Digital Circuits Lab Report

© 2001 Fairchild Semiconductor Corporation DS006518 www.fairchildsemi.com

September 1986

Revised July 2001

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DM7446A, DM7447A BCD to 7-Segment Decoders/Drivers

General Description The DM7446A and DM7447A feature active-LOW outputs designed for driving common-anode LEDs or incandescent indicators directly. All of the circuits have full ripple-blank- ing input/output controls and a lamp test input. Segment identification and resultant displays are shown on a follow- ing page. Display patterns for BCD input counts above nine are unique symbols to authenticate input conditions.

All of the circuits incorporate automatic leading and/or trail- ing-edge, zero-blanking control (RBI and RBO). Lamp test (LT) of these devices may be performed at any time when the BI/RBO node is at a HIGH logic level. All types contain an overriding blanking input (BI) which can be used to con- trol the lamp intensity (by pulsing) or to inhibit the outputs.

Features ■ All circuit types feature lamp intensity modulation

capability

■ Open-collector outputs drive indicators directly

■ Lamp-test provision

■ Leading/trailing zero suppression

Ordering Code:

Connection Diagram

Order Number Package Number Package Description

DM7446AN N16E 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide

DM7447AN N16E 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide

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A Function Table

H = HIGH level, L = LOW level, X = Don’t Care

Note 1: BI/RBO is a wire-AND logic serving as blanking input (BI) and/or ripple-blanking output (RBO).

Note 2: The blanking input (BI) must be OPEN or held at a HIGH logic level when output functions 0 through 15 are desired. The ripple-blanking input (RBI) must be OPEN or HIGH if blanking of a decimal zero is not desired.

Note 3: When a LOW logic level is applied directly to the blanking input (BI), all segment outputs are HIGH regardless of the level of any other input.

Note 4: When ripple-blanking input (RBI) and inputs A, B, C, and D are at a LOW level with the lamp test input HIGH, all segment outputs go H and the rip- ple-blanking output (RBO) goes to a LOW level (response condition).

Note 5: When the blanking input/ripple-blanking output (BI/RBO) is OPEN or held HIGH and a LOW is applied to the lamp-test input, all segment outputs are L .

Logic Diagram

Decimal or Inputs BI/RBO Outputs Note

Function LT RBI D C B A (Note 1) a b c d e f g

0 H H L L L L H L L L L L L H

1 H X L L L H H H L L H H H H

2 H X L L H L H L L H L L H L

3 H X L L H H H L L L L H H L

4 H X L H L L H H L L H H L L

5 H X L H L H H L H L L H L L

6 H X L H H L H H H L L L L L

7 H X L H H H H L L L H H H H (Note 2)

8 H X H L L L H L L L L L L L

9 H X H L L H H L L L H H L L

10 H X H L H L H H H H L L H L

11 H X H L H H H H H L L H H L

12 H X H H L L H H L H H H L L

13 H X H H L H H L H H L H L L

14 H X H H H L H H H H L L L L

15 H X H H H H H H H H H H H H

BI X X X X X X L H H H H H H H (Note 3)

RBI H L L L L L L H H H H H H H (Note 4)

LT L X X X X X H L L L L L L L (Note 5)

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Absolute Maximum Ratings(Note 6) Note 6: The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the absolute maximum ratings. The “Recommended Operating Conditions” table will define the conditions for actual device operation.

Recommended Operating Conditions

Supply Voltage 7V

Input Voltage 5.5V

Operating Free Air Temperature Range 0°C to +70°C Storage Temperature Range −65°C to +150°C

Symbol Parameter Min Nom Max Units

DM7446A

VCC Supply Voltage 4.75 5 5.25 V

VIH HIGH Level Input Voltage 2 V

VIL LOW Level Input Voltage 0.8 V

VOH HIGH Level Output Voltage (a thru g) 30 V

IOH HIGH Level Output Current (BI/RBO) −0.2 µA IOL LOW Level Output Current (a thru g) 40 mA

IOL LOW Level Output Current (BI/RBO) 8 mA

TA Free Air Operating Temperature 0 70 °C DM7447A

VCC Supply Voltage 4.75 5 5.25 V

VIH HIGH Level Input Voltage 2 V

VIL LOW Level Input Voltage 0.8 V

VOH HIGH Level Output Voltage (a thru g) 15 V

IOH HIGH Level Output Current (BI/RBO) −0.2 µA IOL LOW Level Output Current (a thru g) 40 mA

IOL LOW Level Output Current (BI/RBO) 8 mA

TA Free Air Operating Temperature 0 70 °C

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A DM7446A Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted)

Note 7: All typicals are at VCC = 5V, TA = 25°C.

Note 8: ICC is measured with all outputs OPEN and all inputs at 4.5V.

DM7446A Switching Characteristics at VCC = 5V and TA = 25°C

Symbol Parameter Conditions Min Typ

Max Units (Note 7)

VI Input Clamp Voltage VCC = Min, II = −12 mA −1.5 V

VOH HIGH Level Output VCC = Min 2.4 3.7 V

Voltage (BI/RBO) IOH = Max

ICEX HIGH Level Output VCC = Max, VO = 30V 250 µA

Current (a thru g) VIL = Max, VIH = Min

VOL LOW Level VCC = Min, IOL = Max 0.3 0.4 V

Output Voltage VIH = Min, VIL = Max

II Input Current @ Max VCC = Max, VI = 5.5V 1 mA

Input Voltage (Except BI/RBO)

IIH HIGH Level Input VCC = Max, VI = 2.4V 40 µA

Current (Except BI/RBO)

IIL LOW Level Input VCC = Max BI/RBO −4 mA

Current VI = 0.4V Others −1.6

IOS Short Circuit VCC = Max −4 mA Output Current (BI/RBO)

ICC Supply Current VCC = Max 60 103 mA

(Note 8)

Symbol Parameter Conditions Min Max Units

tPLH Propagation Delay Time CL = 15 pF 100 ns

LOW-to-HIGH Level Output RL = 120Ω

tPHL Propagation Delay Time 100 ns

HIGH-to-LOW Level Output

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DM7447A Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted)

Note 9: All typicals are at VCC = 5V, TA = 25°C.

Note 10: ICC is measured with all outputs OPEN and all inputs at 4.5V.

DM7447A Switching Characteristics at VCC = 5V and TA = 25°C

Symbol Parameter Conditions Min Typ

Max Units (Note 9)

VI Input Clamp Voltage VCC = Min, II = −12 mA −1.5 V

VOH HIGH Level Output VCC = Min 2.4 3.7 V

Voltage (BI/RBO) IOH = Max

ICEX HIGH Level Output VCC = Max, VO = 15V 250 µA

Current (a thru g) VIL = Max, VIH = Min

VOL LOW Level Output VCC = Min, IOL = Max 0.3 0.4 V

Voltage VIH = Min, VIL = Max

II Input Current @ Max VCC = Max, VI = 5.5V 1 mA

Input Voltage

IIH HIGH Level Input Current VCC = Max, VI = 2.4V 40 µA

IIL LOW Level Input VCC = Max BI/RBO −4 mA

Current VI = 0.4V Others −1.6

IOS Short Circuit VCC = Max −4 mA Output Current (BI/RBO)

ICC Supply Current VCC = Max 60 103 mA

(Note 10)

Symbol Parameter Conditions Min Max Units

tPLH Propagation Delay Time CL = 15 pF 100 ns

LOW-to-HIGH Level Output RL = 120Ω

tPHL Propagation Delay Time 100 ns

HIGH-to-LOW Level Output

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16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide Package Number N16E

Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right at any time without notice to change said circuitry and specifications.

LIFE SUPPORT POLICY

FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be rea- sonably expected to result in a significant injury to the user.

2. A critical component in any component of a life support device or system whose failure to perform can be rea- sonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.

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BCD_7Seg_7447.ms14