Real Time Clock Topology Guidelines; Rtc External Example Circuit; Example External Circuitry For The Soc Rtc; Rtc Routing Guidelines - Intel Quark SoC X1000 Design Manual

RTC Design Guidelines—Intel
12.3

Real Time Clock Topology Guidelines

12.3.1

RTC External Example Circuit

M
Figure 42.

Example External Circuitry for the SoC RTC

VCC3P3_S5
R4
3.6K
Notes:
1. Reference designators are arbitrarily assigned.
2. VCC3P3_S5 is active whenever the system is plugged-in.
3. Vbatt is voltage provided by the battery and is optional.
4. VccRTC, RTCX1, and RTCX2 are Intel SoC pins.
5. VccRTC powers SoC RTC well.
6. RTCX1 is the input to the internal oscillator. RTCX1 can be driven by external clock generator to desired
frequency.
7. RTCX2 is the feedback for the external crystal. When single ended external clock generator is used, this
pin should be grounded.
8. R1 = 10M
9. The exact capacitor values for C1 and C2 must be based on the crystal maker recommendations. Typical
values for C1 and C2 are 18 pF, based on crystal load of 12.5 pF.
10. C3 = 0.22F/5.5V. Panasonic SD Series Super Cap,EEC-SDHD224V, ESR=75
11. Schottky Diodes (Black) are MBR0504T1G, Regular diodes are 1N4148, IN914 equivalents.
Table 46.

RTC Routing Guidelines

Parameter
Total Length
Resistor
Notes:
1. Spacing, S > 15 mils (0.381 mm).
June 2014
Order Number: 330258-002US
®
Quark™ SoC X1000
Schottky Diodes
R2
240
R3
1K
C3
0.22F/5.5V
32.768 KHz
Vbatt
3V Lithium Battery
(Optional Use)
R2 = 240 R3 = 1K R4 = 3.6K
  
Segment/Signal
Name
RTCX1
RTCX2
R1
1uF
Xtal
C1
1uF
R5 = 20K
 
Stackup
Units
(MS/SL/DSL)
MS
NA
VCCRTC
0.1uF
RTCRSTB
RTCX2
10M
R1
RTCX2
C2
.

Routing
Recommendation
mils 1,000
M
10
®
Intel Quark™ SoC X1000
PDG
87