Analog Devices Inc./Maxim Integrated DS1862B+

Overview

The DS1862B+ from Maxim Integrated is a closed-loop laser-driver control IC with integrated digital diagnostics for XFP MSA-compliant 10Gbps optical transceiver modules. It implements automatic power control (APC), temperature-indexed extinction ratio control via lookup table (LUT), and monitors seven analog inputs-including bias monitor (IBIASMON), monitor diode current (BMD), RSSI, and dual auxiliary channels-for real-time laser regulation and safety fault detection.

For engineers reviewing the DS1862B+ datasheet, DS1862B+ pinout, DS1862B+ application, or DS1862B+ equivalent, this page delivers verified technical context, confirmed I²C interface timing (400kHz max), APC calibration accuracy (±5% over 0.2–1.5mA range), 25-ball CSBGA package mapping, and validated alternatives for XFP laser control systems requiring eye-safety quick-trip logic and EEPROM-stored calibration.

Technical Context

The DS1862B+ integrates a 13-bit ADC with round-robin multiplexing across seven monitored channels (five basic + two auxiliary), supporting factory- and user-calibrated gain/offset scaling per channel. Its APC loop dynamically adjusts BIASSET sink current to match photodiode feedback (BMD) against programmable register values, with loop bandwidth of 6–30kHz depending on IMD/IAPC ratio.

Extinction ratio control uses a 127-entry, temperature-indexed LUT stored in EEPROM; indexing is driven either by internal temperature sensor or external sensor on AUX2MON, with 2°C resolution across –40°C to +102°C. MODSET provides programmable sink current (0–1200μA) in five selectable ranges, while FETG enables external safety disconnect during fault conditions.

Key Specifications

Pinout & Package

DS1862B+ is housed in a 25-ball Chip Scale Ball Grid Array (CSBGA) package measuring 5mm × 5mm, optimized for compact XFP module integration. Pin functions are validated per Maxim's official datasheet Rev 1 (12/07).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar laser control and digital diagnostic applications.

Compared with MAX32664A+T and ADN2880ACPZ-R7, the DS1862B+ uniquely delivers MSA-compliant, hardware-accelerated APC + LUT extinction ratio control in a single chip-enabling direct replacement in XFP modules without host software changes or external DACs.

Availability

DS1862B+ is available at Aetrix Electronics and suitable for 10Gbps optical transceivers, laser safety subsystems, and field-programmable XFP modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for DS1862B+ 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

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for demanding industrial, communications, and computing applications.

The DS1862B+ belongs to Maxim's optical communications product line, engineered specifically to meet XFP MSA digital diagnostic requirements while integrating closed-loop laser control, safety monitoring, and EEPROM-based configuration storage.

FAQ

What is the primary function of the DS1862B+ in an XFP module?

The DS1862B+ serves as the core laser driver and digital diagnostic controller in XFP modules. It performs automatic power control (APC) by regulating BIASSET current to maintain constant optical output, implements temperature-compensated extinction ratio control using a 127-entry lookup table, and monitors seven analog signals-including BMD, RSSI, and VCC rails-to enforce safety thresholds and report diagnostics via I²C. Its design directly satisfies XFP MSA requirements for closed-loop control and real-time monitoring.

Does the DS1862B+ support both internal and external temperature sensing for LUT indexing?

Yes, the DS1862B+ supports both internal temperature sensing and external temperature sensing via the AUX2MON pin for LUT indexing. The internal sensor is always active and controls temperature-related alarm flags. When TEMP_INT/EXT = 1 (bit in Table 04h, Byte 8Bh), AUX2MON takes over LUT indexing-enabling precise extinction ratio tuning using an external thermistor or diode sensor-while the internal sensor continues monitoring for safety flag generation. This dual-path capability ensures robust thermal management in diverse module designs.

How does the DS1862B+ ensure laser eye safety compliance?

The DS1862B+ enforces laser eye safety through three hardware-verified mechanisms: (1) Quick-trip logic that disables laser bias within 30μs of detecting overtemperature, overcurrent, or over-optical-power faults; (2) FETG output capable of driving an external MOSFET to physically disconnect the laser; and (3) P-DOWN/RST pin that triggers full hardware reset. All paths operate independently of I²C communication, ensuring fail-safe behavior even during host processor lockup. These features align with IEC 60825-1 Class 1 safety requirements for optical transceivers.

What are the key electrical characteristics of the DS1862B+ I²C interface?

The DS1862B+ I²C interface operates in standard mode with a maximum clock frequency of 400kHz, matching common host controller capabilities in XFP systems. It features open-drain SDA/SCL pins with internal pullups (9–15kΩ), VIH ≥ 0.7×VCC3, VIL ≤ 0.3×VCC3, and tSU:DAT ≥ 100ns setup time. Communication requires MOD-DESEL (E2) to be pulled low first. EEPROM writes take 16ms per 4-byte block, and all register accesses follow XFP MSA-defined memory map (Tables 01h–05h), ensuring interoperability across vendor platforms.

Can the DS1862B+ monitor both VCC2 and VCC3 supply rails simultaneously?

No, the DS1862B+ monitors either VCC2 or VCC3-not both simultaneously. The selection is made via configuration bits in Table 04h, allowing users to choose which rail to measure for supply fault detection. VCC2 (1.6–3.6V) supports optional variable-supply XFP features, while VCC3 (2.9–5.5V) powers the main logic and analog blocks. If VCC2 is unused, it must be tied to VCC3 per datasheet Note 2. The monitored rail's voltage is digitized with 1.6mV resolution and ±0.25–0.5%FS accuracy after internal calibration.