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Analog Devices Inc. LTC7815HUHF#PBF
- Part No.:
- LTC7815HUHF#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC7815HUHF#PBF.pdf
- Description:
- LOW IQ, 2.25MHZ, TRIPLE OUTPUT,
- Quantity:
- Payment:
- Shipping:
Inventory:4,575
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Product details
Overview
LTC7815HUHF#PBF from Analog Devices is a triple-output synchronous DC/DC controller integrating two buck and one boost stages, driving all-N-channel MOSFETs. It operates from 4.5V–38V input (down to 2.5V post-startup), delivers up to 60V boost output, supports phase-locked switching up to 2.25MHz, and achieves 28μA quiescent current in Sleep Mode-enabling high-efficiency power management in automotive start-stop systems.
For engineers reviewing the LTC7815HUHF#PBF datasheet, LTC7815HUHF#PBF pinout, LTC7815HUHF#PBF application, or LTC7815HUHF#PBF equivalent, key selection criteria include its triple-output topology, 38-pin 5mm × 7mm QFN package, 0.8V/1.2V precision references, OPTI-LOOP compensation, and programmable light-load modes (Burst, pulse-skipping, forced CCM).
Technical Context
The LTC7815HUHF#PBF implements three independent current-mode control loops: two 180° out-of-phase buck channels with 98% max duty cycle and one in-phase boost channel supporting 100% synchronous duty cycle even in Burst Mode. Its constant-frequency architecture uses an internal VCO with resistor-programmable frequency (320kHz–2.25MHz) or external PLL synchronization.
Each channel features dedicated ITH error amplifier outputs, differential current sense inputs (RSENSE or DCR), and independent RUN pins for sequencing. The device integrates dual LDOs (INTVCC and EXTVCC switchover), precision voltage references (0.8V for bucks, 1.2V for boost), and fault indicators (PGOOD1, OV3) with defined hysteresis and trip thresholds.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Dual buck + single boost synchronous controller-enables compact multi-rail power with shared gate drivers and sensing. |
| Input voltage range | 4.5V to 38V main bias; supports cold-crank operation down to 2.5V when biased from boost output or auxiliary supply. |
| Output voltage ranges | Buck: 0.8V–24V (0.8V reference); Boost: up to 60V (1.2V reference)-covers wide system rail requirements. |
| Switching frequency | Programmable 320kHz–2.25MHz or phase-locked to external clock-allows EMI optimization and inductor size reduction. |
| Quiescent current | 28μA (one channel active, Sleep Mode)-extends battery runtime in always-on applications. |
| Package | 38-lead 5mm × 7mm QFN with exposed PGND pad-provides thermal performance for high-current gate drive. |
| Operating temperature | –40°C to +150°C junction (H-grade)-qualified for under-hood automotive environments. |
Pinout & Package
Package: 38-lead plastic QFN (5mm × 7mm), exposed PGND pad (Pin 39) requiring PCB soldering for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FREQ (1) | Oscillator frequency control | Resistor-to-GND sets VCO frequency (320kHz–2.25MHz); GND/INTVCC selects fixed low/high frequency. |
| PLLIN/MODE (2) | Synchronization & light-load mode select | Accepts external clock for PLL sync; voltage level selects Burst Mode, pulse-skipping, or forced CCM. |
| SS3 (3) | Boost soft-start control | Capacitor-to-ground ramps VFB3 to 1.2V; enables controlled boost output rise time. |
| SENSE3+ (4) | Boost current sense positive input | Supplies current to comparator; used with SENSE3– for accurate peak-current limiting in boost stage. |
| SENSE3– (5) | Boost current sense negative input | Common-mode range 2.5V–40V; supports high-side sensing across RSENSE or DCR network. |
| VFB3 (6) | Boost feedback input | Compares divided output against 1.2V reference; regulates boost output voltage. |
| ITH3 (7) | Boost error amplifier output | Controls peak inductor current via current comparator; used for loop compensation. |
| SGND (8) | Small-signal ground | Reference for all analog circuitry; must be routed separately from PGND to avoid noise coupling. |
| RUN1 (9) | Buck channel 1 enable | Logic-level input (1.18V threshold); <1.17V disables channel 1 and reduces IQ. |
| RUN2 (10) | Buck channel 2 enable | Independent control of second buck; allows staggered startup or dynamic rail shutdown. |
| RUN3 (11) | Boost channel enable | Enables/disables boost stage independently; supports system-level power sequencing. |
| SENSE2– (12) | Buck channel 2 current sense negative | Current sourcing above INTVCC + 0.5V enables accurate high-side sensing. |
| SENSE2+ (13) | Buck channel 2 current sense positive | Differential input with ±1µA bias; pairs with SENSE2– for RSENSE-based current monitoring. |
| VFB2 (14) | Buck channel 2 feedback | Regulates output to 0.8V reference; supports remote sensing for improved load regulation. |
| ITH2 (15) | Buck channel 2 error amplifier output | Drives current comparator threshold; compensation network connects here for stability tuning. |
| TRACK/SS2 (16) | Buck channel 2 tracking/soft-start | Allows output to track another supply during startup or ramp to final voltage via capacitor. |
| OV3 (17) | Boost overvoltage indicator | Open-drain output asserts low when VFB3 exceeds 110% setpoint; provides fault signaling without external logic. |
| TG2 (18) | Buck channel 2 top-gate driver | High-current floating driver (1.2Ω pull-up/pull-down); drives N-MOSFET gate referenced to SW2. |
| SW2 (19) | Buck channel 2 switch node | Connects to inductor and bottom MOSFET source; forms switching node for buck stage 2. |
| BOOST2 (20) | Buck channel 2 bootstrap supply | Charged via diode from INTVCC; supplies floating gate driver for TG2 (INTVCC to VIN+INTVCC swing). |
| BG2 (21) | Buck channel 2 bottom-gate driver | Ground-referenced driver (2.4Ω pull-up/1.1Ω pull-down); drives N-MOSFET source-connected gate. |
| INTVCC (22) | Internal LDO output | 5.4V ±0.2V regulated supply for logic and gate drivers; requires ≥4.7µF ceramic decoupling to PGND. |
| EXTVCC (23) | External bias input | Switchover LDO input; bypasses VBIAS LDO when >4.7V, improving efficiency at high input voltages. |
| VBIAS (24) | Main bias supply | Primary input (4.5V–38V); powers internal LDO and logic; requires local bypass to SGND. |
| BOOST3 (26) | Boost channel bootstrap supply | Supports TG3 floating operation; voltage swing = INTVCC to (VIN+INTVCC) for high-side N-MOSFET drive. |
| TG3 (27) | Boost channel top-gate driver | 1.2Ω pull-up/pull-down driver; enables 100% duty cycle operation even in Burst Mode. |
| SW3 (28) | Boost channel switch node | Connects to inductor and boost diode/anode; forms switching node for boost stage. |
| BG3 (29) | Boost channel bottom-gate driver | Ground-referenced driver; controls synchronous rectifier MOSFET in boost path. |
| BOOST1 (30) | Buck channel 1 bootstrap supply | Identical function to BOOST2; supplies TG1 floating driver. |
| SW1 (31) | Buck channel 1 switch node | Primary switching node for first buck regulator; connects to inductor and BG1 drain. |
| TG1 (32) | Buck channel 1 top-gate driver | 2.5Ω pull-up/1.5Ω pull-down; drives high-side N-MOSFET with fast 25ns rise/fall times. |
| PGOOD1 (33) | Buck channel 1 power-good indicator | Open-drain output asserts low if VFB1 deviates >±10%; includes 40µs fault delay and hysteresis. |
| TRACK/SS1 (34) | Buck channel 1 tracking/soft-start | Enables output voltage ramp or tracking of another rail; internal 5µA pull-up supports RC timing. |
| ITH1 (35) | Buck channel 1 error amplifier output | Same function as ITH2/ITH3; connects to compensation network for loop stability. |
| VFB1 (36) | Buck channel 1 feedback input | Regulates first buck output to 0.8V reference; supports precision ±0.8% initial accuracy over temp. |
| SENSE1+ (37) | Buck channel 1 current sense positive | Differential input with ±1µA bias; used with SENSE1– for accurate current limit setting. |
| SENSE1– (38) | Buck channel 1 current sense negative | Current sourcing above INTVCC + 0.5V enables high-side sensing in buck configurations. |
| PGND (39) | Power ground | Exposed pad; connects to bottom MOSFET sources and CIN(–); mandatory PCB soldering for thermal integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Triple-output topology | Two 180° out-of-phase bucks + one in-phase boost-reduces input ripple and enables compact multi-rail designs. |
| OPTI-LOOP compensation | Adapts loop response to wide range of output capacitance and ESR-simplifies stability tuning across diverse output caps. |
| 100% synchronous duty cycle (boost) | Enables dropout-free boost operation during low-input conditions-critical for cold-crank automotive operation. |
| Low-IQ Sleep Mode | 28μA with one buck active-extends battery life in always-on telematics and infotainment modules. |
| Phase-lockable frequency | 320kHz–2.25MHz synchronization-allows EMI spreading and coexistence with other switching regulators. |
| Independent RUN control | Three digital enable pins-supports flexible power sequencing, dynamic rail shutdown, and fault isolation. |
Applications
| Automotive Start-Stop Systems | Battery-Powered Telematics |
|---|---|
Use Scenario: Power management in vehicles with engine auto-shutdown/restart cycles, where input voltage drops to 2.5V during cranking. IC Role / Device Role / Timing Role: Triple-output controller generating stable 5V, 3.3V, and 10V rails from 12V battery, maintaining regulation through cold-crank events. Use Value: 2.5V minimum operating input and 98% buck dropout ensure uninterrupted MCU, CAN transceiver, and sensor power during engine restart. | Use Scenario: Compact GPS/GNSS and cellular modems in portable asset trackers with limited battery capacity. IC Role / Device Role / Timing Role: Generates isolated 3.3V logic rail and 5V RF rail while minimizing standby power loss. Use Value: 28μA Sleep Mode IQ extends operational lifetime between charges; programmable light-load modes optimize efficiency across load range. |
| Distributed Power Architectures | Industrial Control Panels |
Use Scenario: Centralized 24V bus powering multiple remote loads requiring different voltage levels (e.g., 12V actuators, 5V sensors, 3.3V microcontrollers). IC Role / Device Role / Timing Role: Local DC/DC conversion at point-of-load using buck/buck/boost topology to reduce distribution losses. Use Value: High 2.25MHz switching enables small external magnetics; independent RUN pins allow dynamic rail enable/disable per subsystem demand. | Use Scenario: Human-machine interface (HMI) panels with LCD backlight, touch controller, and ARM Cortex-M host processor. IC Role / Device Role / Timing Role: Supplies 5V for display, 3.3V for MCU, and adjustable boost rail for LED backlight dimming control. Use Value: 60V boost capability supports wide-range LED string configurations; PGOOD1/OV3 signals enable system-level fault monitoring. |
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 | Single buck + dual boost topology; 0.8V reference only; lower max boost voltage (40V); no PGOOD1 output. | Optimized for boost-heavy applications (e.g., LED drivers); lacks buck/buck/boost flexibility for mixed-rail systems. | Select when primary need is high-voltage boost with secondary buck, not triple independent regulation. |
| MP2918GL-Z | Dual buck + single boost; 4.5V–36V input; 20μA IQ; no PLL sync; smaller 32-pin 4mm × 4mm QFN package. | Targeted at space-constrained consumer electronics; lacks automotive temperature grade and cold-crank support below 3V. | Choose for cost-sensitive, non-automotive applications where footprint and ultra-low IQ outweigh frequency flexibility and ruggedness. |
Compared with LTC7813IUHF#PBF and MP2918GL-Z, the LTC7815HUHF#PBF uniquely combines automotive H-grade temperature range (–40°C to +150°C), cold-crank operation down to 2.5V, phase-lockable 2.25MHz switching, and independent RUN control-making it optimal for demanding multi-rail automotive and industrial power systems.
Availability
LTC7815HUHF#PBF is available at Aetrix Electronics and suitable for automotive start-stop systems, battery-powered telematics, and distributed power architectures requiring stable component supply across extended temperature and input voltage ranges.
Supply support for LTC7815HUHF#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 (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.
The LTC7815HUHF#PBF belongs to ADI's Power by Linear™ controller family, designed specifically for high-efficiency, multi-output DC/DC conversion in harsh-environment applications including automotive under-hood and industrial control systems.
FAQ
What is the minimum input voltage required for LTC7815HUHF#PBF startup?
The LTC7815HUHF#PBF requires a minimum 4.5V on VBIAS to initiate startup. However, once running and biased from the boost output or an auxiliary supply, it sustains operation down to 2.5V-enabling reliable function during automotive cold-crank events. This behavior is confirmed in the Absolute Maximum Ratings and Applications sections of the official datasheet.
Does LTC7815HUHF#PBF support synchronization to an external clock?
Yes, the LTC7815HUHF#PBF supports external clock synchronization via the PLLIN/MODE pin. When an external clock is applied, the internal phase-locked loop aligns the rising edge of TG1 with the external clock's rising edge, and all three controllers operate in forced continuous conduction mode. The supported sync frequency range is 320kHz to 2.25MHz, as specified in the Oscillator and PLL electrical characteristics table.
What is the purpose of the EXTVCC pin on LTC7815HUHF#PBF?
The EXTVCC pin on LTC7815HUHF#PBF provides an alternative input to the internal INTVCC LDO. When EXTVCC exceeds 4.7V, the device automatically switches to this supply, bypassing the VBIAS-powered LDO and improving overall efficiency-especially at high input voltages. EXTVCC must not exceed 14V and should never be left floating, per the Absolute Maximum Ratings and Pin Functions documentation.
How does LTC7815HUHF#PBF manage light-load efficiency across its three channels?
The LTC7815HUHF#PBF offers three selectable light-load modes via the PLLIN/MODE pin: Burst Mode (lowest IQ), pulse-skipping, or forced continuous conduction mode. Each mode applies uniformly across all three channels. In Burst Mode, the device achieves 28μA quiescent current with one channel active-verified in the Electrical Characteristics table under "Sleep Mode (One Channel On, Buck)".
Can LTC7815HUHF#PBF drive both high-side and low-side N-channel MOSFETs in the boost stage?
Yes, the LTC7815HUHF#PBF drives both high-side (via TG3) and low-side (via BG3) N-channel MOSFETs in the boost stage. TG3 is a floating driver capable of 100% duty cycle operation-even in Burst Mode-as confirmed in the FEATURES list and PIN FUNCTIONS description for TG3. BG3 is a ground-referenced driver with 1.2Ω pull-up and 1.0Ω pull-down resistance, enabling efficient synchronous rectification.
LTC7815HUHF#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 ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-QFN (5x7)
LTC7815HUHF#PBF FAQ
1.How can I place an order for LTC7815HUHF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7815HUHF#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 LTC7815HUHF#PBF reliable?
The price and inventory of LTC7815HUHF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7815HUHF#PBF is usually 5 days.
3.What payment methods are accepted for LTC7815HUHF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7815HUHF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7815HUHF#PBF?
LTC7815HUHF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7815HUHF#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 LTC7815HUHF#PBF?
For technical support, including LTC7815HUHF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7815HUHF#PBF requirements.
6.How does Aetrix verify that LTC7815HUHF#PBF is sourced from the original manufacturer or authorized distributors?
All LTC7815HUHF#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 LTC7815HUHF#PBF meets industry standards.
7.What is the process for return or replacement of LTC7815HUHF#PBF?
All LTC7815HUHF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7815HUHF#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 LTC7815HUHF#PBF part is unused and in its original packaging.
Return procedure for LTC7815HUHF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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