SS pins for soft-start ramping and timed short-circuit shutdown.
It integrates an internal 5 V LDO (INTVCC) with EXTVCC switchover capability, a standalone 3.3 V linear regulator (3.3VOUT), and open-drain PGOOD indicating both outputs are within ±7.5% of setpoint. Output overvoltage protection latches the bottom MOSFET until VOSENSE returns to regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Frequency | 250–550 kHz, adjustable via PLLFLTR voltage or external sync on PLLIN - enables EMI reduction and input capacitor size optimization. |
| Output Voltage Accuracy | ±1% over temperature (LTC3728LC grade) - ensures stable core voltage for modern microprocessors. |
| Input Voltage Range | 4.5 V to 28 V (30 V absolute max) - supports wide battery chemistries and industrial DC rails. |
| Reference Voltage | 0.800 V ±1%, precision trimmed - sets output via external resistor divider with minimal drift. |
| Shutdown Quiescent Current | 20 µA - enables ultra-low-power system standby without external disable circuitry. |
| PGOOD Threshold | ±7.5% window around regulated output - provides reliable power sequencing feedback for host processors. |
| Max Duty Cycle | 99.4% - supports high VIN-to-VOUT conversion ratios and low-dropout operation. |
| Current Sense Threshold | 65–88 mV (adjustable via ITH voltage) - enables accurate current limiting with low-value RSENSE for minimal power loss. |
Pinout & Package
Package: 32-lead (5 mm × 5 mm) plastic QFN with exposed SGND pad (UH package). Thermal resistance θJA = 34°C/W. Exposed pad must be soldered to PCB and connected to SGND.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS1, RUN/SS2 | Soft-start & short-circuit timer input | Capacitor-to-ground sets ramp time; falling below 1.0 V disables respective channel; discharge current triggers latchoff during sustained overcurrent. |
| VOSENSE1, VOSENSE2 | Error amplifier feedback input | Connects to resistive divider across output - compares actual VOUT to 0.8 V reference for regulation. |
| SENSE1+, SENSE1−, SENSE2+, SENSE2− | Differential current sense inputs | Measure voltage across RSENSE to regulate peak inductor current; reject common-mode noise up to 5 V. |
| TG1, TG2 | Top N-MOSFET gate driver outputs | Floating drivers with swing = INTVCC − 0.5 V referenced to SW node - drive high-side switches in synchronous buck topology. |
| BG1, BG2 | Bottom N-MOSFET gate driver outputs | Ground-referenced drivers (0 to INTVCC) - enable synchronous rectification for high efficiency. |
| SW1, SW2 | Switch node connections | Connect to inductor and source of top MOSFET - voltage swings from Schottky drop below GND to VIN. |
| BOOST1, BOOST2 | Bootstrap supply terminals | Capacitors between BOOST and SW provide floating bias for TG drivers - critical for high-side N-MOSFET operation. |
| FCB | Forced continuous/burst mode select | Voltage < 0.8 V forces continuous conduction; 0.8–(INTVCC−2) V enables Burst Mode®; >4.3 V disables burst (constant-frequency). |
| PGOOD | Open-drain power-good indicator | Pulled low if either VOSENSE deviates >±7.5% - used for system power sequencing and fault reporting. |
| 3.3VOUT | Integrated linear regulator output | Supplies 10 mA DC (50 mA peak) - powers auxiliary circuitry without external LDO. |
| INTVCC | Internal 5 V LDO output | Power source for logic and drivers; bypassed by EXTVCC > 4.7 V - improves efficiency when powered from regulated output. |
| SGND | Small-signal ground | Must be routed separately from PGND to minimize noise coupling into sensitive analog blocks (error amps, references). |
| PGND | Power ground | Return path for bottom MOSFET sources, Schottky cathodes, and CIN - connects to exposed pad in UH package. |
Key Features
| Feature | Design Value |
|---|---|
| 180° dual-phase interleaving | Halves input ripple current vs single-phase design - reduces required CIN by ~70% and eases EMI filtering. |
| OPTI-LOOP® compensation | Allows stable loop response across wide range of ceramic output capacitor values and ESR - eliminates need for electrolytic bulk caps. |
| Three selectable operating modes | Burst Mode® (high light-load efficiency), constant-frequency (low-noise), forced continuous (output sink capability) - selected via FCB pin voltage. |
| Integrated 3.3 V linear regulator | Delivers 10 mA with ±2% load regulation - powers monitoring ICs or level shifters without external regulator. |
| Output overvoltage protection | Latches bottom MOSFET on until VOSENSE recovers - prevents damage to downstream loads during transient events. |
| Programmable short-circuit latchoff | Uses RUN/SS capacitor time constant to detect sustained overcurrent - configurable disable via external pull-up current. |
Applications
| Notebook CPU Core Power | Telecom DC/DC Distribution |
|---|---|
|
Use Scenario: Dual-output 5 V/3.3 V power for Intel/AMD processor cores and I/O rails in ultraportable notebooks. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing high-current, low-voltage regulation with tight transient response. Use Value: 180° phase offset cuts input RMS current by 30%, reducing thermal stress on input capacitors and PCB traces. |
Use Scenario: High-efficiency intermediate bus converter in 48 V telecom systems powering multiple point-of-load regulators. IC Role / Device Role / Timing Role: Primary controller generating stable 12 V or 5 V intermediate rail with precise tracking and sequencing. Use Value: ±1% output accuracy and PGOOD signaling ensure reliable startup and fault isolation in redundant power architectures. |
| Battery-Powered Test Equipment | Industrial Embedded Control |
|
Use Scenario: Portable oscilloscopes and logic analyzers requiring clean, low-noise 3.3 V and 1.2 V rails from Li-ion battery input. IC Role / Device Role / Timing Role: Dual-channel controller with Burst Mode® for extended battery life and constant-frequency mode for low-noise analog sections. Use Value: 20 µA shutdown current and programmable soft-start minimize inrush - critical for hot-plug battery operation. |
Use Scenario: DIN-rail mounted PLC modules needing robust 5 V and 3.3 V supplies tolerant of 24 V industrial bus transients. IC Role / Device Role / Timing Role: Controller with wide 4.5–28 V input range, overvoltage protection, and latchoff-enabled short-circuit resilience. Use Value: Integrated 3.3VOUT and EXTVCC switchover allow self-powered operation - eliminating auxiliary supply components. |
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 and PMBus interface; fixed 500 kHz frequency; no PLL sync or FCB mode selection. | Targets digital power systems requiring telemetry and dynamic margining; lacks analog mode flexibility of LTC3728LCUH#TRPBF. | Choose MP2918GL-Z when digital control and telemetry outweigh need for analog burst/continuous mode tuning. |
| ISL95836IRZ | Intel VR12.5-compliant dual-phase controller; supports DVID, PROCHOT#, and adaptive voltage positioning; no integrated 3.3 V LDO. | Designed specifically for mobile CPU VR applications with strict Intel compliance requirements; not suitable for generic dual-rail designs. | Choose ISL95836IRZ only for Intel platform designs requiring VR12.5 compliance and dynamic voltage ID support. |
Compared with MP2918GL-Z and ISL95836IRZ, the LTC3728LCUH#TRPBF offers unmatched analog configurability (PLL sync, FCB-selectable modes, OPTI-LOOP), integrated auxiliary regulators, and broad industrial input range - making it ideal for non-Intel, mixed-signal, or cost-sensitive dual-rail systems where digital interface is unnecessary.
Availability
LTC3728LCUH#TRPBF is available at Aetrix Electronics and suitable for notebook computing, telecom power distribution, and portable instrumentation requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LTC3728LCUH#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LTC3728L/LTC3728LX product line was designed for high-efficiency, dual-phase synchronous buck regulation in space-constrained, thermally demanding applications such as portable computing and telecom infrastructure.
FAQ
What is the operating temperature range for the LTC3728LCUH#TRPBF?
The LTC3728LCUH#TRPBF is rated for 0°C to +85°C ambient operation. This corresponds to the "C" grade variant in the LTC3728L family, confirmed by the part marking "3728L" on the UH package and order information table specifying 0°C to 85°C for LTC3728LCUH#TRPBF. Junction temperature must not exceed 125°C under all conditions.
Does the LTC3728LCUH#TRPBF support external frequency synchronization?
Yes, the LTC3728LCUH#TRPBF supports external synchronization via the PLLIN pin. The internal phase-locked loop aligns the rising edge of TG1 to the rising edge of the external clock applied to PLLIN. The PLLFLTR pin serves as both the phase detector output and DC frequency control input, allowing frequency adjustment from 260 kHz to 550 kHz using a DC voltage (0–2.4 V).
How does the FCB pin affect operating mode selection in the LTC3728LCUH#TRPBF?
The FCB pin selects among three distinct operating modes: pulling FCB < 0.8 V forces continuous conduction mode; setting FCB between 0.8 V and (INTVCC − 2 V) enables Burst Mode® operation for high light-load efficiency; tying FCB > 4.3 V disables burst and enforces constant-frequency discontinuous conduction mode. All modes apply identically to both controller channels.
What protection features are integrated into the LTC3728LCUH#TRPBF?
The LTC3728LCUH#TRPBF integrates output overvoltage protection (latching bottom MOSFET until VOSENSE recovers), foldback current limiting during output shorts, programmable short-circuit latchoff using RUN/SS capacitor timing, undervoltage lockout (3.5–4.0 V), and thermal shutdown. PGOOD provides system-level fault indication when either output deviates >±7.5%.
Can the LTC3728LCUH#TRPBF drive MOSFETs directly without external gate drivers?
Yes, the LTC3728LCUH#TRPBF integrates high-current gate drivers: TG1/TG2 (top-side, floating) and BG1/BG2 (bottom-side, ground-referenced) deliver sufficient peak current (3 A) and transition speed (55–100 ns) to directly drive standard N-channel MOSFETs in typical 5–10 A applications. External drivers are only needed for very high-current or high-speed designs beyond its native capability.
LTC3728LCUH#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 32-WFQFN Exposed Pad
- 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:
- 0°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
LTC3728LCUH#TRPBF FAQ
1.How can I place an order for LTC3728LCUH#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3728LCUH#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 LTC3728LCUH#TRPBF reliable?
The price and inventory of LTC3728LCUH#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3728LCUH#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3728LCUH#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3728LCUH#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3728LCUH#TRPBF?
LTC3728LCUH#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3728LCUH#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 LTC3728LCUH#TRPBF?
For technical support, including LTC3728LCUH#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3728LCUH#TRPBF requirements.
6.How does Aetrix verify that LTC3728LCUH#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3728LCUH#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 LTC3728LCUH#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3728LCUH#TRPBF?
All LTC3728LCUH#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3728LCUH#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 LTC3728LCUH#TRPBF part is unused and in its original packaging.
Return procedure for LTC3728LCUH#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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