Asahi Kasei Microdevices/AKM AK8135F

Overview

AK8135F from Asahi Kasei Microdevices (AKM) is a low-power, multi-output clock generator IC with integrated VCFS for precise frequency tuning. It accepts a 24.576 MHz crystal input and delivers seven synchronized outputs: CLK1 (24.576 MHz), CLK2 (24.99972 MHz), CLK3 (33.332965 MHz), and four 27.000 MHz reference outputs (REF1–REF4), all operating at 3.3 V with ±85 ppm VCFS pull range and 150 ps typical period jitter. It targets high-accuracy timing in digital video recorders and broadcast equipment.

For engineers reviewing the AK8135F datasheet, AK8135F pinout, AK8135F application, or AK8135F equivalent, key selection criteria include its dual VCFS architecture, 30-pin VSOP package compatibility, low 24 mA typical supply current at 3.3 V, 72 dB typical C/N on REF outputs, and support for system-level clock synchronization via analog voltage control inputs VIN1/VIN2.

Technical Context

The AK8135F integrates two independent Voltage Controlled Frequency Synthesizers (VCFS1 and VCFS2), each driven by dedicated analog control inputs (VIN1 and VIN2), enabling fine-grained ±85 ppm tuning of four 27.000 MHz outputs (REF1–REF4) while maintaining low jitter. Its architecture separates VCFS paths from the primary PLL-based CLK1–CLK3 generation, allowing independent enable/disable control via REF1PD and REF34PD pins.

Each output is assigned to a specific internal circuit block: CLK1 derives directly from the crystal oscillator via 1:1 division; CLK2 and CLK3 use PLL-based fractional synthesis (1/12 and 1/16 ratios per Figure 1); REF1–REF4 are generated exclusively by VCFS1 (REF1, REF2) and VCFS2 (REF3, REF4), with power-down capability and mode-select logic tied to digital control pins.

Key Specifications

Pinout & Package

AK8135F is housed in a lead-free 30-pin Very Small Outline Package (VSOP), optimized for compact PCB layouts in space-constrained consumer electronics. The package features six VDD and seven GND pins distributed across the perimeter to minimize power-ground loop inductance and suppress supply noise coupling into sensitive clock paths.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AK8135F, AK8134F reduces cost and complexity for single-domain systems but sacrifices dual-VCFS flexibility and fractional clock outputs; Si5332-A01A-GM offers superior programmability and output count but demands I²C infrastructure and consumes nearly triple the current, making it less suitable for thermally constrained consumer enclosures.

Availability

AK8135F is available at Aetrix Electronics and suitable for HDD/DVD/BD recorders, digital televisions, and set-top boxes requiring stable component supply, industrial temperature operation, and analog genlock capability.

Supply support for AK8135F 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 Corporation (AKM) is a Japanese semiconductor company specializing in analog, mixed-signal, and sensor ICs, with leadership in audio codecs, Hall-effect sensors, and precision timing devices.

The AK8135F belongs to AKM's low-power multi-clock generator product line, designed specifically for broadcast and consumer video equipment where crystal-referenced accuracy, analog VCFS tuning, and multi-rail power integrity are essential for HDMI, SDI, and MPEG timing compliance.

FAQ

What is the function of the REF1PD and REF34PD pins on the AK8135F?

The REF1PD pin controls enable/disable of the REF1 output (27.000 MHz from VCFS1): logic high enables the output, logic low forces it low. The REF34PD pin simultaneously controls REF3, REF4, and powers down VCFS2. Both pins feature internal 52 kΩ pull-up resistors, ensuring safe default states. This design allows dynamic power management-disabling unused outputs reduces total current consumption by up to 8 mA, as confirmed in IDD3/IDD4 test conditions.

Does the AK8135F support genlock functionality, and how is it implemented?

Yes, the AK8135F supports analog genlock via its dual VCFS architecture. VIN1 (Pin 28) and VIN2 (Pin 27) accept external DC control voltages (0.5VDD ±1.0 V) to tune REF1–REF2 and REF3–REF4 frequencies within ±85 ppm of 27.000 MHz. This enables real-time alignment to external timing references such as tri-level sync or black burst signals. The typical VCFS pulling profile shown in Figure 4 confirms linear response across the control voltage range, making AK8135F suitable for professional video capture and broadcast equipment.

What are the recommended decoupling practices for the AK8135F's six VDD pins?

Each of the six VDD pins (VDD1–VDD6) must be decoupled with a 0.1 µF ceramic capacitor placed as close as possible to the respective pin, with the capacitor grounded to its corresponding GND pin (GND1–GND7). This practice is explicitly required in the Recommended Operating Conditions section to suppress supply noise coupling into PLL and VCFS blocks. Failure to follow this layout guideline risks increased period jitter beyond the specified 150 ps typical value, particularly on CLK2 and CLK3 outputs which rely on sensitive fractional synthesis.

Can the AK8135F generate the exact 25.000 MHz and 33.333 MHz frequencies listed in its datasheet?

The AK8135F outputs CLK2 at 24.99972 MHz and CLK3 at 33.332965 MHz-values intentionally offset from nominal 25.000 MHz and 33.333 MHz to avoid integer-related spurs and meet broadcast timing standards like ETSI EN 300 429. These frequencies are derived from the 24.576 MHz crystal via precise PLL division ratios (1/12 and 1/16 per Figure 1). The datasheet specifies output clock accuracy as ±30 ppm relative to target values under defined test conditions, confirming functional equivalence for MPEG transport and SD-SDI applications.

Is the AK8135F RoHS compliant, and what does the marking "Pb free" indicate?

Yes, the AK8135F is fully RoHS compliant and assembled in a lead-free package. Per AKM's official notice on page 11, all AKM integrated circuits in lead-free packages carry "Pb free" labeling on anti-static bags and shipping boxes. This designation confirms compliance with Directive 2011/65/EU and absence of lead, mercury, cadmium, hexavalent chromium, PBB, and PBDE above threshold limits-critical for export to EU, Japan, and China markets.