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Analog Devices Inc. LTC7815EUHF#PBF
- Part No.:
- LTC7815EUHF#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC7815EUHF#PBF.pdf
- Description:
- LOW IQ, 2.25MHZ, TRIPLE OUTPUT,
- Quantity:
- Payment:
- Shipping:
Inventory:2,347
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Product details
Overview
LTC7815EUHF#PBF from Analog Devices is a triple-output synchronous DC/DC controller supporting buck/buck/boost topologies, driving all-N-channel MOSFET stages with 2.25MHz phase-lockable switching frequency, 0.8V/0.8V/1.2V precision references, and 28μA no-load quiescent current - enabling high-efficiency power conversion in automotive start-stop and battery-powered digital systems.
For engineers reviewing the LTC7815EUHF#PBF datasheet, LTC7815EUHF#PBF pinout, LTC7815EUHF#PBF application, or LTC7815EUHF#PBF equivalent, key selection considerations include its triple-output independent control, cold-crank operation down to 2.5V input, OPTI-LOOP compensation for wide output capacitance tolerance, and 38-lead 5mm × 7mm QFN package with exposed PGND pad.
Technical Context
The LTC7815EUHF#PBF integrates three independent current-mode controllers: two 180° out-of-phase buck regulators (Channels 1 & 2) and one boost regulator (Channel 3) synchronized to Channel 1. Each channel features programmable ITH-based current limit, separate RUN pins for individual enable/disable, and dedicated TRACK/SS or SS inputs for soft-start and voltage tracking.
Its constant-frequency architecture supports phase-locking via PLLIN/MODE pin across 320kHz–2.25MHz, with selectable light-load modes (Burst Mode®, pulse-skipping, forced continuous), RSENSE or DCR sensing, and 100% duty cycle capability for the boost synchronous MOSFET even in Burst Mode® operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Buck/Buck/Boost triple-output synchronous controller - enables compact multi-rail power supplies without discrete controllers. |
| Switching Frequency | 320kHz to 2.25MHz, phase-lockable - allows EMI reduction via synchronization and small external magnetics. |
| Input Voltage Range | 4.5V to 38V bias supply; operates down to 2.5V after startup when biased from boost output - supports automotive cold-crank and wide-input industrial systems. |
| Quiescent Current | 28μA (one buck channel active in Sleep Mode) - extends runtime in always-on battery systems. |
| Feedback References | 0.8V ±1% for buck outputs; 1.2V ±1% for boost output - ensures tight regulation across temperature and load. |
| Package | 38-lead 5mm × 7mm QFN with exposed PGND pad - provides low thermal resistance (θJA = 34.7°C/W) and robust grounding for high-current gate drivers. |
| Gate Drivers | TG1/TG2 pull-up: 2.5Ω; TG3/BG3 pull-up: 1.2Ω - supports fast switching of high-side N-MOSFETs with minimal dead-time loss. |
Pinout & Package
Package: 38-lead (5mm × 7mm) plastic QFN with exposed PGND pad (Pin 39), requiring soldering to PCB for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FREQ (1) | Oscillator frequency programming | Resistor-to-GND sets VCO frequency from 320kHz to 2.25MHz; tied to GND or INTVCC selects fixed 0.94MHz or 1.44MHz. |
| PLLIN/MODE (2) | Synchronization input / light-load mode select | Accepts external clock for phase-locking; voltage level selects Burst Mode® (GND), pulse-skipping (1.2V–INTVCC−1.3V), or forced continuous (INTVCC). |
| SS3 (3) | Boost soft-start control | Internal 5µA pull-up charges external capacitor to ramp VOUT3; regulates VFB3 to smaller of 1.2V or SS3 voltage. |
| SENSE3+ (4) | Boost current sense positive input | Supplies current to internal comparator; used with SENSE3− to set peak current limit based on ITH3 voltage. |
| SENSE3− (5) | Boost current sense negative input | Common-mode range: 2.5V to 40V - enables high-side sensing in boost input path up to 38V. |
| VFB3 (6) | Boost feedback input | Compares output voltage (via resistor divider) to 1.2V reference; OV3 asserts when VFB3 exceeds 110% of setpoint. |
| ITH3 (7) | Boost error amplifier output | Controls current limit threshold; higher ITH3 increases peak inductor current and improves transient response. |
| SGND (8) | Small-signal ground reference | Must be routed separately from PGND to avoid noise coupling into sensitive analog circuits (VFB, ITH, TRACK/SS). |
| RUN1 (9) | Buck Channel 1 enable | Threshold: 1.18V–1.33V rising; hysteresis 70mV - allows independent sequencing and fault isolation per rail. |
| RUN2 (10) | Buck Channel 2 enable | Same threshold/hysteresis as RUN1; enables staggered startup or dynamic rail disable during low-power states. |
| RUN3 (11) | Boost Channel 3 enable | Same threshold/hysteresis as RUN1; permits boost activation only when system requires >VIN output. |
| SENSE2− (12) | Buck Channel 2 current sense negative | Supplies current to comparator when VSENSE2− > INTVCC + 0.5V - supports high-side RSENSE placement. |
| SENSE2+ (13) | Buck Channel 2 current sense positive | Differential input with ±1µA bias - enables accurate current sensing with minimal offset error. |
| VFB2 (14) | Buck Channel 2 feedback input | Regulates to 0.8V reference; PGOOD1 monitors only VFB1, so external monitoring required for VOUT2/VOUT3. |
| ITH2 (15) | Buck Channel 2 error amplifier output | Directly controls current limit and loop compensation; connects to external RC network for OPTI-LOOP tuning. |
| TRACK/SS2 (16) | Buck Channel 2 tracking/soft-start | Regulates VFB2 to smaller of 0.8V or applied voltage - enables precise voltage ramping or tracking of another supply. |
| OV3 (17) | Boost overvoltage indicator | Open-drain output pulled low when VFB3 < 90% of setpoint; high-Z when VFB3 > 110% - provides fault signaling without external logic. |
| TG2 (18) | Buck Channel 2 top-gate driver | Drives high-side N-MOSFET gate with 2.5Ω pull-up/1.5Ω pull-down - supports fast turn-on/turn-off at up to 2.25MHz. |
| SW2 (19) | Buck Channel 2 switch node | Connects to inductor and bootstrap capacitor; voltage swings from GND to VIN - requires low-inductance layout for EMI control. |
| BOOST2 (20) | Buck Channel 2 bootstrap supply | Charged via Schottky diode from INTVCC; supplies floating gate drive for TG2 - enables 100% duty cycle in dropout. |
| BG2 (21) | Buck Channel 2 bottom-gate driver | Drives synchronous rectifier with 2.4Ω pull-up/1.1Ω pull-down - minimizes conduction loss in high-current paths. |
| 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 | Bypasses internal VBIAS LDO when >4.7V; reduces power loss and heat generation in high-input-voltage applications. |
| VBIAS (24) | Main bias supply input | 4.5V–38V operating range; powers internal LDO generating INTVCC - must be bypassed to SGND with ceramic capacitor. |
| BOOST3 (26) | Boost Channel 3 bootstrap supply | Supports high-side N-MOSFET drive in boost stage; voltage swing = INTVCC superimposed on SW3 - enables efficient 60V boost capability. |
| TG3 (27) | Boost Channel 3 top-gate driver | 1.2Ω pull-up/1.0Ω pull-down - optimized for fast switching of high-voltage boost FETs with minimal shoot-through risk. |
| SW3 (28) | Boost Channel 3 switch node | Connects to boost inductor and output diode/FET; voltage swings from GND to VOUT3 - critical for high-voltage layout and snubber design. |
| BG3 (29) | Boost Channel 3 bottom-gate driver | 1.2Ω pull-up/1.0Ω pull-down - drives synchronous rectifier in boost stage for highest efficiency at light loads. |
| BOOST1 (30) | Buck Channel 1 bootstrap supply | Identical function to BOOST2; enables independent bootstrap for Channel 1 with minimal cross-talk. |
| SW1 (31) | Buck Channel 1 switch node | Primary switching node for first buck rail; 180° out-of-phase with SW2 to reduce input ripple current. |
| TG1 (32) | Buck Channel 1 top-gate driver | 2.5Ω pull-up/1.5Ω pull-down - matches TG2 specs for balanced dual-buck performance. |
| PGOOD1 (33) | Buck Channel 1 power-good indicator | Open-drain output asserted low when VFB1 deviates >±10% from 0.8V - enables system-level power sequencing and fault detection. |
| TRACK/SS1 (34) | Buck Channel 1 tracking/soft-start | Same function as TRACK/SS2; allows coordinated startup with other rails or external voltage sources. |
| ITH1 (35) | Buck Channel 1 error amplifier output | Primary compensation point for Channel 1 loop; connects to external RC network for bandwidth and phase margin tuning. |
| VFB1 (36) | Buck Channel 1 feedback input | Monitored by PGOOD1; regulates to 0.8V reference with ±1% accuracy over –40°C to 125°C. |
| SENSE1+ (37) | Buck Channel 1 current sense positive | ±1µA bias current - ensures stable current sensing with low-noise RSENSE networks. |
| SENSE1− (38) | Buck Channel 1 current sense negative | Same common-mode behavior as SENSE2−; supports high-side or low-side sensing configurations. |
| PGND (39) | Power ground (exposed pad) | Must be soldered to PCB plane; connects to bottom-FET sources and CIN− - essential for thermal dissipation and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Triple independent controllers | Enables simultaneous regulation of three isolated rails (e.g., 5V, 3.3V, 10V) with independent sequencing, fault handling, and compensation. |
| OPTI-LOOP compensation | Allows stable loop response across wide ranges of output capacitance (e.g., 10µF–220µF) and ESR (1mΩ–100mΩ) without redesign. |
| Cold-crank operation | Maintains regulation on all outputs when input drops to 2.5V post-startup - critical for automotive stop-start systems. |
| 100% duty cycle support | Boost synchronous MOSFET remains fully enhanced during Burst Mode®, enabling seamless transition to dropout conditions. |
| Low IQ sleep mode | 28μA quiescent current with one buck channel active - extends battery life in IoT sensors and portable medical devices. |
| Phase-lockable frequency | 320kHz–2.25MHz synchronization eliminates beat frequencies in multi-converter systems and simplifies EMI filtering. |
Applications
| Automotive Start-Stop Systems | Battery-Powered Digital Devices |
|---|---|
Use Scenario: Power management in vehicles with engine auto-stop functionality, where battery voltage dips to 2.5V during cranking. IC Role / Device Role / Timing Role: Triple-output controller regulating 5V infotainment, 3.3V MCU, and 10V display backlight from 12V battery with cold-crank resilience. Use Value: Maintains all system rails within spec during 2.5V input transients, eliminating brownouts and enabling reliable restart after stop. | Use Scenario: Portable test equipment requiring isolated 5V, 3.3V, and adjustable boost rail from single Li-ion cell (2.7V–4.2V). IC Role / Device Role / Timing Role: Buck/buck/boost controller generating multiple clean rails while minimizing standby power draw. Use Value: 28μA sleep current extends operational time between charges; phase-locking avoids audible noise in sensitive analog measurement circuits. |
| Distributed DC Power Systems | Multioutput Buck-Boost Applications |
Use Scenario: Industrial PLC backplane supplying 24V, 12V, and 5V from 36V intermediate bus with strict efficiency targets. IC Role / Device Role / Timing Role: High-efficiency triple controller replacing three discrete ICs, reducing board area and BOM count. Use Value: 2.25MHz operation allows use of 0.33µH inductors, cutting solution size by >40% vs. 500kHz alternatives. | Use Scenario: USB-C PD sink negotiating variable input (5V–20V) while delivering fixed 5V, 3.3V, and boosted 12V to peripherals. IC Role / Device Role / Timing Role: Adaptive topology controller selecting optimal buck/buck/boost configuration per rail based on input voltage. Use Value: Seamless transition between buck-only (VIN > VOUT) and buck-boost (VIN < VOUT) modes maintains regulation without firmware intervention. |
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 |
|---|---|---|---|
| LTC7813EUHF#PBF | Dual buck + single boost, same 38-lead QFN package, but lacks independent RUN3 and OV3; max boost output 40V vs. 60V. | Not suitable for >40V boost applications or designs requiring independent boost enable/fault signaling. | Select LTC7815EUHF#PBF when 60V boost capability, OV3 monitoring, or individual RUN3 control is required. |
| MP2965GQZ | Triple buck controller only (no boost); 28-pin QFN; 4.5V–36V input; 0.5V reference; no PLL synchronization. | Cannot replace LTC7815EUHF#PBF in boost-required applications; limited to multi-buck systems with lower reference accuracy. | Choose MP2965GQZ only for cost-sensitive multi-buck designs where boost functionality is unnecessary and 0.8V reference is not mandatory. |
Compared with LTC7813EUHF#PBF and MP2965GQZ, the LTC7815EUHF#PBF uniquely delivers 60V boost capability, independent boost enable/fault signaling, and phase-lockable 2.25MHz operation - making it the only option for high-voltage, synchronized, triple-rail automotive and industrial power systems.
Availability
LTC7815EUHF#PBF is available at Aetrix Electronics and suitable for automotive start-stop systems, battery-operated digital devices, and distributed DC power systems requiring stable component supply, long-term lifecycle support, and guaranteed traceability.
Supply support for LTC7815EUHF#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC7815EUHF#PBF belongs to Analog Devices' Power by Linear™ controller family, designed specifically for high-efficiency, multi-rail DC/DC conversion in space-constrained and thermally demanding environments.
FAQ
What is the minimum input voltage required for the LTC7815EUHF#PBF to operate after startup?
The LTC7815EUHF#PBF can operate from an input supply as low as 2.5V after startup when biased from the output of the boost converter or another auxiliary supply. This cold-crank capability is critical for automotive applications where battery voltage sags during engine cranking. The device requires ≥4.5V on VBIAS for initial startup, but once running, it sustains regulation down to 2.5V on the bias source.
Does the LTC7815EUHF#PBF support synchronization to an external clock, and what is the valid frequency range?
Yes, the LTC7815EUHF#PBF supports external synchronization via the PLLIN/MODE pin. When an external clock is applied, the phase-locked loop forces the rising edge of TG1 to align with the external clock's rising edge. The valid synchronizable frequency range is 320kHz to 2.25MHz, matching its internal programmable oscillator range. Input logic thresholds are VIH = 2.5V and VIL = 0.5V.
How does the LTC7815EUHF#PBF achieve low quiescent current, and what is the typical value in sleep mode?
The LTC7815EUHF#PBF achieves low quiescent current through optimized bias circuitry and selective shutdown of unused channels. In Sleep Mode with one buck channel active, the typical quiescent current is 28μA at 25°C. This value increases to 33–59μA depending on channel combination (e.g., buck + boost) and temperature, enabling extended battery life in always-on systems without sacrificing startup speed.
What is the purpose of the EXTVCC pin on the LTC7815EUHF#PBF, and how does it affect efficiency?
The EXTVCC pin on the LTC7815EUHF#PBF accepts an external 4.7V–14V supply to power the internal INTVCC LDO, bypassing the VBIAS-powered LDO. When EXTVCC exceeds 4.7V, it reduces power dissipation in the internal regulator, lowering die temperature and improving overall system efficiency - especially beneficial in high-input-voltage applications (e.g., 24V or 36V industrial buses) where VBIAS-to-INTVCC dropout loss would otherwise be significant.
Can the LTC7815EUHF#PBF regulate all three outputs independently, and how is this implemented?
Yes, the LTC7815EUHF#PBF regulates all three outputs independently using separate feedback (VFB1/VFB2/VFB3), error amplifiers (ITH1/ITH2/ITH3), current sense (SENSE1+/−, SENSE2+/−, SENSE3+/−), and enable (RUN1/RUN2/RUN3) circuits. Each channel has dedicated soft-start (TRACK/SS1/2, SS3), overvoltage protection (PGOOD1 for Channel 1, OV3 for Channel 3), and programmable frequency control - enabling fully autonomous operation of buck/buck/boost rails with no shared control dependencies.
LTC7815EUHF#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:
- 0°C ~ 85°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-QFN (5x7)
LTC7815EUHF#PBF FAQ
1.How can I place an order for LTC7815EUHF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7815EUHF#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 LTC7815EUHF#PBF reliable?
The price and inventory of LTC7815EUHF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7815EUHF#PBF is usually 5 days.
3.What payment methods are accepted for LTC7815EUHF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7815EUHF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7815EUHF#PBF?
LTC7815EUHF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7815EUHF#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 LTC7815EUHF#PBF?
For technical support, including LTC7815EUHF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7815EUHF#PBF requirements.
6.How does Aetrix verify that LTC7815EUHF#PBF is sourced from the original manufacturer or authorized distributors?
All LTC7815EUHF#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 LTC7815EUHF#PBF meets industry standards.
7.What is the process for return or replacement of LTC7815EUHF#PBF?
All LTC7815EUHF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7815EUHF#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 LTC7815EUHF#PBF part is unused and in its original packaging.
Return procedure for LTC7815EUHF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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