ST HCF4056B User Manual

HCF4056B

BCD TO 7 SEGMENT DECODER /DRIVER WITH STROBED LATCH FUNCTION

■QUIESCENT CURRENT SPECIF. UP TO 20V

■OPERATION OF LIQUID CRYSTALS WITH CMOS CIRCUITS PROVIDES ULTRA LOW POWER DISPLAY.

■EQUIVALENT AC OUTPUT DRIVE FOR LIQUID CRYSTAL DISPLAYS - NO EXTERNAL CAPACITOR REQUIRED

■VOLTAGE DOUBLING ACROSS DISPLAY

[(VDD - VEE) = 18V] RESULTS IN EFFECTIVE 36V (p-p) DRIVE ACROSS SELECTED DISPLAY SEGMENTS

■LOW OR HIGH OUTPUT LEVEL DC DRIVE FOR OTHER TYPES OF DISPLAYS

■ONE CHIP LOGIC LEVEL CONVERSION FOR DIFFERENT INPUT AND OUTPUT LEVEL SWINGS

	DIP	SOP
ORDER CODES
PACKAGE	TUBE	T & R
DIP	HCF4056BEY
SOP	HCF4056BM1	HCF4056M013TR

■FULL DECODING OF ALL INPUT COMBINATIONS : "0 - 9, L, H, P, A" AND BLANK POSITIONS

■INPUT LEAKAGE CURRENT

II = 100nA (MAX) AT VDD = 18V TA = 25°C

■100% TESTED FOR QUIESCENT CURRENT

■MEETS ALL REQUIREMENTS OF JEDEC JESD13B "STANDARD SPECIFICATIONS FOR DESCRIPTION OF B SERIES CMOS DEVICES"

DESCRIPTION

HCF4056B is a monolithic integrated circuit fabricated in Metal Oxide Semiconductor technology available in DIP and SOP packages.

PIN CONNECTION

HCF4056B is a single digit BCD to 7 segment decoder driver circuit that provides a level shifting function on the chip. This feature permits the BCD input-signal swings (VDD to VSS) to be the same as or different from the 7-segment output signal swings (VDD to VEE). For example, the BCD

input-signal swings (VDD to VSS) may be as low as 0 to -3V, whereas the output-display drive signal

swing (VDD to VEE) may be from 0 to -5V. If VDD to VEE exceeds 15V, VDD to VSS should be at least

4V. The 7-segment outputs are controlled by the DISPLAY-FREQUENCY (DF) input, which causes the selected segment outputs to be low, high, or a square wave output (for liquid crystal displays).

September 2002

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HCF4056B

When the DF input is low, the output segments will be high when selected by the BCD inputs. When the DF input is high, the output segments will be low when selected by the BCD inputs. When a square wave is present at the DF input, the selected segments will have a square wave output that is 180° out of phase with the DF input. Those segments which are not selected will have a square wave output that is in phase with the input. DF square wave repetition rates for liquid crystal displays usually range from 30Hz (well above flicker rate) to 200Hz (well below the upper limit of the liquid crystal frequency response). HCF4056B provides a strobed-latch function at the BCD inputs. The decoding of all input combinations in

INPUT EQUIVALENT CIRCUIT

FUNCTIONAL DIAGRAM

this device provides displays of 0 to 9 as well as L, P, H, A, -, and a blank position. The level shifted function permits the use of different input and output signal swings. The input swings from a low

level of VSS to a high level of VDD, while the outputs swing from a low level of VEE to the same

high level of VDD. Thus, the input and output swings can be selected independently of each other over a 3 to 18V range. VSS may be connected to VEE when no level-shift function is required. The HCF4056B, however must be used together with HCF4054B to provide the common DF output.

PIN DESCRIPTION

	PIN No	SYMBOL	NAME AND FUNCTION
	5, 3, 2, 4	20, 21, 22, 23	BCD Inputs
	9, 10, 11, 12,	a to g	7 - Segments Outputs
	13, 15, 14
	6	DISPLAY	Display Frequency Input
		FREQ. IN
	1	STROBE	Strobe Input
	7	VEE	Negative Supply Voltage
	8	VSS	Negative Supply Voltage
	16	VDD	Positive Supply Voltage

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TRUTH TABLE

	INPUT CODE					OUTPUT STATE					DISPLAY
23	22	21	20	a	b	c	d	e	f	g	CHARACTER
L	L	L	L	H	H	H	H	H	H	L	0
L	L	L	H	L	H	H	L	L	L	L	1
L	L	H	L	H	H	L	H	H	L	H	2
L	L	H	H	H	H	H	H	L	L	H	3
L	H	L	L	L	H	H	L	L	H	H	4
L	H	L	H	H	L	H	H	L	H	H	5
L	H	H	L	H	L	H	H	H	H	H	6
L	H	H	H	H	H	H	L	L	L	L	7
H	L	L	L	H	H	H	H	H	H	H	8
H	L	L	H	H	H	H	H	L	H	H	9
H	L	H	L	L	L	L	H	H	H	L	L
H	L	H	H	L	H	H	L	H	H	H	H
H	H	L	L	H	H	L	L	H	H	H	P
H	H	L	H	H	H	H	L	H	H	H	A
H	H	H	L	L	L	L	L	L	L	H	-
H	H	H	H	L	L	L	L	L	L	L	BLANK

ABSOLUTE MAXIMUM RATINGS

Symbol	Parameter	Value	Unit
VDD	Supply Voltage	-0.5 to +22	V
VI	DC Input Voltage	-0.5 to VDD + 0.5	V
II	DC Input Current	± 10	mA
PD	Power Dissipation per Package	200	mW
	Power Dissipation per Output Transistor	100	mW
Top	Operating Temperature	-55 to +125	°C
Tstg	Storage Temperature	-65 to +150	°C

Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied.

All voltage values are referred to VSS pin voltage.

RECOMMENDED OPERATING CONDITIONS

Symbol	Parameter	Value	Unit
VDD	Supply Voltage	3 to 20	V
VI	Input Voltage	0 to VDD	V
Top	Operating Temperature	-55 to 125	°C

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