Asahi Kasei Microdevices/AKM AK8172A

Overview

AK8172A from Asahi Kasei Microdevices is a single-output, PLL-based clock generator IC that synthesizes a precise 72.36 MHz output clock from a 27.000 MHz input reference, operating at 1.7–1.9 V supply with typical current consumption of 3.6 mA and 15 ps (1σ) period jitter. It integrates input buffers, a high-performance PLL, and output buffer in a 4-pin USON package and is used in digital still cameras for timing-critical image sensor and processor clocking.

For engineers reviewing the AK8172A datasheet, AK8172A pinout, AK8172A application, or AK8172A equivalent, key selection considerations include its fixed-ratio PLL architecture (27 MHz → 72.36 MHz), ultra-small 1.3 mm × 1.1 mm USON footprint, low-voltage 1.8 V operation, and guaranteed performance over –20 °C to +85 °C without external crystal or loop filter components.

Technical Context

The AK8172A implements a fully integrated integer-N PLL with no external components required-its loop filter is monolithic, and frequency multiplication is fixed at 72.36 / 27.000 = 2.68×. Input accepts 27 MHz at either 1.8 V or 3.3 V logic levels, while output drives 15 pF load with 45–55% duty cycle and sub-5 ns rise/fall times.

It achieves low-jitter timing via on-die VCO calibration and operates exclusively in single-output mode with no enable/disable control or spread-spectrum capability. Power-up lock time is specified at 0.2 ms, and DC characteristics include VIH/VIL referenced to VDDI and rail-to-rail output swing under ±4 mA load.

Key Specifications

Pinout & Package

AK8172A is housed in a 4-pin, lead-free USON package measuring 1.3 mm × 1.1 mm × 0.4 mm (height), with wettable flank leads for solder inspection. The package has no exposed pad and requires reflow-compatible PCB layout per AKM MS1369-E-00 mechanical drawings.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar clock generator applications.

Compared with AK8171A and Si51211-A01474-GM, the AK8172A provides the lowest jitter and smallest footprint for fixed 72.36 MHz generation, but lacks programmability and multi-output capability-making it optimal for cost- and size-sensitive DSC modules with unchanging timing requirements.

Availability

AK8172A is available at Aetrix Electronics and suitable for digital still camera modules, portable image processors, and compact embedded vision systems requiring stable component supply, consistent parametric performance, and RoHS-compliant lead-free packaging.

Supply support for AK8172A 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

Asahi Kasei Microdevices (AKM) is a Japanese semiconductor company specializing in high-precision analog and mixed-signal ICs, particularly for audio, sensor, and timing applications.

The AK8172A belongs to AKM's AK81xx series of ultra-compact, low-jitter clock generators designed specifically for timing-critical imaging modules where board space, power, and jitter are tightly constrained.

FAQ

What is the exact output frequency of the AK8172A and how is it derived?

The AK8172A delivers a fixed output frequency of 72.36 MHz, synthesized from a 27.000 MHz input clock using an internal integer-N PLL with a precise 72.36 / 27.000 = 2.68× multiplication ratio. This ratio is hardwired and non-programmable; the AK8172A does not support alternate frequencies or external configuration. Its design ensures ±0.1% accuracy over temperature and voltage variation without requiring external components.

Does the AK8172A require external passive components for PLL operation?

No, the AK8172A does not require external passive components for PLL operation. Its loop filter is fully integrated on-die, and the VCO calibration is automatic. Only a 0.1 µF ceramic decoupling capacitor on the VDD pin is mandated per the datasheet. No external resistors, capacitors, or crystals are needed-enabling true "connect-and-run" clock generation in space-constrained layouts.

Can the AK8172A accept a 3.3 V input clock while operating at 1.8 V supply?

Yes, the AK8172A CLKIN pin supports 3.3 V logic levels even when VDD is 1.8 V. The input buffer is designed for dual-voltage compatibility (1.8 V or 3.3 V), with VIH and VIL thresholds defined relative to VDDI-not VDD. This allows interfacing directly with legacy 3.3 V oscillators or FPGA outputs without level shifters, simplifying system integration in hybrid-voltage camera platforms.

What is the maximum allowable load capacitance on the AK8172A CLKOUT pin?

The AK8172A CLKOUT pin is characterized and guaranteed for loads up to 15 pF, including PCB trace capacitance and receiver input capacitance. Exceeding this value may degrade rise/fall times, increase jitter, or cause duty cycle distortion. For reliable operation, total load must remain ≤15 pF; typical CMOS receivers (e.g., image sensor inputs) contribute 2–5 pF each, permitting limited fanout or short trace lengths only.

Is the AK8172A suitable for automotive or industrial temperature grade applications?

No, the AK8172A is rated for –20 °C to +85 °C operation only and is intended for commercial applications such as digital still cameras. It is not qualified to AEC-Q100 or industrial temperature standards (–40 °C to +105 °C). For extended-temperature use, designers must select alternative clock generators explicitly specified and tested across those ranges-AK8172A performance and reliability are not guaranteed outside its published operating conditions.