CY7C67300
Document #: 38-08015 Rev. *H
Page 11 of 98
Booster Interface
EZ-Host has an on chip power booster circuit for use with pow-
er supplies that range between 2.7V and 3.6V. The booster
circuit boosts the power to 3.3V nominal to supply power for
the entire chip. The booster circuit requires an external induc-
tor, diode, and capacitor. During power down mode, the circuit
is disabled to save power. Figure 6 shows how to connect the
booster circuit.
Component details:
• L1: Inductor with inductance of 10 µH and a current rating
of at least 250 mA
• D1: Schottky diode with a current rating of at least 250 mA
• C1: Tantalum or ceramic capacitor with a capacitance of at
least 2.2 µF
Figure 7 shows how to connect the power supply when the
booster circuit is not being used.
Booster Pins
Crystal Interface
The recommended crystal circuit to be used with EZ-Host is
shown in Figure 8 If an oscillator is used instead of a crystal
circuit, connect it to XTALIN and leave XTALOUT uncon-
nected. For further information about the crystal requirements,
see Table 52, Crystal Requirements on page 83.
Noted that the CLKSEL pin (pin 38) is sampled after reset to
determine what crystal or clock source frequency is used. For
normal operation, 12 MHz is required so the CLKSEL pin must
have a 47K ohm pull up resistor to VCC..
Crystal Pins
Figure 6. Power Supply Connection With Booster
Figure 7. Power Supply Connection Without Booster
BOOSTVcc
VSWITCH
VCC
AVCC
C1
D1
L1
3.3V
2.7V to 3.6V
Power Supply
BOOSTVcc
VSWITCH
VCC
AVCC
3.0V to 3.6V
Power Supply
Table 17. Charge Pump Interface Pins
Pin Name
Pin Number
BOOSTVcc
16
VSWITCH
14
Figure 8. Crystal Interface
Table 18. Crystal Pins
Pin Name
Pin Number
XTALIN
29
XTALOUT
28
Y1
C1 = 22 pF
C2 = 22 pF
CY7C67300
XTALIN
XTALOUT
12MHz
Parallel Resonant
Fundamental Mode
500uW
20-33pf ±5%
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