Analog Devices Inc. LTC3525ESC6-5

Overview

LTC3525ESC6-5 from Analog Devices (formerly Linear Technology) is a micropower synchronous step-up DC/DC converter with output disconnect, designed for single- or dual-cell alkaline/NiMH and Li-Ion battery-powered systems. It starts up from as low as 0.85V input, delivers fixed 5V output, supports up to 175mA load from 3V input, achieves up to 95% efficiency, and operates in Burst Mode® with 8µA typical quiescent current.

For engineers reviewing the LTC3525ESC6-5 datasheet, LTC3525ESC6-5 pinout, LTC3525ESC6-5 application, or LTC3525ESC6-5 equivalent, key selection criteria include ultralow start-up voltage (0.85V), output disconnect capability, SC70-6 package footprint, 5V fixed output tolerance (±3%), and thermal shutdown protection - all critical for portable medical, instrumentation, and low-power IoT designs.

Technical Context

The LTC3525ESC6-5 integrates a 0.4Ω N-channel MOSFET switch and a 0.7Ω P-channel synchronous rectifier, enabling high-efficiency boost conversion without an external diode. Its Burst Mode® operation dynamically adjusts peak inductor current from 150mA (light load) to 400mA (heavy load), maintaining >85% efficiency across 0.01–100mA loads at VIN = 2.4V.

Startup uses a dedicated oscillator to bootstrap from sub-1V inputs; once VOUT exceeds VIN by ≥0.2V and either rail reaches ≥1.8V, synchronous rectification engages. Output disconnect is active during shutdown (SHDN < 0.4V), eliminating inrush and enabling zero-load leakage from VOUT to VIN.

Key Specifications

Pinout & Package

Package: 6-Lead Plastic SC70 (SC6), 1.00mm max height, 2.8mm × 1.8mm footprint - optimized for ultra-thin portable devices.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous boost converter applications.

Compared with LTC3525ESC6-5, LTC3429B offers higher current headroom but sacrifices ultralow start-up voltage and quiescent current, while LTC3529 provides greater power density at the cost of output disconnect functionality and SC70 compatibility - making LTC3525ESC6-5 optimal for space-constrained, battery-critical applications demanding sub-1V startup and nanoamp shutdown.

Availability

LTC3525ESC6-5 is available at Aetrix Electronics and suitable for glucose meters, portable instrumentation, and digital cameras requiring stable component supply with guaranteed long-term availability and consistent parametric performance.

Supply support for LTC3525ESC6-5 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 acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for legacy Linear parts including the LTC3525 family.

The LTC3525 product line was designed specifically for ultralow-power, battery-operated portable electronics where minimal start-up voltage, output disconnect, and SC70 packaging are essential - targeting medical, consumer, and industrial handheld devices.

FAQ

What is the minimum input voltage required for LTC3525ESC6-5 to start up and regulate?

The LTC3525ESC6-5 starts up from an input voltage as low as 0.85V, verified across temperature and process corners. This allows reliable operation from single NiMH or alkaline cells nearing end-of-life. Once started, it can maintain regulation down to 0.5V input under light loads. The startup condition requires both VOUT exceeding VIN by ≥0.2V and either VIN or VOUT reaching ≥1.8V - a behavior confirmed in the LTC3525ESC6-5 datasheet Figure 15 and electrical characteristics table.

Does LTC3525ESC6-5 include output disconnect, and how does it function?

Yes, LTC3525ESC6-5 includes true output disconnect. When SHDN is pulled below 0.4V, an internal P-channel FET disconnects VOUT from VIN, reducing shutdown current to <1µA and preventing backfeed or inrush into downstream circuits. This feature is explicitly documented in the "Features" section, "Pin Functions", and "Operation" chapter of the LTC3525ESC6-5 datasheet, and is active only in shutdown mode - not during normal operation.

What is the recommended output capacitor value for LTC3525ESC6-5, and why?

The minimum recommended output capacitor for LTC3525ESC6-5 is 10µF X5R/X7R ceramic, placed close to VOUT and GND pins. For reduced ripple, 22µF is preferred - especially critical for noise-sensitive analog circuits like ADC references or audio DACs. Larger values (>47µF) increase light-load peak inductor current, degrading Burst Mode® efficiency. This guidance is specified in the "Component Selection" section and validated in Figures G22–G23 of the LTC3525ESC6-5 datasheet.

Can LTC3525ESC6-5 operate with input voltage higher than its 5V output?

Yes, LTC3525ESC6-5 can operate with VIN ≥ VOUT (e.g., 5.5V input), but in this mode the synchronous rectifier is disabled, resulting in lower efficiency and reduced output current capability. The device remains in regulation, and output disconnect still functions during shutdown. This behavior is explicitly described in the "Operation" section of the LTC3525ESC6-5 datasheet under "The output disconnect feature also allows the LTC3525 to maintain regulation with an input voltage equal to or greater than VOUT."

What is the thermal performance of LTC3525ESC6-5 in the SC70-6 package?

LTC3525ESC6-5 has a junction-to-ambient thermal resistance (θJA) of 256°C/W in free air and 150°C/W on a PCB with ground plane, per the "Package Description" section. Its thermal shutdown activates at 125°C junction temperature, protecting against sustained overload. The SC70-6 package's 1mm profile and dual GND pins aid heat dissipation - validated in thermal characterization data for the LTC3525ESC6-5 family across –40°C to 125°C operating junction temperature range.