5075 series
FUNCTIONAL DESCRIPTION
Oscillation Start-up Detector Function
The devices also feature an oscillation start-up detector circuit. This circuit functions to disable the outputs
until the oscillation starts. This prevents unstable oscillator output at oscillator start-up when power is applied.
TYPICAL PERFORMANCE (5075B1)
The following characteristics measured using the crystal below. Note that the characteristics will vary with the
crystal used.
ꢀ Crystal used for measurement
ꢀ Crystal parameters
Parameter
C0 [pF]
f
= 27MHz
1.5
O
L1
C1
C0
R1
γ (= C0/C1)
300
Frequency Pulling Range
250
200
150
250
200
150
100
50
100
50
0
0
−50
−50
−100
−150
−200
−100
−150
−200
−250
−250
0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50
0.00 0.30 0.60 0.90 1.20 1.501.651.80 2.10 2.40 2.70 3.00 3.30
VC [V]
VC [V]
V
= 2.5V, f
= 27MHz, Ta = R.T.
V
= 3.3V, f
= 27MHz, Ta = R.T.
OUT
DD
OUT
DD
Measurement circuit
Pulling Sensitivity
250
VDD
200
XT
Crystal
VDD = 2.5V
150
XTN
Q
VC
100
50
0
CLOUT = 15pF
(Including probe
capacitance)
0.1µF
VSS
VDD = 3.3V
0.0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.3
VC [V]
V
= 2.5V, 3.3V, f
= 27MHz, Ta = R.T.
DD
OUT
SEIKO NPC CORPORATION —9
NPC [ NIPPON PRECISION CIRCUITS INC ]
