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Analog Devices Inc. LT8608BHDC#TRPBF
- Part No.:
- LT8608BHDC#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LT8608BHDC#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 1.5A 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,756
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Product details
Overview
LT8608BHDC#TRPBF from Analog Devices is a 42V, 1.5A synchronous step-down regulator with 2.5µA quiescent current in pulse-skipping mode, peak current mode control, and internal compensation. It delivers regulated 3.3V/5V outputs from automotive or industrial 12V/24V rails with <10mVP-P ripple and 92% efficiency at 0.5A. Designed for low-EMI battery-powered systems requiring ultralow IQ.
For engineers reviewing the LT8608BHDC#TRPBF datasheet, LT8608BHDC#TRPBF pinout, LT8608BHDC#TRPBF application, or LT8608BHDC#TRPBF equivalent, key selection criteria include its –40°C to 150°C junction temperature rating, 8-lead 2mm × 2mm DFN package with exposed pad, pulse-skipping operation (no SYNC pin), and 35ns minimum on-time enabling high VIN/VOUT ratios.
Technical Context
The LT8608BHDC#TRPBF implements a constant-frequency peak current mode architecture with internal 0.778V reference and fixed 8.5% PG threshold. Its pulse-skipping mode-hardwired in the DFN variant-maintains continuous oscillator operation and clock-aligned switching, differing fundamentally from Burst Mode's sleep-cycle behavior.
It features programmable switching frequency (200kHz–2.2MHz via RT resistor), 35ns minimum on-time for high duty-cycle operation, and integrated top/bottom NMOS switches with 350mΩ/230mΩ RDS(ON). The device lacks SYNC and TR/SS pins, confirming fixed pulse-skipping functionality and eliminating soft-start or tracking capability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.0V to 42V - supports 12V/24V automotive and industrial input rails without external pre-regulation. |
| Quiescent Current | 2.5µA typical at no load - enables >1-year battery life in always-on IoT sensors and telematics modules. |
| Output Current | 1.5A continuous - sufficient for powering microcontrollers, CAN transceivers, and analog front-ends from a single buck stage. |
| Switching Frequency | Programmable 200kHz–2.2MHz via RT resistor - allows optimization of inductor size vs. efficiency (e.g., 2.2µH @ 2MHz fits <10mm² footprint). |
| Feedback Reference | 0.778V ±12mV - sets output voltage accuracy; used with resistor divider to configure 3.3V, 5V, or custom outputs. |
| Min On-Time | 35ns - enables 3.3V output from 36V input at 2MHz (D ≈ 9.2%), critical for high-ratio industrial supplies. |
| PG Threshold | ±8.5% of VFB - provides robust power-good signaling for FPGA/CPU sequencing with defined fault window. |
Pinout & Package
LT8608BHDC#TRPBF uses an 8-lead, 2mm × 2mm plastic DFN package with exposed thermal pad (Pin 9) soldered to PCB ground for θJA = 40°C/W. Unlike the MSOP variant, this DFN omits SYNC and TR/SS pins and internally floats SYNC to enable fixed pulse-skipping operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BST | Bootstrap supply for high-side NMOS gate drive | Requires 0.1µF ceramic capacitor to SW; no series resistor allowed - critical for maintaining top switch RDS(ON) at high duty cycles. |
| SW | Switch node connecting internal FETs to external inductor | High di/dt node; must be minimized on PCB to reduce EMI and switching losses - connects directly to inductor and BST cap. |
| INTVCC | Internal 3.5V regulator output | Bypass with ≥1µF low-ESR ceramic to GND; cannot power external circuitry - supplies gate drivers and control logic. |
| RT | Resistor-based oscillator frequency programming | Grounded resistor sets fSW; value determines operating point (e.g., 18.2kΩ = 2.0MHz) - defines trade-off between size and efficiency. |
| EN/UV | Enable and input undervoltage lockout input | 1.05V rising threshold with 50mV hysteresis - enables VIN brownout protection or controlled startup via resistor divider. |
| VIN | Main input power supply | Must be locally bypassed with low-ESR capacitor; feeds internal circuitry and top switch - connects to input bulk cap positive terminal. |
| PG | Open-drain power-good flag | Pulls low if VOUT deviates >±8.5% or fault occurs; valid above 3.2V VIN - used for system reset or sequencer enable. |
| FB | Feedback input for output voltage regulation | Regulated to 0.778V; connects to resistor divider tap - determines output setpoint; 10pF phase lead recommended with high-value dividers. |
| GND | Power and signal ground reference | Exposed pad (Pin 9); must be soldered to PCB ground plane - primary thermal path and return for high-current paths. |
Key Features
| Feature | Design Value |
|---|---|
| Pulse-skipping mode (fixed) | Guaranteed operation without Burst Mode artifacts - eliminates low-frequency ripple, enabling noise-sensitive ADCs and RF circuits. |
| Ultralow 2.5µA quiescent current | Enables multi-year operation from coin cells or energy harvesters - achieved by disabling non-essential circuitry during light-load intervals. |
| 35ns minimum on-time | Supports 3.3V output from 36V input at 2MHz - avoids frequency foldback and maintains regulation under high VIN/VOUT conditions. |
| Integrated 350mΩ/230mΩ NMOS switches | Eliminates external MOSFETs and gate drivers - reduces BOM count and layout complexity while maintaining >92% efficiency at 0.5A. |
| ±8.5% PG accuracy | Provides deterministic power sequencing margin - ensures downstream logic receives stable VOUT before release from reset. |
Applications
| Automotive Infotainment Power | Industrial Sensor Node Supply |
|---|---|
Use Scenario: Powers SoC, display interface, and audio codec in head unit with 12V battery input subject to cold-crank dips. IC Role / Device Role / Timing Role: Primary 3.3V/5V step-down regulator delivering 1.5A with fast transient response to handle burst-mode CPU loads. Use Value: 35ns min-on-time sustains regulation during 4.5V cold-crank events; pulse-skipping avoids audible noise in audio subsystems. | Use Scenario: Powers wireless sensor module (MCU + LoRa transceiver) in remote condition-monitoring equipment. IC Role / Device Role / Timing Role: Always-on buck converter supplying 3.3V from LiSOCl₂ battery with 2.5µA IQ to maximize shelf life. Use Value: 2.5µA quiescent current extends 2Ah battery life to >10 years in sleep mode; 42V abs max withstands load-dump transients. |
| Railway Signaling Interface | Medical Portable Diagnostic Device |
Use Scenario: Generates isolated 5V rail for CAN FD communication interface in train control electronics operating from 72V nominal bus. IC Role / Device Role / Timing Role: High-input-voltage buck stage stepping 72V down to 5V with pulse-skipping EMI control for EMC compliance. Use Value: Programmable 200kHz–2.2MHz switching allows EMI filtering below 150kHz or spread-spectrum avoidance in safety-critical bands. | Use Scenario: Supplies 3.3V to precision analog front-end and ARM Cortex-M4 in handheld ultrasound probe. IC Role / Device Role / Timing Role: Low-noise, low-ripple power source for ADC reference and op-amp biasing with tight regulation stability. Use Value: <10mVP-P output ripple prevents SNR degradation in 16-bit ADCs; ±8.5% PG ensures clean power-up sequencing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8609SIDD#TRPBF | Same 42V/1.5A rating but adds spread-spectrum modulation and enhanced EMI performance; includes SYNC pin. | Required where CISPR 25 Class 5 EMI limits apply (e.g., automotive ADAS); supports external clock sync. | Select when EMI reduction is mandatory and board space allows MSOP-10; not pin-compatible due to different pin count and function mapping. |
| TPS62865ARGRR | 6V max input, 4A output, 1.8V–5.5V adjustable output; 1.4µA IQ but limited to 6V VIN. | Suitable only for low-input applications (e.g., USB PD, single-cell Li-ion); lacks high-VIN capability and automotive temp grade. | Choose for cost-sensitive consumer electronics with ≤6V input; unsuitable for automotive or industrial 12V+ rails due to VIN limit. |
Compared with LT8608BHDC#TRPBF, LT8609SIDD#TRPBF offers superior EMI control via spread spectrum but requires PCB redesign for MSOP-10 and external components; TPS62865ARGRR delivers higher current at lower IQ but cannot replace LT8608BHDC#TRPBF in 12V–42V systems due to fundamental VIN limitation.
Availability
LT8608BHDC#TRPBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial sensor nodes, and railway signaling applications requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT8608BHDC#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 industrial, automotive, communications, and healthcare markets.
The LT8608/LT8608B product line delivers ultralow-IQ synchronous buck regulators for battery-critical and high-reliability systems, emphasizing wide VIN range, robust thermal performance, and EMI-conscious design.
FAQ
What is the guaranteed operating junction temperature range for LT8608BHDC#TRPBF?
The LT8608BHDC#TRPBF is guaranteed over –40°C to 150°C junction temperature, validated per Analog Devices' H-grade qualification standards. This rating enables deployment in under-hood automotive environments and high-temperature industrial enclosures without derating. The LT8608BHDC#TRPBF achieves this via process enhancements and thermal design optimizations specific to the H-temperature grade.
Does LT8608BHDC#TRPBF support soft-start or output voltage tracking?
No, LT8608BHDC#TRPBF does not support soft-start or tracking. Unlike the MSOP variants (e.g., LT8608HMSE#TRPBF), the DFN package omits the TR/SS pin and internally floats it. Therefore, LT8608BHDC#TRPBF has fixed startup behavior with no user-programmable slew rate - output ramps at the natural rate determined by feedback loop dynamics and output capacitance.
How does the pulse-skipping mode of LT8608BHDC#TRPBF differ from Burst Mode?
LT8608BHDC#TRPBF operates exclusively in pulse-skipping mode: the oscillator runs continuously, and full-amplitude switching pulses are skipped to regulate light loads, resulting in several hundred µA quiescent current. In contrast, Burst Mode (used in LT8608EDC#TRPBF) shuts down most circuitry between bursts, achieving 1.7µA IQ but introducing low-frequency ripple. Pulse-skipping avoids audible noise and simplifies EMI filtering.
Can LT8608BHDC#TRPBF synchronize to an external clock?
No, LT8608BHDC#TRPBF cannot synchronize to an external clock. The DFN package has no SYNC pin; the LT8608B variant internally floats SYNC to enable fixed pulse-skipping operation. External synchronization is only available on MSOP-packaged versions (e.g., LT8608HMSE#TRPBF), which include a dedicated SYNC pin with configurable logic levels for burst, pulse-skipping, or spread-spectrum modes.
What is the purpose of the exposed thermal pad on LT8608BHDC#TRPBF?
The exposed thermal pad (Pin 9) on LT8608BHDC#TRPBF serves as the primary thermal conduction path from the die to the PCB ground plane. It must be soldered to a thermally robust copper area to achieve θJA = 40°C/W and prevent junction temperature exceedance under 1.5A load. Failure to solder the pad risks thermal shutdown or accelerated parametric drift - the pad is electrically GND and forms part of the high-current return path.
LT8608BHDC#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 0.778V
- Voltage - Output (Max):
- 42V
- Current - Output:
- 1.5A
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (2x2)
LT8608BHDC#TRPBF FAQ
1.How can I place an order for LT8608BHDC#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8608BHDC#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 LT8608BHDC#TRPBF reliable?
The price and inventory of LT8608BHDC#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8608BHDC#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8608BHDC#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8608BHDC#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8608BHDC#TRPBF?
LT8608BHDC#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8608BHDC#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 LT8608BHDC#TRPBF?
For technical support, including LT8608BHDC#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8608BHDC#TRPBF requirements.
6.How does Aetrix verify that LT8608BHDC#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8608BHDC#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 LT8608BHDC#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8608BHDC#TRPBF?
All LT8608BHDC#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8608BHDC#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 LT8608BHDC#TRPBF part is unused and in its original packaging.
Return procedure for LT8608BHDC#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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