MM74C911

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 mW (typ.)


Pinout




Specifications

Voltage at Any Pin
except Inputs                                          -0.3V to VCC + 0.3V
Voltage at Any Input
except Digits                                                     -0.3V to +15V
Operating Temperature
Range, (T_A)                                                     -40°C to +85°C
Storage Temperature Range                         -65°C to +150°C
Power Dissipation (P_D)                Refer to P_D(MAX) vs TA Graph
Operating V_CC Range                                                  3V to 6V
Absolute Maximum V_CC                                                      6.5V
Lead Temperature
(Soldering, 10 seconds)                                                   260°C


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 MM74C911 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 of MM74C911 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 labeledSEGMENT OUTPUTENABLE, SOE, is LOW and go into 3-STATE when SOE is HIGH. This feature of MM74C911 allows for duty cycle brightness control, or for disabling the output drive for power conservation.

   The digit outputs of MM74C911 directly drive the base of the digit transistor when the control pin labeled DIGIT INPUT OUTPUT,DIO, is LOW. WhenDIO 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 of MM74C911 can be controlled by the simple cascading of expandable segment display controllers. All inputs of MM74C911 except digit inputs are TTL compatible and do not clamp input voltages above V_CC.