产品详情

Function Counter Bits (#) 4 Technology family F Supply voltage (min) (V) 4.5 Supply voltage (max) (V) 5.5 Input type Bipolar Output type Push-Pull Features Very high speed (tpd 5-10ns) Operating temperature range (°C) 0 to 70 Rating Catalog
Function Counter Bits (#) 4 Technology family F Supply voltage (min) (V) 4.5 Supply voltage (max) (V) 5.5 Input type Bipolar Output type Push-Pull Features Very high speed (tpd 5-10ns) Operating temperature range (°C) 0 to 70 Rating Catalog
PDIP (N) 16 181.42 mm² 19.3 x 9.4 SOIC (D) 16 59.4 mm² 9.9 x 6 SOP (NS) 16 79.56 mm² 10.2 x 7.8
  • Internal Look-Ahead Circuitry for Fast Counting
  • Carry Output for N-Bit Cascading
  • Fully Synchronous Operation for Counting

  • Internal Look-Ahead Circuitry for Fast Counting
  • Carry Output for N-Bit Cascading
  • Fully Synchronous Operation for Counting

This synchronous, presettable, 4-bit binary counter has internal carry look-ahead circuitry for use in high-speed counting designs. Synchronous operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other when so instructed by the count-enable (ENP, ENT) inputs and internal gating. This mode of operation eliminates the output counting spikes that are normally associated with asynchronous (ripple-clock) counters. However, counting spikes can occur on the ripple-carry (RCO) output. A buffered clock (CLK) input triggers the four flip-flops on the rising (positive-going) edge of CLK.

This counter is fully programmable. That is, it can be preset to any number between 0 and 15. Because presetting is synchronous, a low logic level at the load (LOAD\) input disables the counter and causes the outputs to agree with the setup data after the next clock pulse, regardless of the levels of ENP and ENT.

The clear function is asynchronous, and a low logic level at the clear (CLR\) input sets all four of the flip-flop outputs to low, regardless of the levels of CLK, LOAD\, ENP, and ENT.

The carry look-ahead circuitry provides for cascading counters for n-bit synchronous applications, without additional gating. This function is implemented by the ENP and ENT inputs and an RCO output. Both ENP and ENT must be high to count, and ENT is fed forward to enable RCO. RCO, thus enabled, produces a high-logic-level pulse while the count is 15 (HHHH). The high-logic-level overflow ripple-carry pulse can be used to enable successive cascaded stages. Transitions at ENP or ENT are allowed, regardless of the level of CLK.

The SN74F161A features a fully independent clock circuit. Changes at ENP, ENT, or LOAD\ that modify the operating mode have no effect on the contents of the counter until clocking occurs. The function of the counter (whether enabled, disabled, loading, or counting) is dictated solely by the conditions meeting the setup and hold times.

This synchronous, presettable, 4-bit binary counter has internal carry look-ahead circuitry for use in high-speed counting designs. Synchronous operation is provided by having all flip-flops clocked simultaneously so that the outputs change coincident with each other when so instructed by the count-enable (ENP, ENT) inputs and internal gating. This mode of operation eliminates the output counting spikes that are normally associated with asynchronous (ripple-clock) counters. However, counting spikes can occur on the ripple-carry (RCO) output. A buffered clock (CLK) input triggers the four flip-flops on the rising (positive-going) edge of CLK.

This counter is fully programmable. That is, it can be preset to any number between 0 and 15. Because presetting is synchronous, a low logic level at the load (LOAD\) input disables the counter and causes the outputs to agree with the setup data after the next clock pulse, regardless of the levels of ENP and ENT.

The clear function is asynchronous, and a low logic level at the clear (CLR\) input sets all four of the flip-flop outputs to low, regardless of the levels of CLK, LOAD\, ENP, and ENT.

The carry look-ahead circuitry provides for cascading counters for n-bit synchronous applications, without additional gating. This function is implemented by the ENP and ENT inputs and an RCO output. Both ENP and ENT must be high to count, and ENT is fed forward to enable RCO. RCO, thus enabled, produces a high-logic-level pulse while the count is 15 (HHHH). The high-logic-level overflow ripple-carry pulse can be used to enable successive cascaded stages. Transitions at ENP or ENT are allowed, regardless of the level of CLK.

The SN74F161A features a fully independent clock circuit. Changes at ENP, ENT, or LOAD\ that modify the operating mode have no effect on the contents of the counter until clocking occurs. The function of the counter (whether enabled, disabled, loading, or counting) is dictated solely by the conditions meeting the setup and hold times.

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类型 标题 下载最新的英语版本 日期
* 数据表 Synchronous 4-Bit Binary Counter 数据表 (Rev. B) 2001年 9月 4日

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包含信息:
  • RoHS
  • REACH
  • 器件标识
  • 引脚镀层/焊球材料
  • MSL 等级/回流焊峰值温度
  • MTBF/时基故障估算
  • 材料成分
  • 鉴定摘要
  • 持续可靠性监测
包含信息:
  • 制造厂地点
  • 封装厂地点

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