Renesas 74SSTV16857PAG

Overview

74SSTV16857PAG from Renesas Electronics (formerly IDT) is a 14-bit registered buffer IC designed for DDR SDRAM memory subsystems, operating at 2.3–2.7 V with SSTL_2 I/O compatibility, differential CLK/CLK inputs, LVCMOS RESET control, and TSSOP-48 package. It supports PC1600–PC3200 DIMM applications with 200–220 MHz clock frequency and drives up to 18 SDRAM loads.

For engineers reviewing the 74SSTV16857PAG datasheet, 74SSTV16857PAG pinout, 74SSTV16857PAG application, or 74SSTV16857PAG equivalent, key selection criteria include SSTL_2 Class II compliance, industrial temperature range (–40°C to +85°C), flow-through architecture for signal integrity, reset-synchronized low-state initialization, and precise timing margins (tSU = 0.65 ns, tPDM = 1.1–2.8 ns).

Technical Context

The 74SSTV16857PAG implements a 1:1 registered flow-through buffer with dual-rail supply (VDD/VDDQ), differential clock reception, and independent LVCMOS RESET that forces all outputs low and disables receivers before clock stabilization. Its internal registers are edge-triggered on CLK/CLK transitions, supporting AC-coupled SSTL_2 data paths compliant with JEDEC JESD8-15A.

It features matched output impedance (rOH/rOL = 7–20 Ω, ΔrO ≤ 4 Ω), VREF-based input thresholding (VIH/VIL = VREF ± 310 mV AC), and termination-aware design with VTT = VREF ± 40 mV - enabling direct interface to DDR1 SDRAM modules without external level-shifting or termination tuning.

Key Specifications

Pinout & Package

74SSTV16857PAG is housed in a 48-pin Thin Shrink Small Outline Package (TSSOP), lead-free and RoHS-compliant (Green), with 0.5 mm pitch and exposed thermal pad (not electrically connected). Pin layout follows flow-through architecture: data inputs D1–D14 on one side, corresponding registered outputs Q1–Q14 on opposite side, differential clocks and RESET centrally located for minimal skew.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar registered buffer applications.

Compared with 74SSTV16857PAG, the 74FCT16857CTPAG lacks SSTL_2 and VREF support - making it incompatible with DDR1 memory interfaces - while the SN74SSTVF16857ZQLR offers enhanced DDR2 timing but at higher power and cost, with no benefit for pure DDR1 implementations.

Availability

74SSTV16857PAG is available at Aetrix Electronics and suitable for DDR1 registered DIMM modules, server memory subsystems, and industrial control memory expansion requiring stable component supply, long-lifecycle support, and industrial-temperature qualification.

Supply support for 74SSTV16857PAG 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

Renesas Electronics Corporation is a global semiconductor leader delivering microcontrollers, analog, power, and memory solutions for automotive, industrial, infrastructure, and IoT applications.

The 74SSTV16857PAG belongs to Renesas' legacy IDT memory interface portfolio, specifically engineered for DDR1 SDRAM registered DIMM timing and signal integrity - targeting memory module manufacturers and server OEMs.

FAQ

What is the function of the RESET pin on the 74SSTV16857PAG?

The RESET pin on the 74SSTV16857PAG is an LVCMOS-compatible active-low control that forces all 14 outputs to a low state, disables input receivers, and resets internal registers before a stable clock is applied. It must be held low during power-up to ensure predictable initialization, and its timing is validated to tPHL ≤ 5 ns from RESET assertion to Q output transition. This behavior is critical for safe DDR1 bus initialization in the 74SSTV16857PAG.

Does the 74SSTV16857PAG support both PC2700 and PC3200 DDR1 standards?

Yes, the 74SSTV16857PAG supports both PC2700 (200 MHz) and PC3200 (220 MHz) DDR1 standards. It operates at 2.3–2.7 V for PC1600–PC2700 and 2.5–2.7 V for PC3200, with verified timing parameters including tPDM = 1.1–2.4 ns and tSU = 0.65 ns at 220 MHz. These specifications are explicitly confirmed in the official Renesas datasheet for the 74SSTV16857PAG.

What is the role of VREF and how should it be implemented for the 74SSTV16857PAG?

VREF on the 74SSTV16857PAG sets the AC input threshold for all SSTL_2 data inputs (D1–D14), defined as VDDQ/2 ±40 mV. It must be supplied externally via a precision resistor divider or dedicated VREF generator, with low-noise routing and local 10 nF bypassing. Deviation beyond ±40 mV invalidates VIH/VIL specifications. This reference directly determines signal sampling accuracy in the 74SSTV16857PAG's DDR1 interface.

Can the 74SSTV16857PAG be used in place of the 74SSTVN16857PAG?

Yes - the 74SSTV16857PAG and 74SSTVN16857PAG are functionally identical and pin-compatible, differing only in marking ('V' vs 'VN') and minor internal test binning. Both meet the same JEDEC SSTL_2 Class II specifications, share identical timing, DC characteristics, and TSSOP-48 packaging. The 74SSTV16857PAG is fully substitutable for the 74SSTVN16857PAG in all DDR1 memory applications.

What is the maximum capacitive load the 74SSTV16857PAG can drive reliably?

Per the Renesas datasheet, the 74SSTV16857PAG is characterized to drive up to the equivalent of 18 SDRAM loads - defined as 18 × 10 pF = 180 pF total load capacitance per output, with CL = 30 pF used in timing measurements. Output impedance matching (rOH/rOL = 7–20 Ω) and propagation delay stability (tPDM variation < 0.3 ns across load) are guaranteed within this limit for the 74SSTV16857PAG.