LH79520_N NXP Semiconductors, LH79520_N Datasheet - Page 51

• Manufacturer Part Number: LH79520_N
• Description: The LH79520, powered by an ARM720T, is a completeSystem-on-Chip with a high level of integration tosatisfy a wide range of requirements and expectations
• Manufacturer: NXP Semiconductors

System-on-Chip
SUGGESTED EXTERNAL COMPONENTS
nents for the 32.768 kHz crystal circuit to be used with
the NXP LH79520. The NAND gate represents the
logic inside the SoC. See the chart for crystal specifics.
Preliminary data sheet
Figure 33 shows the suggested external compo-
Figure 33. Suggested External Components, 32.768 kHz Oscillator (XTAL32IN and XTAL32OUT)
NOTES:
1. Y1 is a parallel-resonant type crystal. (See table)
2. The nominal values for C1 and C2 shown are for
3. The values for C1 and C2 are dependent upon
4. R1 must be in the circuit.
5. Ground connections should be short and return
6. Tolerance for R1, C1, C2 is ≤ 5%.
a crystal specified at 12.5 pF load capacitance (CL).
the cystal's specified load capacitance and PCB
stray capacitance.
to the ground plane which is connected to the
processor's core ground pins.
INTERNAL TO
THE LH79520
EXTERNAL TO
THE LH79520
Rev. 01 — 16 July 2007
NXP Semiconductors
ENABLE
XTAL32IN
RECOMMENDED CRYSTAL SPECIFICATIONS
PARAMETER
32.768 kHz Crystal
Tolerance
Aging
Load Capacitance
ESR (MAX.)
Drive Level
Recommended Part
for the 14.7456 MHz crystal circuit to be used with the
NXP LH79520. The NAND gate represents the logic
inside the SoC. See the chart for crystal specifics.
Figure 34 shows the suggested external components
C1
15 pF
GND
32.768 kHz
10 MΩ
Y1
R1
DESCRIPTION
Parallel Mode
±30 ppm
±3 ppm
12.5 pF
50 kΩ
1.0 µW (MAX.)
MTRON SX1555 or equivalent
XTAL32OUT
C2
18 pF
GND
79520-172
LH79520
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