Fairchild VHC, VHCT service manual

February 1998
Revised April 1999

VHC/VHCT Introduction

Fairchild Semiconductor’s Very High-speed CMOS (VHC)
logic family provides stand ard logic users a high-technol­ogy upgrade from older logic families such as HCMOS.
VHC delivers nearly three times the sp eed of compara ble
HCMOS functions at twice the output current drive. Despite
the higher performance, power consumption and device
generated noise is at or below that of HC making VHC
design-in simple and familiar. Enhanced datasheet spe cifi­cations such as output noise and pow er-dow n leaka ge fur­ther simplify design-in. VHC is specified over a 2.0V to

range of operation. A complete set of 3.3V speci-

5.5V V

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fications aid in today’s low voltage designs. VHC inputs are
protected against over-voltage to 7.0V under all V

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condi-

Feature Benefit

3X faster than HCMOS Meets higher speed demands of new designs
2X the outp ut current drive of HCMOS; ±8 mA Extends drive capability for on-board signal routing
Guaranteed 3.3V specifications Eases design in low-voltage applications
Input over-voltage tolerant to 7.0V regardless of V

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Guaranteed noise specifications Simplifies component choice in noise sensitive applications
Wide range of package options: PDIP, JEDEC SOIC,

EIAJ SOIC, TSSOP

tions. This feature is beneficial in mixed supply voltage
applications where 5V logic is driving 3.3V VHC.

VHCT options exist for many VHC functions similar to HCT
options of HCMOS parts. For t hese parts in put threshol ds
have been adjusted to provide TTL leve ls of V

and V

= 2.0V. This allows VHCT to be interfaced

IHmin

ILmax

directly with TTL parts and sub-systems. VH CT versions
operate in a standard 4.5V to 5.5V TTL supply range.

VHC/VHCT is a general purpose family available in a large
number of gate, MS I and octal buffer functions. Pack age
options include PDIP, JEDEC SOIC, EIAJ SOIC and
TSSOP.

Safely interfaces parts and sub-systems of differing supply voltages

Applicable as upgrade to older technologies and for your most
advanced designs

VHC/VHCT Introduction

= 0.8V

VHC vs HC Specifications

VHC HC VHC HC

04 04 244 244

Unit

DC Spec

I

OH/IOL

I

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V

OLP/VOLV

V

ILD/VIHD

AC Spec (T

t

PHL,PLH

t

PZH, PZL

t

PHZ,PLZ

C

PD

−40°C to +85°C)

A

(TA = 20°C) 18 20 19 50 pF

−8/8 −4/4 −8/8 −6/6 mA 4.5V

20.0 20.0 40.0 80 µA5.5V

0.8/−0.8 not spec’d 0.8/−0.8 not spec’d V 5.0V

1.5/3.5 not spec’d 1.5/3.5 not spec’d V 5.0V

8.5 24 8.5 29 ns 5.0 ± 0.5V

10.5 38 ns 5.0 ± 0.5V

10.5 38 ns 5.0 ± 0.5V

© 1999 Fairchild Semiconductor Corporation MS500119.prf www.fairchildsemi.com

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