t

SS

t

Startup_delay

EN

Device starts switching

and ramps V

OUT

V

OUT

11

TPS62801

www.ti.com

SLVSDD1A – DECEMBER 2017 – REVISED MARCH 2018

Product Folder Links: TPS62801

Submit Documentation Feedback

Copyright © 2017–2018, Texas Instruments Incorporated

Feature Description (continued)

8.3.2 Softstart

Once the device has been enabled with EN high, it initializes and powers up its internal circuits. This occurs

Figure 8. Device Startup

8.3.3 VSEL/MODE Pin

This pin has multiple functions, depending on the device option. See table. In device options with only one fixed

output voltage, the R2D function is disabled and the pin just operates as a digital input for Mode selection.

8.3.3.1 Output Voltage Selection (R2D Converter)

The output voltage is set with a single external resistor connected between the VSEL/MODE pin and GND. Once

the device has been enabled and the control logic as well the internal reference has been powered up, a R2D

current through the external resistor and an internal ADC reads back the resulting voltage level. Depending on

the level, an internal feedback divider network is selected to set the correct output voltage. Once this R2D

current flow through the external resistor.

After power up, the pin is configured as an input for Mode Selection. Therefore, the output voltage is set only

once. If the Mode selection function is used in combination with the VSEL function, ensure that there is no

additional current path or capacitance greater than 30pF total to GND, during R2D conversion. Otherwise the

additional current to GND is interpreted as a lower resistor value and a false output voltage will be set. Table 1

operate with resistor values out of the E96 table and requires 1% resistor value accuracy. Ensure that there is no

Otherwise a false voltage will be set.

Connecting VSEL/MODE to GND selects a pre-defined output voltage (TPS62801 = 1.2V, TPS62802 = 1.8V). In

this case, no external resistor is needed and enables a smaller solution size.

8.3.3.2 Mode Selection: Power Save Mode / Forced PWM Operation

A low level at this pin selects Power Save Mode operation, and a high level selects forced PWM operation. The

Mode can be changed during operation after the device has been powered up. In device options with output

voltage selection (VSEL) function (TPS62801, TPS62802), the Mode selection function is only available after the

R2D converter has read out the external resistor.