ZHCSMK6D September 2021 – November 2024 TPSM82864A , TPSM82866A
PRODMIX
- 1
- 1 特性
- 2 應用
- 3 說明
- 4 Device Options
- 5 Pin Configuration and Functions
- 6 Specifications
- 7 Detailed Description
- 8 Application and Implementation
- 9 Device and Documentation Support
- 10Revision History
- 11Mechanical, Packaging, and Orderable Information
7.4.4 Output Voltage and Mode Selection (VSET/MODE)
The TPSM8286xA family devices are configurable as either an adjustable output voltage or a fixed output voltage, depending on the needs of each individual application. This feature simplifies the logistics during mass production, as one part number offers several fixed output voltage options as well as an adjustable output voltage option. During the enable delay (tDelay), the device configuration is set by an external resistor connected to the VSET/MODE pin through an internal R2D (resistor to digital) converter. This configures the VREF input to the error amplifier (EA) to be either the VFB voltage (0.6-V typical) or the selected output voltage. Table 7-2 shows the options.
| RESISTOR AT VSET/MODE PIN (E96 SERIES, ±1% ACCURACY, 200 ppm/°C OR BETTER) | FIXED OR ADJUSTABLE OUTPUT VOLTAGE |
|---|---|
| 249 k or logic high | Adjustable (through a resistive divider on the FB pin) |
| 205 k | 3.30 V |
| 162 k | 2.50 V |
| 133 k | 1.80 V |
| 105 k | 1.50 V |
| 68.1 k | 1.35 V |
| 56.2 k | 1.20 V |
| 44.2 k | 1.10 V |
| 36.5 k | 1.05 V |
| 28.7 k | 1.00 V |
| 23.7 k | 0.95 V |
| 18.7 k | 0.90 V |
| 15.4 k | 0.85 V |
| 12.1 k | 0.80 V |
| 10 k or logic low | Adjustable (through a resistive divider on the FB pin) |
The R2D converter has an internal current source, which applies current through the external resistor, and an internal ADC, which reads back the resulting voltage level. Depending on the detected resistance, the output voltage is set. After this R2D conversion is finished, the current source is turned off to avoid current flowing through the external resistor. Make sure that the additional leakage current path is less than 20 nA and the capacitance is not greater than 30 pF from this pin to GND during R2D conversion, otherwise a false VOUT value is set. For more details, refer to the Benefits of a Resistor-to-Digital Converter in Ultra-Low Power Supplies White Paper. When the device is set to a fixed output voltage, the FB pin must be connected to the output directly. See Figure 7-4.
Figure 7-4 Fixed Output Voltage Application CircuitAfter the start-up period (tStart-up), a different operation mode can be selected. When VSET/MODE is set to high, the device is in forced PWM mode. Otherwise, the VSET/MODE resistor pulls the pin low and the device operates in power save mode.