3. The nReset pin must be held low for at least 10μs after the stabilization of the external power supplies.

6.14.2 Clocking Specifications

The CC330x device uses two clocks for operation:

• A fast clock running at 40MHz for WLAN/BLE functions

• A slow clock running at 32.768kHz for low power modes

The fast clock is integrated inside the CC330xMOD and does not need to be supplied externally. The slow clock

can be generated internally from the CC330x device or can be supplied externally to the CC330xMOD.

6.14.2.1 Slow Clock Generated Internally

To minimize external components, the slow clock can be generated by an internal oscillator. However, this

clock is less accurate and consumes more power than sourcing the slow clock externally. For this scenario the

SLOW_CLK_IN pin must be left not connected.

6.14.2.2 Slow Clock Using an External Oscillator

For excellent power consumption, the slow clock can be generated externally by an oscillator or sourced from

elsewhere in the system. The external source must meet the requirements shown below. This clock can be fed

into the CC330xMOD pin SLOW_CLK_IN and must be stable before nReset is deasserted and the device is

enabled.

Table 6-1. External Slow Clock Requirements

Parameter

Description

MIN

TYP

MAX

Unit

Input slow clock frequency

Square wave

32768

Hz

Frequency accuracy

Inital + temperature + aging

±250

ppm

Input Duty cycle

30%

50%

70%

Tr/Tf

Rise and fall time

10% to 90% (rise) and 90% to 10%

(fall) of digital signal level

100

ns

VIL

Input low level

0

0.35 × VIO

V

VIH

Input high level

0.65 × VIO

1.95

V

Input impedence

1

MΩ

Input capacitance

5

pF

CC3300MOD, CC3301MOD

SWRS333A – JULY 2025 – REVISED AUGUST 2025

www.ti.com

14

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