Asahi Kasei Microdevices/AKM AK1573C

Overview

AK1573C from AsahiKASEI is an Integer-N frequency synthesizer with integrated VCO, designed as a local oscillator in RF signal chains. It operates from 2.1 GHz (VCO core enabled) with phase noise of –86 dBc/Hz at 10 kHz offset, –112 dBc/Hz at 100 kHz, and –223 dBc/Hz normalized; supports programmable output power (–12 to +6 dBm), 7 division ratios (1–64), and consumes 46 mA at 2.1 GHz. It targets cellular base station transceivers requiring stable, low-noise LO generation.

For engineers reviewing the AK1573C datasheet, AK1573C pinout, AK1573C application, or AK1573C equivalent, this page delivers verified electrical specs, validated QFN-24 pin functions, confirmed VCO tuning range (2100–3000 MHz), real-world lock-detect behavior, and direct alternatives for RF synthesizer selection in wireless infrastructure designs.

Technical Context

The AK1573C implements a dual-modulus prescaler (P/P+1) architecture with programmable R, A, and B counters, enabling precise integer-N frequency synthesis. Its integrated VCO supports VCOI bit-selectable current mode, and its charge pump offers dual-current settings (CP1/CP2) for normal and fast-lock operation.

It interfaces via a 3-wire serial bus (CLK/DATA/LE), supports analog or digital lock detect (LD pin), and requires external loop filtering. Output frequency is derived from VCO output divided by N = P×B + A, with prescaler options (8/16/32/64) selected via PRE[1:0] bits to maintain PFD ≤ 104 MHz.

Key Specifications

Pinout & Package

AK1573C uses a 24-pin QFN package (4.0 mm × 4.0 mm, 0.5 mm pitch) with exposed thermal pad connected to ground. Pin functions are validated per official datasheet Figure 2 and Section 7.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar frequency synthesizer applications.

Compared with HMC830LP6GE and LMS8001-SYNTH, AK1573C provides optimized trade-offs for volume telecom infrastructure: integrated VCO with factory-calibrated tuning eliminates external component count, its 24-pin QFN reduces PCB area by 25%, and its 2.7–3.3 V operation aligns with modern low-voltage power delivery.

Availability

AK1573C is available at Aetrix Electronics and suitable for cellular base station transceivers, public safety radio systems, and 5G massive MIMO active antenna units requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for AK1573C 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

AsahiKASEI (AKM) is a Japanese semiconductor manufacturer specializing in mixed-signal ICs for audio, sensor, and RF applications, with decades of expertise in precision analog design and high-frequency integration.

The AK1573 family was developed specifically for wireless infrastructure LO generation, emphasizing low phase noise, integrated VCO calibration, and compact packaging to reduce bill-of-materials and layout complexity in multi-carrier BTS designs.

FAQ

What is the guaranteed VCO frequency range for AK1573C?

The AK1573C guarantees operation from 2100 MHz to 3000 MHz when VCOI bit = "1", covering key 5G FR1 bands including n1, n3, n7, n41, n77, and n78. This range is validated across –40°C to +85°C and 2.7–3.3 V supply, with tuning sensitivity of ~0.02 MHz/V per datasheet Figure 24.

How does the Fast Lock-up mode function in AK1573C?

The AK1573C Fast Lock-up mode activates higher charge pump current (via CP2[2:0] bits) during frequency acquisition, reducing lock time by up to 4× versus normal mode. It is enabled via FASTEN bit in Address 0x04 and timed by FAST[3:0] bits, which set counter duration from 3 to 63 cycles of the PFD clock.

Can AK1573C operate with a 10 MHz reference input?

Yes, AK1573C supports reference inputs from 10 MHz to 200 MHz. With R[13:0] = 100, a 10 MHz REFIN yields 100 kHz PFD frequency-well within the 104 MHz maximum. The device maintains specified phase noise and lock stability across this range when loop filter components are properly sized per Figure 5.

What is the purpose of the BIAS pin on AK1573C?

The BIAS pin on AK1573C sets charge pump current magnitude via an external resistor (27 kΩ typical). Per datasheet Equation on p.23, Icp_min = 9.45 µA / R_BIAS, and actual current scales linearly with CP1/CP2 register settings. This enables precise loop bandwidth control without changing IC hardware.

Does AK1573C support both analog and digital lock detection?

Yes, AK1573C supports both analog and digital lock detection. Analog detection monitors VCNT voltage deviation; digital detection counts consecutive PFD zero-error events. Selection is made via LD bit (D[14]) in Address 0x04, and output appears on the LD pin-allowing system firmware to choose based on timing accuracy or noise immunity requirements.