CY29948AC

Clock Buffers, Drivers Overview

The CY29948AC is a low-voltage clock distribution buffer supporting 2.5 V or 3.3 V operation with a maximum frequency of 200 MHz. It features a 1:12 output ratio, accepting either differential LVPECL or single-ended LVCMOS/LVTTL inputs. The device provides 12 LVCMOS/LVTTL-compatible outputs capable of driving up to 24 transmission lines in series-terminated configurations. Key electrical parameters include a typical output-to-output skew of 150 ps and propagation delays ranging from 4.0 ns to 10.9 ns depending on voltage and input source. It operates within a commercial temperature range of 0°C to +70°C.

Clock Buffers, Drivers Feature Summary

• Supports 200 MHz clock frequencies with 2.5 V or 3.3 V power supplies
• Accepts differential LVPECL or single-ended LVCMOS/LVTTL clock inputs
• Provides 12 LVCMOS/LVTTL outputs with effective fanout of 1:24 for series termination
• Features synchronous output enable and three-state control to eliminate glitches

Clock Buffers, Drivers Applications

• Nested clock trees in demanding synchronous systems
• Primary system clock distribution alongside test clocks
• Driving 50 Ω series or parallel terminated transmission lines

Clock Buffers, Drivers Procurement Notes

Verify the specific suffix 'AC' against official ordering codes. Datasheet lists CY29948AXC for Commercial (0°C to +70°C) and CY29948AXI for Industrial (-40°C to +85°C). Confirm if 'AC' denotes a specific package variant or legacy designation not explicitly detailed in the current Rev *J document.

Clock Buffers, Drivers Selection Notes

Select this component when a 1:12 fanout buffer is required for high-speed synchronous designs. Ensure the input signal matches the supported LVPECL or LVCMOS/LVTTL standards. Verify that the thermal resistance of 65 °C/W is acceptable for the application's ambient conditions without additional heatsinking.

Clock Buffers, Drivers Part Context

The CY29948 belongs to Cypress Semiconductor's family of low-voltage clock buffers. It is pin-compatible with MPC948, MPC948L, and MPC9448 devices, facilitating direct replacements in existing designs requiring similar clock distribution capabilities.

Clock Buffers, Drivers Replacement Considerations

Pin-compatible substitutes include MPC948, MPC948L, and MPC9448. Verify voltage levels and temperature ranges match the original design requirements before substitution.

Clock Buffers, Drivers FAQ

How does the CY29948 handle output glitching during enable/disable?

The device uses a synchronous output enable input (SYNC_OE) that is internally synchronized to the input clock. This synchronization eliminates potential output glitching or runt pulse generation.

What is the maximum effective fanout for series terminated lines?

Each output can drive one or two traces, providing an effective fanout of 1:24 for the entire device when using series terminated transmission lines.

Can the outputs be controlled independently?

No, the outputs are controlled collectively via the SYNC_OE pin for enabling/disabling and the TS# pin for three-stating. All outputs respond simultaneously to these control signals.