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Analog Devices Inc. LTC3728IUH#TRPBF
- Part No.:
- LTC3728IUH#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC3728IUH#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,710
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Product details
Overview
LTC3728IUH#TRPBF from Analog Devices (formerly Linear Technology) is a dual-phase, 550kHz synchronous step-down switching regulator controller driving two independent N-channel MOSFET stages in 180° out-of-phase operation. It features ±1% output voltage accuracy, 0.8V reference, power good indicator, and supports input voltages from 3.5V to 36V - enabling use in notebook computers, telecom DC distribution, and battery-powered digital systems.
For engineers reviewing the LTC3728IUH#TRPBF datasheet, LTC3728IUH#TRPBF pinout, LTC3728IUH#TRPBF application, or LTC3728IUH#TRPBF equivalent, key selection considerations include dual-phase current-mode control, OPTI-LOOP® compensation for wide output capacitance/ESR tolerance, phase-lockable 250–550kHz frequency range, and integrated 3.3V LDO output delivering up to 10mA.
Technical Context
The LTC3728IUH#TRPBF implements constant-frequency current-mode control with two independent error amplifiers (ITH1/ITH2), differential current sense inputs (SENSE1±/SENSE2±), and dual 180° phased PWM generators synchronized via internal PLL or external PLLIN. Its architecture minimizes input ripple by interleaving phases and enables dropout operation down to 99% duty cycle.
It integrates a 5V INTVCC LDO (4.8–5.2V), a 3.3V linear regulator (3.25–3.45V, 10mA), and protection features including output overvoltage latch (VOSENSE > 0.84V), foldback current limiting, and RUN/SS-based short-circuit shutdown with defeatable latchoff - all operating across –40°C to +85°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Dual-phase synchronous buck controller - drives external high-side and low-side N-MOSFETs per channel. |
| Switching Frequency | 250kHz to 550kHz, phase-lockable via PLLIN or adjustable via PLLFLTR voltage (0–2.4V). |
| Input Voltage Range | 3.5V to 36V - supports 12V/24V industrial rails and multi-cell Li-ion, LiPo, or lead-acid batteries. |
| Output Voltage Accuracy | ±1% over line, load, and temperature - ensures stable regulation for microprocessor core and I/O supplies. |
| Reference Voltage | 0.800V ±0.008V - precision feedback threshold compatible with future low-voltage ASICs and FPGAs. |
| Power Good Threshold | ±7.5% of set output voltage on both channels - open-drain PGOOD asserts low if either output deviates beyond tolerance. |
| Shutdown Quiescent Current | 20μA - enables ultra-low-power standby in portable and always-on embedded systems. |
Pinout & Package
Package: 32-lead (5mm × 5mm) plastic QFN with exposed pad (SGND). Thermal performance requires soldering exposed pad to PCB ground plane.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOSENSE1 / VOSENSE2 | Remote feedback input (per channel) | Accepts resistive divider output from regulated rail; enables accurate remote sensing at load point. |
| SENSE1+ / SENSE1− / SENSE2+ / SENSE2− | Differential current sense inputs | Measure voltage across RSENSE to regulate peak inductor current; supports high common-mode rejection. |
| TG1 / TG2 / BG1 / BG2 | Gate drivers (top/bottom N-MOS) | High-current (3A peak) drivers with controlled transition times (50–90ns); TG floats with SW node. |
| RUN/SS1 / RUN/SS2 | Soft-start & short-circuit timer | Capacitor-based ramp controls startup current; also triggers timed latchoff during sustained overcurrent. |
| FCB | Mode select (Burst/Continuous/Fixed-freq) | Voltage-controlled selection: <0.8V = forced continuous; 0.8–(INTVCC−1V) = Burst Mode; >4.3V = constant-frequency. |
| PGOOD | Open-drain status output | Asserts low when either VOSENSE deviates >±7.5%; requires external pull-up to ≤7V. |
| 3.3VOUT | Integrated linear regulator output | Provides 3.3V @ 10mA (50mA peak); powers auxiliary circuitry without external LDO. |
| PLLIN / PLLFLTR | Phase-locked loop interface | PLLIN accepts external sync clock; PLLFLTR sets oscillator frequency or receives phase detector output. |
Key Features
| Feature | Design Value |
|---|---|
| OPTI-LOOP® compensation | Enables stable loop response across wide COUT/ESR variations - eliminates need for custom compensation per output cap. |
| 180° dual-phase interleaving | Reduces RMS input ripple by ~70% vs single-phase - cuts required input capacitance and EMI filtering cost. |
| Three selectable operating modes | Burst Mode (high efficiency at light load), constant-frequency (low noise), or forced continuous (PWM for reverse current). |
| Integrated 3.3V LDO | Eliminates external bias rail for level shifters, logic, or monitoring ICs - saves board space and BOM count. |
| Output overvoltage protection | Latches bottom MOSFET on until VOSENSE returns within 7.5% - prevents damage to downstream loads during transients. |
| Low dropout operation | Supports 99% duty cycle - maintains regulation even when VIN approaches VOUT (e.g., 5.5V → 5V). |
Applications
| High-Efficiency Notebook Power | Telecom DC Distribution |
|---|---|
|
Use Scenario: Dual-rail power supply generating 5V@5A and 3.3V@5A from 12V or 24V intermediate bus in thin-and-light notebooks. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing interleaved switching, current sharing, and precise voltage tracking. Use Value: 180° phase shift halves input capacitor RMS current - enabling smaller, lower-cost ceramic input caps and reducing EMI filter size. |
Use Scenario: Redundant 48V-to-12V/5V conversion in telecom shelf power modules with strict thermal and efficiency targets. IC Role / Device Role / Timing Role: High-voltage input controller supporting 36V max VIN, driving discrete MOSFETs optimized for low RDS(on) and fast switching. Use Value: Wide 3.5–36V input range accommodates brownout and surge conditions; ±1% accuracy ensures compliance with ITU-T LPS requirements. |
| Battery-Powered Test Equipment | Industrial Embedded Systems |
|
Use Scenario: Portable oscilloscope or multimeter using Li-ion battery (8.4–12.6V) to power analog front-end (±5V) and digital logic (3.3V). IC Role / Device Role / Timing Role: Dual-output controller with independent soft-start (RUN/SS pins) and power-good sequencing for safe system boot. Use Value: 20μA shutdown IQ extends battery runtime in sleep mode; integrated 3.3V LDO powers ADC references and MCU peripherals. |
Use Scenario: DIN-rail mounted PLC I/O module requiring isolated 5V and 3.3V rails from unregulated 24VDC field supply. IC Role / Device Role / Timing Role: Robust controller with overvoltage protection, foldback current limiting, and –40°C to +85°C guaranteed operation. Use Value: Output OVP latches bottom FET during transient overvoltage - protects sensitive FPGA and Ethernet PHY interfaces. |
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 |
|---|---|---|---|
| MP8765GL-Z | Single-chip dual-phase controller with integrated MOSFETs (40V max VIN); no external gate drivers or 3.3V LDO. | Lower component count but limited to ≤40V input and fixed 500kHz freq; unsuitable for >36V or programmable frequency needs. | Select MP8765GL-Z only when board space is critical and input voltage stays below 40V - LTC3728IUH#TRPBF offers higher flexibility and ruggedness. |
| LTC3855EUFD#PBF | Single-phase controller with similar 3.5–36V range, OPTI-LOOP, and 3.3V LDO - lacks dual-phase interleaving and PGOOD for dual outputs. | Requires two separate controllers for dual-rail designs; no inherent phase synchronization or input ripple reduction benefit. | Choose LTC3855EUFD#PBF for simpler single-output systems; LTC3728IUH#TRPBF is superior where interleaved dual-rail efficiency and reduced EMI are mandatory. |
Compared with MP8765GL-Z and LTC3855EUFD#PBF, the LTC3728IUH#TRPBF uniquely delivers true dual-phase interleaving with independent channel control, integrated 3.3V bias rail, and robust protection - making it optimal for high-efficiency, low-noise, dual-output DC/DC designs where input ripple, thermal management, and design flexibility are critical.
Availability
LTC3728IUH#TRPBF is available at Aetrix Electronics and suitable for notebook computing, telecom power distribution, and battery-operated test instrumentation requiring stable component supply, long-term lifecycle support, and guaranteed –40°C to +85°C operation.
Supply support for LTC3728IUH#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 LTC3728IUH#TRPBF belongs to ADI's high-efficiency power controller product line, designed specifically for dual-phase, high-current synchronous buck conversion in space-constrained, thermally demanding applications such as portable computing and infrastructure equipment.
FAQ
What is the maximum input voltage rating for the LTC3728IUH#TRPBF?
The LTC3728IUH#TRPBF has an absolute maximum input voltage (VIN) rating of 36V. Operation is specified from 3.5V to 30V, with 36V representing the upper limit before risk of permanent damage. This allows compatibility with 24V industrial buses and multi-cell Li-ion battery packs while maintaining safety margin.
Does the LTC3728IUH#TRPBF support synchronization to an external clock?
Yes, the LTC3728IUH#TRPBF supports external synchronization via the PLLIN pin. When an external clock signal is applied, the internal phase-locked loop aligns the rising edge of TG1 with the rising edge of the PLLIN signal - enabling precise timing coordination across multiple converters or with system clocks.
How does the FCB pin affect operating mode selection in the LTC3728IUH#TRPBF?
The FCB pin on the LTC3728IUH#TRPBF selects among three modes: <0.8V forces continuous conduction mode (CCM); 0.8–(INTVCC−1V) enables Burst Mode® for high light-load efficiency; ≥4.3V disables Burst Mode and enforces constant-frequency discontinuous operation. This provides direct hardware control over efficiency/noise trade-offs.
What is the function of the 3.3VOUT pin on the LTC3728IUH#TRPBF?
The 3.3VOUT pin on the LTC3728IUH#TRPBF is the output of an integrated linear regulator delivering 3.3V ±2% at up to 10mA DC (50mA peak). It powers auxiliary circuitry such as level shifters, monitoring ICs, or logic - eliminating the need for an external 3.3V LDO and simplifying system power architecture.
Can the LTC3728IUH#TRPBF operate with only one channel enabled?
Yes, the LTC3728IUH#TRPBF supports independent channel control: pulling RUN/SS1 low disables Channel 1 while Channel 2 remains active if RUN/SS2 is high. Both channels must be disabled to shut down the 5V INTVCC and 3.3VOUT regulators - enabling flexible partial-system power management.
LTC3728IUH#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):
- 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:
- 32-QFN (5x5)
LTC3728IUH#TRPBF FAQ
1.How can I place an order for LTC3728IUH#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3728IUH#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 LTC3728IUH#TRPBF reliable?
The price and inventory of LTC3728IUH#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3728IUH#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3728IUH#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3728IUH#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3728IUH#TRPBF?
LTC3728IUH#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3728IUH#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 LTC3728IUH#TRPBF?
For technical support, including LTC3728IUH#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3728IUH#TRPBF requirements.
6.How does Aetrix verify that LTC3728IUH#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3728IUH#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 LTC3728IUH#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3728IUH#TRPBF?
All LTC3728IUH#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3728IUH#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 LTC3728IUH#TRPBF part is unused and in its original packaging.
Return procedure for LTC3728IUH#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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