Revised January 1999 MM74C911 4-Digit Expandable Segment Display Controller General Description The MM74C911 display controller is an interface element with memory that drives a 4-digit, 8-segment LED display. The MM74C911 allows individual control of any segment in the 4-digit display. The number of segments per digit can be expanded without any external components. For example, two MM74C911’s can be cascaded to drive a 16-segment alpha-numeric display. The display controllers receive data information through 8 data lines a, b…DP, and digit information through 2 address inputs K1 and K2. The input data is written into the register selected by the address information when CHIP ENABLE, CE, and WRITE ENABLE, WE, are LOW and is latched when either CE or WE return HIGH. Data hold time is not required. A self-contained internal oscillator sequentially presents the stored data to high drive (100 mA typ.) 3-STATE output drivers which directly drive the LED display. The drivers are active when the control pin labeled SEGMENT OUTPUT ENABLE, SOE, is LOW and go into 3-STATE when SOE is HIGH. This feature allows for duty cycle brightness control, or for disabling the output drive for power conservation. The digit outputs directly drive the base of the digit transistor when the control pin labeled DIGIT INPUT OUTPUT, DIO, is LOW. When DIO is HIGH, the digit lines turn into inputs and the internal scanning multiplexer is disabled. When any digit line is forced HIGH by an external device, usually another MM74C911, the data information for that digit is presented to the output. In this manner, 16-segment alpha-numeric displays, 24- or 32-segment displays, or an array of discrete LED's can be controlled by the simple cascading of expandable segment display controllers. All inputs except digit inputs are TTL compatible and do not clamp input voltages above VCC. Features ■ Direct segment drive (100 mA typ.) 3-STATE ■ 4 registers addressed like RAM ■ Internal oscillator and scanning circuit ■ Direct base drive to digit transistor ■ Segment expandability without external components ■ TTL compatible inputs ■ Power saver mode—5 µW (typ.) Ordering Code: Order Number MM74C991N Package Number N28B Package Description 28-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS−010, 0.600” Wide Connection Diagram Pin Assignments for DIP Top View © 1999 Fairchild Semiconductor Corporation DS005915.prf www.fairchildsemi.com MM74C911 4-Digit Expandable Segment Display Controller October 1987 MM74C911 Truth Tables Input Control Output Control Digit CE Address WE DIO SOE 0 0 Operation Digit Lines Operation D4 D3 D2 D1 K2 K1 R R R R Refresh Display 0 0 0 0 Write Digit 1 0 1 R R R R Disable Segment Outputs 0 0 0 1 Latch Digit 1 1 0 0 0 0 0 Digits Are Now Inputs 0 0 1 0 Write Digit 2 1 0 0 0 0 1 Display Digit 1 0 0 1 1 Latch Digit 2 1 0 0 0 1 0 Display Digit 2 0 1 0 0 Write Digit 3 1 0 0 1 0 0 Display Digit 3 0 1 0 1 Latch Digit 3 1 0 1 0 0 0 Display Digit 4 0 1 1 0 Write Digit 4 1 1 0 0 0 0 Power Saver Mode 0 1 1 1 Latch Digit 4 1 X X X Disable Writing R = Refresh (digit lines sequentially pulsed) X = Don’t Care Functional Description ten into. In normal operation, the internal multiplexer scans the registers and refreshes the display. In cascaded operation, 1 MM74C911 serves as a master refresh device and cascaded MM74C911’s are slaved to it through digit lines operating as inputs. The MM74C911 display controller is manufactured on standard metal gate CMOS technology. A single 5V 74 series TTL supply can be used for power and should be bypassed at the VCC pin to suppress current transients. The digit outputs directly drive the base of a grounded emitter digit transistor without the need of a Darlington configuration. If an MM74C911 is driving a digit transistor and also supplying digit information to a cascaded MM74C911, base resistors are needed in the digit transistors to provide an adequate high level to the digit inputs of the cascaded MM74C911. The MM74C911 appears to a microprocessor as memory and to the user as a self-scan display. Since every segment is under microprocessor control, great versatility is obtained. Low power standby operation occurs with both SOE and DIO inputs HIGH. This condition forces the MM74C911 to a quiescent state typically drawing less than 1 µA of supply current with a standby supply voltage as low as 3V. As seen in the Block Diagram, these display controllers contain four 8-bit registers; any one may be randomly writ- Logic Diagram www.fairchildsemi.com 2 Operating VCC Range Absolute Maximum VCC 3V to 6V 6.5V Lead Temperature Voltage at Any Pin (Soldering, 10 seconds) −0.3V to VCC + 0.3V except Inputs Voltage at Any Input Note 1: “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. Except for “Operating Range”, they are not meant to imply that the device should be operated at these limits. The table of “Electrical Characteristics” provides conditions for actual device operation. −0.3V to +15V except Digits Operating Temperature −40°C to +85°C Range, (TA) −65°C to +150°C Storage Temperature Range Power Dissipation (PD) 260°C Note 2: All voltage reference to ground. Refer to PD(MAX) vs TA Graph DC Electrical Characteristics Min/Max limits apply at −40°C ≤ TJ ≤ +85°C, unless otherwise noted Symbol Parameter Conditions VCC = 5V VIN(1) Logical “1” Input Voltage VIN(0) Logical “0” Input Voltage IIN(1) Logical “1” Input Current VCC = 5V, VIN = 15V IIN(0) Logical “0” Input Current VCC = 5V, VIN = 0V ICC Supply Current (Normal) VCC = 5V, Outputs Open ICC Supply Current (Power Saver) Min Typ Max 3.0 V 1.5 V 1.0 µA 0.50 2.5 mA 1 600 µA 0.03 10 µA 0.8 V 0.005 −1.0 VCC = 5V, SOE, DIO = “1”, Units −0.005 µA D1, D2, D3, D4 = “0” IOUT 3-STATE Output Current VO = 5V VO = 0V −10 −0.03 CMOS/LPTTL INTERFACE VIN(1) Logical “1” Input Voltage VCC = 4.75V VIN(0) Logical “0” Input Voltage VCC = 4.75V VCC − 2 V OUTPUT DRIVE ISH IDH HIGH Level Segment Current HIGH Level Digit Current VCC = 5V, VO = 3.4V TJ = 25°C −60 −100 mA TJ = 100°C −40 −60 mA TJ = 25°C −10 −20 mA TJ = 100°C −7 −10 mA TJ = 25°C −15 −40 mA TJ = 100°C −10 −15 mA VCC = 5V, IO = −360 µA 4.6 VCC = 5V, VO = 3V VCC = 5V, VO = 1V VOUT(1) Logical “1” Output Voltage, V Any Digit VOUT(0) Logical “0” Output Voltage, VCC = 5V, IO = 360 µA 0.4 V Any Output θJA Thermal Resistance (Note 3) 100 °C/W Note 3: θJA measured in free-air with device soldered into printed circuit board. 3 www.fairchildsemi.com MM74C911 Absolute Maximum Ratings(Note 1) (Note 2) MM74C911 AC Electrical Characteristics (Note 4) VCC = 5V, tr = tf = 20 ns, CL = 50 pF Symbol tCW tAW tWW tDW tWD tWA tWC t1H, t0H tH1, tH0 tD1, tD0 tIB Parameter Chip Enable to Write Enable Set-Up Time Address to Write Enable Set-Up Time Write Enable Width Data to Write Enable Set-Up Time Write Enable to Data Hold Time Write Enable to Address Hold Time Write Enable to Chip Enable Hold Time Min Typ TJ = 25°C Conditions 35 15 Max Units ns TJ = 125°C 50 20 ns TJ = 25°C 35 15 ns TJ = 125°C 50 20 ns TJ = 25°C 400 225 ns TJ = 125°C 450 250 ns TJ = 25°C 390 225 ns TJ = 125°C 430 250 ns TJ = 25°C 0 −10 ns TJ = 125°C 0 −15 ns TJ = 25°C 0 −10 ns TJ = 125°C 0 −15 ns TJ = 25°C 55 30 ns TJ = 125°C 75 40 ns Logical “1”, Logical “0” Levels into 3-STATE RL=10k, CL=10 pF TJ = 25°C 275 500 ns TJ = 125°C 325 600 ns 3-STATE to Logical “1” or RL=10k, CL=10 pF Logical “0” Levels TJ = 25°C 325 600 ns TJ = 125°C 375 700 ns Propagation Delay from Digit Input to TJ = 25°C 500 1000 ns Segment Output TJ = 125°C 700 1400 ns Interdigit Blanking Time TJ = 25°C 5 10 TJ = 125°C 10 20 µs TJ = 25°C 525 Hz TJ = 125°C 375 µs fMUX Multiplex Scan Frequency CIN Input Capacitance (Note 5) 5 7.5 pF COUT 3-STATE Output Capacitance (Note 5) 30 50 pF Note 4: AC Parameters are guaranteed by DC correlated testing. Note 5: Capacitance guaranteed by periodic testing. Switching Time Waveforms Write Data Waveforms www.fairchildsemi.com 3-STATE Waveforms 4 Hz (Continued) Multiplexing Output Waveforms Read Data Waveforms Note A: All other digit lines are at a low level. DIO at a HIGH level. Typical Performance Characteristics VCE is the saturation voltage of the digit drive transistor. Segment outputs if shorted to ground will exceed maximum power dissipation of the device. Power Dissipation vs Temperature for Plastic Packages Applications Segment Output Structure Digit Output Structure 5 www.fairchildsemi.com MM74C911 Switching Time Waveforms MM74C911 Input Protection Segment Expansion Typical Application *Base resistors may be necessary to limit base current. www.fairchildsemi.com 6 MM74C911 4-Digit, 16-Segment Alpha-Numeric Display Segment Identification 7 www.fairchildsemi.com MM74C911 4-Digit Expandable Segment Display Controller Physical Dimensions inches (millimeters) unless otherwise noted 28-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-010, 0.600” Wide Package Number N28B 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.