74HC688 Datasheet, PDF (2/7 Pages) NXP Semiconductors – 8-bit magnitude comparator

Philips Semiconductors
8-bit magnitude comparator
Product specification
74HC/HCT688
FEATURES
• Compare two 8-bit words
• Output capability: standard
• I_CC category: MSI
GENERAL DESCRIPTION
The 74HC/HCT688 are high-speed Si-gate CMOS devices
and are pin compatible with low power Schottky TTL
(LSTTL). They are specified in compliance with JEDEC
standard no. 7A.
The 74HC/HCT688 are 8-bit magnitude comparators.
They perform comparison of two 8-bit binary or BCD
words.
The output provides P = Q.
QUICK REFERENCE DATA
GND = 0 V; T_amb = 25 °C; t_r = t_f = 6 ns
SYMBOL PARAMETER
CONDITIONS
t_PHL/ t_PLH
C_I
C_PD
propagation delay
P_n, Q_n to P = Q
E to P = Q
input capacitance
power dissipation capacitance per package
C_L = 15 pF; V_CC = 5 V
notes 1 and 2
Notes
1. C_PD is used to determine the dynamic power dissipation (P_D in µW):
P_D = C_PD × V_CC2 × f_i + ∑ (C_L × V_CC2 × f_o)
where:
f_i = input frequency in MHz
f_o = output frequency in MHz
∑ (C_L × V_CC2 × f_o) = sum of outputs
C_L = output load capacitance in pF
V_CC = supply voltage in V
2. For HC the condition is V_I = GND to V_CC
For HCT the condition is V_I = GND to V_CC − 1.5 V
TYPICAL
HC
HCT
17
17
8
12
3.5
3.5
30
30
ORDERING INFORMATION
See “74HC/HCT/HCU/HCMOS Logic Package Information”.
UNIT
ns
ns
pF
pF
December 1990
2