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Analog Devices Inc. LTC7815IUHF#PBF
- Part No.:
- LTC7815IUHF#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC7815IUHF#PBF.pdf
- Description:
- LOW IQ, 2.25MHZ, TRIPLE OUTPUT,
- Quantity:
- Payment:
- Shipping:
Inventory:3,654
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Product details
Overview
LTC7815IUHF#PBF from Analog Devices is a triple-output synchronous DC/DC controller implementing buck/buck/boost topology with all-N-channel MOSFET drive capability. It delivers 5V/7A and 3.3V/10A buck outputs plus a programmable boost output up to 60V, operates from 4.5V–38V input (or 2.5V post-startup), features 28μA quiescent current in sleep mode, and supports phase-lockable switching up to 2.25MHz - enabling compact, high-efficiency power for automotive start-stop and battery-powered digital systems.
For engineers reviewing the LTC7815IUHF#PBF datasheet, LTC7815IUHF#PBF pinout, LTC7815IUHF#PBF application, or LTC7815IUHF#PBF equivalent, key selection considerations include its triple-output architecture, independent RUN pin control per channel, OPTI-LOOP compensation, 0.8V/1.2V precision references, and 38-lead 5mm × 7mm QFN package with exposed PGND pad.
Technical Context
The LTC7815IUHF#PBF integrates three independent current-mode controllers: two 180° out-of-phase buck stages and one boost stage synchronized to buck channel 1. Each channel uses constant-frequency PWM with adjustable frequency (320kHz–2.25MHz) via resistor or external clock on FREQ/PLLIN/MODE pins.
It employs RSENSE or DCR current sensing, supports Burst Mode®, pulse-skipping, and forced continuous conduction modes via PLLIN/MODE pin, and includes dedicated gate drivers (TG/BG) with <2.5Ω pull-up/pull-down resistance, <30ns transition times, and 100% duty cycle capability for the boost high-side MOSFET.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Buck/Buck/Boost triple-output synchronous controller - enables single-chip generation of multiple regulated rails including >VIN output. |
| Input Voltage Range | 4.5V to 38V main bias; down to 2.5V after startup when biased from boost output - supports cold-crank automotive operation. |
| Switching Frequency | 320kHz to 2.25MHz, programmable via resistor or PLL-synchronized - allows EMI optimization and small magnetics. |
| Quiescent Current | 28μA (one buck channel active in sleep mode) - extends battery runtime in always-on systems. |
| Feedback References | 0.8V ±1% for buck channels; 1.2V ±1% for boost channel - ensures tight output regulation across temperature. |
| Package | 38-lead 5mm × 7mm QFN with exposed PGND pad - provides low thermal resistance (θJA = 34.7°C/W) and robust grounding. |
| Operating Temp | –40°C to +125°C junction - qualified for automotive and industrial environments. |
Pinout & Package
38-lead plastic QFN (5mm × 7mm) with exposed PGND pad (Pin 39), requiring soldering to PCB for thermal and electrical performance. Pin functions are validated per Linear/ADI LTC7815 datasheet Rev. F.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FREQ (1) | Oscillator frequency programming | Resistor-to-GND sets VCO frequency from 320kHz–2.25MHz; tied to INTVCC or GND for fixed high/low frequency. |
| PLLIN/MODE (2) | Sync input / light-load mode select | Accepts external clock for synchronization; selects Burst Mode (GND), pulse-skipping (1.2V–INTVCC−1.3V), or forced CCM (INTVCC). |
| SS3 (3) | Boost soft-start control | Internal 5µA current source ramps voltage; regulates VFB3 to smaller of 1.2V or SS3 voltage - controls boost output ramp rate. |
| SENSE3+ (4) | Boost current sense positive input | Supplies current to boost current comparator; common-mode range up to 40V - supports high-VIN boost configurations. |
| SENSE3– (5) | Boost current sense negative input | Differential input referenced to SW3; used with RSENSE or DCR for accurate peak-current limiting in boost stage. |
| VFB3 (6) | Boost feedback input | Compares divided output voltage against 1.2V reference; OV3 asserts when VFB3 exceeds 110% setpoint. |
| ITH3 (7) | Boost error amplifier output | Controls peak inductor current trip point; higher ITH3 voltage increases current limit - enables loop compensation. |
| SGND (8) | Small-signal ground reference | Must be routed separately from PGND to avoid noise coupling into sensitive analog circuitry (VFB, ITH, SENSE). |
| RUN1 (9) | Buck channel 1 enable | Logic-high (>1.24V) enables channel 1; <1.18V disables - allows independent sequencing and power gating. |
| RUN2 (10) | Buck channel 2 enable | Independent enable/disable control identical to RUN1 - supports staggered startup and dynamic rail management. |
| RUN3 (11) | Boost channel enable | Enables/disables boost stage independently; all three RUN pins <0.7V places IC in shutdown (<20μA IQ). |
| OV3 (17) | Boost overvoltage flag | Open-drain output pulled low when VFB3 <90% setpoint; high-Z when >110% - provides fault signaling without external logic. |
| INTVCC (22) | Internal LDO output | 5.4V ±0.2V regulated supply for gate drivers and control logic; requires ≥4.7µF ceramic decoupling to PGND. |
| EXTVCC (23) | External bias input | Accepts 4.7V–14V to bypass internal VBIAS LDO; reduces power loss and heat when auxiliary supply is available. |
| VBIAS (24) | Main bias input | Primary 4.5V–38V supply input; powers internal LDO generating INTVCC - must be bypassed to SGND. |
| BG1, BG2, BG3 (21,25,29) | Bottom-gate drivers | Drive N-MOSFET sources to PGND; 1.1–2.4Ω pull-down resistance ensures fast turn-off and shoot-through prevention. |
| BOOST1, BOOST2, BOOST3 (20,26,30) | Bootstrap supplies | Provide floating gate drive for top N-MOSFETs; swing from INTVCC to (SWx + INTVCC) - require bootstrap capacitors. |
| SW1, SW2, SW3 (19,28,31) | Switch node connections | Connect to inductor and bootstrap capacitor; handle full switching voltage/current - require low-inductance layout. |
| TG1, TG2, TG3 (18,27,32) | Top-gate drivers | Floating drivers with INTVCC swing superimposed on SWx; 1.0–1.2Ω pull-down enables 100% duty cycle in boost Burst Mode. |
| PGOOD1 (33) | Buck 1 power-good indicator | Open-drain output asserting low when VFB1 deviates >±10% from 0.8V - enables system power sequencing and fault detection. |
| TRACK/SS1, TRACK/SS2 (14,34) | Buck soft-start/tracking inputs | Regulate VFB1/VFB2 to smaller of 0.8V or applied voltage; internal 5µA pull-up enables RC soft-start or voltage tracking. |
| SENSE1+, SENSE2+ (13,37) | Buck current sense positive | Inputs to differential comparators; support RSENSE or DCR sensing with common-mode range up to 28V. |
| SENSE1–, SENSE2– (12,38) | Buck current sense negative | Reference inputs; supply current to comparator when >INTVCC - enables accurate current sensing across wide VIN range. |
| VFB1, VFB2 (14,36) | Buck feedback inputs | Compare divided output voltage against 0.8V reference; PGOOD1 monitors VFB1 only. |
| ITH1, ITH2 (15,35) | Buck error amplifier outputs | Set peak current limit per buck channel; used for loop compensation and current foldback protection. |
| PGND (39) | Power ground (exposed pad) | Must be soldered to large PCB copper area - serves as return for all high-current paths and thermal dissipation path. |
Key Features
| Feature | Design Value |
|---|---|
| Triple independent controllers | Enables simultaneous buck/buck/boost conversion with per-channel RUN control, soft-start, and fault reporting - eliminates need for multiple controllers in multi-rail systems. |
| OPTI-LOOP compensation | Allows stable loop response across wide range of output capacitance (including low-ESR ceramics) and ESR values - simplifies design across diverse load conditions. |
| 100% duty cycle boost operation | Maintains regulation even at VIN ≈ VOUT by fully enhancing top MOSFET - critical for battery backup and hold-up applications where VIN may dip near output voltage. |
| Low-IQ sleep mode | 28μA quiescent current with one buck channel active - extends operational time in always-on IoT sensors and telematics modules. |
| Phase-lockable frequency | Synchronizes all three channels to external clock (320kHz–2.25MHz) - eliminates beat frequencies and eases EMI filtering in dense PCB layouts. |
| Wide input range with cold-crank support | Regulates outputs down to 2.5V input after startup - meets ISO 16750-2 automotive cold-crank requirements without external supervision. |
Applications
| Automotive Start-Stop Systems | Battery-Powered Digital Devices |
|---|---|
Use Scenario: Power management in vehicles with engine stop-start functionality, where battery voltage drops to 2.5V during cranking. IC Role / Device Role / Timing Role: Triple-output controller generating 5V for infotainment, 3.3V for microcontrollers, and 12V boost rail for sensors - all remaining in regulation during cold-crank events. Use Value: Eliminates need for discrete supervisors or secondary converters; 28μA sleep IQ preserves battery charge during extended parking. |
Use Scenario: Portable medical monitors requiring long battery life and multiple isolated rails for analog front-end, digital processing, and display backlight. IC Role / Device Role / Timing Role: Primary power controller delivering tightly regulated 3.3V/5V buck outputs and adjustable boost for white LED backlight - managed via independent RUN pins. Use Value: OPTI-LOOP compensation ensures stability with varied capacitor types; 2.25MHz switching enables ultra-compact 1μH inductors. |
| Distributed DC Power Systems | Multioutput Buck-Boost Applications |
Use Scenario: Industrial edge gateway with separate 5V, 3.3V, and 12V rails distributed across modular PCBs, powered from 24V DC bus. IC Role / Device Role / Timing Role: Centralized controller driving local buck converters and a boost stage for isolated communication interfaces - synchronized via PLLIN/MODE to reduce conducted EMI. Use Value: Phase interleaving between buck channels reduces input ripple current; EXTVCC option lowers thermal load when 12V rail is available. |
Use Scenario: Test equipment requiring both sub-VIN and super-VIN outputs from a single 12V supply - e.g., 3.3V logic, 5V analog, and 24V actuator drive. IC Role / Device Role / Timing Role: Integrated buck/buck/boost controller eliminating discrete boost IC and dual buck controllers - simplifies BOM and layout. Use Value: Single 38-pin QFN replaces three ICs; 0.8V/1.2V references ensure ±1% output accuracy across temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-output synchronous controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC7813IUHF#PBF | Dual buck + single boost, but lacks independent RUN pins for each channel and has no PGOOD1 output - limited sequencing and monitoring capability. | Suitable for simpler systems where channel enable independence and power-good signaling are not required. | Select LTC7815IUHF#PBF when per-channel RUN control, PGOOD1, or enhanced cold-crank support (2.5V operation) is needed. |
| MP2918GL-Z | Triple buck-only controller (no boost); 4.5V–32V input; 12μA IQ; 32-pin QFN - lacks boost capability and cold-crank extension below 4.5V. | Applicable only where all rails are ≤VIN; cannot generate >VIN outputs like sensor bias or interface voltages. | Choose LTC7815IUHF#PBF when a boost output up to 60V or operation below 4.5V is mandatory. |
Compared with LTC7813IUHF#PBF and MP2918GL-Z, the LTC7815IUHF#PBF uniquely combines triple-output buck/buck/boost topology, per-channel RUN control, 2.5V cold-crank operation, and integrated PGOOD/OV flags - making it the only solution for automotive multi-rail systems requiring both sub- and super-VIN regulation with full fault visibility.
Availability
LTC7815IUHF#PBF is available at Aetrix Electronics and suitable for automotive start-stop systems, battery-powered digital devices, and distributed DC power systems requiring stable component supply, long-term lifecycle support, and guaranteed temperature-grade compliance.
Supply support for LTC7815IUHF#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 (acquired Linear Technology in 2017) designs high-performance analog, mixed-signal, and power management ICs for precision, reliability, and efficiency in demanding applications.
The LTC7815IUHF#PBF belongs to the LTC78xx family of high-efficiency synchronous controllers, engineered specifically for multi-rail automotive, industrial, and portable power systems requiring wide input range, low quiescent current, and flexible output configuration.
FAQ
What is the minimum input voltage required for LTC7815IUHF#PBF to operate after startup?
The LTC7815IUHF#PBF can maintain regulation with input voltage as low as 2.5V after startup when biased from the boost output or another auxiliary supply. This capability is essential for automotive cold-crank scenarios. During initial startup, however, the VBIAS pin requires ≥4.5V to exit undervoltage lockout. The LTC7815IUHF#PBF achieves this using internal circuitry that transitions from VBIAS to auxiliary bias once regulation is established.
How does the LTC7815IUHF#PBF support power sequencing across its three outputs?
The LTC7815IUHF#PBF provides independent RUN1, RUN2, and RUN3 pins, each controlling enable/disable of its respective buck or boost channel. By applying controlled voltage ramps or logic signals to these pins, designers implement precise power-up and power-down sequencing - for example, enabling the 3.3V buck first, then the 5V buck, and finally the boost rail. The LTC7815IUHF#PBF also supports tracking via TRACK/SS1 and TRACK/SS2 pins to align buck output ramps with external supplies.
Can the LTC7815IUHF#PBF drive high-side N-channel MOSFETs in the boost stage at 100% duty cycle?
Yes, the LTC7815IUHF#PBF's TG3 and BG3 drivers support 100% duty cycle operation in the boost stage, even during Burst Mode®. This is enabled by its dedicated charge pump (BOOST3) and optimized gate drive timing, allowing the high-side N-MOSFET to remain fully enhanced when VIN approaches or equals the boost output voltage - critical for battery backup and hold-up applications. The LTC7815IUHF#PBF datasheet confirms this behavior under "Maximum Duty Factor for TG" specifications.
What is the purpose of the EXTVCC pin on the LTC7815IUHF#PBF, and how should it be used?
The EXTVCC pin on the LTC7815IUHF#PBF accepts an external 4.7V–14V supply to power the INTVCC LDO, bypassing the internal VBIAS regulator. This reduces power dissipation and heat generation when a clean, efficient auxiliary rail (e.g., a pre-regulated 5V or 12V) is available. The LTC7815IUHF#PBF automatically switches to EXTVCC when its voltage exceeds 4.7V (with 200mV hysteresis), and reverts to VBIAS if EXTVCC falls below 4.5V. Proper decoupling of EXTVCC to PGND is required.
Does the LTC7815IUHF#PBF include built-in protection features, and how are they implemented?
Yes, the LTC7815IUHF#PBF integrates multiple protections: undervoltage lockout (UVLO) on VBIAS (4.15V rising, 3.5V falling), overvoltage protection on VFB1/VFB2 (±10% trip with hysteresis), and dedicated OV3 open-drain flag for boost overvoltage. It also features current-limit foldback, thermal shutdown (150°C TJMAX), and shoot-through prevention via controlled TG/BG timing delays. These protections are implemented in hardware and do not require external components - the LTC7815IUHF#PBF asserts PGOOD1 low on buck1 fault and drives OV3 high-Z on boost overvoltage.
LTC7815IUHF#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 38-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck, Buck, Boost
- Number of Outputs:
- 3
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 38V
- Frequency - Switching:
- 320kHz ~ 2.25MHz
- Duty Cycle (Max):
- 100%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-QFN (5x7)
LTC7815IUHF#PBF FAQ
1.How can I place an order for LTC7815IUHF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7815IUHF#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 LTC7815IUHF#PBF reliable?
The price and inventory of LTC7815IUHF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7815IUHF#PBF is usually 5 days.
3.What payment methods are accepted for LTC7815IUHF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7815IUHF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7815IUHF#PBF?
LTC7815IUHF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7815IUHF#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 LTC7815IUHF#PBF?
For technical support, including LTC7815IUHF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7815IUHF#PBF requirements.
6.How does Aetrix verify that LTC7815IUHF#PBF is sourced from the original manufacturer or authorized distributors?
All LTC7815IUHF#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 LTC7815IUHF#PBF meets industry standards.
7.What is the process for return or replacement of LTC7815IUHF#PBF?
All LTC7815IUHF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7815IUHF#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 LTC7815IUHF#PBF part is unused and in its original packaging.
Return procedure for LTC7815IUHF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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