The **SN74LVC74APWR** is a high-performance, low-voltage CMOS device featuring two independent D-type positive-edge-triggered flip-flops. It is part of the 74LVC family, which is widely used for logic level translation and high-speed switching. --- ### 1. General Specifications | Feature | Details | | :--- | :--- | | **Logic Family** | LVC (Low-Voltage CMOS) | | **Function** | Dual D-Type Flip-Flop with Set and Reset | | **Package** | TSSOP-14 (Thin Shrink Small Outline Package) | | **Operating Voltage (Vcc)** | 1.65V to 3.6V | | **Input Tolerance** | 5V Tolerant (allows 5V to 3.3V translation) | | **Max Frequency** | ~100 MHz to 150 MHz (depending on Vcc) | | **Operating Temp** | -40°C to 125°C | --- ### 2. Functional Diagram & Pinout Each of the two flip-flops inside the chip consists of the following pins: * **D (Data Input):** The logic level to be transferred to the output. * **CLK (Clock):** Triggers the data transfer on the **positive edge** (low-to-high transition). * **CLR (Clear):** Asynchronous active-low input to reset the output (Q = Low). * **PRE (Preset):** Asynchronous active-low input to set the output (Q = High). * **Q & $\bar{Q}$:** Complementary outputs. --- ### 3. Logic Table (Truth Table) The behavior of a single flip-flop unit is defined as follows: | PRE | CLR | CLK | D | Q | $\bar{Q}$ | | :---: | :---: | :---: | :---: | :---: | :---: | | L | H | X | X | H | L | | H | L | X | X | L | H | | L | L | X | X | H* | H* | | H | H | $\uparrow$ | L | L | H | | H | H | $\uparrow$ | H | H | L | | H | H | L | X | $Q_0$ | $\bar{Q}_0$ | *\*Note: PRE=L and CLR=L is an unstable state; avoid this during normal operation.* --- ### 4. Key Electronic Characteristics * **Low Power Consumption:** Ideal for battery-powered applications, with a typical $I_{cc}$ of 10 $\mu$A. * **High Drive Capability:** Can source or sink up to 24 mA at 3.3V. * **Partial Power-Down (Ioff):** Supports $I_{off}$ circuitry, which prevents damaging backflow current when the device is powered down but signals are still present at the inputs. * **Speed:** Very low propagation delay (typically 4.4 ns at 3.3V). --- ### 5. Common Applications 1. **Level Shifting:** Because the inputs are 5V tolerant, it can interface between 5V microcontrollers and 3.3V peripherals. 2. **Frequency Division:** Connecting the $\bar{Q}$ output back to the D input creates a "Divide-by-2" circuit. 3. **Data Synchronization:** Used to synchronize asynchronous signals to a system clock. 4. **State Storage:** Basic memory element for state machines.