74HC/HCT4538

General description

The 74HC/HCT4538 are high-speed Si-gate CMOS devices and are pin compatible with '4538' of the '4000B' series. They are specified in compliance with JEDEC standard no. 7A.

The 74HC/HCT4538 are dual retriggerable-resettable monostable multivibrators. Each multivibrator has an active LOW trigger/retrigger input (nA₀), an active HIGH trigger/retrigger input (nA₁) , an overriding active LOW direct reset input (nR_D), an output (nQ) and its complement (nQ), and two pins (nC_TC and nRC_TC) for connecting the external timing components C_t and R_t. Typical pulse width variation over temperature range is ± 0.2%.

The '4538' may be triggered by either the positive or the negative edges of the input pulse. The duration and accuracy of the output pulse are determined by the external timing components C_t and R_t. The output pulse width (T) is equal to 0.7 x R_t x' C_t. The linear design techniques guarantee precise control of the output pulse width.

A LOW level at nR_D terminates the output pulse immediately.

Schmitt-trigger action in the trigger inputs makes the circuit highly tolerant to slower rise and fall times.

Features

• Separate reset inputs
• Triggering from leading or trailing edge
• Output capability: standard
• I_CC category: MSI
• Power-on reset on-chip

Products/packages

Pricing/ordering/availability

Applications

• Motor control
• Attic fan timers
• Delay circuits
• Automotive applications
• Precision timing
• Domestic appliances.

Block diagrams/pinning

Design support

Support Documents

HCT_USER_GUIDE; HC/T User Guide (1997-11-01)

Parametrics/similar products

Similar products
74HC/HCT4538 links to the similar products page containing an overview of products that are similar in function or related to the type number(s) as listed on this page. The similar products page includes products from the same catalog tree(s), relevant selection guides and products from the same functional category.

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