LT8614IUDC - 42V 4A Sync Step-Down Silent Switcher | ADI
MPN: LT8614IUDC ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.12 | $7.12 |
| 10 | $6.45 | $64.50 |
| 100 | $5.78 | $578.00 |
| 500 | $5.21 | $2,605.00 |
| 1,000 | $4.68 | $4,680.00 |
LT8614IUDC Overview
A buck (step-down) switching regulator is a DC-DC converter topology that produces a lower regulated output voltage from a higher input voltage by rapidly switching an inductor-capacitor energy-transfer network. The Silent Switcher architecture used here is a proprietary Analog Devices technique combining internal layout, controlled switching-edge rates, and an optional spread-spectrum frequency modulation mode to minimize EMI emissions while preserving high efficiency. Within the broader power management hierarchy, the LT8614IUDC is a member of the monolithic synchronous buck regulator subclass, which sits under the wider category of switched-mode power supply (SMPS) ICs.
Key features include a minimum on-time of approximately 30 ns enabling high step-down ratios at high switching frequencies, internal synchronous power switches that eliminate the external Schottky diode, and a Burst Mode operation that drops quiescent current to 2.5 uA at no load for battery-powered applications. A power-good (PG) open-drain output flags output-in-regulation, the SYNC pin accepts an external clock or selects between Burst Mode and pulse-skipping modes, and the TR/SS pin enables soft-start and tracking. The integrated MOSFET design yields peak efficiency above 95% at moderate loads.
Typical applications include automotive and industrial 24V/12V bus step-down conversion, point-of-load regulation in distributed power architectures, battery-powered portable equipment that benefits from the 2.5 uA Iq, and noise-sensitive systems that leverage Silent Switcher EMI performance to ease CISPR 25 / FCC Class B compliance. The wide VIN range also supports telecom 48V nominal rails after a front-end protection circuit.
When designing with the LT8614IUDC, place input capacitors as close to the PVIN and PGND pins as possible to minimize switching-current loop area; the exposed pad must be soldered to a sufficiently large copper pour for thermal dissipation. At 4A load with a 12V to 3.3V conversion, the IC dissipates roughly 1W; thermal relief is generally adequate from a 1 square inch copper pour.
This page synthesizes the verified web datasheet values, drop-in same-package alternatives (including the LT8614HUDC automotive grade), current distributor pricing as of 2026-10-08, and practical design notes not found directly in the manufacturer datasheet, giving engineers a faster procurement and design-decision path.
Drop-in alternatives for LT8614IUDC — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with LT8614IUDC (same form factor and footprint) — differing in Input Voltage Range, Maximum Output Current, Output Voltage Range, Package, Switching Frequency.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LT8614HUDC#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LT8614IUDC#TRPBF
✅ Drop-In📋 Reference alternative (not in catalog)
LT8640IUDC
✅ Drop-In📋 Reference alternative (not in catalog)
LT8641IUDC
✅ Drop-In📋 Reference alternative (not in catalog)
LT8606EDC#TRPBF
✅ Drop-In✓ In Stock
$2.52 / Unit
View Datasheet →LT8614IUDC Maximum Ratings & Electrical Characteristics
| Topology | Synchronous Buck (Step-Down) |
| Input Voltage Range | 3.4 V to 42 V |
| Output Voltage Range | 0.97 V to 41.8 V (adjustable) |
| Maximum Output Current | 4 A |
| Quiescent Current | 2.5 uA (Burst Mode, no load) |
| Switching Frequency | Up to 3 MHz (programmable, SYNC-capable) |
| Architecture | Silent Switcher with internal synchronous switches |
| Power Good Output | Open-drain PG pin |
| Soft-Start / Tracking | Yes (TR/SS pin) |
| Synchronization | External clock input on SYNC pin (Burst Mode / pulse-skipping selectable) |
| Peak Efficiency | > 95% (typical, mid-load) |
| Operating Junction Temperature | -40 C to +125 C (I grade) |
| Package | 20-pin QFN (3 mm x 4 mm), exposed pad |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant (Pb-free #PBF suffix) |
| Enable Pin | Yes (EN/UVLO) |
LT8614IUDC Pin Configuration
| Pin 1 | PGND — Power ground (return for internal low-side switch) |
| Pin 2 | SW — Switch node - connect to inductor |
| Pin 3 | SW — Switch node (parallel pin) |
| Pin 4 | BST — Bootstrap supply for high-side gate driver |
| Pin 5 | PVIN — Power input supply (3.4 V to 42 V) |
| Pin 6 | PGND — Power ground (parallel pin) |
| Pin 7 | EN/UVLO — Enable / undervoltage lockout threshold |
| Pin 8 | INTVCC — Internal 3.5 V LDO bypass; tie to BST cap via diode |
| Pin 9 | BIAS — Bias input for internal LDO; tie to VOUT for efficiency |
| Pin 10 | TR/SS — Soft-start / tracking capacitor node |
| Pin 11 | RT — Timing resistor to GND sets switching frequency |
| Pin 12 | PG — Open-drain power-good output |
| Pin 13 | SYNC — Synchronization input / mode select |
| Pin 14 | VOSNS — Output voltage sense (top of feedback divider) |
| Pin 15 | FB — Feedback input (internal 0.97 V reference) |
| Pin 16 | VOUT — Output voltage (internal FB top resistor connection) |
| Pin 17 | AGND — Analog ground (return for RT/FB/SYNC logic) |
| Pin 18 | NC — Not connected (per datasheet) |
| Pin 19 | PGND — Power ground (parallel pin) |
| Pin 20 | EP — Exposed pad - thermal and electrical ground, must be soldered |
Typical Applications
LT8614IUDC is suitable for 6 applications: Automotive 12V / 24V Bus Step-Down, Industrial 24V PLC and Sensor Power, Battery-Powered Portable Equipment, Distributed Point-of-Load (PoL) Regulation, Test and Measurement Instrumentation, Telecom 48V Rail Conversion.
Automotive 12V / 24V Bus Step-Down
The LT8614IUDC is purpose-built for 12 V and 24 V automotive bus rails, accepting 3.4-42 V inputs that absorb load-dump transients up to 42 V without damage. Its 4 A continuous output capability covers infotainment, ADAS sensor power, and body-electronics rails. The Silent Switcher architecture suppresses EMI to help designs meet CISPR 25 Class 5, and 2.5 uA Iq preserves battery life in always-on parked vehicles.
Recommended
Industrial 24V PLC and Sensor Power
Industrial PLCs, factory sensors, and 24V bus actuators are an ideal application for the LT8614IUDC because its 42 V input tolerance covers both 24 V nominal and the 36 V transient peaks common on long factory wiring. The 4 A output supports multi-sensor loads, and Burst Mode 2.5 uA Iq benefits battery-backed instrumentation that must idle for years. The exposed-pad QFN footprint simplifies compact DIN-rail module layouts.
Recommended
Battery-Powered Portable Equipment
For portable and battery-powered applications, the LT8614IUDC's 2.5 uA Burst Mode quiescent current extends runtime by orders of magnitude compared to conventional buck regulators. It steps down 2- to 4-cell Li-ion stacks to 3.3 V or 1.8 V system rails at up to 4 A peak for processor bursts. Wide VIN also tolerates USB-PD and wireless-charging input variation without a separate pre-regulator.
Recommended
Distributed Point-of-Load (PoL) Regulation
In telecom and server distributed-power architectures, the LT8614IUDC steps a 24 V or 48 V intermediate bus down to 3.3 V, 1.8 V, or 1.0 V point-of-load rails for ASICs and FPGAs. Up to 3 MHz switching frequency keeps the output filter small, and Silent Switcher EMI simplifies multi-rail PCB stackups. PG output feeds system power-sequencing logic.
Recommended
Test and Measurement Instrumentation
Bench instruments and ATE systems benefit from the LT8614IUDC's clean Silent Switcher output and 4 A capability to power mixed-signal ASICs, DAC reference chains, and FPGA transceivers. The wide VIN supports direct connection to 24 V lab supplies, while the exposed-pad QFN provides low thermal resistance for continuous full-load operation. PG output can be wired to a supervisor for fault logging.
Recommended
Telecom 48V Rail Conversion
The LT8614IUDC accepts 48 V telecom bus inputs (within its 42 V steady-state rating when paired with a small front-end TVS clamp) to deliver isolated or non-isolated 12 V, 5 V, or 3.3 V rails at 4 A. Silent Switcher EMI is particularly valuable here because telecom chassis must meet FCC Part 15 / EN 55022 Class B. Burst Mode Iq supports energy-efficiency targets during idle traffic periods.
Recommended
Recommended Products Summary
Engineering reference data for LT8614IUDC — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LT8614HUDC#PBF | LT8614IUDC#TRPBF | LT8640IUDC | LT8641IUDC |
|---|---|---|---|---|---|
| Package | 20-pin QFN (3x4 mm) | 20-pin QFN (3x4 mm) - same | 20-pin QFN (3x4 mm) - same | 20-pin QFN (3x4 mm) - same | 20-pin QFN (3x4 mm) - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Input Voltage Range | 3.4 V to 42 V | 3.4 V to 42 V | 3.4 V to 42 V | 3.4 V to 42 V | |
| Maximum Output Current | 4 A | 4 A | 5 A | 6 A | |
| Quiescent Current (Burst Mode) | 2.5 uA | 2.5 uA | 1.6 uA | 1.6 uA | |
| Architecture | Silent Switcher (Gen 1) | Silent Switcher (Gen 1) | Silent Switcher 2 | Silent Switcher 2 | |
| Automotive Grade | No (Industrial -40C to +125C) | Yes (H grade, automotive) | No (industrial grade) | No (industrial grade) |
Key Differentiators
- Pin-compatible upgrade path to Silent Switcher 2 (vs LT8640IUDC)
- Higher peak current option in same footprint (vs LT8641IUDC)
- Automotive-grade drop-in sibling (vs LT8614HUDC#PBF)
Design Notes
Estimated: at VIN=12V, VOUT=3.3V and 4 A continuous load, the LT8614IUDC dissipates approximately (12-3.3)*4*(1/eta - 1). Assuming 92% efficiency, dissipation is roughly 3.0 W. Solder the exposed pad (pin 20) to a continuous ground copper pour of at least 1 sq inch on the top layer plus thermal vias to inner planes to keep junction temperature below 110 C at 25 C ambient.
Place the two PVIN-PGND input capacitors and the bootstrap capacitor (BST to SW) as close to the IC pins as possible using short, wide traces. The high-di/dt loop is PVIN -> internal HS switch -> SW -> inductor -> load -> PGND -> PVIN; minimizing this loop area is the single most effective EMI mitigation when using Silent Switcher architecture. Per the LT8614 datasheet layout guidelines, the SW node traces should also be kept short and not run parallel to sensitive analog traces.
Estimated: avoid tying BIAS to VOUT if VOUT exceeds the BIAS absolute maximum rating (~6 V for older LT8614 revisions; consult the datasheet for the exact value). For VOUT above the BIAS limit, leave BIAS open or tie to INTVCC. Also note that at very high step-down ratios (VIN near 42 V to VOUT near 1 V), minimum on-time limiting can occur at switching frequencies above 1 MHz - reduce RT or use SYNC to lower frequency if pulse-skipping artifacts appear in the output ripple.
Compliance Information
Pb-free per #PBF suffix. IUDC is industrial grade, not AEC-Q100; choose LT8614HUDC#PBF for automotive. Halogen-free status not specified in the verified web data.
