Analog Devices Inc. ADP1109AN-3.3

Overview

ADP1109AN-3.3 from Analog Devices is a micropower step-up DC-to-DC converter in 8-lead plastic DIP package, delivering fixed 3.3 V output from 2 V–3 V input, with 120 kHz oscillator frequency, 320 µA ground current, and logic-controlled shutdown. It enables compact battery-powered voltage boosting in portable instrumentation and handheld computing.

For engineers reviewing the ADP1109AN-3.3 datasheet, ADP1109AN-3.3 pinout, ADP1109AN-3.3 application, or ADP1109AN-3.3 equivalent, key selection criteria include input voltage range (2 V–3 V), output regulation accuracy (±5.3% over temperature), quiescent current (450–590 µA), and compatibility with low-ESR tantalum or OS-CON output capacitors.

Technical Context

The ADP1109AN-3.3 implements a gated-oscillator boost topology with internal 1.25 V reference and comparator hysteresis (8–14 mV) to ensure loop stability without external compensation. Its integrated NPN power switch features 0.4–0.8 V saturation voltage at 500 mA and supports duty cycles from 40% to 70% under full load.

Oscillation is controlled by feedback from the SENSE (FB) pin, directly tied internally to laser-trimmed resistors for 3.3 V output. Shutdown is asserted by applying logic low (<0.8 V) to Pin 7, reducing quiescent current to 450 µA while disabling switching action.

Key Specifications

Pinout & Package

ADP1109AN-3.3 is housed in an 8-lead plastic DIP (N-8) package with 0.300-inch width, 0.100-inch lead pitch, and through-hole mounting. Pins 2, 5, and 6 are internally unconnected and must remain floating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-up regulator applications.

Compared with MAX680ESA+ and TPS61200DRCR, ADP1109AN-3.3 offers proven reliability in 0°C–70°C industrial environments, fixed 3.3 V output with zero external feedback, and robust 1.2 A switch current headroom - making it preferred for long-lifecycle portable instrumentation where design simplicity and field-proven stability outweigh ultra-low IQ or miniaturization goals.

Availability

ADP1109AN-3.3 is available at Aetrix Electronics and suitable for cellular telephones, hand-held inventory computers, portable instrumentation, laser diode drivers, and battery backup supplies requiring stable component supply across extended production lifecycles.

Supply support for ADP1109AN-3.3 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 since 1965.

The ADP1109 series was designed specifically for micropower, low-component-count DC-to-DC conversion in battery-powered portable electronics - emphasizing simplicity, reliability, and wide input voltage tolerance without sacrificing regulation accuracy.

FAQ

What is the maximum output current supported by the ADP1109AN-3.3?

The ADP1109AN-3.3 does not specify a guaranteed maximum continuous output current in its datasheet, but application examples show reliable operation at 100 mA from a 2.4 V input. The internal switch is rated for 1.2 A peak current, and practical output is limited by thermal dissipation, inductor saturation, and diode forward voltage. For sustained 3.3 V delivery, design for ≤100 mA with adequate PCB copper area and low-ESR output capacitance to maintain regulation and ripple within spec.

Can the ADP1109AN-3.3 operate from a single alkaline cell?

Yes, the ADP1109AN-3.3 operates from 2 V minimum input, matching the discharge curve of a single alkaline cell (1.5 V nominal, down to ~0.9 V). However, output regulation is only guaranteed above 2 V per the datasheet's VIN specification. Below 2 V, the device may cease switching or deliver unregulated output - so system design should include brown-out detection or battery voltage monitoring to disable loads before reaching 2 V.

Is the ADP1109AN-3.3 pin-compatible with other variants in the ADP1109 family?

Yes, all ADP1109 variants - including ADP1109AN-3.3, ADP1109AN-5, ADP1109AN-12, and ADP1109AN - share identical 8-lead DIP (N-8) pinouts and electrical interfaces. The only functional difference is the internal feedback resistor network, which sets the output voltage. No PCB changes are required when substituting between fixed-output versions or the adjustable variant, provided external component values match the target output.

What type of output capacitor is recommended for the ADP1109AN-3.3?

Analog Devices recommends ≥22 µF low-ESR tantalum or OS-CON capacitors for the ADP1109AN-3.3 output stage. These provide superior ripple suppression (16–40 mV) compared to standard aluminum electrolytics due to lower ESR and ESL. Ceramic capacitors alone are discouraged because their ultralow ESR can cause instability in the gated-oscillator control loop; a hybrid approach (e.g., 22 µF tantalum + 1 µF ceramic) is acceptable if validated for ripple and startup behavior.

Does the ADP1109AN-3.3 include overcurrent or thermal protection?

No, the ADP1109AN-3.3 does not integrate overcurrent limiting or thermal shutdown circuitry. Its internal NPN switch relies on external inductor saturation and diode selection to limit peak current. Designers must select an inductor with ≥300 mA saturation rating and verify worst-case switch current (e.g., at minimum VIN and maximum load) stays below 1.2 A to avoid damage. Thermal derating is required above +70°C ambient, as the device is only specified for 0°C to +70°C operation.