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INTEGRATED CIRCUITS

74F148

8-input priority encoder

Product specification

1990 Mar 01

IC15 Data Handbook

m n r

Philips Semiconductors	Product specification


8-input priority encoder	74F148

FEATURES

•Code conversions

•Multi-channel D/A converter

•Decimal-to-BCD converter

•Cascading for priority encoding of ªNº 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 I7 having 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) output and an Enable Output (EO) are provided with the three data outputs. The GS is active-Low when any input is Low: this indicates when any input is active. The EO 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 and GS are active-High when the Enable Input is High.

PIN CONFIGURATION


		I4	1	16	VCC
		I5
		I5	2	15		EO
		I6
		I6	3	14		GS
		I7			I3
		I7	4	13	I3
					I2
		EI	5	12	I2
					I1
	A2		6	11	I1
					I0
	A1		7	10	I0
GND
GND			8	9		A0

			SF00181

		TYPICAL			TYPICAL
TYPE	PROPAGATION			SUPPLY CURRENT
		DELAY			(TOTAL)

74F148		6.0ns			23mA

ORDERING INFORMATION

		COMMERCIAL RANGE
DESCRIPTION		VCC = 5V ±10%,				PKG DWG #
		Tamb = 0°C to +70°C
16-pin plastic DIP		N74F148N				SOT38-4

16-pin plastic SO		N74F148D				SOT109-1

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

Priority input (active Low)

1.0/1.0

20μA/0.6mA

Enable input (active Low)

1.0/2.0

20μA/1.2mA

Enable output (active Low)

50/33

1.0mA/20mA

Group select output (active Low)

50/33

1.0mA/20mA

Address outputs (active Low)

50/33

1.0mA/20mA

A0 ± A2

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

Philips Semiconductors	Product specification

8-input priority encoder	74F148

LOGIC SYMBOL

IEC/IEEE SYMBOL

	10	11	12	13	1	2	3	4
												10	10/Z10	HPRI/BIN		0 α	9
												11	10/Z10			0 α
												11	11/Z11			1 α	7
												12	11/Z11			1 α
	I0	I1	I2	I3	I4	I5	I6	I7				12	2/Z12			2 α	8
	I0	I1	I2	I3	I4	I5	I6	I7				13	2/Z12			2 α
												13	3/Z13
								EO	15				3/Z13
								EO	15			1	4/Z14
5	EI											2	4/Z14		≥	1
5	EI
								GS	14				5/Z15
								GS	14				5/Z15		10
												3			11
												3	6/Z16		12
				A0	A1	A2							6/Z16		12		15
				A0	A1	A2						4			13	18	15
												4	7/Z17		13	18
													7/Z17		14		14
												5			14	α	14
												5	EN = α/V18		15	α
													EN = α/V18		16
															16
VCC = Pin 16				9	7	6									17
VCC = Pin 16				9	7	6
GND = Pin 8									SF00182								SF00183
									SF00182								SF00183
LOGIC DIAGRAM
			EI		I7		I6		I5	I4	I3	I2	I1		I0
				5		4		3	2	1	13	12	11		10
						9			9			9	14	15
VCC = Pin 16					A2				A1			A0	GS	EO
GND = Pin 8
													SF00184
March 1, 1990											3

Philips Semiconductors	Product specification

8-input priority encoder	74F148

FUNCTION TABLE

INPUTS

OUTPUTS

H = High voltage level

L = Low voltage level

X = Don't care

APPLICATION

LSB

ENABLE

MSB


A0		A1		A2		A3		FLAG

16-Input Priority Encoder

SF00185

March 1, 1990

Philips Semiconductors	Product specification

8-input priority encoder	74F148

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	PARAMETER	RATING	UNIT

VCC	Supply voltage	±0.5 to +7.0	V
VIN	Input voltage	±0.5 to +7.0	V
IIN	Input current	±30 to +5	mA
VOUT	Voltage applied to output in High output state	±0.5 to VCC	V
IOUT	Current applied to output in Low output state	40	mA
Tamb	Operating free-air temperature range	0 to +70	°C
Tstg	Storage temperature range	±65 to +150	°C

RECOMMENDED OPERATING CONDITIONS

SYMBOL	PARAMETER		LIMITS		UNIT

		MIN	NOM	MAX
		MIN	NOM	MAX

VCC	Supply voltage	4.5	5.0	5.5	V
VIH	High-level input voltage	2.0			V
VIL	Low-level input voltage			0.8	V
IIK	Input clamp current			±18	mA
IOH	High-level output current			±1	mA
IOL	Low-level output current			20	mA
Tamb	Operating free-air temperature range	0		+70	°C

DC ELECTRICAL CHARACTERISTICS

(Over recommended operating free-air temperature range unless otherwise noted.)

SYMBOL

PARAMETER

TEST CONDITIONS1

LIMITS

UNIT

MIN

TYP2

MAX

VOH

High-level output voltage

VCC = MIN, VIL = MAX

±10%VCC

2.5

VIH = MIN, IOH = MAX

±5%VCC

2.7

3.4

VOL

Low-level output voltage

VCC = MIN, VIL = MAX

±10%VCC

0.30

0.50

VIH = MIN, IOL = MAX

±5%VCC

0.30

0.50

VIK

Input clamp voltage

VCC = MIN, II = IIK

±0.73

±1.2

Input current at maximum input voltage

VCC = MAX, VI = 7.0V

100

μA

IIH

High-level input current

VCC = MAX, VI = 2.7V

μA

IIL

Low-level input current

VCC = MAX, VI = 0.5V

±0.6

I1 ± I7, EI

±1.2

Short-circuit output current3

= MAX

±60

±150

Supply current (total)4

= MAX

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 VCC = 5V, Tamb = 25°C.

3.Not more than one output should be shorted at a time. For testing IOS, the use of high-speed test apparatus and/or sample-and-hold techniques are preferable in order to minimize internal heating and more accurately reflect operational values. Otherwise, prolonged shorting 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, IOS tests should be performed last.

4.To measure ICC, outputs must be open, VIN on all inputs = 4.5V.

March 1, 1990

Philips Semiconductors	Product specification

8-input priority encoder	74F148

AC ELECTRICAL CHARACTERISTICS

							LIMITS

SYMBOL		PARAMETER	TEST		VCC = +5.0V			VCC = +5.0V ± 10%		UNIT
SYMBOL		PARAMETER	CONDITION	Tamb = +25°C				Tamb = 0°C to +70°C		UNIT
			CONDITION	CL = 50pF, RL = 500Ω				CL = 50pF, RL = 500Ω
				CL = 50pF, RL = 500Ω				CL = 50pF, RL = 500Ω
				MIN		TYP	MAX	MIN	MAX

tPLH	Propagation delay		Waveform 2	3.5		6.0	9.0	3.5	10.0	ns
tPLH			Waveform 2							ns
tPHL	In to An			3.5		6.0	9.0	3.5	10.0
tPLH	Propagation delay		Waveform 1	1.5		3.0	6.5	1.5	7.5	ns
tPLH			Waveform 1							ns
tPHL	In to EO			1.5		2.5	6.5	1.5	7.5
tPLH	Propagation delay		Waveform 2	2.0		4.0	8.0	2.0	9.0	ns
tPLH			Waveform 2							ns
tPHL	In to GS			2.0		4.0	8.0	2.0	9.0
tPLH	Propagation delay		Waveform 2	3.5		6.0	8.5	3.5	9.5	ns
tPLH			Waveform 2							ns
tPHL	EI to An			3.0		5.5	8.0	3.0	9.0
tPLH	Propagation delay		Waveform 2	2.5		4.5	7.0	2.5	8.0	ns

	EI to GS			3.0		5.5	7.5	3.0	8.5
tPHL	EI to GS			3.0		5.5	7.5	3.0	8.5
tPLH	Propagation delay		Waveform 2	3.0		5.0	7.0	3.0	8.0	ns
tPLH			Waveform 2							ns
tPHL	EI to EO			3.5		5.0	7.5	3.5	9.0

AC WAVEFORMS

For all waveforms, VM = 1.5V.
In, EI
VM	VM
tPHL	tPLH
VM	VM
An, EO, GS
	SF00186

Waveform 1. For Inverting Outputs

In, EI	VM	VM
	tPHL	tPLH
An, EO, GS	VM	VM
An, EO, GS
		SF00187
Waveform 2.	For Non-Inverting Outputs

TEST CIRCUIT AND WAVEFORMS

	VCC	90%	tw	90%	AMP (V)
		90%		90%
	NEGATIVE	VM		VM
	PULSE	VM		VM
VIN	VOUT	10%		10%	0V
VIN	VOUT				0V
PULSE	D.U.T.	tTHL (tf )		tTLH (tr )
GENERATOR		tTHL (tf )		tTLH (tr )
RT	CL RL	tTLH (tr )		tTHL (tf )
		90%		90%	AMP (V)
	POSITIVE	90%		90%
	POSITIVE	VM		VM
	PULSE	VM		VM
Test Circuit for Totem-Pole Outputs		10%	tw	10%	0V
Test Circuit for Totem-Pole Outputs					0V

DEFINITIONS:

RL = Load resistor;

see AC ELECTRICAL CHARACTERISTICS for value. CL = Load capacitance includes jig and probe capacitance; see AC ELECTRICAL CHARACTERISTICS for value.

RT = Termination resistance should be equal to ZOUT of pulse generators.

Input Pulse Definition

family	INPUT PULSE REQUIREMENTS

	amplitude	VM	rep. rate	tw	tTLH	tTHL
	amplitude	VM	rep. rate	tw	tTLH	tTHL
74F	3.0V	1.5V	1MHz	500ns	2.5ns	2.5ns

SF00006

March 1, 1990

Philips Semiconductors	Product specification

8-input priority encoder	74F148

DIP16: plastic dual in-line package; 16 leads (300 mil)	SOT38-4

1990 Mar 01

Philips Semiconductors	Product specification

8-input priority encoder	74F148

SO16: plastic small outline package; 16 leads; body width 3.9 mm	SOT109-1

1990 Mar 01

Philips Semiconductors	Product specification

8-input priority encoder	74F148

NOTES

1990 Mar 01

Philips Semiconductors	Product specification

8-input priority encoder	74F148

Data sheet status

Data sheet	Product	Definition [1]
status	status

Objective	Development	This data sheet contains the design target or goal specifications for product development.
specification		Specification may change in any manner without notice.

Preliminary	Qualification	This data sheet contains preliminary data, and supplementary data will be published at a later date.
specification		Philips Semiconductors reserves the right to make chages at any time without notice in order to
		improve design and supply the best possible product.

Product	Production	This data sheet contains final specifications. Philips Semiconductors reserves the right to make
specification		changes at any time without notice in order to improve design and supply the best possible product.

[1] Please consult the most recently issued datasheet before initiating or completing a design.

Definitions

Short-form specification Ð 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 Ð 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 Ð 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 Ð 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 Ð 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

print code	Date of release: 10-98
Document order number:	9397-750-05078

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		I4	1	16	VCC
		I5
		I5	2	15		EO
		I6
		I6	3	14		GS
		I7			I3
		I7	4	13	I3
					I2
		EI	5	12	I2
					I1
	A2		6	11	I1
					I0
	A1		7	10	I0
GND
GND			8	9		A0


		I4	1	16	VCC
		I5
		I5	2	15		EO
		I6
		I6	3	14		GS
		I7			I3
		I7	4	13	I3
					I2
		EI	5	12	I2
					I1
	A2		6	11	I1
					I0
	A1		7	10	I0
GND
GND			8	9		A0


		I4	1	16	VCC
		I5
		I5	2	15		EO
		I6
		I6	3	14		GS
		I7			I3
		I7	4	13	I3
					I2
		EI	5	12	I2
					I1
	A2		6	11	I1
					I0
	A1		7	10	I0
GND
GND			8	9		A0