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Analog Devices Inc. LTC1628CUH#PBF
- Part No.:
- LTC1628CUH#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC1628CUH#PBF.pdf
- Description:
- IC REG CTRLR BUCK 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,429
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Product details
Overview
LTC1628CUH#PBF from Analog Devices (formerly Linear Technology) is a dual-phase, synchronous step-down switching regulator controller driving two independent N-channel MOSFET stages. It delivers ±1% output voltage accuracy, supports 3.5V–36V input, enables 99% duty cycle dropout operation, and features OPTI-LOOP® compensation for optimized transient response across wide output capacitance/ESR ranges - used in high-efficiency dual-rail power supplies for notebook computers and portable instrumentation.
For engineers reviewing the LTC1628CUH#PBF datasheet, LTC1628CUH#PBF pinout, LTC1628CUH#PBF application, or LTC1628CUH#PBF equivalent, key selection criteria include its dual 180° out-of-phase control architecture, FCB-selectable Burst Mode®/constant-frequency/continuous conduction modes, integrated 3.3V linear regulator (10mA), and support for remote voltage sensing with overvoltage protection and foldback current limiting.
Technical Context
The LTC1628CUH#PBF implements a constant-frequency current-mode control architecture with two independent channels operating 180° out of phase to reduce input ripple current and EMI. Each channel uses a transconductance error amplifier (gm = 1.3 mmho, GBW = 3 MHz) and a precision 0.8V reference to regulate feedback via VOSENSE pins.
It integrates dual gate drivers (TG/BG) with <90 ns transition times, a dedicated 3.3V LDO (±2% load regulation), INTVCC/EXTVCC switchover logic, and programmable oscillator (140–310 kHz via FREQSET). The RUN/SS pins provide soft-start ramping and timed short-circuit latchoff, while FLTCPL (not present on LTC1628-PG variants) enables fault coupling between channels - though LTC1628CUH#PBF is the non-PG variant and lacks PGOOD and FLTCPL functionality.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 36V - supports wide battery chemistries including 12V lead-acid, 24V industrial rails, and multi-cell Li-ion packs. |
| Output Voltage Accuracy | ±1% - ensures stable core voltage delivery for microprocessors and FPGAs requiring tight regulation. |
| Switching Frequency Range | 140 kHz to 310 kHz - adjustable via FREQSET pin; higher frequencies allow smaller magnetics but increase switching loss. |
| Duty Cycle Max | 99.4% - enables ultra-low dropout operation essential for high-current, low-VOUT applications like 5V→3.3V conversion. |
| Feedback Reference Voltage | 0.800 V ±1% - precise internal reference enabling accurate scaling of output voltages using external resistor dividers. |
| 3.3V LDO Output | 3.3V ±2%, 10mA DC - powers auxiliary circuitry (e.g., level shifters, supervisors) without requiring a separate regulator. |
| Shutdown Quiescent Current | 20 µA - minimizes battery drain during system sleep states in portable equipment. |
Pinout & Package
Package: 32-lead (5mm × 5mm) plastic QFN with exposed thermal pad (SGND). Exposed pad must be soldered to PCB for thermal and electrical integrity.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| VOSENSE1 / VOSENSE2 | Remote feedback input (per channel) | Accepts scaled output voltage from external resistive divider; enables precise regulation despite PCB trace IR drop. |
| RUN/SS1 / RUN/SS2 | Soft-start & run control (per channel) | Capacitor-to-ground sets ramp time; falling below 1.0V disables respective controller; also triggers timed short-circuit latchoff. |
| ITH1 / ITH2 | Error amplifier output & compensation node | Controls peak inductor current threshold; voltage directly scales current limit; used for loop compensation network connection. |
| TG1/TG2, BG1/BG2 | Top/bottom N-MOSFET gate drivers | High-current drivers (3A peak) with fast transitions (<90 ns); TG floats relative to SW node via BOOST capacitor. |
| BOOST1 / BOOST2 | Floating supply for top-gate drivers | Charged via external bootstrap capacitor + Schottky diode; enables high-side N-MOSFET drive without P-MOS or charge pump. |
| SENSE1+/SENSE1−, SENSE2+/SENSE2− | Differential current sense inputs | Measure voltage across RSENSE to detect inductor current; enable cycle-by-cycle current limiting and foldback protection. |
| FREQSET | Oscillator frequency programming | Open = ~220 kHz; grounded = ~140 kHz; 2.4V = ~310 kHz; allows EMI tuning and magnetics optimization. |
| FCB | Forced continuous / burst mode select | Voltage <0.8V forces continuous PWM; 0.8–2.7V enables Burst Mode®; >4.3V disables burst (constant frequency). |
| STBYMD | Standby mode control | GND = shut down both controllers; open = normal operation; >2V enables 3.3V/5V standby regulators independently of RUN/SS state. |
| 3.3VOUT | Integrated linear regulator output | Provides regulated 3.3V at up to 10mA; eliminates need for discrete LDO in auxiliary power domains. |
| INTVCC / EXTVCC | Internal 5V LDO output / external VCC input | INTVCC powers internal circuitry; EXTVCC >4.7V bypasses LDO for higher efficiency (e.g., fed from main output). |
| SGND / PGND | Small-signal ground / power ground | Separate ground returns required: SGND for analog/feedback paths; PGND for high-current MOSFET sources and CIN return. |
Key Features
| Feature | Design Value |
|---|---|
| 180° out-of-phase dual control | Halves input ripple current vs single-phase design, reducing required CIN by ~50% and lowering EMI emissions. |
| OPTI-LOOP® compensation | Enables stable loop response across 10× variation in output capacitance and ESR - simplifies design across diverse ceramic/polymer cap selections. |
| Selectable operating modes | Burst Mode® (high light-load efficiency), constant frequency (low noise), or forced continuous (for reverse-current capability or secondary winding regulation). |
| Integrated 3.3V LDO | Delivers 10mA with ±2% load regulation - powers supervisory ICs, ADC references, or level translators without external components. |
| Foldback current limiting | Reduces MOSFET power dissipation during sustained overload by lowering current limit as output voltage collapses - prevents thermal runaway. |
| Dropout detection & recovery | Forces periodic bottom-FET turn-on during 99%+ duty cycles to recharge bootstrap capacitors - maintains gate drive integrity even at VIN ≈ VOUT. |
Applications
| Portable Computing Power Supply | Battery-Powered Test Instrumentation |
|---|---|
Use Scenario: Dual-rail power for CPU core (5V) and I/O (3.3V) in ultraportable notebooks with Li-ion battery input (7–24V). IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing independent 5A/5A outputs with out-of-phase switching to minimize input capacitor stress. Use Value: Achieves >90% efficiency across 0.1–5A load range using Burst Mode®, reduces thermal footprint via 5mm×5mm QFN, and enables compact layout with shared input bulk cap. | Use Scenario: Precision analog front-end and digital logic supply in handheld multimeters or oscilloscopes powered by 4×AA alkaline cells (4.8–6.8V). IC Role / Device Role / Timing Role: Primary DC/DC controller generating stable 5V and 3.3V rails while supporting deep sleep modes with 20µA shutdown IQ. Use Value: Extends battery life via adaptive light-load efficiency, maintains regulation during battery sag with 3.5V UVLO, and provides clean 3.3V LDO for ADC reference without added parts. |
| Industrial DC Power Distribution | Automotive Infotainment Core Supply |
Use Scenario: Centralized 24V-to-5V/3.3V conversion for distributed sensor nodes in factory automation systems. IC Role / Device Role / Timing Role: High-reliability dual-output controller with remote sensing, overvoltage protection, and latch-off shutdown for fault containment. Use Value: Ensures ±1% rail stability over temperature (–40°C to 85°C), withstands 36V transients per ABSOLUTE MAX ratings, and supports redundant power path design via independent channel control. | Use Scenario: Main processor and memory supply in automotive head units operating from 9–16V vehicle battery with cold-crank (4.5V) tolerance. IC Role / Device Role / Timing Role: Dual-phase buck controller delivering 5V@4A and 3.3V@3A with 180° interleaving to meet CISPR-25 conducted EMI limits. Use Value: Meets automotive input range requirements (UVLO = 3.5V), suppresses input ripple via phase interleaving, and includes robust protection (OVP, foldback, latchoff) for harsh environments. |
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-output buck (integrated MOSFETs); fixed 500kHz freq; no FCB mode selection; no 3.3V LDO. | Lower BOM count but less flexible frequency/efficiency trade-off; unsuitable where Burst Mode® or auxiliary 3.3V rail is required. | Select MP8765GL-Z only when integrated power stage suffices and external 3.3V LDO is acceptable. |
| LTC3855EUH#PBF | Pin-compatible upgrade with higher 600kHz max freq, improved current sense accuracy (±0.5%), and enhanced thermal performance (θJA = 28°C/W). | Direct replacement for new designs needing higher efficiency at light loads or tighter current monitoring; retains identical pinout and feature set. | Choose LTC3855EUH#PBF for next-gen designs requiring better accuracy, higher frequency, or lower thermal resistance. |
Compared with MP8765GL-Z, LTC1628CUH#PBF offers greater flexibility in operating mode selection and integrated auxiliary power, while LTC3855EUH#PBF improves upon it with higher precision, frequency range, and thermal efficiency - making LTC1628CUH#PBF optimal for cost-sensitive, thermally constrained legacy designs requiring Burst Mode® and 3.3V LDO integration.
Availability
LTC1628CUH#PBF is available at Aetrix Electronics and suitable for notebook computing power supplies, portable instrumentation, and industrial DC distribution systems requiring stable component supply with long-term lifecycle support.
Supply support for LTC1628CUH#PBF 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 LTC1628CUH#PBF belongs to ADI's legacy Linear Technology Power Management portfolio, designed specifically for high-efficiency, dual-rail, synchronous step-down conversion in space-constrained portable and industrial systems.
FAQ
What is the maximum input voltage rating for the LTC1628CUH#PBF?
The LTC1628CUH#PBF has an absolute maximum input voltage (VIN) rating of 36V. Operation above 36V risks permanent damage. Its functional input range is 3.5V to 30V, with guaranteed operation up to 36V under transient conditions per Absolute Maximum Ratings. Always ensure input filtering and clamping protect against automotive load-dump or industrial surge events exceeding this limit.
Does the LTC1628CUH#PBF include a power good (PGOOD) output?
No, the LTC1628CUH#PBF does not include a PGOOD output. That function is exclusive to the LTC1628-PG variants (e.g., LTC1628CUH#TRPBF-PG). The LTC1628CUH#PBF is the base version and omits the PGOOD pin and associated circuitry - confirmed by pinout diagrams showing FLTCPL instead of PGOOD and absence of PGOOD specifications in its Electrical Characteristics table.
How is the switching frequency programmed on the LTC1628CUH#PBF?
The switching frequency of the LTC1628CUH#PBF is programmed via the FREQSET pin. Leaving it open sets ~220 kHz; grounding it yields ~140 kHz; applying 2.4V achieves ~310 kHz. The oscillator's frequency range is 140 kHz to 310 kHz, and the pin accepts DC or AC signals for dynamic frequency modulation. This adjustment directly impacts inductor size, efficiency, and EMI profile in the final design.
Can the LTC1628CUH#PBF drive external N-channel MOSFETs in both high-side and low-side positions?
Yes, the LTC1628CUH#PBF drives external N-channel MOSFETs in both positions: TG1/TG2 drive high-side N-MOSFET gates using floating bootstrap supplies (BOOST1/BOOST2), while BG1/BG2 drive low-side N-MOSFET gates referenced to PGND. This configuration enables higher efficiency than P-MOS high-side solutions and supports synchronous rectification for reduced conduction loss.
What is the purpose of the STBYMD pin on the LTC1628CUH#PBF?
The STBYMD pin on the LTC1628CUH#PBF controls three operational states: grounded = shuts down both controllers; open = enables normal RUN/SS-controlled startup; pulled >2V = activates the internal 3.3V and 5V standby regulators regardless of RUN/SS state. This allows "always-on" auxiliary power for wake-up circuitry in battery-powered systems, independent of main converter operation.
LTC1628CUH#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 32-WFQFN Exposed Pad
- Packaging:
- Tube
- 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:
- 220kHz
- Duty Cycle (Max):
- 99.4%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, Power Good, Soft Start
- Operating Temperature:
- 0°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
LTC1628CUH#PBF FAQ
1.How can I place an order for LTC1628CUH#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1628CUH#PBF 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 LTC1628CUH#PBF reliable?
The price and inventory of LTC1628CUH#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1628CUH#PBF is usually 5 days.
3.What payment methods are accepted for LTC1628CUH#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1628CUH#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1628CUH#PBF?
LTC1628CUH#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1628CUH#PBF 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 LTC1628CUH#PBF?
For technical support, including LTC1628CUH#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1628CUH#PBF requirements.
6.How does Aetrix verify that LTC1628CUH#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1628CUH#PBF 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 LTC1628CUH#PBF meets industry standards.
7.What is the process for return or replacement of LTC1628CUH#PBF?
All LTC1628CUH#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1628CUH#PBF, 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 LTC1628CUH#PBF part is unused and in its original packaging.
Return procedure for LTC1628CUH#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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