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Analog Devices Inc. LTC7817EUHF#TRPBF
- Part No.:
- LTC7817EUHF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC7817EUHF#TRPBF.pdf
- Description:
- 40V, 8UA IQ, 3MHZ, TRPLE BCKBST
- Quantity:
- Payment:
- Shipping:
Inventory:3,672
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Product details
Overview
LTC7817EUHF#TRPBF from Analog Devices is a triple-output synchronous DC/DC controller implementing two independent buck stages and one boost stage, all driving N-channel MOSFETs. It operates from 4.5V–40V input (or down to 1V post-startup), delivers up to 40V on buck/boost outputs, supports 100kHz–3MHz programmable switching frequency, and features 14μA no-load quiescent current - enabling high-efficiency power conversion in automotive cold-crank and battery-backed industrial systems.
For engineers reviewing the LTC7817EUHF#TRPBF datasheet, LTC7817EUHF#TRPBF pinout, LTC7817EUHF#TRPBF application, or LTC7817EUHF#TRPBF equivalent, key selection criteria include its AEC-Q100 qualification, PassThru™ boost capability for automotive start-stop, OPTI-LOOP® compensation for wide output capacitor/ESR tolerance, and dual-buck phase interleaving for reduced input ripple.
Technical Context
The LTC7817EUHF#TRPBF uses constant-frequency peak current mode control with independent clock generation per channel: buck channels 1 and 2 operate 180° out-of-phase, while boost channel 3 aligns with channel 1. Its architecture supports RSENSE or DCR current sensing, selectable light-load modes (Burst, Pulse-Skipping, Forced Continuous), and precise voltage references: 0.8V for bucks and 1.2V (or 8V/10V fixed) for boost via VPRG3 pin configuration.
It integrates three gate drivers (TG/BG per channel), internal 5.1V INTVCC LDO, EXTVCC switchover LDO, and a phase-lockable oscillator. The controller maintains regulation during cold-crank events (VIN ≥1V after startup), enables 99% buck duty cycle for ultra-low dropout, and provides PassThru™ operation (100% boost duty cycle) to minimize losses when VIN approaches or exceeds VOUT3.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | Dual buck + single boost synchronous controller - enables compact, high-efficiency multi-rail supplies without external logic coordination |
| Input Voltage Range | 4.5V–40V (VBIAS); 1V–40V (VIN post-startup) - supports automotive battery transients and wide industrial input ranges |
| Switching Frequency | 100kHz–3MHz programmable (via FREQ pin resistor) or phase-locked - allows EMI optimization and small magnetics |
| No-Load Quiescent Current | 14μA (14V→3.3V, Channel 1 active) - extends runtime in always-on battery systems |
| Reference Voltages | 0.8V ±12mV (buck), 1.2V ±18mV (boost, VPRG3 floating) - ensures tight output regulation across temperature |
| Output Voltage Range | Buck: 0.8V–40V; Boost: up to 40V - supports diverse rail requirements including 3.3V, 5V, 12V, and 24V outputs |
| Package | 38-lead 5mm × 7mm QFN with exposed PGND pad - provides low thermal resistance (θJA = 34.7°C/W) and robust automotive-grade layout |
Pinout & Package
Package: 38-lead (5mm × 7mm) plastic QFN with exposed PGND pad (Pin 39), rated for –40°C to 125°C junction temperature. Exposed pad must be soldered to PCB ground for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FREQ (1) | Oscillator frequency programming | Resistor-to-ground sets 100kHz–3MHz; GND = 380kHz, INTVCC = 2.25MHz - enables precise EMI control |
| PLLIN/MODE (2) | External sync input / light-load mode select | Accepts external clock for phase-locking; GND/floating = Burst Mode, INTVCC = forced continuous - critical for noise-sensitive applications |
| SS3 (3) | Boost soft-start control | 1mA pull-up; capacitor to ground sets ramp time (1ms/10nF) - prevents inrush into boost output |
| SENSE3+ (4) | Boost current sense positive input | Supplies current to comparator when >INTVCC - enables accurate high-side sensing in boost topology |
| SENSE3– (5) | Boost current sense negative input | Current sink; >INTVCC enables sleep-mode current sourcing - reduces system-level IQ |
| VFB3 (6) | Boost feedback input | Regulated to 1.2V (or tied directly to output if VPRG3 = GND/INTVCC for 8V/10V fixed) - defines boost output voltage |
| ITH3 (7) | Boost error amplifier output | Controls current limit threshold; compensation network connects here - determines transient response and stability |
| SGND (8) | Small-signal ground reference | Must be isolated from PGND and CIN– - prevents noise coupling into sensitive analog circuitry |
| RUN1 (9) | Buck channel 1 enable | Threshold = 1.20V (±50mV hysteresis); <1.1V disables channel - supports independent rail sequencing |
| RUN2 (10) | Buck channel 2 enable | Same threshold as RUN1 - enables independent control of second buck output |
| RUN3 (11) | Boost channel enable | Same threshold as RUN1 - allows staged startup of boost rail |
| SENSE2– (12) | Buck channel 2 current sense negative | Sinks current when >INTVCC - contributes to ultra-low IQ sleep mode |
| SENSE2+ (13) | Buck channel 2 current sense positive | Differential input for RSENSE/DCR sensing - sets overcurrent trip point with ITH2 |
| VFB2 (14) | Buck channel 2 feedback input | Regulated to 0.8V; tie to INTVCC for two-phase single-output configuration - simplifies dual-buck parallel design |
| ITH2 (15) | Buck channel 2 error amplifier output | Compensation node; same function as ITH1 - enables independent loop tuning per buck channel |
| TRACK/SS2 (16) | Buck channel 2 tracking/soft-start | 12.5µA pull-up; tracks external supply or sets ramp time (0.65ms/10nF) - ensures controlled startup |
| VPRG3 (17) | Boost output voltage programming | Float = adjustable (via VFB3), GND = 8V fixed, INTVCC = 10V fixed - eliminates external resistors for common boost rails |
| TG2 (18) | Buck channel 2 top-gate driver | Drives N-MOSFET gate with INTVCC-referenced swing - requires BOOST2 capacitor for bootstrap operation |
| SW2 (19) | Buck channel 2 switch node | Connects to inductor and bottom MOSFET source - high di/dt node requiring careful layout |
| BOOST2 (20) | Buck channel 2 bootstrap supply | Capacitor between BOOST2 and SW2 generates floating gate drive - enables high-side N-MOSFET use |
| BG2 (21) | Buck channel 2 bottom-gate driver | Drives N-MOSFET gate from PGND to INTVCC - low-side driver with fast 15ns turn-off |
| INTVCC (22) | Internal 5.1V LDO output | Powers control circuitry and gate drivers; requires ≥4.7µF ceramic decoupling - primary bias for internal logic |
| EXTVCC (23) | External bias input for INTVCC LDO | Switchover at 4.7V; bypasses VBIAS LDO when active - reduces total system IQ by shifting bias current |
| VBIAS (24) | Main bias supply input | 4.5V–40V range; powers internal LDO and logic - primary supply when EXTVCC not used |
| BG3 (25) | Boost channel bottom-gate driver | Drives N-MOSFET gate from PGND to INTVCC - configured as low-side switch in boost topology |
| BOOST3 (26) | Boost channel bootstrap supply | Capacitor between BOOST3 and SW3 generates floating gate drive for TG3 - enables high-side N-MOSFET in boost |
| TG3 (27) | Boost channel top-gate driver | Drives N-MOSFET gate with INTVCC-referenced swing - supports PassThru™ 100% duty cycle operation |
| SW3 (28) | Boost channel switch node | Connects to inductor and diode/capacitor - high-voltage node reaching up to VOUT3 + INTVCC |
| BG1 (29) | Buck channel 1 bottom-gate driver | Same function as BG2 - enables interleaved operation with channel 2 for lower input ripple |
| BOOST1 (30) | Buck channel 1 bootstrap supply | Same function as BOOST2 - forms bootstrap loop with SW1 and TG1 |
| SW1 (31) | Buck channel 1 switch node | Same function as SW2 - primary high-current path for first buck stage |
| TG1 (32) | Buck channel 1 top-gate driver | Same function as TG2 - drives high-side N-MOSFET with synchronized 180° phase offset |
| PGOOD1 (33) | Power-good indicator for VOUT1 | Open-drain output asserting when VOUT1 deviates >±10% - enables system monitoring and fault handling |
| TRACK/SS1 (34) | Buck channel 1 tracking/soft-start | Same function as TRACK/SS2 - supports rail sequencing with other supplies |
| ITH1 (35) | Buck channel 1 error amplifier output | Same function as ITH2 - independent compensation for first buck loop |
| VFB1 (36) | Buck channel 1 feedback input | Regulated to 0.8V - primary feedback for main buck output |
| SENSE1+ (37) | Buck channel 1 current sense positive | Same function as SENSE2+ - differential input for accurate current limiting |
| SENSE1– (38) | Buck channel 1 current sense negative | Same function as SENSE2– - enables IQ reduction via current sourcing above 3.2V |
| PGND (39) | Power ground (exposed pad) | Connects to MOSFET sources and CIN– - mandatory solder connection for thermal management and noise control |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 qualified | Rated for automotive applications (–40°C to 125°C), supporting ISO 16750-2 load dump and cold-crank requirements |
| PassThru™ boost operation | 100% duty cycle capability minimizes conduction loss when VIN ≥ VOUT3 - essential for automotive start-stop efficiency |
| OPTI-LOOP® compensation | Allows stable loop response across wide range of output capacitor values and ESR - reduces design iterations for different bulk capacitance |
| Ultra-low 14μA quiescent current | Enables >1-year battery life in always-on telematics modules powered from 12V lead-acid with 3.3V/5V rails |
| 180° interleaved dual buck | Halves input ripple current vs. single-phase design - reduces required input capacitance and EMI filter size |
| VPRG3-programmable boost output | Selects 8V or 10V fixed output without external resistors - simplifies BOM and layout for common infotainment supply rails |
Applications
| Automotive Infotainment Power Supply | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering head unit SoC (3.3V/1.2V), display backlight (12V), and CAN transceiver (5V) from 9V–16V battery with cold-crank support. IC Role / Device Role / Timing Role: Triple-output controller generating three independent regulated rails with coordinated soft-start and PGOOD monitoring. Use Value: Eliminates need for discrete regulators and sequencing ICs; PassThru™ maintains 12V rail during 1V cold-crank events without brownout. |
Use Scenario: Providing 5V logic, 24V field power, and isolated 3.3V sensor interface from 24V industrial bus with high EMC immunity. IC Role / Device Role / Timing Role: Dual-buck (5V/3.3V) + boost (24V) controller with interleaved operation reducing conducted EMI. Use Value: 180° phase shift cuts input ripple by 50%, allowing smaller input capacitors and meeting EN 61000-6-4 Class A limits. |
| Avionics Remote Data Concentrator | Military Vehicle Communication Node |
Use Scenario: Converting 28V aircraft bus to 5V FPGA core, 3.3V peripherals, and 12V RF front-end in space-constrained enclosure. IC Role / Device Role / Timing Role: High-density triple-output controller with 5mm×7mm QFN package and integrated gate drivers. Use Value: Reduces component count by 7 parts vs. discrete controllers; AEC-Q100 qualification meets DO-160D section 20 environmental stress requirements. |
Use Scenario: Powering encrypted radio baseband (1.8V), PA bias (12V), and 5V USB host from 24V vehicle battery with MIL-STD-1275E compliance. IC Role / Device Role / Timing Role: Controller supporting 1V cold-crank hold-up and programmable 100kHz–3MHz switching for EMI tailoring. Use Value: 3MHz option enables use of 1.0µH inductors, shrinking solution size by 40% vs. 500kHz designs while maintaining efficiency >90%. |
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#TRPBF | Single buck + dual boost topology; no PassThru™; 1.2V boost reference only (no 8V/10V fixed option) | Better suited for applications requiring two independent boost outputs (e.g., dual-display backlight), less optimal for automotive cold-crank | Select when needing dual boost rather than dual buck; verify cold-crank behavior with external circuitry |
| MP2918GL-Z | Triple buck-only controller; no boost capability; max input 28V; no AEC-Q100 rating; 25μA IQ | Targeted at cost-sensitive industrial computing, not automotive or high-voltage boost applications | Choose for pure multi-rail buck systems below 28V where boost functionality is unnecessary |
Compared with LTC7817EUHF#TRPBF, the LTC7813EUHF#TRPBF offers dual boost but lacks PassThru™ and cold-crank resilience, while the MP2918GL-Z provides triple buck at lower cost and voltage range but omits boost entirely - making LTC7817EUHF#TRPBF uniquely suited for automotive and industrial systems requiring buck/buck/boost with AEC-Q100 compliance.
Availability
LTC7817EUHF#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC I/O modules, and avionics remote data concentrators requiring stable component supply, AEC-Q100 qualification, and cold-crank operation down to 1V.
Supply support for LTC7817EUHF#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving automotive, industrial, communications, and aerospace markets.
The LTC7817EUHF#TRPBF belongs to the Power by Linear™ controller family, designed specifically for high-efficiency, multi-rail DC/DC conversion in harsh environments - emphasizing ultra-low IQ, wide input range, and automotive reliability.
FAQ
What is the minimum input voltage for LTC7817EUHF#TRPBF after startup?
The LTC7817EUHF#TRPBF maintains regulation with input voltages as low as 1V after startup when biased from the boost output or an auxiliary supply. This capability is critical for automotive cold-crank scenarios where battery voltage dips below 6V. The controller achieves this by operating its internal circuitry from INTVCC or EXTVCC rather than directly from VBIAS during low-VIN conditions. Full functionality, including gate drive strength and reference accuracy, is preserved across the 1V–40V post-startup range.
How does the LTC7817EUHF#TRPBF achieve ultra-low quiescent current?
The LTC7817EUHF#TRPBF achieves 14μA no-load IQ through multiple design techniques: intelligent current sourcing from SENSE1–/SENSE2– pins (≥3.2V), EXTVCC switchover to bypass the VBIAS LDO, and optimized sleep-mode biasing. When SENSE1– ≥3.2V, it supplies most of the sleep-mode current instead of VBIAS, reducing input-referred IQ. Combined with selective channel shutdown and Burst Mode operation, this enables >1-year battery life in always-on telematics applications powered from 12V lead-acid batteries.
Can LTC7817EUHF#TRPBF support phase-interleaved operation between its two buck channels?
Yes, the LTC7817EUHF#TRPBF natively supports 180° phase interleaving between buck channels 1 and 2. This is implemented in hardware and requires no external synchronization components. Interleaving reduces input ripple current by up to 50% compared to parallel non-interleaved operation, allowing smaller input capacitors and lower EMI filter requirements. The feature is active by default and enhances system efficiency and thermal performance in high-current applications like automotive ADAS domain controllers.
What are the boost output voltage options for LTC7817EUHF#TRPBF?
The LTC7817EUHF#TRPBF supports three boost output configurations via the VPRG3 pin: floating (adjustable via external resistor divider on VFB3, regulated to 1.2V), grounded (fixed 8V output), or tied to INTVCC (fixed 10V output). This flexibility eliminates the need for external feedback resistors in common automotive applications requiring standardized 8V or 10V rails for displays or sensors, while retaining full adjustability for custom voltage requirements.
Is LTC7817EUHF#TRPBF compatible with both RSENSE and DCR current sensing?
Yes, the LTC7817EUHF#TRPBF supports both RSENSE and DCR current sensing on all three channels. For RSENSE, connect the sense resistor between the switch node and PGND, feeding SENSE+ and SENSE–. For DCR, use the inductor's DC resistance with an RC network from SWx to SENSEx– and from SENSEx+ to INTVCC. The controller's current comparator accepts either method, and the ITH voltage adjusts the current limit threshold accordingly - providing design flexibility for efficiency vs. cost trade-offs.
LTC7817EUHF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 38-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck, Boost
- Number of Outputs:
- 3
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 40V
- Frequency - Switching:
- 100kHz ~ 3MHz
- Duty Cycle (Max):
- 100%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-QFN (5x7)
LTC7817EUHF#TRPBF FAQ
1.How can I place an order for LTC7817EUHF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7817EUHF#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 LTC7817EUHF#TRPBF reliable?
The price and inventory of LTC7817EUHF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7817EUHF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC7817EUHF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7817EUHF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7817EUHF#TRPBF?
LTC7817EUHF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7817EUHF#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 LTC7817EUHF#TRPBF?
For technical support, including LTC7817EUHF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7817EUHF#TRPBF requirements.
6.How does Aetrix verify that LTC7817EUHF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC7817EUHF#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 LTC7817EUHF#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC7817EUHF#TRPBF?
All LTC7817EUHF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7817EUHF#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 LTC7817EUHF#TRPBF part is unused and in its original packaging.
Return procedure for LTC7817EUHF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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