Analog Devices Inc. AD9901KPZ

Overview

AD9901KPZ from Analog Devices is an ultrahigh-speed digital phase/frequency discriminator IC designed for PLL error detection in RF and IF signal chains. It directly compares TTL/CMOS or ECL inputs up to 200 MHz, delivers linear phase detection with no dead zone, and operates from a single +5 V (TTL) or –5.2 V (ECL) supply. Its open-collector outputs support post-filtering interface matching in low-phase-noise reference loops.

For engineers reviewing the AD9901KPZ datasheet, AD9901KPZ pinout, AD9901KPZ application, or AD9901KPZ equivalent, this page provides verified functional identity, confirmed 20-lead PLCC package mapping, validated dual-mode (TTL/ECL) input/output behavior, and real-world locking performance data at 70 MHz and 200 MHz.

Technical Context

The AD9901KPZ implements a dual-path architecture: a phase detection path using two D-flip-flops and an XOR gate for near-lock operation, plus independent frequency discriminator flip-flops (S/R type) that activate when input frequencies differ by >2× to force coarse lock. Input signals are divided-by-two before XOR comparison, ensuring square-wave inputs regardless of duty cycle and shifting nonlinearity to phase extremes.

Its transfer function is linear near lock with constant gain of 0.286 V/rad (typical), enabled by trench-oxide isolation and high-speed logic design. At 200 MHz, linear phase detection range is ±50°; at 70 MHz, it extends to ±270°. Output duty cycle directly encodes phase difference, and dc mean value after low-pass filtering yields K_φ(φ_I – φ_O) error voltage.

Key Specifications

Pinout & Package

The AD9901KPZ is packaged in a 20-lead plastic leaded chip carrier (PLCC, package option P-20A), with gull-wing leads and pin 1 identifier marked on top surface. Thermal impedance is θ_JA = 88.2°C/W and θ_JC = 45.2°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar phase/frequency discriminator applications.

Compared with AD9901KPZ, AD9902KPZ offers extended linear range in identical packaging for seamless upgrade, while LMX2594EVM shifts architecture from discrete discriminator-based PLL to fully integrated synthesizer-requiring redesign but enabling advanced features like fractional-N division and digital calibration.

Availability

AD9901KPZ is available at Aetrix Electronics and suitable for low-phase-noise reference loops, fast-tuning agile IF systems, and secure frequency-hopping communications requiring stable component supply across industrial and defense electronics programs.

Supply support for AD9901KPZ 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 precision instrumentation, communications, and aerospace markets since 1965.

The AD9901KPZ belongs to Analog Devices' high-speed timing and PLL component family, engineered specifically for ultralow-jitter, prescaler-free phase/frequency discrimination in demanding RF and radar signal chains.

FAQ

What logic families does the AD9901KPZ support?

The AD9901KPZ supports TTL, CMOS, and ECL logic families. In TTL/CMOS mode, it operates from a +5.0 V supply with inputs referenced to ground; in ECL mode, it uses a –5.2 V supply with differential inputs. The BIAS pin configures the internal bias network accordingly, and both modes share identical functional pinouts on the 20-lead PLCC package.

Does the AD9901KPZ require external prescalers for 200 MHz operation?

No, the AD9901KPZ does not require external prescalers for 200 MHz operation. Its internal high-speed trench-oxide isolated process and optimized flip-flop/XOR architecture enable direct comparison of 200 MHz reference and VCO inputs. This eliminates prescaler-induced latency, spurious tones, and phase uncertainty common in traditional PLL designs using slower discriminators.

What is the purpose of the RSET pin on the AD9901KPZ?

The RSET pin on the AD9901KPZ sets the maximum output current via an external resistor: I_SET = 0.47 V / R_SET. In TTL mode, RSET connects to ground; in ECL mode, it connects to –5.2 V. This allows dynamic adjustment of output drive strength-reducing power consumption at lower frequencies while maintaining signal integrity into downstream filter networks.

How does the AD9901KPZ eliminate the "dead zone" in phase detection?

The AD9901KPZ eliminates the dead zone by shifting nonlinear gain regions to the endpoints of its transfer curve-not near lock-using divide-by-two input conditioning and XOR-based phase comparison. This ensures constant, non-zero gain (0.286 V/rad typical) across the central ±180° range, preventing zero-error-signal conditions that cause increased phase noise and instability in conventional digital phase detectors.

Is the AD9901KPZ pin-compatible with other members of the AD990x family?

Yes, the AD9901KPZ is pin-compatible with AD9902KPZ in the 20-lead PLCC package (P-20A). Both share identical pin functions, electrical interface behavior, and thermal characteristics. This allows direct substitution where extended linear phase range (±320° vs. ±270° at 30 MHz) is needed, without PCB or layout changes.