My Inquiry
My Account
Analog Devices Inc. LTC3728IG#TRPBF
- Part No.:
- LTC3728IG#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC3728IG#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,199
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3728IG#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–30V 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 power supplies for notebook computers and telecom systems.
For engineers reviewing the LTC3728IG#TRPBF datasheet, LTC3728IG#TRPBF pinout, LTC3728IG#TRPBF application, or LTC3728IG#TRPBF equivalent, key selection considerations include its dual 180°-phased architecture for reduced input ripple, FCB-selectable operating modes (Burst Mode®, constant-frequency PWM, forced continuous), integrated 3.3V LDO, PGOOD monitoring, and robust overvoltage/short-circuit protection with latchoff and foldback.
Technical Context
The LTC3728IG#TRPBF implements a dual-channel, constant-frequency current-mode control architecture with independent error amplifiers (ITH1/ITH2), differential current sense inputs (SENSE1±/SENSE2±), and phase-locked oscillator enabling synchronization to external clock (PLLIN) or DC voltage (PLLFLTR). Each channel features dedicated RUN/SS pins for soft-start and timed short-circuit shutdown, plus independent VOSENSE feedback with ±7.5% PGOOD threshold.
It integrates an internal 5V INTVCC LDO and external EXTVCC switchover (4.7V threshold), a dedicated 3.3V linear regulator (10mA DC, 50mA peak), and dual high-current gate drivers (TG/BG) with 90ns max transition times. Output overvoltage protection latches the bottom MOSFET until recovery, while dropout detection enables 99.4% duty cycle operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 30V (36V absolute max) - supports wide battery chemistries and industrial DC rails. |
| Output Voltage Accuracy | ±1% at 0.8V reference - ensures tight regulation for modern microprocessor core supplies. |
| Switching Frequency | 250kHz to 550kHz, phase-lockable - enables EMI reduction via synchronization and input capacitor optimization. |
| Phase Configuration | 180° out-of-phase dual controllers - cuts RMS input ripple by ~70% vs. single-phase, reducing CIN size and cost. |
| Operating Modes | Burst Mode®, constant-frequency PWM, forced continuous - selectable via FCB pin for efficiency vs. noise trade-offs. |
| Integrated LDOs | 5V INTVCC (50mA peak) + 3.3V (10mA DC, 50mA peak) - powers internal circuitry and auxiliary loads without external regulators. |
| Protection Features | Output overvoltage latch, current foldback, RUN/SS-based short-circuit timeout, UVLO (3.5V), PGOOD (±7.5%) - enables robust system-level fault management. |
Pinout & Package
Package: 28-Lead Plastic SSOP (G package), –40°C to +85°C operating temperature range. Exposed pad connected to SGND for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS1, RUN/SS2 (Pins 1, 15) | Soft-start & short-circuit timer control | Capacitor-based ramp sets current slew rate; falling below 1.0V disables respective controller; enables timed latchoff during sustained overcurrent. |
| SENSE1+, SENSE2+ / SENSE1–, SENSE2– (Pins 2,14 / 3,13) | Differential current sense inputs | Measure RSENSE voltage drop to set peak inductor current limit; support accurate current-mode control and foldback. |
| VOSENSE1, VOSENSE2 (Pins 4, 12) | Remote output voltage feedback | Accepts resistive divider signal for precision regulation; referenced to 0.8V internal bandgap; enables remote sensing compensation. |
| FCB (Pin 7) | Mode selection & secondary winding control | Voltage <0.8V forces continuous PWM; 0.8–(INTVCC–1)V enables Burst Mode®; >INTVCC–1V disables Burst Mode for constant-frequency operation. |
| ITH1, ITH2 (Pins 8, 11) | Error amplifier output & compensation node | Controls peak current threshold per channel; interface for OPTI-LOOP compensation network (RC/CC). |
| TG1, TG2 / BG1, BG2 (Pins 27,16 / 23,19) | Top/bottom N-MOSFET gate drivers | Drive external high-side and low-side switches; TG swing = INTVCC–0.5V superimposed on SW node; BG swing = GND to INTVCC. |
| PGOOD (Pin 28) | Open-drain power-good indicator | Pulled low if either VOSENSE deviates >±7.5% from setpoint; enables system sequencing and fault reporting. |
| 3.3VOUT (Pin 10) | Integrated linear regulator output | Provides regulated 3.3V at 10mA DC (50mA peak); eliminates need for external 3.3V supply in dual-rail designs. |
Key Features
| Feature | Design Value |
|---|---|
| 180° dual-phase operation | Reduces input capacitor RMS current by ~70%, enabling smaller, lower-cost CIN and lower EMI without shielding. |
| OPTI-LOOP compensation | Allows stable loop response across wide ranges of output capacitance (e.g., ceramic + polymer) and ESR without redesign. |
| Three selectable operating modes | Burst Mode® (high light-load efficiency), constant-frequency PWM (low-noise), forced continuous (secondary winding regulation). |
| Integrated 3.3V LDO | Supplies auxiliary circuitry (e.g., level shifters, logic) directly - eliminates discrete regulator and saves board space. |
| Robust protection suite | Includes output overvoltage latch, current foldback, RUN/SS-based short-circuit timeout, and UVLO - reduces external protection components. |
Applications
| High-Efficiency Notebook Power Supply | Telecom DC/DC Distribution |
|---|---|
Use Scenario: Dual-rail 5V/3.3V conversion from 12V or 19V adapter in ultra-thin notebooks with strict thermal and EMI limits. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing two independent output rails with interleaved switching to minimize input ripple and heat. Use Value: 180° phasing cuts input capacitor RMS current by ~70%, allowing smaller 22μF input vs. 100μF single-phase - saving PCB area and cost. | Use Scenario: Point-of-load regulation in telecom line cards requiring stable 5V and 3.3V rails from 48V backplane with burst-mode efficiency at standby. IC Role / Device Role / Timing Role: Dual-channel controller with Burst Mode® operation enabling <20μA shutdown IQ and high efficiency down to 1% load. Use Value: Burst Mode® reduces no-load power dissipation by >5× vs. constant-frequency mode - critical for energy-efficient telecom systems. |
| Portable Instrument Dual-Rail Supply | Battery-Powered Digital System |
Use Scenario: Powering mixed-signal FPGA + ADC/DAC subsystems in handheld test equipment using Li-ion (8.4V–12.6V) input. IC Role / Device Role / Timing Role: Dual-phase controller delivering tightly regulated 5V (digital) and 3.3V (analog) outputs with remote sensing and PGOOD sequencing. Use Value: ±1% output accuracy and 0.8V reference ensure precise ADC reference stability and FPGA core voltage compliance. | Use Scenario: Power management in ruggedized portable data loggers using 3S LiPo (9–12.6V) with extended runtime requirements. IC Role / Device Role / Timing Role: Controller with 99.4% max duty cycle and wide 3.5V–30V input range supporting deep battery discharge without dropout. Use Value: Very low dropout operation extends usable battery life by >12% compared to controllers limited to 95% duty cycle. |
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 |
|---|---|---|---|
| LTC3728EUH#TRPBF | Same die, 32-pin 5mm × 5mm QFN package; θJA = 68°C/W (4-layer) vs. 90°C/W (SSOP); exposed pad soldered to SGND. | Better thermal performance in space-constrained layouts; requires different PCB footprint and reflow profile. | Select for higher power density or improved thermal management; not pin-compatible with LTC3728IG#TRPBF. |
| MP8765GL-Z | Dual-phase controller with integrated MOSFETs (60V max VIN); fixed 500kHz freq; no PLLIN sync; no 3.3V LDO; lower IQ (15μA shutdown). | Targeted at cost-sensitive, lower-power applications (<10A per rail); lacks remote sensing and multi-mode flexibility. | Choose when board space is critical and integrated FETs acceptable; not functionally equivalent due to missing features (PLL, 3.3V LDO, OPTI-LOOP). |
Compared with LTC3728IG#TRPBF, the LTC3728EUH#TRPBF offers superior thermal resistance in QFN packaging but requires layout revision, while the MP8765GL-Z trades feature richness (no PLL, no 3.3V LDO, no OPTI-LOOP) for integration and lower cost - making LTC3728IG#TRPBF optimal for high-performance, flexible, and thermally managed dual-rail designs.
Availability
LTC3728IG#TRPBF is available at Aetrix Electronics and suitable for notebook computing, telecom DC distribution, and portable instrumentation requiring stable component supply, long-term lifecycle support, and guaranteed –40°C to +85°C operation.
Supply support for LTC3728IG#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 power management semiconductors, formed through the acquisition of Linear Technology in 2017.
The LTC3728IG#TRPBF belongs to ADI's high-efficiency power controller product line, designed specifically for dual-phase synchronous buck topologies in space- and thermally-constrained applications demanding precision regulation, low EMI, and robust protection.
FAQ
What is the maximum duty cycle supported by the LTC3728IG#TRPBF?
The LTC3728IG#TRPBF supports a maximum duty cycle of 99.4%, enabling very low dropout operation essential for battery-powered systems where input voltage may sag close to the output level. This capability is implemented via internal dropout detection that forces periodic top-FET off-time to recharge the bootstrap capacitor, ensuring reliable gate drive even at extreme VIN/VOUT ratios.
Does the LTC3728IG#TRPBF require external MOSFETs?
Yes, the LTC3728IG#TRPBF is a controller-only IC and requires external N-channel MOSFETs for both high-side (top) and low-side (bottom) switching positions. It provides dedicated TG and BG gate drivers with specified rise/fall times (≤90ns) and peak current capability (3A), optimized for driving discrete power FETs in synchronous buck configurations.
How does the FCB pin affect operating mode selection in the LTC3728IG#TRPBF?
The FCB pin on the LTC3728IG#TRPBF selects among three distinct operating modes: pulling FCB <0.8V forces continuous PWM; holding FCB between 0.8V and (INTVCC–1)V enables Burst Mode® for high light-load efficiency; tying FCB to INTVCC disables Burst Mode® for constant-frequency operation. This pin also supports secondary winding regulation by forcing synchronous operation across both channels.
What is the purpose of the RUN/SS pins on the LTC3728IG#TRPBF?
The RUN/SS1 and RUN/SS2 pins on the LTC3728IG#TRPBF serve dual functions: soft-start control via external capacitor ramping, and timed short-circuit shutdown. During startup, CSS charging controls current slew rate; during fault conditions, if VOSENSE drops below 70% of nominal, the RUN/SS capacitor discharges to trigger latchoff - configurable via pull-up current to defeat latching.
Can the LTC3728IG#TRPBF synchronize to an external clock source?
Yes, the LTC3728IG#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, enabling precise frequency and phase alignment across multiple converters to reduce beat frequencies and system-level EMI.
LTC3728IG#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
LTC3728IG#TRPBF FAQ
1.How can I place an order for LTC3728IG#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3728IG#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 LTC3728IG#TRPBF reliable?
The price and inventory of LTC3728IG#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3728IG#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3728IG#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3728IG#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3728IG#TRPBF?
LTC3728IG#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3728IG#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 LTC3728IG#TRPBF?
For technical support, including LTC3728IG#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3728IG#TRPBF requirements.
6.How does Aetrix verify that LTC3728IG#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3728IG#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 LTC3728IG#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3728IG#TRPBF?
All LTC3728IG#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3728IG#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 LTC3728IG#TRPBF part is unused and in its original packaging.
Return procedure for LTC3728IG#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3728IG#TRPBF Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
