View 74C925_938208.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

MM74C925 * MM74C926 * MM74C927 * MM74C928 4-Digit Counters with Multiplexed 7-Segment Output Drivers
October 1987 Revised January 1999
MM74C925 * MM74C926 * MM74C927 * MM74C928 4-Digit Counters with Multiplexed 7-Segment Output Drivers
General Description
The MM74C925, MM74C926, MM74C927 and MM74C928 CMOS counters consist of a 4-digit counter, an internal output latch, NPN output sourcing drivers for a 7-segment display, and an internal multiplexing circuitry with four multiplexing outputs. The multiplexing circuit has its own free-running oscillator, and requires no external clock. The counters advance on negative edge of clock. A HIGH signal on the Reset input will reset the counter to zero, and reset the carry-out LOW. A LOW signal on the Latch Enable input will latch the number in the counters into the internal output latches. A HIGH signal on Display Select input will select the number in the counter to be displayed; a LOW level signal on the Display Select will select the number in the output latch to be displayed. The MM74C925 is a 4-decade counter and has Latch Enable, Clock and Reset inputs. The MM74C926 is like the MM74C925 except that it has a display select and a carry-out used for cascading counters. The carry-out signal goes HIGH at 6000, goes back LOW at 0000. The MM74C927 is like the MM74C926 except the second most significant digit divides by 6 rather than 10. Thus, if the clock input frequency is 10 Hz, the display would read tenths of seconds and minutes (i.e., 9:59.9). The MM74C928 is like the MM74C926 except the most significant digit divides by 2 rather than 10 and the carry-out is an overflow indicator which is HIGH at 2000, and it goes back LOW only when the counter is reset. Thus, this is a 31/2-digit counter.
Features
s Wide supply voltage range: s Guaranteed noise margin: s High noise immunity: 3V to 6V 1V 0.45 VCC (typ.)
s High segment sourcing current: 40 mA @ VCC - 1.6V, VCC = 5V s Internal multiplexing circuitry
Design Considerations
Segment resistors are desirable to minimize power dissipation and chip heating. The DS75492 serves as a good digit driver when it is desired to drive bright displays. When using this driver with a 5V supply at room temperature, the display can be driven without segment resistors to full illumination. The user must use caution in this mode however, to prevent overheating of the device by using too high a supply voltage or by operating at high ambient temperatures. The input protection circuitry consists of a series resistor, and a diode to ground. Thus input signals exceeding VCC will not be clamped. This input signal should not be allowed to exceed 15V.
Ordering Code:
Order Number MM74C925N MM74C926N MM74C927N MM74C928N Package Number N16E N18A N18A N18A Package Description 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide 18-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide 18-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide 18-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide
(c) 1999 Fairchild Semiconductor Corporation
DS005919.prf
www.fairchildsemi.com
MM74C925 * MM74C926 * MM74C927 * MM74C928
Connection Diagrams
Pin Assignments for DIP
Top View MM74C925
Top View MM74C926, MM74C927, MM74C928
Functional Description
Reset -- Asynchronous, active high Low, displays output of latch Latch Enable -- High, flow through condition Low, latch condition Clock --Negative edge sensitive Display Select -- High, displays output of counter Segment Output -- Current sourcing with 40 mA @VOUT = VCC - 1.6V (typ.) Also, sink capability = 2 LTTL loads Digit Output -- Current sourcing with 1 mA @VOUT = 1.75V. Also, sink capability = 2 LTTL loads Carry-Out -- 2 LTTL loads. See carry-out waveforms.
Logic Diagrams
MM74C925
www.fairchildsemi.com
2
MM74C925 * MM74C926 * MM74C927 * MM74C928
Logic Diagrams
(Continued) MM74C926
MM74C927
MM74C928
3
www.fairchildsemi.com
MM74C925 * MM74C926 * MM74C927 * MM74C928
Absolute Maximum Ratings(Note 1)
Voltage at Any Output Pin Voltage at Any Input Pin Operating Temperature Range (TA) Storage Temperature Range Power Dissipation (PD) -40C to +85C -65C to +150C Refer to PD(MAX) vs TA Graph GND - 0.3V to VCC + 0.3V GND - 0.3V to +15V
Operating VCC Range VCC Lead Temperature (Soldering, 10 seconds)
3V to 6V 6.5V 260C
Note 1: "Absolute Maximum Ratings" are those values beyond which the safety of the device cannot be guaranteed. Except for "Operating Temperature Range" they are not meant to imply that the devices should be operated at these limits. The Electrical Characteristics table provides conditions for actual device operation.
DC Electrical Characteristics
Min/Max limits apply at -40C tj + 85C, unless otherwise noted Symbol CMOS TO CMOS VIN(1) VIN(0) VOUT(1) Logical "1" Input Voltage Logical "0" Input Voltage Logical "1" Output Voltage (Carry-Out and Digit Output Only) VOUT(0) IIN(1) IIN(0) ICC Logical "0" Output Voltage Logical "1" Input Current Logical "0" Input Current Supply Current VCC = 5V, IO = 10 A VCC = 5V, VIN = 15V VCC = 5V, VIN = 0V VCC = 5V, Outputs Open Circuit, VIN = 0V or 5V CMOS/LPTTL INTERFACE VIN(1) VIN(0) VOUT(1) Logical "1" Input Voltage Logical "0" Input Voltage Logical "1" Output Voltage (Carry-Out and Digit Output Only) VOUT(0) VOUT Logical "0" Output Voltage Output Voltage (Segment Sourcing Output) RON Output Resistance (Segment Sourcing Output) Output Resistance (Segment Output) Temperature Coefficient ISOURCE ISOURCE ISINK jA Output Source Current (Digit Output) Output Source Current (Carry-Out) Output Sink Current (All Outputs) Thermal Resistance MM74C925: (Note 2) 75 70 100 90 C/W C/W MM74C926, MM74C927, MM74C928
Note 2: jA measured in free-air with device soldered into printed circuit board.
Parameter VCC = 5V VCC = 5V
Conditions
Min
Typ
Max
Units
3.5 1.5 4.5 0.5 0.005 -1 -0.005 20 1000 1
V V V V A A A
VCC = 5V, IO = -10 A
VCC = 4.75V VCC = 4.75V VCC = 4.75V, IO = -360 A VCC = 4.75V, IO = 360 A IOUT = -65 mA, VCC = 5V, Tj = 25C IOUT = -40 mA, VCC = 5V Tj = 100C Tj = 150C IOUT = -65 mA, VCC = 5V, Tj = 25C IOUT = -40 mA, VCC = 5V Tj = 100C Tj = 150C
VCC - 2 0.8 2.4 0.4 VCC - 2 VCC - 1.6 VCC - 2 VCC - 1.3 VCC - 1.2 VCC - 1.4 20 30 35 0.6 32 40 50 0.8
V V V V V V V %/C mA mA mA
OUTPUT DRIVE
VCC = 4.75V, VOUT = 1.75V, Tj = 150C VCC = 5V, VOUT = 0V, Tj = 25C VCC = 5V, VOUT = VCC, Tj = 25C
-1 -1.75 1.75
-2 -3.3 3.6
www.fairchildsemi.com
4
MM74C925 * MM74C926 * MM74C927 * MM74C928
AC Electrical Characteristics
TA = 25C, CL = 50 pF, unless otherwise noted
Symbol fMAX tr, tf tWR tWLE Parameter Maximum Clock Frequency Maximum Clock Rise or Fall Time Reset Pulse Width Latch Enable Pulse Width
(Note 3)
Conditions Min 2 1.5 250 320 250 320 2500 3200 0 0 320 400 1000 5 Typ 4 3 15 Tj = 25C Tj = 100C Tj = 25C Tj = 100C Tj = 25C Tj = 100C Tj = 25C Tj = 100C Tj = 25C Tj = 100C 100 125 100 125 1250 1600 -100 -100 160 200 Max Units MHz MHz s ns ns ns ns ns ns ns ns ns ns Hz pF
VCC = 5V, VCC = 5V VCC = 5V VCC = 5V VCC = 5V VCC = 5V VCC = 5V VCC = 5V Any Input (Note 4)
Tj = 25C
Square Wave Clock Tj = 100C
tSET(CK, LE) Clock to Latch Enable Set-Up Time tLR tSET(R, LE) fMUX CIN Latch Enable to Reset Wait Time Reset to Latch Enable Set-Up Time Multiplexing Output Frequency Input Capacitance
Note 3: AC Parameters are guaranteed by DC correlated testing. Note 4: Capacitance is guaranteed by periodic testing.
Typical Performance Characteristics
Typical Segment Current vs Output Voltage Maximum Power Dissipation vs Ambient Temperature
Note: VD = Voltage across digit driver
Typical Average Segment Current vs Segment Resistor Value
5
www.fairchildsemi.com
MM74C925 * MM74C926 * MM74C927 * MM74C928
Typical Performance Characteristics
Segment Output Driver
(Continued) Input Protection
Common Cathode LED Display
Segment Identification
www.fairchildsemi.com
6
MM74C925 * MM74C926 * MM74C927 * MM74C928
Switching Time Waveforms
Input Waveforms Multiplexing Output Waveforms
T = 1/fMUX
Carry-Out Waveforms
7
www.fairchildsemi.com
MM74C925 * MM74C926 * MM74C927 * MM74C928
Physical Dimensions inches (millimeters) unless otherwise noted
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide Package Number N16E
www.fairchildsemi.com
8
MM74C925 * MM74C926 * MM74C927 * MM74C928 4-Digit Counters with Multiplexed 7-Segment Output Drivers
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
18-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide Package Number N18A
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: 2. A critical component in any component of a life support 1. Life support devices or systems are devices or systems device or system whose failure to perform can be reawhich, (a) are intended for surgical implant into the sonably expected to cause the failure of the life support body, or (b) support or sustain life, and (c) whose failure device or system, or to affect its safety or effectiveness. to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the www.fairchildsemi.com user.
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.
This datasheet has been downloaded from: www..com Datasheets for electronic components.

▲Up To Search▲

Price & Availability of 74C925

	To Download 74C925 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .