Analog Devices Inc. LT1303IS8-5#TRPBF

Overview

LT1303IS8-5#TRPBF from Analog Devices (formerly Linear Technology) is a micropower fixed-output 5V step-up DC/DC converter with integrated low-battery detector, designed for space-constrained battery-powered systems. It delivers 200mA at 5V from as low as 1.8V input, achieves up to 88% efficiency, and draws only 120µA quiescent current - enabling long runtime in palmtop computers and portable instruments.

For engineers reviewing the LT1303IS8-5#TRPBF datasheet, LT1303IS8-5#TRPBF pinout, LT1303IS8-5#TRPBF application, or LT1303IS8-5#TRPBF equivalent, key selection criteria include its 5V fixed output, 1.8V–5V input range, 170mV typical switch saturation voltage, Burst Mode™ operation for ultra-low standby power, and open-collector LBO output for system-level battery monitoring.

Technical Context

The LT1303IS8-5#TRPBF implements a current-mode boost topology with an internal NPN power switch and Burst Mode™ control to minimize quiescent current under light loads. Its feedback loop regulates output by comparing the SENSE pin voltage against a precise 5.0V ±2% internal reference, while the low-battery comparator monitors LBI against a 1.24V threshold to assert LBO when input drops below ~2.2V.

Operation relies on external components: a 22µH inductor (e.g., Sumida CD54-220), Schottky diode (e.g., 1N5817), and 100µF output capacitor. The 8-lead SOIC package supports compact layout with separate PGND and GND pins to isolate high-current return paths from signal ground.

Key Specifications

Pinout & Package

LT1303IS8-5#TRPBF is housed in an 8-lead plastic SOIC (S8) package with standard 1.27mm pitch, measuring 4.9mm × 3.9mm × 1.45mm. Thermal resistance θ_JA is 150°C/W, requiring minimal copper area for thermal management in handheld designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-up DC/DC converter applications.

Compared with LT1303IS8-5#TRPBF, LT1305CS8-5#TRPBF offers higher current but consumes more quiescent power, while TPS61200DRCT trades integrated battery detection for lower I_Q and adjustable output - making LT1303IS8-5#TRPBF optimal for cost-sensitive, fixed-5V, battery-monitoring applications with ≤200mA loads.

Availability

LT1303IS8-5#TRPBF is available at Aetrix Electronics and suitable for portable instrumentation, handheld medical devices, and battery-powered consumer electronics requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for LT1303IS8-5#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 acquired Linear Technology in 2017 and maintains its portfolio of high-performance analog and power management ICs, emphasizing reliability, precision, and low-power innovation for industrial and portable applications.

The LT1303 family was designed specifically for micropower, battery-critical systems where extended runtime, small solution size, and integrated system monitoring (e.g., low-battery detect) are essential - targeting palmtops, PDAs, and portable test equipment.

FAQ

What is the maximum input voltage rating for the LT1303IS8-5#TRPBF?

The absolute maximum input voltage for LT1303IS8-5#TRPBF is 10V, as specified in the Absolute Maximum Ratings table. However, the device is designed for operation between 1.8V and 5V input. Exceeding 5V may cause unregulated output behavior or damage if sustained, and the internal switch and reference circuits are characterized only within the 1.8–5V functional range. Always use appropriate input filtering and clamping for systems with potential voltage transients.

Can the LT1303IS8-5#TRPBF be used with a 3.7V lithium-ion battery?

Yes, LT1303IS8-5#TRPBF operates reliably across the full 3.0V to 4.2V discharge curve of a single-cell Li-ion battery. Its 1.8V minimum input ensures compatibility down to deeply discharged states, and its fixed 5V output remains tightly regulated with <0.15%/V line regulation. The LBO pin can be configured via a simple resistor divider to signal low battery at ~3.2V, providing early warning before system brownout.

Does the LT1303IS8-5#TRPBF require an external feedback resistor network?

No, LT1303IS8-5#TRPBF does not require an external feedback resistor network. As the "-5" variant, it features an internal 5V reference connected directly to the SENSE pin, eliminating external resistors. This simplifies design, improves output accuracy over temperature (±2% vs. typical ±5% with external dividers), and reduces component count - a key advantage over the adjustable LT1303 version.

How does the low-battery detector in the LT1303IS8-5#TRPBF function?

The LT1303IS8-5#TRPBF low-battery detector compares voltage at the LBI pin against an internal 1.24V reference. When LBI falls below this threshold (e.g., due to a resistive divider from VIN), the open-collector LBO pin pulls low. LBO is disabled during shutdown. Typical trip point with a 100kΩ divider is ~2.2V input; hysteresis can be added externally via a resistor from LBO to LBI to prevent chatter near the threshold.

What type of inductor is recommended for use with the LT1303IS8-5#TRPBF?

LT1303IS8-5#TRPBF works best with 10–33µH surface-mount ferrite inductors rated for ≥1.25A saturation current and low DC resistance, such as Sumida CD54-220 (22µH). The inductor must avoid saturation at peak switch current (up to 1.25A at 2V input) and maintain di/dt <400mA/µs. Drum-core or rod-core types with shielded construction minimize EMI; unshielded types require careful layout to avoid coupling into adjacent analog traces.