Page 1
INTEGRATED CIRCUITS
74F148
8-input priority encoder
Product specification
IC15 Data Handbook
1990 Mar 01
Page 2
Philips Semiconductors Product specification
74F1488-input priority encoder
FEA TURES
•Code conversions
•Multi-channel D/A converter
•Decimal-to-BCD converter
•Cascading for priority encoding of “N” bits
•Input enable capability
•Priority encoding-automatic selection of highest priority input line
•Output enable-active Low when all inputs are High
•Group signal output-active when any input is Low
DESCRIPTION
The 74F148 8-input priority encoder accepts data from eight
active-Low inputs and provides a binary representation on the three
active-Low outputs. A priority is assigned to each input so that when
two or more inputs are simultaneously active, the input with the
highest priority is represented on the output, with input line I
the highest priority . A High on the Enable Input (EI
) will force all
outputs to the inactive (High) state and allow new data to settle
without producing erroneous information at the outputs. A Group
Signal (GS
three data outputs. The GS
this indicates when any input is active. The EO
) output and an Enable Output (EO) are provided with the
is active-Low when any input is Low:
is active-Low when
all inputs are High. Using the Enable Output along with the Enable
Input allows priority encoding of N input signals. Both EO
are active-High when the Enable Input is High.
7 having
and GS
PIN CONFIGURATION
1
I4
5
2
I
I
6
3
I
7
4
EI
5
2
A
6
1
A
TYPICAL
TYPE
PROPAGATION
DELAY
74F148 6.0ns 23mA
16
V
CC
EO
15
GS
14
I3
13
I2
12
1
I
11
I0
107
98GND A0
SF00181
TYPICAL
SUPPLY CURRENT
(TOTAL)
ORDERING INFORMATION
COMMERCIAL RANGE
DESCRIPTION
16-pin plastic DIP N74F148N SOT38-4
16-pin plastic SO N74F148D SOT109-1
VCC = 5V ±10%,
T
= 0°C to +70°C
amb
PKG DWG #
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS DESCRIPTION 74F (U.L.) HIGH/LOW LOAD VALUE HIGH/LOW
I1 – I7 Priority inputs (active Low) 1.0/2.0 20µA/1.2mA
I0 Priority input (active Low) 1.0/1.0 20µA/0.6mA
EI Enable input (active Low) 1.0/2.0 20µA/1.2mA
EO Enable output (active Low) 50/33 1.0mA/20mA
GS Group select output (active Low) 50/33 1.0mA/20mA
A0 – A2 Address outputs (active Low) 50/33 1.0mA/20mA
NOTE: One (1.0) FAST unit load is defined as: 20µA in the High state and 0.6mA in the Low state.
March 1, 1990 853–0345 98994
2
Page 3
Philips Semiconductors Product specification
74F1488-input priority encoder
LOGIC SYMBOL
10 11 12 13 1 2 3 4
I0 I1 I2 I4 I5 I6 I7I3
5EI
VCC = Pin 16
GND = Pin 8
LOGIC DIAGRAM
A0 A1 A2
976
EI
5
IEC/IEEE SYMBOL
10
11
12
13
EO
GS
7
I
4 3 2 1 13 12 11 10
I6I5I4I3I2I1I0
SF00182
15
14
1
2
3
4
5
HPRI/BIN
10/Z10
11/Z11
2/Z12
3/Z13
4/Z14
5/Z15
6/Z16
7/Z17
EN = α/V18
0 α
1 α
2 α
≥ 1
10
11
12
13
14
15
16
17
18
α
9
7
8
15
14
SF00183
V
= Pin 16
CC
GND = Pin 8
March 1, 1990
9
A2
9
A1
9
A0
GS14EO
15
SF00184
3
Page 4
Philips Semiconductors Product specification
74F1488-input priority encoder
FUNCTION TABLE
INPUTS OUTPUTS
EI I0 I1 I2 I3 I4 I5 I6 I7 GS A0 A1 A2 EO
H X X X X X X X X H H H H H
L HHHHHHHHHHHHL
L X X X X X X X L L L L L H
L XXXXXXLHLHLLH
L XXXXXLHHLLHLH
L XXXXLHHHLHHLH
L X X X L H H H H L L L H H
L XXLHHHHHLHLHH
L XLHHHHHHL LHHH
L L H H H H H H H L H H H H
H = High voltage level
L = Low voltage level
X = Don’t care
APPLICATION
LSB
I0 I1 I2 I4 I5 I6 I7I3
EI
EO
GS
A0 A1 A2
0A1A2A3 FLAG
A
16-Input Priority Encoder
ENABLE
I0 I1 I2 I4 I5 I6 I7I3
EI
EO
GS
MSB
A0 A1 A2
SF00185
March 1, 1990
4
Page 5
Philips Semiconductors Product specification
SYMBOL
PARAMETER
UNIT
1
SYMBOL
PARAMETER
TEST CONDITIONS
1
UNIT
VOHHigh-level output voltage
V
VOLLow-level output voltage
V
IILLow-level input current
V
MAX, V
5V
74F1488-input priority encoder
ABSOLUTE MAXIMUM RATINGS
(Operation beyond the limits set forth in this table may impair the useful life of the device.
Unless otherwise noted these limits are over the operating free-air temperature range.)
SYMBOL
V
V
I
IN
V
I
OUT
T
T
CC
IN
OUT
amb
stg
Supply voltage –0.5 to +7.0 V
Input voltage –0.5 to +7.0 V
Input current –30 to +5 mA
Voltage applied to output in High output state –0.5 to V
Current applied to output in Low output state 40 mA
Operating free-air temperature range 0 to +70 °C
Storage temperature range –65 to +150 °C
RECOMMENDED OPERATING CONDITIONS
V
V
V
I
I
I
T
CC
IH
IL
IK
OH
OL
amb
Supply voltage 4.5 5.0 5.5 V
High-level input voltage 2.0 V
Low-level input voltage 0.8 V
Input clamp current –18 mA
High-level output current –1 mA
Low-level output current 20 mA
Operating free-air temperature range 0 +70 °C
PARAMETER RATING UNIT
CC
V
LIMITS
MIN NOM MAX
DC ELECTRICAL CHARACTERISTICS
(Over recommended operating free-air temperature range unless otherwise noted.)
LIMITS
MIN TYP
p
p
V
IK
I
I
I
IH
I
OS
I
CC
Input clamp voltage VCC = MIN, II = I
Input current at maximum input voltage VCC = MAX, VI = 7.0V 100 µA
High-level input current VCC = MAX, VI = 2.7V 20 µA
p
Short-circuit output current
Supply current (total)
4
3
I0
I1 – I7, EI
VCC = MIN, VIL = MAX ±10%V
VIH = MIN, IOH = MAX ±5%V
CC
VCC = MIN, VIL = MAX ±10%V
VIH = MIN, IOL = MAX ±5%V
IK
CC
=
= 0.
I
CC
VCC = MAX –60 –150 mA
VCC = MAX 23 35 mA
CC
CC
2.5
2.7 3.4
NOTES:
1. For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions for the applicable type.
2. All typical values are at V
3. Not more than one output should be shorted at a time. For testing I
= 5V, T
CC
techniques are preferable in order to minimize internal heating and more accurately reflect operational values. Otherwise, prolonged shorting
amb
= 25°C.
, the use of high-speed test apparatus and/or sample-and-hold
OS
of a High output may raise the chip temperature well above normal and thereby cause invalid readings in other parameter tests. In any
sequence of parameter tests, I
4. To measure I
, outputs must be open, VIN on all inputs = 4.5V .
CC
tests should be performed last.
OS
2
MAX
0.30 0.50
0.30 0.50
–0.73 –1.2 V
–0.6 mA
–1.2 mA
March 1, 1990
5
Page 6
Philips Semiconductors Product specification
74F1488-input priority encoder
AC ELECTRICAL CHARACTERISTICS
LIMITS
SYMBOL PARAMETER
t
t
t
t
t
t
t
t
t
t
t
t
PLH
PHL
PLH
PHL
PLH
PHL
PLH
PHL
PLH
PHL
PLH
PHL
Propagation delay
In to An
Propagation delay
In to EO
Propagation delay
In to GS
Propagation delay
EI
to An
Propagation delay
EI to GS
Propagation delay
EI to EO
TEST
CONDITION
Waveform 2
Waveform 1
Waveform 2
Waveform 2
Waveform 2
Waveform 2
VCC = +5.0V
T
= +25°C
amb
C
= 50pF, RL = 500Ω
L
MIN TYP MAX MIN MAX
3.5
3.5
1.5
1.5
2.0
2.0
3.5
3.0
2.5
3.0
3.0
3.5
6.0
6.0
3.0
2.5
4.0
4.0
6.0
5.5
4.5
5.5
5.0
5.0
9.0
9.0
6.5
6.5
8.0
8.0
8.5
8.0
7.0
7.5
7.0
7.5
VCC = +5.0V ± 10%
T
= 0°C to +70°C
amb
C
= 50pF, RL = 500Ω
L
3.5
3.5
10.0
10.0
1.5
1.5
2.0
2.0
3.5
3.0
2.5
3.0
3.0
3.5
7.5
7.5
9.0
9.0
9.5
9.0
8.0
8.5
8.0
9.0
UNIT
ns
ns
ns
ns
ns
ns
AC WAVEFORMS
For all waveforms, VM = 1.5V.
In, EI
An, EO, GS
V
M
t
PHL
V
M
V
M
Waveform 1. For Inverting Outputs
TEST CIRCUIT AND WAVEFORMS
V
CC
V
PULSE
GENERATOR
IN
R
T
Test Circuit for Totem-Pole Outputs
D.U.T.
V
OUT
V
M
t
PHL
V
M
t
PLH
V
M
V
M
SF00187
t
PLH
In, EI
V
M
SF00186
An, EO, GS
Waveform 2. For Non-Inverting Outputs
t
NEGATIVE
PULSE
R
C
L
L
POSITIVE
PULSE
90%
10%
V
M
10%
t
THL (tf
t
TLH (tr
90%
V
M
w
V
M
10%
)
)
t
w
t
TLH (tr
t
THL (tf
)
)
90%
V
M
90%
10%
AMP (V)
0V
AMP (V)
0V
DEFINITIONS:
R
= Load resistor;
L
see AC ELECTRICAL CHARACTERISTICS for value.
= Load capacitance includes jig and probe capacitance;
C
L
see AC ELECTRICAL CHARACTERISTICS for value.
R
= Termination resistance should be equal to Z
T
pulse generators.
March 1, 1990
OUT
of
family
74F
6
Input Pulse Definition
INPUT PULSE REQUIREMENTS
V
amplitude
3.0V
M
1.5V
rep. rate
1MHz 500ns
t
w
t
TLHtTHL
2.5ns 2.5ns
SF00006
Page 7
Philips Semiconductors Product specification
74F1488-input priority encoder
DIP16: plastic dual in-line package; 16 leads (300 mil) SOT38-4
1990 Mar 01
7
Page 8
Philips Semiconductors Product specification
74F1488-input priority encoder
SO16: plastic small outline package; 16 leads; body width 3.9 mm SOT109-1
1990 Mar 01
8
Page 9
Philips Semiconductors Product specification
74F1488-input priority encoder
NOTES
1990 Mar 01
9
Page 10
Philips Semiconductors Product specification
74F1488-input priority encoder
Data sheet status
Data sheet
status
Objective
specification
Preliminary
specification
Product
specification
Product
status
Development
Qualification
Production
Definition
This data sheet contains the design target or goal specifications for product development.
Specification may change in any manner without notice.
This data sheet contains preliminary data, and supplementary data will be published at a later date.
Philips Semiconductors reserves the right to make chages at any time without notice in order to
improve design and supply the best possible product.
This data sheet contains final specifications. Philips Semiconductors reserves the right to make
changes at any time without notice in order to improve design and supply the best possible product.
[1]
[1] Please consult the most recently issued datasheet before initiating or completing a design.
Definitions
Short-form specification — The data in a short-form specification is extracted from a full data sheet with the same type number and title. For
detailed information see the relevant data sheet or data handbook.
Limiting values definition — Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). Stress above one
or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or
at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended
periods may affect device reliability.
Application information — Applications that are described herein for any of these products are for illustrative purposes only. Philips
Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or
modification.
Disclaimers
Life support — These products are not designed for use in life support appliances, devices or systems where malfunction of these products can
reasonably be expected to result in personal injury . Philips Semiconductors customers using or selling these products for use in such applications
do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application.
Right to make changes — Philips Semiconductors reserves the right to make changes, without notice, in the products, including circuits, standard
cells, and/or software, described or contained herein in order to improve design and/or performance. Philips Semiconductors assumes no
responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these
products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless
otherwise specified.
Philips Semiconductors
811 East Arques Avenue
P.O. Box 3409
Sunnyvale, California 94088–3409
Telephone 800-234-7381
Copyright Philips Electronics North America Corporation 1998
All rights reserved. Printed in U.S.A.
print code Date of release: 10-98
Document order number: 9397-750-05078
yyyy mmm dd
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