74HC40105 Datasheet, PDF (2/25 Pages) NXP Semiconductors – 4-bit x 16-word FIFO register

Philips Semiconductors
4-bit x 16-word FIFO register
Product specification
74HC/HCT40105
FEATURES
• Independent asynchronous inputs and outputs
• Expandable in either direction
• Reset capability
• Status indicators on inputs and outputs
• 3-state outputs
• Output capability: standard
• I_CC category: MSI
GENERAL DESCRIPTION
The 74HC/HCT40105 are high-speed Si-gate CMOS
devices and are pin compatible with the “40105” of the
“4000B” series. They are specified in compliance with
JEDEC standard no. 7A.
The 74HC/HCT40105 are first-in/first-out (FIFO) “elastic”
storage registers that can store sixteen 4-bit words. The
“40105” is capable of handling input and output data at
different shifting rates. This feature makes it particularly
useful as a buffer between asynchronous systems. Each
word position in the register is clocked by a control flip-flop,
which stores a marker bit. A “1” signifies that the position’s
data is filled and a “0” denotes a vacancy in that position.
The control flip-flop detects the state of the preceding
flip-flop and communicates its own status to the
succeeding flip-flop. When a control flip-flop is in the “0”
state and sees a “1” in the preceding flip-flop, it generates
a clock pulse that transfers data from the preceding four
data latches into its own four data latches and resets the
preceding flip-flop to “0”. The first and last control flip-flops
have buffered outputs. Since all empty locations “bubble”
automatically to the input end, and all valid data ripples
through to the output end, the status of the first control
flip-flop (data-in ready output - DIR) indicates if the FIFO is
full, and the status of the last flip-flop (data-out ready
output - DOR) indicates if the FIFO contains data. As the
earliest data is removed from the bottom of the data stack
(output end), all data entered later will automatically ripple
toward the output.
QUICK REFERENCE DATA
GND = 0 V; T_amb = 25 °C; t_r = t_f = 6 ns
SYMBOL
PARAMETER
CONDITIONS
t_PHL/ t_PLH
t_PHL
f_max
C_I
C_PD
propagation delay
MR to DIR, DOR
SO to Q_n
propagation delay
SI to DIR
SO to DOR
maximum clock frequency
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
TYP.
HC
HCT
UNIT
16
15
ns
37
35
ns
16
18
ns
17
18
ns
33
31
MHz
3.5
3.5
pF
134
145
pF
1998 Jan 23
2