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Analog Devices Inc. LTC7817JUHF#WTRPBF
- Part No.:
- LTC7817JUHF#WTRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC7817JUHF#WTRPBF.pdf
- Description:
- 40V, 8UA IQ, 3MHZ, TRPLE BCKBST
- Quantity:
- Payment:
- Shipping:
Inventory:2,869
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Product details
Overview
LTC7817JUHF#WTRPBF from Analog Devices is a high-performance triple-output synchronous DC/DC controller (buck/buck/boost) driving all-N-channel MOSFET stages, featuring 4.5V–40V input range, 3MHz max switching frequency, 14μA no-load quiescent current, AEC-Q100 qualification, and PassThru™ boost operation for automotive cold-crank resilience down to 1V input. It enables compact, efficient power architectures in start-stop automotive ECUs.
For engineers reviewing the LTC7817JUHF#WTRPBF datasheet, LTC7817JUHF#WTRPBF pinout, LTC7817JUHF#WTRPBF application, or LTC7817JUHF#WTRPBF equivalent, this page delivers verified technical context, exact pin functions, confirmed automotive-grade thermal specs (–40°C to 150°C), real-world efficiency curves, and validated alternative options - all grounded in the official Rev A datasheet and Analog Devices' published electrical characteristics.
Technical Context
The LTC7817JUHF#WTRPBF implements a constant-frequency peak current-mode architecture with independent control loops per channel: two 180°-out-of-phase buck controllers (Channels 1 & 2) and one boost controller (Channel 3) synchronized to Channel 1. Its OPTI-LOOP® compensation supports wide output capacitance/ESR ranges without external tuning.
It integrates three gate drivers (TG/BG per channel), dual LDOs (INTVCC at 5.1V, EXTVCC switchover at 4.7V), programmable frequency (100kHz–3MHz via FREQ pin or PLLIN/MODE), and selectable light-load modes (Burst, Pulse-Skipping, Forced Continuous). The VPRG3 pin configures boost output to 8V, 10V, or adjustable via VFB3.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V–40V bias supply; operates down to 1V after startup when biased from boost output or auxiliary rail - enables cold-crank survival in automotive systems. |
| Switching Frequency | Programmable 100kHz–3MHz (fixed or phase-lockable); 380kHz default (FREQ = GND), 2.25MHz (FREQ = INTVCC) - supports high-density designs with small magnetics. |
| Quiescent Current | 14μA (14V→3.3V, Channel 1 active); 1.5μA shutdown - extends battery runtime in always-on vehicle modules. |
| Output Voltage References | 0.8V ±12mV (buck channels, 0°C–85°C); 1.2V ±18mV (boost, VPRG3 = FLOAT) - ensures tight regulation across temperature for safety-critical rails. |
| Max Duty Cycle | 99% (buck TG), 100% (boost BG PassThru™) - maintains regulation during deep input dips (e.g., 1V cold crank) without dropout. |
| Operating Junction Temp | –40°C to 150°C (J-grade) - qualified per AEC-Q100 Grade 1 for under-hood automotive applications. |
| Package | 38-lead 5mm × 7mm QFN with exposed PGND pad - provides low thermal resistance (θJA = 34.7°C/W) and robust EMI performance. |
Pinout & Package
38-lead plastic QFN (5mm × 7mm), exposed thermal pad (Pin 39 = PGND), RoHS-compliant, tape-and-reel packaged. Requires soldering of exposed pad to PCB ground for rated thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FREQ (1) | Oscillator frequency programming | Sets switching frequency: GND = 380kHz, INTVCC = 2.25MHz, resistor-to-GND enables 100kHz–3MHz tuning - critical for EMI compliance and layout optimization. |
| PLLIN/MODE (2) | Sync input / light-load mode select | Accepts external clock for phase-locking; selects Burst Mode (GND/floating), Pulse-Skipping (100kΩ to INTVCC), or Forced Continuous (INTVCC) - directly controls efficiency vs. noise trade-off. |
| SS3 (3) | Boost soft-start control | Soft-start ramp for Channel 3: 1ms/10nF capacitor - prevents inrush into high-capacitance loads like infotainment displays. |
| SENSE3+ (4) | Boost current sense positive input | Differential input for RSENSE/DCR sensing; supplies current to comparator when > INTVCC - enables accurate overcurrent protection in boost path. |
| SENSE3– (5) | Boost current sense negative input | Differential input tied to boost switch node; supplies current to comparator when > INTVCC - completes current sensing loop with SENSE3+. |
| VFB3 (6) | Boost feedback voltage input | Regulates to 1.2V reference (VPRG3 = FLOAT) or connects directly to output (VPRG3 = GND/INTVCC for 8V/10V fixed) - defines final boost output accuracy. |
| ITH3 (7) | Boost error amplifier output | Compensation node for boost loop; sets current limit threshold with SENSE3± - requires RC network to ground for stability. |
| SGND (8) | Small-signal ground reference | Common analog ground for all three controllers; must be routed separately from PGND to avoid noise coupling into feedback paths. |
| RUN1 (9) | Buck Channel 1 enable | Logic-level control: <1.1V disables Channel 1; <0.7V shuts down entire IC - enables independent sequencing of multiple rails. |
| RUN2 (10) | Buck Channel 2 enable | Independent enable for second buck; allows dynamic reconfiguration (e.g., disable non-critical rail during low-power mode). |
| RUN3 (11) | Boost Channel 3 enable | Independent enable for boost; critical for systems requiring backup power only during specific events (e.g., CAN wake-up). |
| SENSE2– (12) | Buck Channel 2 current sense negative | Differential input tied to Channel 2 switch node; supplies current to comparator when > INTVCC - completes current sensing for buck 2. |
| SENSE2+ (13) | Buck Channel 2 current sense positive | Differential input for RSENSE/DCR; matches SENSE1± within ±3.5mV - ensures balanced current sharing in dual-buck configurations. |
| VFB2 (14) | Buck Channel 2 feedback input | Regulates to 0.8V reference; tie to INTVCC for two-phase single-output configuration sharing VFB1/ITH1/SS1 - reduces component count for high-current rails. |
| ITH2 (15) | Buck Channel 2 error amplifier output | Compensation node; sets current limit with SENSE2± - identical design meaning as ITH1/ITH3 but isolated per channel. |
| TRACK/SS2 (16) | Buck Channel 2 tracking/soft-start | Enables output tracking (via resistor divider) or soft-start (capacitor to ground: 0.65ms/10nF) - ensures controlled power-up sequence with other system rails. |
| VPRG3 (17) | Boost output voltage programming | Selects 8V (GND), 10V (INTVCC), or adjustable (FLOAT) - eliminates external resistors for common automotive boost voltages. |
| TG2 (18) | Buck Channel 2 top-gate driver | Floating N-channel driver output; swing = SW2 + INTVCC - drives high-side MOSFET with precise timing (15ns off-to-on delay). |
| SW2 (19) | Buck Channel 2 switch node | Connection point for inductor and bottom MOSFET source; high di/dt node requiring tight layout and local decoupling. |
| BOOST2 (20) | Buck Channel 2 bootstrap supply | Bootstrapped supply for TG2; connect capacitor between BOOST2 and SW2, plus Schottky to INTVCC - sustains high-side drive during 100% duty cycle. |
| BG2 (21) | Buck Channel 2 bottom-gate driver | Ground-referenced N-channel driver; swing = 0V to INTVCC - drives low-side MOSFET with 1.0Ω pull-down resistance. |
| INTVCC (22) | Internal 5.1V LDO output | Powers internal logic and gate drivers; requires ≥4.7μF ceramic decoupling - primary bias source unless EXTVCC is used. |
| EXTVCC (23) | External bias input for INTVCC LDO | Switchover at 4.7V; bypasses VBIAS LDO to reduce total quiescent current - ideal for biasing from buck output rails. |
| VBIAS (24) | Main bias input supply | Primary power input (4.5V–40V); supplies INTVCC LDO when EXTVCC < 4.7V - must be bypassed locally to PGND. |
| BG3 (25) | Boost Channel 3 bottom-gate driver | Drives boost low-side MOSFET; 1.0Ω pull-down - enables 100% duty cycle PassThru™ operation during cold crank. |
| BOOST3 (26) | Boost Channel 3 bootstrap supply | Bootstrapped supply for TG3; swing = VOUT3 + INTVCC - supports high-voltage boost outputs up to 40V. |
| TG3 (27) | Boost Channel 3 top-gate driver | Floating driver for boost high-side MOSFET; 15ns off-to-on delay - ensures precise timing for high-efficiency boost conversion. |
| SW3 (28) | Boost Channel 3 switch node | Connection for boost inductor and low-side MOSFET; high dv/dt node requiring careful routing and snubbing. |
| BG1 (29) | Buck Channel 1 bottom-gate driver | Ground-referenced driver (0V–INTVCC); 1.0Ω pull-down - identical to BG2/BG3 but dedicated to primary buck rail. |
| BOOST1 (30) | Buck Channel 1 bootstrap supply | Capacitor between BOOST1 and SW1 + Schottky to INTVCC - standard bootstrap implementation for buck high-side drive. |
| SW1 (31) | Buck Channel 1 switch node | Primary buck switch node; interfaces with main processor/core rail inductor and input capacitors. |
| TG1 (32) | Buck Channel 1 top-gate driver | Floating driver with 2.0Ω pull-up/1.0Ω pull-down - optimized for fast switching at 3MHz with minimal shoot-through risk. |
| PGOOD1 (33) | Power-good indicator for Channel 1 | Open-drain output asserting when VOUT1 is within ±10% of regulation - provides system-level fault signaling to microcontroller. |
| TRACK/SS1 (34) | Buck Channel 1 tracking/soft-start | Same function as TRACK/SS2: tracking via divider or soft-start via capacitor (0.65ms/10nF) - enables coordinated startup with other system supplies. |
| ITH1 (35) | Buck Channel 1 error amplifier output | Main compensation node; transconductance = 1.8mmho - determines loop bandwidth and transient response for primary buck rail. |
| VFB1 (36) | Buck Channel 1 feedback input | Regulates to 0.8V ±12mV; monitors output via resistor divider - highest-precision feedback path for critical core voltage rails. |
| SENSE1+ (37) | Buck Channel 1 current sense positive | Differential input for RSENSE/DCR; matches SENSE2+ within ±3.5mV - ensures matched current limiting across dual bucks. |
| SENSE1– (38) | Buck Channel 1 current sense negative | Differential input tied to SW1; supplies sleep-mode current when ≥3.2V - reduces VBIAS-referred IQ by shifting bias to output rail. |
| PGND (39) | Power ground (exposed pad) | Connects to bottom MOSFET sources and CIN–; must be soldered to PCB ground plane - essential for thermal management and noise control. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Grade 1 qualification | Validated for –40°C to 150°C junction operation in automotive environments - meets reliability requirements for engine control, ADAS, and body electronics. |
| PassThru™ boost operation | 100% duty cycle capability on boost low-side MOSFET - maintains regulated output during 1V cold-crank events without dropout or reset. |
| OPTI-LOOP® compensation | Adapts loop response to wide range of output capacitor ESR and capacitance values - eliminates need for custom compensation per design. |
| Three independent light-load modes | Burst Mode (low IQ), Pulse-Skipping (low ripple), Forced Continuous (low noise) - selectable per application requirement without hardware change. |
| VPRG3-programmable boost output | Hardware-selectable 8V/10V/adjustable boost voltage - removes external resistor networks for common automotive backup rail voltages. |
| 14μA no-load quiescent current | Measured at 14V→3.3V with Channel 1 active - enables >1-year battery life in always-on telematics modules with periodic wake-up. |
Applications
| Automotive Engine Control Unit (ECU) | ADAS Camera Power Supply |
|---|---|
Use Scenario: Powering microcontroller, CAN transceiver, and sensor interface in under-hood ECU subject to cold-crank (1V) and load-dump (40V) transients. IC Role / Device Role / Timing Role: Triple-output controller generating 3.3V (core), 5V (peripherals), and 10V (sensor bias) with PassThru™ boost maintaining regulation during 1V input dips. Use Value: Eliminates need for separate boost converter and linear post-regulators; AEC-Q100 qualification ensures long-term reliability in harsh thermal environments. |
Use Scenario: Providing clean, sequenced 1.2V (image sensor core), 2.8V (sensor I/O), and 5V (ISP/FPGA) rails for automotive surround-view camera module. IC Role / Device Role / Timing Role: Dual-buck (1.2V/2.8V) with 180° interleaving reduces input ripple; boost (5V) powers high-current image signal processor with soft-start (SS3) preventing inrush. Use Value: 3MHz switching enables ultra-small 0805 inductors; low 14μA IQ extends battery backup time during vehicle sleep mode. |
| Industrial PLC I/O Module | Avionics Display Backlight Driver |
Use Scenario: Generating isolated 24V (field bus), 5V (logic), and 3.3V (microcontroller) from 24V nominal industrial supply with wide input tolerance. IC Role / Device Role / Timing Role: Buck/buck/boost topology uses 24V input to generate 24V (PassThru™ boost), 5V (buck), and 3.3V (buck) - avoids inefficient linear regulation. Use Value: 40V absolute max input rating withstands 36V transients; 150°C junction rating supports convection-cooled enclosures without forced air. |
Use Scenario: Driving LED backlight strings in cockpit display requiring 36V boost output, 5V logic rail, and 3.3V MCU rail from 28V aircraft supply. IC Role / Device Role / Timing Role: Boost channel configured for 36V output (VPRG3 = FLOAT, VFB3 divider); buck channels supply logic rails with independent RUN control for display power sequencing. Use Value: 40V max boost output supports long LED strings; phase-locked 3MHz operation minimizes EMI in sensitive avionics RF bands. |
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#WTRPBF | Dual-buck-only (no boost); 40V input; 15μA IQ; same 38-lead QFN package and AEC-Q100 Grade 1 rating. | Cannot replace LTC7817JUHF#WTRPBF in boost-required applications (e.g., cold-crank backup); suitable only when third output is generated externally. | Select when system already includes discrete boost stage or requires lower BOM cost without integrated boost functionality. |
| MPQ8645PGU-AEC1-Z | Monolithic triple-output buck/buck/boost (integrated MOSFETs); 3.5V–36V input; 25μA IQ; 40-pin QFN; AEC-Q100 Grade 1. | Lower external component count but limited to 12A/10A/6A max output currents; no PassThru™ mode; fixed 2.1MHz frequency. | Select for space-constrained designs where integrated FETs outweigh need for 100% boost duty cycle and programmable frequency. |
Compared with LTC7817JUHF#WTRPBF, the LTC7813IUHF#WTRPBF omits boost capability entirely - requiring external circuitry for cold-crank resilience - while the MPQ8645PGU-AEC1-Z trades programmability and PassThru™ flexibility for monolithic simplicity and reduced board area.
Availability
LTC7817JUHF#WTRPBF is available at Aetrix Electronics and suitable for automotive engine control units, ADAS camera modules, and industrial PLC I/O systems requiring stable component supply, AEC-Q100 qualification, and cold-crank resilience.
Supply support for LTC7817JUHF#WTRPBF 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 healthcare markets.
The LTC7817JUHF#WTRPBF belongs to Analog Devices' Power by Linear™ controller family, designed specifically for high-efficiency, high-reliability multi-rail power conversion in automotive and industrial environments with extreme input voltage transients.
FAQ
What is the maximum operating junction temperature for the LTC7817JUHF#WTRPBF?
The LTC7817JUHF#WTRPBF is rated for an operating junction temperature range of –40°C to 150°C and is qualified per AEC-Q100 Grade 1. This specification is explicitly stated in the "ORDER INFORMATION" table and "ABSOLUTE MAXIMUM RATINGS" section of the Rev A datasheet, confirming its suitability for under-hood automotive applications where ambient temperatures exceed 105°C.
Does the LTC7817JUHF#WTRPBF support 100% duty cycle operation in boost mode?
Yes, the LTC7817JUHF#WTRPBF supports 100% duty cycle operation on the boost low-side MOSFET (BG3) via its PassThru™ feature. This is documented in the "FEATURES" list ("PassThru™ Operation: 100% Duty Cycle for Boost Synchronous MOSFET") and enables uninterrupted regulation during automotive cold-crank events where input voltage drops to 1V.
How does the VPRG3 pin configure the boost output voltage on the LTC7817JUHF#WTRPBF?
The VPRG3 pin on the LTC7817JUHF#WTRPBF selects boost output voltage: floating for adjustable regulation via VFB3 (1.2V reference), GND for fixed 8V output, or INTVCC for fixed 10V output. This is specified in the "PIN FUNCTIONS" section (Page 10) and confirmed in the "ELECTRICAL CHARACTERISTICS" table (VFB3 values at VPRG3 = GND/INTVCC).
What is the typical quiescent current of the LTC7817JUHF#WTRPBF at no load?
The typical no-load quiescent current of the LTC7817JUHF#WTRPBF is 14μA, measured under conditions of 14V input to 3.3V output with only Channel 1 active and RUN2/RUN3 = 0V. This value is explicitly listed in the "FEATURES" section and verified in the "ELECTRICAL CHARACTERISTICS" table under "Controller Operation".
Can the LTC7817JUHF#WTRPBF synchronize its switching frequency to an external clock?
Yes, the LTC7817JUHF#WTRPBF can synchronize its switching frequency to an external clock applied to the PLLIN/MODE pin. The "ELECTRICAL CHARACTERISTICS" table specifies a synchronizable frequency range of 0.1MHz to 3MHz, and the "PIN FUNCTIONS" section confirms that an external clock forces the rising TG1 edge to align with the external clock's rising edge.
LTC7817JUHF#WTRPBF 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 ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-QFN (5x7)
LTC7817JUHF#WTRPBF FAQ
1.How can I place an order for LTC7817JUHF#WTRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7817JUHF#WTRPBF 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 LTC7817JUHF#WTRPBF reliable?
The price and inventory of LTC7817JUHF#WTRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7817JUHF#WTRPBF is usually 5 days.
3.What payment methods are accepted for LTC7817JUHF#WTRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7817JUHF#WTRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7817JUHF#WTRPBF?
LTC7817JUHF#WTRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7817JUHF#WTRPBF 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 LTC7817JUHF#WTRPBF?
For technical support, including LTC7817JUHF#WTRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7817JUHF#WTRPBF requirements.
6.How does Aetrix verify that LTC7817JUHF#WTRPBF is sourced from the original manufacturer or authorized distributors?
All LTC7817JUHF#WTRPBF 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 LTC7817JUHF#WTRPBF meets industry standards.
7.What is the process for return or replacement of LTC7817JUHF#WTRPBF?
All LTC7817JUHF#WTRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7817JUHF#WTRPBF, 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 LTC7817JUHF#WTRPBF part is unused and in its original packaging.
Return procedure for LTC7817JUHF#WTRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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