SLASF47 May 2022 DAC53202 , DAC63202
PRODUCTION DATA
When the DAC data registers are written, the voltage on DAC output (VOUT) immediately transitions to the new code following the slew rate and settling time specified in the Electrical Characteristics.
The slew rate control feature allows the user to control the rate at which the output voltage (VOUT) changes. When this feature is enabled (using the SLEW-RATE-X[3:0] bits), the DAC output changes from the current code to the code in the DAC-X-MARGIN-HIGH or DAC-X-MARGIN-LOW registers (when margin high or low commands are issued to the DAC) using the step size and time-period per step set in CODE-STEP-X and SLEW-RATE-X bits in the DAC-X-FUNC-CONFIG register:
Table 7-5 and Table 7-6 show different settings available for CODE-STEP-X and SLEW-RATE-X. With the default slew rate control setting of no-slew, the output changes immediately at a rate limited by the output drive circuitry and the attached load.
When the slew rate control feature is used, the output changes happen at the programmed slew rate. Figure 7-10 shows that this configuration results in a staircase formation at the output. Do not write to CODE-STEP-X, SLEW-RATE-X, or DAC-X-DATA during the output slew operation. Equation 5 provides the equation for the calculating the slew time (tSLEW).
where:
REGISTER | CODE-STEP-X[2] | CODE-STEP-X[1] | CODE-STEP-X[0] | CODE STEP SIZE |
---|---|---|---|---|
DAC-X-FUNC-CONFIG | 0 | 0 | 0 | 1 LSB (default) |
0 | 0 | 1 | 2 LSB | |
0 | 1 | 0 | 3 LSB | |
0 | 1 | 1 | 4 LSB | |
1 | 0 | 0 | 6 LSB | |
1 | 0 | 1 | 8 LSB | |
1 | 1 | 0 | 16 LSB | |
1 | 1 | 1 | 32 LSB |
REGISTER | SLEW-RATE-X[3] | SLEW-RATE-X[2] | SLEW-RATE-X[1] | SLEW-RATE-X[0] | TIME PERIOD (PER STEP) |
---|---|---|---|---|---|
DAC-X-FUNC-CONFIG | 0 | 0 | 0 | 0 | No slew (default) |
0 | 0 | 0 | 1 | 4 µs | |
0 | 0 | 1 | 0 | 8 µs | |
0 | 0 | 1 | 1 | 12 µs | |
0 | 1 | 0 | 0 | 18 µs | |
0 | 1 | 0 | 1 | 27 µs | |
0 | 1 | 1 | 0 | 40.5 µs | |
0 | 1 | 1 | 1 | 60.75 µs | |
1 | 0 | 0 | 0 | 91.13 µs | |
1 | 0 | 0 | 1 | 136.69 µs | |
1 | 0 | 1 | 0 | 239.2 µs | |
1 | 0 | 1 | 1 | 418.61 µs | |
1 | 1 | 0 | 0 | 732.56 µs | |
1 | 1 | 0 | 1 | 1281.98 µs | |
1 | 1 | 1 | 0 | 2563.96 µs | |
1 | 1 | 1 | 1 | 5127.92 µs |