Analog Devices Inc. ADN2526ACPZ

Overview

ADN2526ACPZ from Analog Devices is a 11.3 Gbps differential laser diode driver with active back-termination, designed for direct modulation of TOSAs with 5 Ω–50 Ω differential resistance. It delivers 24 ps typical rise/fall times, 10–100 mA programmable bias current, and 10–80 mA differential modulation current, enabling high-fidelity optical eye generation in SFP+/XFP 10G transceivers.

For engineers reviewing the ADN2526ACPZ datasheet, ADN2526ACPZ pinout, ADN2526ACPZ application, or ADN2526ACPZ equivalent, key selection criteria include its SFP+ MSA compliance, ALS-controlled shutdown timing (2 µs assert / 10 µs negate), crosspoint adjustment capability, IBMON bias monitoring accuracy (±2% at 70–100 mA), and thermal performance under 125°C junction limit in compact 3 mm × 3 mm LFCSP.

Technical Context

The ADN2526ACPZ implements an active back-termination architecture using feedback-synthesized 25 Ω per side (50 Ω differential) to absorb reflections from misterminated TOSA loads, enabling robust optical eye quality without requiring precise load impedance matching. Its input stage features integrated 100 Ω differential termination and ac-coupling support for NRZ data up to 11.3 Gbps.

Bias and modulation currents are independently controlled via analog voltage inputs (BSET and MSET), each with 1 kΩ input resistance and defined gain (90 mA/V for BSET; 50–100 mA/V for MSET depending on load). The ALS pin provides LVTTL-compatible digital enable/disable control with sub-µs response, while CPA allows optical crosspoint tuning from 35% to 65%.

Key Specifications

Pinout & Package

ADN2526ACPZ is housed in a 3 mm × 3 mm, 16-pin LFCSP package with exposed pad (EPAD) that must be connected to VCC or ground plane for thermal and electrical integrity. Pin count and layout conform to SFP+ MSA mechanical requirements.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar differential laser driver applications.

Compared with MAX3735AETE+ and LMH6525MA/NOPB, the ADN2526ACPZ uniquely integrates active back-termination, SFP+ MSA compliance, and laser-specific safety/monitoring features-enabling production-ready 10G optical modules without added discrete components or firmware overhead.

Availability

ADN2526ACPZ is available at Aetrix Electronics and suitable for 10G optical transceivers, SFP+/XFP modules, and SONET/SDH line cards requiring stable component supply across industrial temperature ranges and long product lifecycles.

Supply support for ADN2526ACPZ 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 industrial markets since 1965.

The ADN2526ACPZ belongs to Analog Devices' high-speed optical interface product line, engineered specifically for 10G-class laser driver applications in pluggable optical modules with emphasis on signal integrity, thermal efficiency, and MSA compliance.

FAQ

What is the maximum differential load resistance supported by the ADN2526ACPZ?

The ADN2526ACPZ supports differential laser loads from 5 Ω to 50 Ω, as confirmed in the General Description and Specifications table. Its active back-termination architecture maintains signal integrity even when driving significantly misterminated TOSAs-enabling robust optical eye quality without requiring precise load impedance matching. This range covers most commercially available 10G DFB and EML laser diodes used with the ADN2526ACPZ.

Does the ADN2526ACPZ require external termination resistors on its data inputs?

No, the ADN2526ACPZ includes internal 100 Ω differential termination between DATAP and DATAN pins, as specified in Table 4 and Figure 17. This eliminates the need for external resistors and minimizes signal reflections at the input. However, ac-coupling capacitors (e.g., 10 nF) are mandatory to handle common-mode voltage mismatch between the data source and the ADN2526ACPZ input stage.

How does the CPA pin affect optical performance in the ADN2526ACPZ?

The CPA pin on the ADN2526ACPZ adjusts the optical eye crosspoint from 35% to 65% by controlling internal current steering, directly impacting eye symmetry and extinction ratio. When left floating, CPA defaults to ~1.9 V, setting crosspoint to 50%. Applying an external voltage shifts the balance-critical for compensating laser nonlinearity or channel skew. This feature is validated in Figure 31 and Applications Information section of the ADN2526ACPZ datasheet.

What is the ALS pin response time for the ADN2526ACPZ?

The ALS pin on the ADN2526ACPZ asserts (disables IBIAS and IMOD) within 2 µs of a rising edge and negates (re-enables) within 10 µs of a falling edge, as measured per Figure 2 and specified in Table 1. This timing ensures fast, safe laser shutdown during hot-swap events or fault conditions while allowing rapid reactivation-meeting SFP+ MSA requirements for module control sequencing.

Can the ADN2526ACPZ drive a TOSA with 3.3 V common-mode voltage on IMODP/IMODN?

No-the ADN2526ACPZ IMODP and IMODN pins operate with a dc common-mode voltage equal to VCC (3.3 V), and their allowable voltage range is VCC − 1.1 V to VCC + 1.1 V (i.e., 2.2 V to 4.4 V), per Table 1. A 3.3 V common-mode level falls within this window, but the output must be ac-coupled to the TOSA to avoid violating compliance limits under dynamic modulation swing. This requirement is explicitly stated in the Theory of Operation section.