74F524

8-BIT REGISTERED COMPARATOR


Family
Fairchild FAST (Advanced Schottky TTL)
Source
1985 Fairchild FAST Data Book, pages 4-378 ... 4-385. The 1980 data book carries the 'F524 in its Section 3 selection guide only (page 3-35, description and logic symbol).
Status
Released data sheet
Ratings
Vcc = +5.0 V +/-5%, TA = 0 to +70 deg C

DESCRIPTION | FUNCTIONAL DESCRIPTION | CONNECTION DIAGRAM (20-pin DIP) | SELECT TRUTH TABLE | NUMBER REPRESENTATION SELECT TABLE | STATUS TRUTH TABLE (Hold Mode) | INPUT LOADING / FAN-OUT | DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE | AC CHARACTERISTICS | AC OPERATING REQUIREMENTS

DESCRIPTION

The 'F524 is an 8-bit bidirectional register with parallel input and
output plus serial input and output progressing from LSB to MSB. All
data inputs, serial and parallel, are loaded by the rising edge of the
input clock. The device functions are controlled by two control lines
(S0, S1) to execute shift, load, hold and read out.

An 8-bit comparator examines the data stored in the registers and on the
data bus. Three true-HIGH, open-collector outputs representing 'register
equal to bus', 'register greater than bus' and 'register less than bus'
are provided. These outputs can be disabled to the OFF state by the use
of Status Enable (/SE). A mode control has also been provided to allow
twos complement as well as magnitude compare. Linking inputs are
provided for expansion to longer words.

  o 8-Bit Bidirectional Register with Bus-Oriented Input-Output
  o Independent Serial Input-Output to Register
  o Register Bus Comparator with 'Equal to', 'Greater then' and 'Less
    than' Outputs
  o Cascadable in Groups of Eight Bits
  o Open-Collector Comparator Outputs for AND-Wired Expansion
  o Twos Complement or Magnitude Compare

FUNCTIONAL DESCRIPTION

The 'F524 contains eight D-type flip-flops connected as a shift register
with provision for either parallel or serial loading. Parallel data may
be read from or loaded into the registers via the data bus I/O0-I/O7.
Serial data is entered from the C/SI input and may be shifted into the
register and out through the C/SO output. Both parallel and serial data
entry occur on the rising edge of the input clock (CP). The operation of
the shift register is controlled by two signals S0 and S1 according to
the Select Truth Table. The 3-state parallel output buffers are enabled
only in the Read mode.

One port of an 8-bit comparator is attached to the data bus while the
other port is tied to the outputs of the internal register. Three
active-OFF, open-collector outputs indicate whether the contents held in
the shift register are 'greater than', (GT), 'less than' (LT), or 'equal
to' (EQ) the data on the input bus. A HIGH signal on the Status Enable
(/SE) input disables these outputs to the OFF state. A mode control
input (M) allows selection between a straightforward magnitude compare
or a comparison between twos complement numbers.

For 'greater than' or 'less than' detection, the C/SI input must be held
HIGH, as indicated in the Status Truth Table. The internal logic is
arranged such that a LOW signal on the C/SI input disables the 'greater
than' and 'less than' outputs. The C/SO output will be forced HIGH if
the 'equal to' status condition exists, otherwise C/SO will be held LOW.
These facilities enable the 'F524 to be cascaded for word length greater
than eight bits.

Word length expansion (in groups of eight bits) can be achieved by
connecting the C/SO output of the more significant byte to the C/SI
input of the next less significant byte and also to its own /SE input
(see Figure a). The C/SI input of the most significant device is held
HIGH while the /SE input of the least significant device is held LOW.
The corresponding status outputs are AND-wired together. In the case of
twos complement number compare, only the Mode input to the most
significant device should be HIGH. The Mode inputs to all other cascaded
devices are held LOW.

Suppose that an inequality condition is detected in the most significant
device. Assuming that the byte stored in the register is greater than
the byte on the data bus, the EQ and LT outputs will be pulled LOW and
the GT output will float HIGH. Also the C/SO output of the most
significant device will be forced LOW, disabling the subsequent devices
but enabling its own status outputs. The correct status condition is
thus indicated. The same applies if the registered byte is less than the
data byte, only in this case the EQ and GT outputs go LOW and LT output
floats HIGH.

If an equality condition is detected in the most significant device, its
C/SO output is forced HIGH. This enables the next less significant
device and also disables its own status outputs. In this way, the status
output priority is handed down to the next less significant device which
now effectively becomes the most significant byte. The worst case
propagation delay for a compare operation involving 'n' cascaded 'F524s
will be when an equality condition is detected in all but the least
significant byte. In this case, the status priority has to ripple all
the way down the chain before the correct status output is established.
Typically, this will take 35 + 6(n-2) ns.

CONNECTION DIAGRAM (20-pin DIP)

Pin  Function                     Pin  Function
---  ---------------------------  ---  ---------------------------
  1  S0    Mode Select 0           20  Vcc
  2  I/O0  Parallel I/O bit 0      19  S1    Mode Select 1
  3  I/O1  Parallel I/O bit 1      18  /SE   Status Enable
  4  I/O2  Parallel I/O bit 2      17  C/SI  Status/Serial input
  5  I/O3  Parallel I/O bit 3      16  C/SO  Status/Serial output
  6  I/O4  Parallel I/O bit 4      15  EQ    Register = bus
  7  I/O5  Parallel I/O bit 5      14  GT    Register > bus
  8  I/O6  Parallel I/O bit 6      13  LT    Register < bus
  9  I/O7  Parallel I/O bit 7      12  M     Compare Mode Select
 10  GND                           11  CP    Clock Pulse

EQ, GT and LT are open-collector outputs, so the corresponding pins of
cascaded packages can be tied together to AND-wire the status.

SELECT TRUTH TABLE

S0  S1   Operation
--  --   ---------------------------------------------
 L   L   Hold -- Retains data in shift register
 L   H   Read -- Read contents in register onto data bus
 H   L   Shift -- Allows serial shifting on next rising clock edge
 H   H   Load -- Load data on bus into register

NUMBER REPRESENTATION SELECT TABLE

M   Operation
--  ----------------------
 L  Magnitude compare
 H  Twos complement compare

STATUS TRUTH TABLE (Hold Mode)

       Inputs                          Outputs
---------------------------------  ---------------------
/SE  C/SI  Data Comparison          EQ   GT   LT   C/SO
---  ----  ----------------------   ---  ---  ---  ----
 H    X    X                         H    H    H    1
 L    L    OA-OH >   I/O0-I/O7       L    H    H    L
 L    L    OA-OH =   I/O0-I/O7       H    H    H    L

 L    L    OA-OH <   I/O0-I/O7       L    H    H    L
 L    H    OA-OH >   I/O0-I/O7       L    H    L    L
 L    H    OA-OH =   I/O0-I/O7       H    L    L    H
 L    H    OA-OH <   I/O0-I/O7       L    L    H    L

1 = HIGH if data are equal, otherwise LOW.
H = HIGH voltage level;  L = LOW voltage level;  X = immaterial.

INPUT LOADING / FAN-OUT

Pin Names     Description                             U.L. HIGH/LOW
------------  --------------------------------------  -------------
S0, S1        Mode Select Inputs                      0.5 / 0.375
C/SI          Status Priority or Serial Data Input    0.5 / 0.375
CP            Clock Pulse Input (Active Rising Edge)  0.5 / 0.375
/SE           Status Enable Input (Active LOW)        0.5 / 0.375
M             Compare Mode Select Input               0.5 / 0.375
I/O0 - I/O7   Parallel Data Inputs or                 1.75 / 0.406
              3-State Parallel Data Outputs           75 / 15
C/SO          Status Priority or Serial Data Output   25 / 12.5
LT            Register Less Than Bus Output           OC* / 12.5
EQ            Register Equal Bus Output               OC* / 12.5
GT            Register Greater Than Bus Output        OC* / 12.5

*OC = Open Collector

DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE

Symbol  Parameter             Min  Typ  Max  Units  Conditions
------  --------------------  ---  ---  ---  -----  -------------------------
ICC     Power Supply Current       128  180  mA     S0, S1, /SE, C/SI = HIGH
                                                    CP, I/O0-I/O7,
                                                    Register = LOW

AC CHARACTERISTICS

                                              TA = +25 C      74F
                                              Vcc = +5.0V     TA/Vcc = Com
Symbol  Parameter                      CL     Min  Typ   Max  Min  Max   Units
------  -----------------------------  -----  ---- ----  ---- ---- ----  -----
fmax    Maximum Shift Frequency         --    50.0 75.0    --  50   --   MHz
tPLH    Prop Delay I/On to EQ          50 pF   9.0 16.5  20.0  9.0 21.0  ns
tPHL    Prop Delay I/On to EQ          50 pF   5.0  9.5  12.0  5.0 13.0  ns
tPLH    Prop Delay I/On to GT          50 pF   8.5 14.1  19.0  8.5 20.0  ns
tPHL    Prop Delay I/On to GT          50 pF   6.5 13.0  16.5  6.5 17.5  ns
tPLH    Prop Delay I/On to LT          50 pF   7.0 15.5  20.0  7.0 21.0  ns
tPHL    Prop Delay I/On to LT          50 pF   4.5 10.0  14.0  4.5 15.0  ns
tPLH    Prop Delay I/On to C/SO        50 pF   8.0 15.2  19.5  8.0 20.5  ns
tPHL    Prop Delay I/On to C/SO        50 pF   6.0 12.5  16.0  6.0 17.0  ns
tPLH    Prop Delay CP to EQ            50 pF  10.0 20.0  25.0 10.0 26.0  ns
tPHL    Prop Delay CP to EQ            50 pF   4.0  8.5  16.5  4.0 17.5  ns
tPLH    Prop Delay CP to GT            50 pF  10.0 16.5  21.0 10.0 22.0  ns
tPHL    Prop Delay CP to GT            50 pF   8.5 17.0  22.0  8.5 23.0  ns
tPLH    Prop Delay CP to LT            50 pF   9.0 20.0  25.0  9.0 26.0  ns
tPHL    Prop Delay CP to LT            50 pF   5.5 13.5  17.0  5.5 18.0  ns
tPLH    Prop Delay CP to C/SO          50 pF   8.5 16.5  21.0  8.5 22.0  ns
          (Compare)
tPLH    Prop Delay CP to C/SO          50 pF   5.0 10.0  13.0  5.0 14.0  ns
          (Serial Shift)
tPHL    Prop Delay CP to C/SO          50 pF   4.5  9.0  11.5  4.5 12.5  ns
          (Serial Shift)
tPLH    Prop Delay C/SI to GT          50 pF   9.0 15.0  19.0  9.0 20.0  ns
tPHL    Prop Delay C/SI to GT          50 pF   3.0  6.5   8.5  3.0  9.5  ns
tPLH    Prop Delay C/SI to LT          50 pF   8.0 15.5  20.0  8.0 21.0  ns
tPHL    Prop Delay C/SI to LT          50 pF   3.5  6.5   8.5  3.5  9.5  ns
tPLH    Prop Delay S0, S1 to EQ        50 pF  15.0 25.0  33.0 15.0 35.0  ns
tPHL    Prop Delay S0, S1 to EQ        50 pF   9.0 15.0  19.0  9.0 20.0  ns
tPLH    Prop Delay S0, S1 to GT        50 pF  10.5 18.0  23.0 10.5 24.0  ns
tPHL    Prop Delay S0, S1 to GT        50 pF  10.5 18.0  23.0 10.5 24.0  ns
tPLH    Prop Delay S0, S1 to LT        50 pF  13.0 22.0  28.0 13.0 30.0  ns
tPHL    Prop Delay S0, S1 to LT        50 pF  12.0 19.0  24.0 12.0 25.0  ns
tPLH    Prop Delay S0, S1 to C/SO      50 pF   6.5 11.5  14.5  6.5 15.5  ns
tPHL    Prop Delay S0, S1 to C/SO      50 pF   5.5 14.0  18.0  5.5 19.0  ns
tPLH    Prop Delay /SE to EQ           50 pF   3.5  8.0  10.5  3.5 11.5  ns
tPHL    Prop Delay /SE to EQ           50 pF   2.5  6.0   8.0  2.5  9.0  ns
tPLH    Prop Delay /SE to GT           50 pF   6.5 12.5  16.0  6.5 17.0  ns
tPHL    Prop Delay /SE to GT           50 pF   3.5  6.5   8.0  3.5  9.0  ns
tPLH    Prop Delay /SE to LT           50 pF   5.0 10.5  13.5  5.0 14.5  ns
tPHL    Prop Delay /SE to LT           50 pF   3.5  6.0   8.0  3.5  9.0  ns
tPLH    Prop Delay C/SI to C/SO        50 pF   4.0  8.5  11.0  4.0 12.0  ns
tPHL    Prop Delay C/SI to C/SO        50 pF   4.0  8.5  11.0  4.0 12.0  ns
tPLH    Prop Delay M to GT             50 pF   8.0 15.0  19.5  8.0 20.5  ns
tPHL    Prop Delay M to GT             50 pF   6.0 12.0  15.5  6.0 16.5  ns
tPLH    Prop Delay M to LT             50 pF   8.0 17.0  22.0  8.0 23.0  ns
tPHL    Prop Delay M to LT             50 pF   5.5  9.5  12.0  4.5 13.0  ns
tPZH    Output Enable Time S0, S1 to   50 pF   4.5 10.0  13.0  4.5 14.0  ns
          I/On
tPZL    Output Enable Time S0, S1 to   50 pF   5.5 11.0  15.0  5.5 16.0  ns
          I/On
tPHZ    Output Disable Time S0, S1 to  50 pF   3.5  8.0  12.0  3.5 13.0  ns
          I/On
tPLZ    Output Disable Time S0, S1 to  50 pF   4.5  9.6  12.5  4.5 13.5  ns
          I/On

AC OPERATING REQUIREMENTS

                                                TA = +25 C   74F
                                                Vcc = +5.0V  TA/Vcc = Com
Symbol  Parameter                              Min  Typ Max  Min  Max  Units
------  -----------------------------------    ---- --- ---  ---- ---  -----
ts (H)  Setup Time, HIGH -- I/On to CP          6.0  --  --   6.0  --  ns
ts (L)  Setup Time, LOW -- I/On to CP           6.0  --  --   6.0  --  ns
th (H)  Hold Time, HIGH -- I/On to CP             0  --  --     0  --  ns
th (L)  Hold Time, LOW -- I/On to CP              0  --  --     0  --  ns
ts (H)  Setup Time, HIGH -- S0 or S1 to CP     10.0  --  --  10.0  --  ns
ts (L)  Setup Time, LOW -- S0 or S1 to CP      10.0  --  --  10.0  --  ns
th (H)  Hold Time, HIGH -- S0 or S1 to CP         0  --  --     0  --  ns
th (L)  Hold Time, LOW -- S0 or S1 to CP          0  --  --     0  --  ns
ts (H)  Setup Time, HIGH -- C/SI to CP          7.0  --  --   7.0  --  ns
ts (L)  Setup Time, LOW -- C/SI to CP           7.0  --  --   7.0  --  ns
th (H)  Hold Time, HIGH -- C/SI to CP             0  --  --     0  --  ns
th (L)  Hold Time, LOW -- C/SI to CP              0  --  --     0  --  ns
tw (H)  Clock Pulse Width, HIGH                 5.0  --  --   5.0  --  ns

Data sheet transcription as plain text

VERILOG MODEL

No model for this device yet — only the data sheet transcription above.


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