Accurate Timing From Microseconds to Days Programmable Delays From 1 Time Constant to 255 Time Constants Outputs Compatible With TTL and CMOS Wide Supply-Voltage Range External Sync and Modulation Capability
The uA2240C consists of a time-base oscillator, an 8-bit counter, a control flip-flop, and a voltage regulator. The frequency of the time-base oscillator is set by the time constant of an external resistor and capacitor at R/C and can be synchronized or modulated by signals applied to the modulation input. The output of the time-base section is applied directly to the input of the counter section and also appears at (TIME BASE). TIME BASE may be used to monitor the frequency of the oscillator, to provide an output pulse to other circuitry, or (with the time-base section disabled) to drive the counter input from an external source. The counter input is activated on a negative-going transition. The reset input stops the time-base oscillator and sets each binary output, Q0Q7, and the time-base output to a TTL high level. After resetting, the trigger input starts the oscillator and all Q outputs go low. Once triggered, the uA2240C will ignore any signals at the trigger input until it is reset. The uA2240C timer/counter may be operated in the free-running mode or with output-signal feedback to the reset input for automatic reset. Two or more binary outputs may be connected together to generate complex pulse patterns, or each output may be used separately to provide eight output frequencies. Using two circuits in cascade can provide precise time delays up to three years. The uA2240C is characterized for operation from to 70°C.
AVAILABLE OPTIONS SYMBOLIZATION DEVICE uA2240C PACKAGE SUFFIX N OPERATING TEMPERATURE RANGE 70°C VT max 25°C 2V
VCC REGULATOR TIME BASE R/C MODULATION TRIGGER RESET GND
PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters.
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absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, VCC (see Note 18 V Output voltage: 18 V Output current: 10 mA Regulator output current. 5 mA Continuous total dissipation at (or below) 25°C free-air temperature. 650 mW Operating free-air temperature range. to 70°C Lead temperature mm (1/16 inch) from case for 10 seconds. 260°C
NOTE 1: Voltage values are with respect to the network ground terminal.
MIN Supply voltage, VCC (see Note 2) Timing resistor Timing capacitor Counter input frequency (Pin 14) Pull-up resistor, time-based output Trigger and reset input pulse voltage Trigger and reset input pulse duration External clock input pulse voltage External clock input pulse duration NOTE 2: For operation with VCC 4.5 V, short regulator output to VCC. NOM MAX 10 1000 UNIT M µF MHz V µs
PARAMETER Regulator output voltage Modulation input open circuit voltage Trigger threshold voltage High-level trigger current Reset threshold voltage High-level reset current Counter input (time base) threshold voltage Low-level output current, Q7 High-level output current, Q7 Supply current TEST CIRCUIT VCC 5 V, VCC 15 V, VCC 5 V, VCC 15 V, VCC 5 V, VCC 5 V, VCC 5 V, VCC 5 V, VCC 5 V, VCC 5 V, VOL 0.4 V VOH 15 V, VCC 5 V, VCC 4 V TEST CONDITIONS TRIGGER and RESET open or grounded TRIGGER and RESET open or grounded TRIGGER and RESET open or grounded TRIGGER and RESET open or grounded RESET 0 V TRIGGER 2 V, TRIGGER 0 V TRIGGER 0 V TRIGGER and RESET open or grounded TRIGGER 2 V, RESET 2 V, TRIGGER 0 V, TRIGGER 0 V, RESET 0 V, TRIGGER 0 V RESET 5 V RESET at RESET 0 V MIN 5.8 2.8 TYP mA MAX UNIT mA µA
operating characteristics at 25°C free-air temperature (unless otherwise noted)
PARAMETER Initial error of time base Temperature coefficient of timebase period Supply voltage sensitivity of timebase period Time-base output frequency Propagation delay time Output rise time 2 TEST CIRCUIT VCC 5 V, TEST CONDITIONS TRIGGER 5 V, RESET 0 V VCC 5 V VCC 15 V MIN TYP R = MIN, C = MIN From TRIGGER input From RESET input Q7 MAX ±5 UNIT % ppm/°C V kHz µs
ns Output fall time 180 For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions. This is the time-base period error due only to the uA2240C and expressed as a percentage of nominal (1.00 RC). NOTE 3: Propagation delay time is measured from the 50% point on the leading edge of an input pulse to the 50% point on the leading edge of the resulting change of state at Q0.