184.108.40.206 16-MHz Crystal
The TPS659038-Q1 and TPS659039-Q1 have the ability to accept a 16-MHz crystal input. Providing the 16-MHz crystal input to the device allows the output of a stable and accurate 32-kHz clock to be used by the applications processor. The crystal input is divided down by 500 internally to produce the 32-kHz output clock. The crystal should be connected to the device as shown in Figure 7-6.
Figure 7-6 Crystal Input Configuration
As shown in Figure 7-6, the OSC16MCAP pin requires a 2.2-µF 6.3-V filtering capacitor near the ball. Also, the crystal requires between 9 pF and 11 pF of load capacitance on both terminals. To meet this requirement, using two 10-pF capacitors is recommended. See Table 7-2 for the specific load capacitors that are recommended.
The 16-MHz crystal is not required for operation of the TPS659038-Q1 and TPS659039-Q1 devices. The OSC16M_CFG OTP bit can be set to disable the 16-MHz crystal completely, and enable the following 2 alternative options for system clock generation:
- A 32-kHz square wave can be supplied to the OSC16MIN pin. This option is typically used in applications where the processor requires an accurate system clock and there is one already available in the system. In that case, the available 32-kHz clock can be provided to the PMIC and added to the boot sequence as an output. In this configuration, the OSC16MOUT and OSC16MCAP pins can be left floating, and the internal 16-MHz oscillator is bypassed. Bypassing the 16-MHz oscillator results in a lower quiescent current.
- If the application does not require an accurate system clock for the processor, then providing one to the PMIC is not required. This option produces a lower quiescent current as seen in Section 5. In this configuration, the OSC16MIN pin should be grounded, while the OSC16MOUT and OSCMCAP pins can be left floating. Lastly, the GATE_RESET_OUT OTP bit should be used to allow the device to power up without the presence of the 16.384-MHz crystal nor the 32-kHz clock input.
If the OSC16M_CFG OTP bit is set to 0, a 16-MHz crystal must be present for the proper operation of the device.