Analog Devices Inc./Maxim Integrated DS2174Q+

Overview

DS2174Q+ from Maxim Integrated is a software-programmable enhanced bit error-rate tester (EBERT) for digital transmission facility validation. It generates and synchronizes to pseudorandom patterns up to 2³²−1, supports user-defined repetitive patterns up to 512 bytes, operates at serial clock rates up to 155MHz, and detects errors at BER up to 10⁻². It serves in CSU/DSU, router, and mux test environments.

For engineers reviewing the DS2174Q+ datasheet, DS2174Q+ pinout, DS2174Q+ application, or DS2174Q+ equivalent, key selection considerations include its dual independent transmit/receive paths, programmable polynomial feedback taps (up to 32), 48-bit error/bit counters, 8-bit parallel control interface, and support for QRSS pattern per T1.403.

Technical Context

The DS2174Q+ implements a fully independent transmit and receive data path with separate clock inputs (TCLK/RCLK), enable signals (TCLK_EN/RCLK_EN), and data interfaces (TDATn/RDATn). Its pattern generator uses a programmable-length shift register with up to 32 configurable feedback tap positions, enabling generation of any 2ⁿ−1 pattern where n = 1 to 32.

Synchronization logic supports both polynomial and repetitive pattern modes: polynomial sync completes in 50 + n clock cycles (bit mode), while repetitive sync requires at least one full error-free pattern repetition. Bit error counting activates only after synchronization, and the 48-bit counters accumulate counts for >500 hours at 155MHz before saturation.

Key Specifications

Pinout & Package

DS2174Q+ is housed in a 44-pin Plastic Leaded Chip Carrier (PLCC) package with gull-wing leads, rated for 0°C to +70°C operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bit error-rate tester applications.

Compared with DS2174Q+, DS2175Q+ offers identical functionality with extended thermal rating, while MAX3675 sacrifices pattern depth, counter resolution, and speed for reduced complexity and cost-making DS2174Q+ the optimal choice for OC-3 validation and field-deployable diagnostics.

Availability

DS2174Q+ is available at Aetrix Electronics and suitable for CSU/DSU manufacturing, router line card qualification, and telecom infrastructure field service requiring stable component supply over extended product lifecycles.

Supply support for DS2174Q+ 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 high-speed communication ICs for industrial, telecom, and computing markets.

The DS2174Q+ belongs to Maxim's telecom test equipment product line, engineered specifically for bit error-rate validation in digital transmission systems compliant with T1, E1, and SONET OC-3 standards.

FAQ

What is the maximum pseudorandom pattern length supported by the DS2174Q+?

The DS2174Q+ supports pseudorandom pattern lengths up to 2³²−1, implemented via a programmable shift register with up to 32 user-configurable feedback taps. This enables generation of all standard telecom polynomials including O.151 (2¹⁵−1), O.152 (2¹¹−1), and QRSS (2²⁰−1 with zero-suppression), as confirmed in the device's Control Register 3 and Tap Select Register specifications.

Does the DS2174Q+ support both serial and parallel data interfaces?

Yes, the DS2174Q+ supports bit-serial, nibble-parallel (4-bit), and byte-parallel (8-bit) data interfaces, selected via MODE1/MODE0 bits in Control Register 2. In byte mode, it achieves a net 622Mbps data rate at 80MHz clocking, meeting OC-3 requirements. The RDATn and TDATn pins adapt functionally based on mode, with RDAT0/ TDAT0 serving as LSB in parallel configurations.

How does the DS2174Q+ handle bit error insertion during testing?

The DS2174Q+ inserts bit errors via Control Register 2's EIR[2:0] bits, offering selectable rates from 10⁻¹ to 10⁻⁷ in serial mode (8⁻¹ to 8⁻² in byte mode). It also supports single-bit error injection via the SBE bit, which inverts the next transmitted bit. For QRSS patterns, the DS2174Q+ delays the erred bit by one clock cycle to preserve zero-suppression compliance.

What is the purpose of the TEST pins on the DS2174Q+?

The DS2174Q+ has two TEST pins (Pins 20 and 21), each with an internal 10kΩ pull-up resistor. These are factory test inputs and must be left floating or held high during normal operation. Driving them low may disrupt internal test modes or cause undefined behavior, as stated in the Pin Description section of the datasheet.

Can the DS2174Q+ operate with gapped clock signals?

Yes, the DS2174Q+ supports gapped clock operation via RCLK_EN and TCLK_EN pins. When these enables are deasserted, the internal clock paths are gated while TDATn and RDATn outputs retain their last logic state-ensuring signal integrity during time-slot gaps in TDM systems. The TCLKO output reflects this gapping, providing a synchronized clock enable signal for downstream devices.