SN74LV166A - 8-Bit Parallel-Load Shift Registers

The 'LV166A devices are 8-bit parallel-load shift registers, designed for 2-V to 5.5-V V_CC operation.

The 'LV166A parallel-in or serial-in, serial-out registers feature gated clock (CLK, CLK INH) inputs and an overriding clear (CLR\) input. The parallel-in or serial-in modes are established by the shift/load (SH/LD\) input. When high, SH/LD\ enables the serial (SER) data input and couples the eight flip-flops for serial shifting with each clock (CLK) pulse. When low, the parallel (broadside) data inputs are enabled, and synchronous loading occurs on the next clock pulse. During parallel loading, serial data flow is inhibited. Clocking is accomplished on the low-to-high-level edge of CLK through a 2-input positive-NOR gate, permitting one input to be used as a clock-enable or clock-inhibit function. Holding either CLK or CLK INH high inhibits clocking; holding either low enables the other clock input. This allows the system clock to be free running, and the register can be stopped on command with the other clock input. CLK INH should be changed to the high level only when CLK is high. CLR\ overrides all other inputs, including CLK, and resets all flip-flops to zero.

These devices are fully specified for partial-power-down applications using I_off. The I_off circuitry disables the outputs, preventing damaging current backflow through the devices when they are powered down.

• 2-V to 5.5-V V_CC Operation
• Max t_pd of 10.5 ns at 5 V
• Typical V_OLP (Output Ground Bounce)
      <0.8 V at V_CC = 3.3 V, T_A = 25°C
• Typical V_OHV (Output V_OH Undershoot)
      >2.3 V at V_CC = 3.3 V, T_A = 25°C
• I_off Supports Partial-Power-Down-Mode Operation
• Synchronous Load
• Direct Overriding Clear
• Parallel-to-Serial Conversion
• Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
• ESD Protection Exceeds JESD 22
  • 2000-V Human-Body Model (A114-A)
  • 200-V Machine Model (A115-A)
  • 1000-V Charged-Device Model (C101)