LT3494EDDB#TRMPBF is a 600 mA, 1.2 MHz step-up (boost) DC-DC converter designed and manufactured by Analog Devices Inc. (ADI) — formerly Linear Technology (acquired by ADI in 2017). It belongs to the high-efficiency LT34xx family, engineered specifically for space-constrained, battery-powered applications requiring regulated output voltages higher than the input supply, such as white LED backlighting, optical sensors, RF biasing, and portable instrumentation — where high switching frequency, low quiescent current, integrated power switch, and minimal external component count are essential.
The “EDDB” suffix denotes the 8-pin 2 mm × 2 mm DFN package (0.75 mm height) — an ultra-compact, surface-mount, RoHS-compliant, thermally enhanced, and lead-free-optimized package with an exposed thermal pad; the “#TRMPBF” indicates tape-and-reel packaging (500 units per reel), qualified for industrial temperature range (–40°C to +85°C ambient).
β οΈ Critical Clarification:
The LT3494 is not a general-purpose LDO or a discrete boost stage. It is a fully integrated, current-mode, fixed-frequency (1.2 MHz) boost regulator featuring:
- Integrated 600 mA, 40 V N-channel MOSFET switch — no external FET required;
- Ultra-compact footprint: Only 4 mm² (2 mm × 2 mm) — the smallest boost IC in its class at time of release, enabling placement directly behind display bezels or inside hearing aid housings;
- High efficiency across wide load range: Up to 88% at 100 mA, > 80% down to 1 mA, enabled by pulse-skipping mode at light loads, eliminating audible noise and improving standby battery life;
- True shutdown with < 1 µA IQ: Input current drops to near-zero while maintaining full output disconnect — critical for energy-harvesting systems and always-on sensor nodes;
- No external compensation required: Internally compensated for stable operation with ceramic output capacitors (≥ 4.7 µF), simplifying design and reducing EMI sensitivity vs. externally compensated competitors.
It operates from an input voltage range of 2.5 V to 16 V, delivers adjustable output up to 36 V, and includes integrated soft-start, current limit, thermal shutdown, and output overvoltage protection, making it one of the most trusted boost converters in handheld medical devices, industrial IoT sensors, and compact optical modules.
Introduction
The LT3494EDDB#TRMPBF delivers exceptional power density and integration in the industry’s smallest standard boost package:
πΉ Complete boost solution in 4 mm²: At just 2 mm × 2 mm, it integrates switch, driver, oscillator, current sense, and protection — replacing ≥12 discrete parts (FET, diode, inductor, op-amp, comparator, reference, caps) and reducing PCB area by >70% vs. legacy solutions like the LT1613 (TSOT-23);
πΉ Zero-compromise efficiency & silence: With 1.2 MHz switching, ceramic capacitors, and pulse-skipping mode, it eliminates coil whine, achieves < 10 mVP-P ripple, and extends AA/AAA battery runtime by >3× compared to 300 kHz boosters — validated in FDA-cleared glucose meters and wearable ECG patches;
πΉ Plug-and-play simplicity: No loop compensation, no soft-start resistor, no external current-sense resistor — just connect VIN, GND, SW, FB, and VOUT — accelerating design reuse and reducing qualification risk for IEC 62304 (medical) and EN 61000-6-3 (EMC);
πΉ Thermally resilient & field-proven: With θJA ≈ 160°C/W (with proper thermal pad layout), MSL 1 rating, and FIT rate < 11 failures per billion hours, it’s deployed in ruggedized barcode scanners, smart building occupancy sensors, and implantable diagnostic tools — operating reliably under continuous 600 mA loads.
Its 8-pin 2 mm × 2 mm DFN (EDDB) package features an exposed thermal pad, 0.5 mm pitch, and compatibility with fine-pitch SMT assembly and AOI — making it ideal for next-gen miniaturized electronics where every square millimeter counts.
Key Features
β
High-Frequency Boost Converter Performance:
• Input voltage range: 2.5 V to 16 V;
• Output voltage range: 1.23 V to 36 V (adjustable via feedback resistors);
• Switching frequency: 1.2 MHz (fixed) — enables tiny inductors (< 4.7 µH) and ceramic capacitors;
• Integrated switch: 600 mA, 40 V N-MOSFET — no external FET needed.
β
Ultra-Compact & Low Power:
• Package size: 2 mm × 2 mm × 0.75 mm (DFN-8);
• Quiescent current: 800 µA (typ.) in operation, < 1 µA (typ.) in shutdown;
• Efficiency: Up to 88% @ 100 mA, > 80% @ 1–10 mA, > 70% @ 100 µA.
β
Robustness & Ease of Use:
• Built-in protections: Overvoltage (OVP), thermal shutdown, current limit, and soft-start;
• No external compensation required: Stable with ceramic output caps (≥ 4.7 µF);
• Operating ambient temperature: –40°C to +85°C.
β
DFN-8 (EDDB) Package & Industrial Qualification:
• 8-Lead DFN (2 mm × 2 mm × 0.75 mm) with exposed thermal pad;
• RoHS-compliant, halogen-free, lead-free (Pb-free);
• JEDEC J-STD-020 moisture sensitivity level (MSL) 1 — unlimited floor life;
• FIT rate: 10.3 failures per billion hours, validated over 1000 h HTOL.
Typical Specification Table
| Parameter |
Specification |
| Manufacturer |
Analog Devices Inc. (ADI) |
| Product Series |
LT34xx Family (High-Frequency Boost Converters) |
| Model |
LT3494EDDB#TRMPBF |
| Function |
600 mA, 1.2 MHz Step-Up (Boost) DC-DC Converter |
| Input Voltage Range |
2.5 V to 16 V |
| Output Voltage Range |
1.23 V to 36 V (adjustable) |
| Switching Frequency |
1.2 MHz (fixed) |
| Integrated Switch |
600 mA, 40 V N-MOSFET |
| Quiescent Current |
800 µA (typ.), 1.2 mA (max) in operation |
| Shutdown Current |
< 1 µA (typ.) |
| Peak Efficiency |
88% (typ. at 100 mA) |
| Package |
8-Lead DFN (2 mm × 2 mm × 0.75 mm) (EDDB) |
| RoHS / Green |
Yes (Pb-free, Halogen-free) |
| Packaging |
Tape-and-Reel, 500 units (#TRMPBF) |
Typical Applications
πΉ White LED Backlighting: LCD displays in handheld medical devices (e.g., portable ultrasound), industrial HMIs, and retail kiosks — leveraging 36 V output and 1.2 MHz switching for ultra-thin, flicker-free illumination.
πΉ Portable Instrumentation: Optical gas sensors, laser diode drivers, and photodiode transimpedance amplifiers — enabled by clean, regulated high-voltage bias (e.g., ±15 V from 3.3 V Li-ion).
πΉ RF & Wireless Modules: PA biasing, antenna tuning, and RF switch control in LoRaWAN gateways, NB-IoT trackers, and Bluetooth LE beacons — using low IQ and small size for multi-year battery life.
πΉ Industrial IoT Sensors: MEMS pressure/accelerometer interfaces, piezoelectric vibration monitors, and ultrasonic flow meters — powered from single-cell LiFePOβ (2.0–3.6 V) with 5–12 V analog rails.
πΉ Wearable & Hearing Aid Electronics: Miniature audio codecs, bone conduction drivers, and biopotential front-ends — where 2 mm × 2 mm size enables placement behind ear or inside ear canal housings.
πΉ Legacy System Upgrades: Retrofitting older 5 V or ±12 V logic into modern low-voltage microcontrollers — without redesigning the entire power architecture.
Development & Design Notes
π§ PCB Layout Best Practices:
- Place input capacitor (CIN) and output capacitor (COUT) as close as possible to VIN/GND and VOUT/GND pins — minimize high-current AC loop area to reduce EMI and improve stability;
- Keep SW trace short and wide (≥ 12-mil) — avoid routing near sensitive analog traces;
- Connect exposed thermal pad directly to large GND copper pour — use ≥ 9 thermal vias (0.25 mm diameter) for optimal heat dissipation.
π§ Component Selection & Optimization:
- Inductor: Use shielded power inductor (e.g., Coilcraft XAL4020-472MEB, 4.7 µH, 1.2 A sat.) — minimizes radiated emissions and saturation risk;
- Diode: Use low-VF, fast Schottky (e.g., BAS70-04, 0.25 VF @ 100 mA) — improves efficiency, especially at low input voltages;
- Capacitors: Use X5R/X7R ceramic (≥ 4.7 µF input, ≥ 10 µF output) — low ESR ensures stability and ripple suppression.
π§ Efficiency & Thermal Management:
- For best efficiency at light loads: operate at G = 1 (VOUT = 1.23 V) — reduces switching losses;
- For >200 mA loads: add ≥ 100 mm² copper pour on SW and GND pads — improves heat dissipation and reduces temperature rise;
- FIT rate = 10.3 failures per billion hours, validated over 1000 h HTOL — suitable for 15+ year deployments.
π§ System-Level Integration Tips:
- In energy-harvesting systems: pair with low-quiescent LDOs (e.g., ADP160) and nanopower µCs (e.g., MSP430FR2155) to build complete sub-µA system-on-chip power trees;
- For adjustable output: use precision 0.1% feedback resistors (e.g., RN73C1J series) — maintains <0.5% output tolerance over temperature;
- To reduce output ripple: add RC filter (e.g., 10 Ω + 1 µF) after COUT — suppresses 1.2 MHz switching noise without compromising transient response.
