Analog Devices Inc. ADP1173AN-3.3

Overview

ADP1173AN-3.3 from Analog Devices is a micropower step-up/step-down DC-DC converter IC with fixed 3.3 V output, internal 1 A power switch, 2.0–30 V input range, and 110 µA quiescent current in standby mode. It operates in boost mode (e.g., 3 V → 3.3 V) or buck mode (e.g., 12 V → 3.3 V), supporting portable instrumentation and low-power logic supply generation.

For engineers reviewing the ADP1173AN-3.3 datasheet, ADP1173AN-3.3 pinout, ADP1173AN-3.3 application, or ADP1173AN-3.3 equivalent, key selection factors include its dual-mode topology support, on-chip current limit adjustability via ILIM, integrated 1.245 V reference, low-battery detection capability using the AO/SET gain block, and compatibility with standard DIP-8 PCB footprints.

Technical Context

The ADP1173AN-3.3 implements a gated-oscillator control architecture with 23 µs typical ON time and 19 µs OFF time, enabling high efficiency at light loads. Its comparator uses 1.245 V internal reference with 5–12 mV hysteresis to ensure loop stability without external compensation.

It integrates an uncommitted gain block (AV = 400–1000 V/V) with SET pin input and open-collector AO output capable of sinking 100 µA - configurable as low-battery detector or UVLO circuit. The internal NPN power switch supports both step-up (SW2 to GND, SW1 to inductor) and step-down (SW1 to VIN, SW2 to inductor) configurations.

Key Specifications

Pinout & Package

ADP1173AN-3.3 is housed in an 8-lead plastic DIP (N-8) package with 0.3-inch width and through-hole mounting. Pin spacing matches industry-standard DIP-8 footprints.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADP1173AN-3.3, ADP1173AR-3.3 offers identical regulation performance in a space-saving SO-8 package, while MAX630ESA+ provides lower IQ in a dedicated boost-only solution - neither replicates the full dual-mode flexibility, on-chip current limiting, or auxiliary gain functionality of the ADP1173AN-3.3.

Availability

ADP1173AN-3.3 is available at Aetrix Electronics and suitable for portable instrumentation, flash memory programming, low-power logic supply, and LCD bias generation requiring stable component supply across extended production lifecycles.

Supply support for ADP1173AN-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 ADP1173 family was designed specifically for ultra-low-power, dual-mode DC-DC conversion in battery-operated portable equipment - emphasizing micropower operation, topology flexibility, and minimal external component count.

FAQ

What is the maximum output current capability of the ADP1173AN-3.3 in step-down mode?

The ADP1173AN-3.3 delivers up to 100 mA at 3.3 V from a 12 V input in step-down configuration, as specified in the General Description. This assumes proper inductor selection (e.g., 220 µH, 650 mA saturation rating) and thermal management. At higher input voltages or ambient temperatures, current should be derated per the SOA curves in the datasheet to maintain reliability of the internal 1 A switch.

Can the ADP1173AN-3.3 be used in step-up mode with a 2.4 V input to generate 3.3 V?

Yes, the ADP1173AN-3.3 supports step-up operation down to 2.0 V input, making it suitable for two-cell alkaline or NiMH battery inputs. At 2.4 V input, it delivers regulated 3.3 V output with typical efficiency >75% at 50 mA load. Ensure the inductor (e.g., 100 µH) and Schottky diode (e.g., BAT54) are selected per the Application section to maintain stability and low ripple.

How does the ADP1173AN-3.3 implement low-battery detection?

The ADP1173AN-3.3 uses its internal gain block: the SET pin accepts a resistor divider from VIN to GND, while the inverting input is tied to the 1.245 V reference. When VIN drops below the programmed threshold, the AO pin (open-collector NPN) pulls low, sinking up to 100 µA. This signal can directly drive a microcontroller interrupt or LED indicator without external components.

Is the FB/SENSE pin of the ADP1173AN-3.3 left unconnected or tied to output?

For the ADP1173AN-3.3, the FB/SENSE pin must be connected directly to the regulated 3.3 V output node. Unlike the adjustable ADP1173, this pin is internally connected to laser-trimmed resistors that set the 3.3 V output - leaving it floating or connecting it elsewhere will cause regulation failure or damage due to incorrect feedback path.

What is the purpose of the ILIM pin on the ADP1173AN-3.3, and how is it configured?

The ILIM pin on the ADP1173AN-3.3 sets the maximum switch current limit. Connect it directly to VIN for full 1 A capability. To reduce peak current (e.g., for thermal or EMI reasons), place a 220 Ω resistor between ILIM and VIN - this limits switch current to 400 mA. The current limit has a –0.3%/°C temperature coefficient, ensuring stable protection across operating temperature.