UPD4991ACX Renesas Electronics America, UPD4991ACX Datasheet - Page 50

• Manufacturer Part Number: UPD4991ACX
• Manufacturer: Renesas Electronics America

Specifications of UPD4991ACX

• Lead Free Status / RoHS Status: Supplier Unconfirmed

4.2.1 Dependency on capacitance
2048 Hz output to TP1) where C
Figure 4-3 is only for reference, and that the characteristics vary depending on the crystal resonator used and the
stray capacitance of the board.
48
Figure 4-3 shows the dependency of oscillation frequency f of on load capacitance C
If C
G
(frequency counter)
and C
Measurement
D
are too high (50 pF or more), the oscillation characteristics are degraded at a low voltage. Note that
(+48.8 ppm)
(+39.1 ppm)
(+29.3 ppm)
(+19.5 ppm)
(–19.5 ppm)
(+9.8 ppm)
(–9.8 ppm)
2048.100
2048.080
2048.060
2048.040
2048.020
2048.000
2047.980
2047.960
(±0 ppm)
Figure 4-3. Oscillation Frequency f vs. Load Capacitance C
CHAPTER 4 ELECTRICAL SPECIFICATIONS AND INTERFACE
PD4991
Figure 4-2. Test Circuit for Dependency on Capacitance
D
= 20 pF, T
TP1
5.0 V
10
V
V
DD
SS
X
X
OUT
A
IN
= 25 C, and V
C
(2048 Hz is output to TP1.)
X
T
C
C
A
G
D
= 25° C
20
V
DD
DD
= 5 V in the test circuit shown in Figure 4-2.
X : 32.768 kHz (C
C
C
C = 10 F Tantalum electrolytic
G
D
Nihon Dempa Kogyo Co., Ltd. MX-38T
= 10 to 30 pF
= 20 pF 5% class ceramic
30
C
G
f
= 20 k )
(pF)
G
G
(which is measured with