Ads
related to: pull up resistor vs down speed
Search results
Results from the WOW.Com Content Network
A standard TTL input at logic "1" is normally operated assuming a source current of 40 μA, and a voltage level above 2.4 V, allowing a pull-up resistor of no more than 50 kohms; whereas the TTL input at logic "0" will be expected to sink 1.6 mA at a voltage below 0.8 V, requiring a pull-down resistor less than 500 ohms. [2]
Since the current in a device connected that way goes as the square of the voltage across the load, it provides poor pullup speed relative to its power consumption when pulled down. A resistor (with the current simply proportional to the voltage) would be better, and a current source (with the current fixed, independent of voltage) better yet.
Wired logic works by exploiting the high impedance of open collector outputs (and its variants: open emitter, open drain, or open source) by just adding a pull-up or pull-down resistor to a voltage source, or can be applied to push-pull outputs by using diode logic (with the disadvantage of incurring a diode drop voltage loss).
If all the input voltages are low (logical "0"), the transistor is cut-off. The pull-down resistor R 1 biases the transistor to the appropriate on-off threshold. The output is inverted since the collector-emitter voltage of transistor Q 1 is taken as output, and is high when the inputs are low. Thus, the analog resistive network and the analog ...
The MOSFETs are n-type enhancement mode transistors, arranged in a so-called "pull-down network" (PDN) between the logic gate output and negative supply voltage (typically the ground). A pull up (i.e. a "load" that can be thought of as a resistor, see below) is placed between the positive supply voltage and each logic gate output.
Pull-up resistors are provided by the I3C controller. External pull-up resistors are no longer needed. Clock Stretching – devices are expected to be fast enough to operate at bus speed. The I3C controller is the sole clock source. I²C Extended (10-bit) Addresses. All devices on an I3C bus are addressed by a 7-bit address.
An active-low OR diode logic gate is formed by a keypad containing diodes at each switch, all connected to a shared pull-up resistor. When no switch is closed, the pull-up keeps the output high. But when the switch for any key connects to ground, the output goes low. This OR result can be used as an interrupt signal to indicate that any key has ...
The purpose is to reduce the overall power demand compared to using both a strong pull-up and a strong pull-down. [10] A pure open-drain driver, by comparison, has no pull-up strength except for leakage current: all the pull-up action is on the external termination resistor.
Ads
related to: pull up resistor vs down speed