The SN54290/SN74290, SN54LS290/SN74LS290, SN54293/SN74293, and SN54LS293/SN74LS293 counters are electrically and functionally identical to the SN5490A/SN7490A, SN54LS90/SN74LS90, SN5493A/SN7493A, and SN54LS93/SN74LS93, respectively. Only the arrangement of the terminals has been changed for the '290, 'LS290, '293, and 'LS293.

Each of these monolithic counters contains four master-slave flip-flops and additional gating to provide a divide-by-two counter and a three-stage binary counter for which the count cycle length is divide-by-five for the '290 and 'LS290 and divide-by-eight for the '293 and 'LS293.

All of these counters have a gated zero reset and the '290 and 'LS290 also have gated set-to-nine inputs for use in BCD nine's complement applications.

To use the maximum count length (decade or four-bit binary) of these counters, the B input is connected to the Q_A output. The input count pulses are applied to input A and the outputs are as described in the appropriate function table. A symmetrical divide-by-ten count can be obtained from the '290 and 'LS290 counters by connecting the Q_D output to the A input and applying the input count to the B input which gives a divide-by-ten square wave at output Q_A.

'290, 'LS290...DECADE COUNTERS

'293, 'LS293...4–BIT BINARY COUNTERS

• GND and VCC on Corner Pins (Pins 7 and 14 Respectively)

• Function
• Counter
• Bits (#)
• 4
• Technology Family
• LS
• Supply voltage (Min) (V)
• 4.75
• Supply voltage (Max) (V)
• 5.25
• Input type
• Bipolar
• Output type
• Push-Pull
• Features
• High speed (tpd 10-50ns)

SN74LS293的完整型号有：SN74LS293D、SN74LS293N，以下是这些产品的关键参数及官网采购报价：

SN74LS293D，工作温度：0 to 70，封装：SOIC (D)-14，包装数量MPQ：50个，MSL 等级/回流焊峰值温度：Level-1-260C-UNLIM，引脚镀层/焊球材料：NIPDAU，TI官网SN74LS293D的批量USD价格：1.196（1000+）

SN74LS293N，工作温度：0 to 70，封装：PDIP (N)-14，包装数量MPQ：25个，MSL 等级/回流焊峰值温度：N/A for Pkg Type，引脚镀层/焊球材料：NIPDAU，TI官网SN74LS293N的批量USD价格：1.375（1000+）

14-24-LOGIC-EVM — 支持 14 到 24 引脚 PW、DB、D、DW、NS、DYY 和 DGV 封装的通用逻辑 EVM

该 EVM 设计用于支持采用 14 至 24 引脚 D、DW、DB、NS、PW、DYY 或 DGV 封装的任何逻辑器件。