L9963T datasheet(10/45 Pages) STMICROELECTRONICS

10 / 45 page

3.2.1.2

NSLAVE

NSLAVE pin is latched by the standby logic in the Trimming & Config Latch state, 3TOSC_STBY after POR_MAIN

release. It must be either shorted to VDD or to GND. The internal pull-down is enabled only while in Trimming &

Config Latch state. This allows reducing power consumption. Once Trimming & Config Latch state is left, the

NSLAVE input buffer is permanently disabled, since it is no longer needed.

NSLAVE selects SPI Master (NSLAVE = 1) or Slave (NSLAVE = 0) operation and determines the Digital I/Os

configuration as described in Table 7.

To increase immunity to BCI and guarantee a correct latch of the NSLAVE pin during each power-up, the input is

filtered with an integrated RC filter having fCUT_DIG_IN cut frequency.

Figure 4. NSLAVE pin structure

3.2.1.3

DIS

DIS is a Digital Input-Output pin featuring an internal pull-up resistor towards V3V3_STBY. Its purpose is to be

driven by open-drain outputs. Its functionality is summarized as follows:

•

Input: it is an active high Disable input driven by the MCU:

–

When DIS is released by the MCU longer than TRC_DELAY +TDIS_DEGLITCH the device starts the Go To

Sleep sequence that will bring L9963T to Stand-by state (refer to L9963T FSM).

–

When DIS is pulled down by the MCU longer than TRC_DELAY + (1/ fSTBY_OSC) the device moves from

Stand-by state to Regulators enabling state and then to Normal state.

•

Output: when L9963T is in Stand-by state, and a wakeup event by isolated SPI occurs, it moves to

Regulators enabling state and then to Normal state. Once the latter is reached, DIS is internally pulled-

down by logic for TDIS_PULLDOWN in order to trigger an interrupt in the MCU or a wake up event on a PMIC.

After TDIS_PULLDOWN expires, DIS is released, and if not kept low by an external source, L9963T moves

back to Stand-by state.

To protect DIS internal open drain driver in case of external short to VDD, a current limitation circuitry limits the

current to IDIS_LIM.

L9963T

Pin configuration

DS13590 - Rev 4

page 10/45

L9963T Datasheet(PDF) 10 Page - STMicroelectronics