Analog Devices Inc./Maxim Integrated DS2174QN+

Overview

DS2174QN+ from Maxim Integrated is a software-programmable enhanced bit error-rate tester (EBERT) IC for telecom transmission 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 features independent transmit/receive paths with 48-bit error and bit counters. It is deployed in CSUs, DSUs, and digital muxes for BER testing of T1/E1/T3/OC-3 links.

For engineers reviewing the DS2174QN+ datasheet, DS2174QN+ pinout, DS2174QN+ application, or DS2174QN+ equivalent, key selection considerations include its 44-pin PLCC package, −40°C to +85°C industrial temperature range, programmable polynomial feedback taps (up to 32), 8-bit parallel control interface, and ability to detect errors at BER up to 10⁻² while maintaining sync.

Technical Context

The DS2174QN+ implements dual-path architecture with fully independent transmit and receive data paths, each supporting serial, nibble-parallel (4-bit), or byte-parallel (8-bit) interfaces. Its pattern generator uses a programmable-length shift register with configurable feedback tap positions (up to 32 bits), enabling generation of any 2ⁿ−1 polynomial (n = 1 to 32) including industry standards like QRSS (2²⁰−1 with zero-suppression).

Synchronization logic detects loss-of-pattern after 6 errors in 64 bits and supports auto-resync or manual resync via RSYNC. The receiver's pattern detector operates with 48-bit counters that accumulate bit and error counts continuously-even during unsynchronized periods-and latch results on LC bit toggle for precise BER calculation over defined intervals.

Key Specifications

Pinout & Package

DS2174QN+ is housed in a 44-pin Plastic Leaded Chip Carrier (PLCC) package with gull-wing leads, designed for surface-mount assembly and thermal reliability in telecom infrastructure environments.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS2174QN+, DS2175Q+ offers enhanced testability and timing robustness at identical form factor and temperature grade, while MAX3675EUP+ trades critical telecom features (QRSS, 48-bit counters, OC-3 speed) for compact size and lower cost-making DS2174QN+ the optimal balance of performance, compliance, and deployability in carrier infrastructure.

Availability

DS2174QN+ is available at Aetrix Electronics and suitable for channel service units, data service units, and OC-3 network elements requiring stable component supply across extended product lifecycles and industrial temperature ranges.

Supply support for DS2174QN+ 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) is a semiconductor company specializing in precision analog, mixed-signal, and high-reliability ICs for industrial, communications, and computing markets.

The DS2174QN+ belongs to Maxim's telecom test and measurement product line, engineered specifically for bit-error analysis in T1/E1/T3/OC-3 digital transmission systems with emphasis on field-deployable accuracy and telecom-standard compliance.

FAQ

What is the maximum pseudorandom pattern length supported by the DS2174QN+?

The DS2174QN+ supports pseudorandom pattern lengths up to 2³²−1, implemented via a programmable shift register with up to 32 configurable feedback taps. This enables generation of all industry-standard polynomials-including O.151 (2¹⁵−1), O.152 (2¹¹−1), O.153 (2⁹−1), and QRSS (2²⁰−1)-with hardware-enforced zero-suppression per T1.403 when enabled. The DS2174QN+ achieves this using its dedicated tap select and seed registers (addresses 5h–8h), accessible via the parallel control interface.

Does the DS2174QN+ support QRSS pattern generation with zero-suppression compliance?

Yes, the DS2174QN+ fully supports QRSS (2²⁰−1) pattern generation with T1.403-compliant zero-suppression. When the QRSS bit (CR1.3) is set in Control Register 1, the DS2174QN+ hardware forces a '1' into the output stream whenever the next 14 bits would otherwise be '0'. This behavior is implemented in silicon-not firmware-ensuring deterministic timing and strict adherence to the standard. The DS2174QN+ also provides preconfigured tap/seed values for QRSS in Table 3-C of its datasheet.

How does the DS2174QN+ handle bit error insertion during testing?

The DS2174QN+ supports two error insertion methods: programmable rate-based insertion (10⁻¹ to 10⁻⁷) via EIR[2:0] bits in Control Register 2, and single-bit error injection via the SBE bit. Rate-based insertion applies to all data modes (bit/nibble/byte), though actual error density varies slightly in nibble/byte modes due to parallel sampling. The SBE bit triggers inversion of the next transmitted bit-delayed by one clock cycle for QRSS patterns to preserve zero-suppression rules. All error insertion is fully software-controllable through the parallel port.

What are the timing requirements for the parallel control interface of the DS2174QN+?

The DS2174QN+ parallel control interface uses a nonmultiplexed 4-bit address (A0–A3) and 8-bit data (D0–D7) bus with active-low CS, RD, and WR strobes. Setup/hold times are specified relative to RCLK/TCLK edges for register-access operations involving RSYNC, LC, TL, or SBE bits. For static register reads/writes (e.g., Control Registers 1–4), timing is governed by parallel port AC characteristics: t_DS (data setup) ≥ 15ns, t_DH (data hold) ≥ 5ns, and t_AS (address setup) ≥ 10ns, as detailed in Table 6-A/B of the DS2174QN+ datasheet. No external wait-state logic is required at typical microcontroller speeds.

Can the DS2174QN+ operate in both serial and parallel data interface modes simultaneously?

No, the DS2174QN+ operates in only one data interface mode at a time-bit (serial), nibble (4-bit parallel), or byte (8-bit parallel)-selected via MODE1/MODE0 bits in Control Register 2. The mode setting globally configures both transmit and receive paths: RDAT0–RDAT7 and TDAT0–TDAT7 pins are repurposed accordingly (e.g., RDAT0 alone active in bit mode; RDAT0–3 active in nibble mode; all eight active in byte mode). Simultaneous multi-mode operation is not supported; mode changes require reconfiguration of control registers and may necessitate resynchronization.