6131 Feb65

The 6131 DC ADDER, introduced by DEC Maynard on 2/18/65 and priced at $134.00, is a high-speed module designed for binary addition. It features a majority-logic carry circuit with a fast 10 nanosecond propagation delay and provides complementary sum outputs. It is explicitly noted that this module should not be used with +10B marginal checking.

Key specifications include:

• Register Inputs: Two register inputs and an enable input, each equivalent to two parallel inverters, require 2mA drive at -3 volts and present a 120pF dynamic load.
• Carry Inputs: The carry input at pin L can draw up to 5mA; if not driven by a 6131 pin K output, it requires a clamped load and an external silicon clamp diode connected to the -2-1/4 volt reference output (pin J). The complemented carry input at pin T for the sum logic is typically driven by a lower-order 6131 module's pin U or an ordinary inverter, acting as a 13mA load.
• Sum Outputs: Each sum output can drive 5mA at ground and 10mA at -3 volts. The 3000 ohm resistor output at pin W can drive indicator amplifiers over long wires without sacrificing switching speed.
• Carry Outputs: For maximum speed, the carry output at pin K should only be connected to the pin L carry input of an adjacent 6131 module, offering a driving capability equivalent to a 15mA inverter with a 10mA clamped load. The complementary carry output at pin U also acts like a 15mA inverter with a 1-1/2mA clamped load but cannot drive emitters.
• Power Requirements: -15V/105mA, +10V(A)/0mA, and +10V(B)/70mA.