TOSHIBA TC74VHC138F, TC74VHC138FN, TC74VHC138FT, TC74VHC138FK Technical data

TC74VHC138F/FN/FT/FK

TOSHIBA CMOS Digital Integrated Circuit Silicon Monolithic

TC74VHC138F,TC74VHC138FN,TC74VHC138FT,TC74VHC138FK

3-to-8 Line Decoder

The TC74VHC138 is an advanced high speed CMOS 3-to-8 DECODER fabricated with silicon gate C2MOS technology.

It achieves the high speed operation similar to equivalent Bipolar Schottky TTL while maintaining the CMOS low power dissipation.

When the device is enabled, 3 Binary Select inputs (A, B and C) determine which one of the outputs ( Y0 - Y7 ) will go low.

When enable input G1 is held low or either G2A or G2B is held high, decoding function is inhibited and all outputs go high.

G1, G2A , and G2B inputs are provided to ease cascade connection and for use as an address decoder for memory systems.

An input protection circuit ensures that 0 to 5.5 V can be applied to the input pins without regard to the supply voltage. This device can be used to interface 5 V to 3 V systems and two supply systems such as battery back up. This circuit prevents device destruction due to mismatched supply and input voltages.

Features

•High speed: tpd = 5.7 ns (typ.) at VCC = 5 V

•Low power dissipation: ICC = 4 μA (max) at Ta = 25°C

•High noise immunity: VNIH = VNIL = 28% VCC (min)

•Power down protection is provided on all inputs.

•Balanced propagation delays: tpLH − tpHL

•Wide operating voltage range: VCC (opr) = 2 V to 5.5 V

•Pin and function compatible with 74ALS138

Note: xxxFN (JEDEC SOP) is not available in Japan.

TC74VHC138F

TC74VHC138FN

TC74VHC138FT

TC74VHC138FK

Weight
SOP16-P-300-1.27A	: 0.18 g (typ.)
SOL16-P-150-1.27	: 0.13 g (typ.)
TSSOP16-P-0044-0.65A	: 0.06 g (typ.)
VSSOP16-P-0030-0.50	: 0.02 g (typ.)

1	2007-10-01

TC74VHC138F/FN/FT/FK

Pin Assignment

			A	1				16	VCC
			B	2				15
										Y0
			C	3				14
										Y1
				4				13
	G2A									Y2
				5				12
G2B										Y3
		G1		6				11
										Y4
				7				10
		Y7								Y5
	GND			8				9
										Y6
					(top view)

IEC Logic Symbol

	A	(1)	1	BIN/OCT	0	(15)					A	(1)	0	DMUX		0	(15)
								Y0							0				Y0
		(2)				(14)						(2)		G			(14)
	B		2		1						B					1
								Y1											Y1
		(3)				(13)						(3)			7		(13)
	C		4		2						C		2			2
								Y2											Y2
						(12)											(12)
					3											3
								Y3											Y3
						(11)											(11)
					4											4
								Y4											Y4
		(6)	&			(10)						(6)	&				(10)
	G1				5						G1					5
								Y5											Y5
		(4)				(9)						(4)					(9)
				EN	6											6
G2A								Y6		G2A									Y6
		(5)				(7)						(5)					(7)
					7											7
G2B								Y7		G2B									Y7

Truth Table

Inputs

Outputs

Selected

Enable

Select

Output

Y0

Y1

Y2

Y3

Y4

Y5

Y6

Y7

G1

G2A

G2B

C

B

A

L

X

X

X

X

X

H

H

H

H

H

H

H

H

None

X

H

X

X

X

X

H

H

H

H

H

H

H

H

None

X

X

H

X

X

X

H

H

H

H

H

H

H

H

None

H

L

L

L

L

L

L

H

H

H

H

H

H

H

Y0

H

L

L

L

L

H

H

L

H

H

H

H

H

H

Y1

H

L

L

L

H

L

H

H

L

H

H

H

H

H

2

Y

H

L

L

L

H

H

H

H

H

L

H

H

H

H

Y3

H

L

L

H

L

L

H

H

H

H

L

H

H

H

4

Y

H

L

L

H

L

H

H

H

H

H

H

L

H

H

Y5

H

L

L

H

H

L

H

H

H

H

H

H

L

H

6

Y

H

L

L

H

H

H

H

H

H

H

H

H

H

L

Y7

X: Don’t care

2	2007-10-01

TC74VHC138F/FN/FT/FK

Logic Diagram

		15	Y0
		14	Y1
	A	1
		13
			Y2
Select		12	Y3
	B	2		Data
inputs
		11		outputs
			Y4
		10	Y5
	C	3
		9
			Y6
		7	Y7
		4
	G2A
Enable		5
	G2B
inputs		6
	G1

Absolute Maximum Ratings (Note)

Characteristics	Symbol	Rating	Unit
Supply voltage range	VCC	−0.5 to 7.0	V
DC input voltage	VIN	−0.5 to 7.0	V
DC output voltage	VOUT	−0.5 to VCC + 0.5	V
Input diode current	IIK	−20	mA
Output diode current	IOK	±20	mA
DC output current	IOUT	±25	mA
DC VCC/ground current	ICC	±75	mA
Power dissipation	PD	180	mW
Storage temperature	Tstg	−65 to 150	°C

Note:	Exceeding any of the absolute maximum ratings, even briefly, lead to deterioration in IC performance or
	even destruction.
	Using continuously under heavy loads (e.g. the application of high temperature/current/voltage and the
	significant change in temperature, etc.) may cause this product to decrease in the reliability significantly
	even if the operating conditions (i.e. operating temperature/current/voltage, etc.) are within the absolute
	maximum ratings and the operating ranges.
	Please design the appropriate reliability upon reviewing the Toshiba Semiconductor Reliability Handbook
	(“Handling Precautions”/“Derating Concept and Methods”) and individual reliability data (i.e. reliability test
	report and estimated failure rate, etc).

Operating Ranges (Note)

		Characteristics	Symbol	Rating	Unit
	Supply voltage		VCC	2.0 to 5.5	V
	Input voltage		VIN	0 to 5.5	V
	Output voltage		VOUT	0 to VCC	V
	Operating temperature		Topr	−40 to 85	°C
	Input rise and fall time		dt/dv	0 to 100 (VCC = 3.3 ± 0.3 V)	ns/V
				0 to 20 (VCC = 5 ± 0.5 V)
	Note:	The operating ranges must be maintained to ensure the normal operation of the device.
		Unused inputs must be tied to either VCC or GND.

3	2007-10-01