Datasheet

Signalswing
limitingcircuit
Biasgenerator
andstartup
circuit
XI XO
Signal
shaping
Square/sinewave:
Vpp=VRRTCor
VIO_1P8V
Y
Currentcontrol
circuitandmode
selection
DC
DClevel:
Vpp/2
VBATOK
(1)
Internal
GND
Internal
GND
VBATOK
(1)
032-068
TPS65950
SWCS032E–OCTOBER 2008–REVISED JANUARY 2011 www.ti.com
12.2.3.2 External Clock Description
Figure 12-7 and Figure 12-8 show the 32-kHz oscillator with a 32.768-kHz square or sine signal in master
and slave modes. Figure 12-9 shows an external clock source when the oscillator is configured in bypass
mode. Thus, there are three configurations:
• A square- or sine-wave input can be applied to the 32KXIN pin with an amplitude of 1.85 or 1.8 V. The
32KXOUT pin can be driven to a dc value of the square- or sine-wave amplitude divided by 2. This
configuration, shown in Figure 12-7, is recommended if a large load is applied on the 32KXOUT pin.
• A square- or sine-wave input can be applied to the 32KXIN pin with an amplitude of 1.85 or 1.8 V. The
32KXOUT pin can be left floating. This configuration, showed in Figure 12-8, is used if no charge is
applied on the 32KXOUT pin.
• The oscillator is in bypass mode and a square-wave input can be applied to the 32KXIN pin with an
amplitude of 1.8 V. The 32KXOUT pin can be left floating. This configuration, shown in Figure 12-9, is
used if the oscillator is in bypass mode.
(1) Switches close by default and open only if register access enables very-low-power mode when VBAT < 2.7 V.
Figure 12-7. 32-kHz Oscillator Block Diagram Without Crystal Option 1
138 Clock Specifications Copyright © 2008–2011, Texas Instruments Incorporated
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