ROHM BU2373FV

Video Accessory ICs
High Performance VCOs
for Image Sampling
BU2373FV,BU2374FV
No.11069EBT07
●Description
General-purpose VCO Series ICs (BU2373FV and BU2374FV) have a built-in VCO and phase comparator and facilitate the
configuration of a PLL system through the external connection of a LPF and frequency divider.
Furthermore, in order to facilitate the loop constant settings of the PLL system, the application manual has been enhanced to
ensure studies on the application.
●Features
1) The VCO enables midpoint settings within the range of oscillation through the external resistance.
2) The rising edge trigger type of phase comparator is built in.
3) Power-down mode setting can be made independently with the VCO and the phase comparator.
4) The VCO output frequency division can be selected on the SELECT pin.
5) Compact SSOP-B14 Package is adopted.
●Applications
CRT, LCD monitor, and CD-RW
●Line up matrix
BU2373FV
BU2374FV
VDD=3.0V
○
－
Supply voltage VDD=3.3V
○
○
VDD=5.0V
○
－
VDD=3.0V
37～60MHz
－
VDD=3.3V
37～65MHz
37～60MHz
VDD=5.0V
43～100MHz
－
1/2
1/4
Operating temperature range
-20～75℃
-20～75℃
Package
SSOP-B14
SSOP-B14
Frequency
range
VCO-Frequency dividing mode
●Absolute maximum ratings (Ta=25℃)
Symbol
Ratings
Unit
Supply voltage
VDD
-0.5～7.0
V
Input voltage
VIN
-0.5～VDD+0.5
V
Storage temperature range
Tstg
-30～125
℃
Pd
400
mW
Power dissipation
*1
*2
*3
*4
Operating is not guaranteed.
In the case of exceeding Ta = 25℃, 4.0mW should be reduced per 1℃.
The radiation-resistance design is not carried out.
Power dissipation is measured when the IC is mounted to the printed circuit board.
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1/18
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
●Electrical characteristics
◎BU2373FV(Ta=25℃, VDD=3.0V, unless otherwise specified.)
Limits
Parameter
Symbol
Min.
Typ.
Max.
Unit
Conditions
(VCO)
VCO_IN input impedance
Zi
-
10
-
MΩ
Idd(VCO)
-
15
-
mA
With 60 MHz output
Idd_st(VCO)
-
-
1
µA
VCO_INHIBIT=”H”,
VCOIN=”L”
VI
0.5
-
VDD-0.5
V
Oscillation range
frange
37
-
60
MHz
Bias resistor range
Rbias
1.5
-
2.0
KΩ
*1
Frequency sensitivity
β1
-
23
-
MHz/V
*2
Output duty
Duty
45
50
55
%
Idd(PFD)
-
0.5
-
mA
Idd_st(PFD)
-
-
1
µA
Consumption current
(while in normal mode)
Consumption current
(while in standby mode)
Control voltage
Measured
at a voltage of 1/2 of VDD
(PFD)
Consumption current
(while in normal mode)
Consumption current
(while in standby mode)
When 1 MHz is input to
the FIN_A and B
PFD_INHIBIT=”H”,
FIN_A,B=”L”
*1 Design guaranteed figures
37 MHz to 45 MHz when Rbias = 2.0 kΩ
50 MHz to 60 MHz when Rbias = 1.5 kΩ
*2 Frequency sensitivity
{ f1 (VCOIN=2.0V)  f2 (VCOIN = 1.0V) } / 1.0V
*3 If the SELECT pin is set to “H” and the output frequency is reduced to 1/2, the frequency range and the frequency sensitivity will be all reduced to 1/2.
BU2373FV(Ta=25℃, VDD=5.0V, unless otherwise specified.)
Parameter
Symbol
Limits
Unit
Conditions
Min.
Typ.
Max.
Zi
-
10
-
MΩ
Idd(VCO)
-
25
-
mA
With 60 MHz output
Idd_st(VCO)
-
-
1
µA
VCO_INHIBIT=”H”,
VCOIN=”L”
VI
0.5
-
VDD-0.5
V
Oscillation range
frange
43
-
100
MHz
Bias resistor range
Rbias
1.6
-
2.5
KΩ
*1
Frequency sensitivity
β1
-
25
-
MHz/V
*2
Output duty
Duty
45
50
55
%
Idd(PFD)
-
1
-
mA
Idd_st(PFD)
-
-
1
µA
(VCO)
VCO_IN input impedance
Consumption current
(while in normal mode)
Consumption current
(while in standby mode)
Control voltage
Measured
at a voltage of 1/2 of VDD
(PFD)
Consumption current
(while in normal mode)
Consumption current
(while in standby mode)
When 1 MHz is input to
the FIN_A and B
PFD_INHIBIT=”H”,
FIN_A&B=”L”
*1 Design guaranteed figures
43 MHz to 77 MHz when Rbias = 2.5 kΩ
75 MHz to 100 MHz when Rbias = 1.6 kΩ
*2 Frequency sensitivity
{ f1 (VCOIN = 3.5V)  f2 (VCOIN=1.5 V) } / 2.0V
*3 If the SELECT pin is set to “H” and the output frequency is reduced to 1/2, the frequency range and the frequency sensitivity will be all reduced to 1/2.
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2/18
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
◎BU2374FV(Ta=25℃, VDD=3.3V, unless otherwise specified.)
Limits
Parameter
Symbol
Min.
Typ.
Max.
Unit
Conditions
(VCO)
VCO_IN input impedance
Zi
-
10
-
MΩ
Idd(VCO)
-
12.5
-
mA
With 50 MHz output
Idd_st(VCO)
-
-
1
µA
VCO_INHIBIT=”H”,
VCOIN=”L”
VI
0.5
-
VDD-0.5
V
Oscillation range
frange
37
-
60
MHz
Bias resistor range
Rbias
2.0
-
3.0
KΩ
*1
Frequency sensitivity
β1
-
23
-
MHz/V
*2
Output duty
Duty
45
50
55
%
Idd(PFD)
-
0.5
-
mA
Idd_st(PFD)
-
-
1
µA
Consumption current
(while in normal mode)
Consumption current
(while in standby mode)
Control voltage
Measured at a voltage
of 1/2 of VDD
(PFD)
Consumption current
(while in normal mode)
Consumption current
(while in standby mode)
When 1 MHz is input to
the FIN_A and B
PFD_INHIBIT=”H”,
FIN_A, B=”L”
*1 Design guaranteed figures
37 MHz to 54 MHz when Rbias =2 .0 kΩ
53 MHz to 60 MHz when Rbias = 3.0 kΩ
*2 Frequency sensitivity
{ f1 (VCOIN = 2.0V)  f2 (VCOIN = 1.0 V) } / 1.0V
*3 If the SELECT pin is set to “H” and the output frequency is reduced to 1/4, the frequency range and the frequency sensitivity will be all reduced to 1/4.
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3/18
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
55
54
54
53
53
52
52
51
50
49
51
50
49
48
48
From top:VDD=3.15V
VDD=3.00V
VDD=2.85V
47
46
0
25
50
75
Temperature：T[℃]
46
0
25
50
Temperature：T[℃]
75
60
40
0.0
100
80
80
80
40
From top: VDD=3.45V
VDD=3.30V
VDD=3.15V
20
Output Frequency：f[MHz]
100
60
40
From top:VDD=3.45V
VDD=3.30V
VDD=3.15V
20
0.5
1.0 1.5 2.0 2.5
Control Voltage：VI[V]
3.0
3.5
Fig.4 Control Voltage – Output Frequency
(VDD=3.3V,Rbias=1.6KΩ,Ta=25℃)
40
0.0
0.5
1.0 1.5 2.0 2.5
Control Voltage：VI[V]
3.0
0.0
3.5
Fig.5 Control Voltage – Output Frequency
(VDD=3.3V,Rbias=2.0 KΩ,Ta=25℃)
125
From top:VDD=5.25V
VDD=5.00V
VDD=4.75V
25
75
50
From top:VDD=5.25V
VDD=5.00V
VDD=4.75V
25
0
0
0.0
1.0
2.0
3.0
4.0
Control Voltage：VI[V]
5.0
Fig.7 Control Voltage – Output Frequency
(VDD=5.0V,Rbias=1.6KΩ,Ta=25℃)
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Output Frequency：f[MHz]
125
Output Frequency：f[MHz]
125
100
0.5
1.0 1.5 2.0 2.5
Control Voltage：VI[V]
3.0
3.5
Fig.6 Control Voltage – Output Frequency
(VDD=3.3V,Rbias=2.2 KΩ,Ta=25℃)
150
50
3.5
From top:VDD=3.45V
VDD=3.30V
VDD=3.15V
20
150
75
3.0
60
150
100
1.0 1.5 2.0 2.5
Control Voltage：VI[V]
0
0
0.0
0.5
Fig.3 Control Voltage – Output Frequency
(VDD=3.0V,Rbias=2.0KΩ,Ta=25℃)
100
60
From top: VDD=3.15V
VDD=3.00V
VDD=2.85V
20
100
Fig.2 Control Voltage – Output Frequency
(VDD=3.0V,Rbias=1.8KΩ,Ta=25℃)
0
Output Frequency：f[MHz]
80
0
-25
Output Frequency：f[MHz]
Output Frequency：f[MHz]
45
100
Fig.1 Control Vole  Output Frequency
(VDD=3.0V,Rbias=1.5KΩ,Ta=25℃)
From top:VDD=3.15V
VDD=3.00V
VDD=2.85V
47
45
-25
100
Output Frequency：f[MHz]
55
Duty：Duty[%]
Duty：Duty[%]
●Reference data
(BU2373FV－Power Voltage Fluctuation Data)
100
75
50
From top:VDD=5.25V
VDD=5.00V
VDD=4.75V
25
0
0.0
1.0
2.0
3.0
4.0
Control Voltage：VI[V]
5.0
Fig.8 Control Voltage – Output Frequency
(VDD=5.0V,Rbias=2.4KΩ,Ta=25℃)
4/18
0.0
1.0
2.0
3.0
4.0
5.0
Control Voltage：VI[V]
Fig.9 Control Voltage – Output Frequency
(VDD=5.0V,Rbias=2.7KΩ,Ta=25℃)
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
●Reference data
(BU2373FV－Temperature Fluctuation Data)
80
80
80
60
40
From top:T=25℃
T=-20℃
T=75℃
20
0
60
40
From top:T=75℃
T=25℃
T=-20℃
20
0.5
1.0
1.5
2.0
Control Voltage：VI[V]
2.5
3.0
Fig.10 Control Voltage – Output Frequency
(VDD=3.0V,Rbias=1.5KΩ)
60
40
From top:T=75℃
T=25℃
T=-20℃
20
0
0
0.0
0.0
0.5
1.0
1.5
2.0
2.5
Control Voltage：VI[V]
0.0
3.0
Fig.11 Control Voltage – Output Frequency
(VDD=3.0V,Rbias=1.8KΩ)
80
80
40
From top:T=75℃
T=25℃
T=-20℃
20
Output Frequency：f[MHz]
80
Output Frequency：f[MHz]
100
Output Frequency：f[MHz]
100
60
60
40
From top:T=75℃
T=25℃
T=-20℃
20
0
0.0
0.5
1.0 1.5 2.0 2.5
Control Voltage：VI[V]
3.0
3.5
Fig.13 Control Voltage – Output Frequency
(VDD=3.3V,Rbias=1.6KΩ)
From top:T=75℃
T=25℃
T=-20℃
20
0
0.0
0.5
1.0 1.5 2.0 2.5
Control Voltage：VI[V]
3.0
3.5
Fig.14 Control Voltage – Output Frequency
(VDD=3.3V,Rbias=2.0KΩ)
0.0
125
From top:T=75℃
T=25℃
T=-20℃
25
75
50
From top:T=75℃
T=25℃
T=-20℃
25
0
0
0.0
1.0
2.0
3.0
4.0
Control Voltage：VI[V]
5.0
Fig.16 Control Voltage – Output Frequency
(VDD=5.0V,Rbias=1.6KΩ)
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0.0
1.0
2.0
3.0
4.0
5.0
Control Voltage：VI[V]
Fig.17 Control Voltage– Output Frequency
(VDD=5.0V,Rbias=2.4KΩ)
5/18
Output Frequency：f[MHz]
125
Output Frequency：f[MHz]
125
100
0.5
1.0 1.5 2.0 2.5
Control Voltage：VI[V]
3.0
3.5
Fig.15 Control Voltage – Output Frequency
(VDD=3.3V,Rbias=2.2KΩ)
150
50
3.0
40
150
75
1.0
1.5
2.0
2.5
Control Voltage：VI[V]
60
150
100
0.5
Fig.12 Control Voltage – Output Frequency
(VDD=3.0V,Rbias=2.0 KΩ)
100
0
Output Frequency：f[MHz]
Output Frequency：f[MHz]
100
Output Frequency：f[MHz]
100
Output Frequency：f[MHz]
100
100
75
50
From top:T=75℃
T=25℃
T=-20℃
25
0
0.0
1.0
2.0
3.0
4.0
Control Voltage：VI[V]
5.0
Fig.18 Control Voltage – Output Frequency
(VDD=5.0V,Rbias=2.7KΩ)
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
●Reference data
(BU2373FV－Recommended Oscillation Range, Frequency - Frequency Sensitivity)
65
30
35
Recommended Oscillation Range”H”
55
50
45
40
Recommended Oscillation Range”L”
30
25
20
Recommended Oscillation Range”L”
30
1.6
1.7
1.8
1.9
Bias Resistor:Rbias[KO]
2.0
1.5
Fig.19 Bias Resistance
- Recommended Oscillation Range
(VDD=3.0V, Select=”L”)
55
50
45
40
30
25
20
1.7
1.8
1.9
2.0
2.1
Bias resistor:Rbias[KO]
60
50
30
1.6
1.8
2.0
2.2
2.4
Bias Resistor:Rbias[KO]
2.6
Fig.25 Bias Resistance –
Recommended Oscillation Range
(VDD=5.0V, Select=”L”)
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10
5
40
45
50
55
60
Output Frequency：f[MHz]
65
Fig.24 Output Frequency
- Frequency Sensitivity
(VDD=3.3V, Select=”L”)
30
45
35
25
40
Recommended Oscillation Range”L”
15
35
Frequency Sensitivity：ß1[MHz/v]
70
20
Recommended Oscillation Range”H”
Output Frequency：f[MHz]
80
25
2.2
55
Recommended Oscillation Range”H”
90
60
Fig.21 Output Frequency
- Frequency Sensitivity
(VDD=3.0V, Select=”L”)
Fig.23 Bias Resistance Recommended Oscillation Range
(VDD=3.3V, Select=”H”)
110
100
40
45
50
55
Output Frequency：f[MHz]
0
1.6
2.2
Fig.22 Bias Resistance
- Recommended Oscillation Range
(VDD=3.3V, Select=”L”)
Output Frequency：f[MHz]
35
15
30
1.8
1.9
2.0
2.1
Bias Resistor:Rbias[KO]
5
30
Recommended Oscillation Range”L”
Recommended Oscillation Range”L”
1.7
10
Recommended Oscillation Range”H”
35
1.6
15
2.0
35
Output Frequency：f[MHz]
Output Frequency：f[MHz]
1.6
1.7
1.8
1.9
Bias Resistor:Rbias[KO]
Recommended Oscillation Range”H”
60
20
Fig.20 Bias Resistance
- Recommended Oscillation Range
(VDD=3.0V, Select=”H”)
70
65
25
0
15
1.5
Frequency Sensitivity：ß1[MHz/v]
35
Frequency Sensitivity：ß1[MHz/v]
Recommended Oscillation Range”H”
Output Frequency：f[MHz]
Output Frequency：f[MHz]
60
Recommended Oscillation Range”L”
15
1.6
1.8
2.0
2.2
2.4
Resistor:Rbias[KO]
2.6
Fig.26 Bias Resistance –
Recommended Oscillation Range
(VDD=5.0V, Select=”H”)
6/18
25
20
15
10
5
0
40
50
60
70
80
90
Output Frequency：f[MHz]
100
Fig.27 Output Frequency
- Frequency Sensitivity
(VDD=5.0V, Select=”L”)
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
●Reference data
(BU2374FV－Power Voltage Fluctuation Data)
80
80
80
60
40
From top:VDD=3.45V
VDD=3.30V
VDD=3.15V
20
60
40
From top:VDD=3.45V
VDD=3.30V
VDD=3.15V
20
Output Frequency：f[MHz]
100
Output Frequency：f[MHz]
100
Output Frequency：f[MHz]
100
0
0
0.0
0.5
1.0 1.5 2.0 2.5
Control Voltage：VI[V]
3.0
Fig.28 Control Voltage  Output Frequency
(VDD=3.3V,Rbias=2.0KΩ,Ta=25℃)
40
From top:VDD=3.45V
VDD=3.30V
VDD=3.15V
20
0
0.0
3.5
60
0.5
1.0 1.5 2.0 2.5
Control Voltage：VI[V]
3.0
3.5
Fig.29 Control Voltage  Output Frequency
(VDD=3.3V,Rbias=2.4 KΩ,Ta=25℃)
0.0
0.5
1.0 1.5 2.0 2.5
Control Voltage：VI[V]
3.0
3.5
Fig.30Control Voltage  Output Frequency
(VDD=3.3V,Rbias=3.0KΩ,Ta=25℃)
●Reference data
(BU2374FV－Temperature Fluctuation Data)
80
80
80
60
40
From top:T=75℃
T=25℃
T=-20℃
20
Output Frequency：f[MHz]
100
Output Frequency：f[MHz]
100
Output Frequency：f[MHz]
100
60
40
From top:T=75℃
T=25℃
T=-20℃
20
60
40
0
0
0
0.0
0.5
1.0 1.5 2.0 2.5
Control Voltage：VI[V]
3.0
0.0
3.5
Fig.31 Control Voltage  Output Frequency
(VDD=3.3V,Rbias=2.0KΩ)
From top:T=75℃
T=25℃
T=-20℃
20
0.5
1.0 1.5 2.0 2.5
Control Voltage：VI[V]
3.0
0.0
3.5
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Control Voltage：VI[V]
Fig.32 Control Voltage  Output Frequency
(VDD=3.3V,Rbias=2.4KΩ)
Fig.33 Control Voltage  Output Frequency
(VDD=3.3V,Rbias=3.0KΩ)
25
80
20
Recommended Oscillation Range”H”
60
40
Recommended Oscillation Range”L”
20
50
Frequency sensitivity: ß1[MHz/v]
100
Output Frequency：f[MHz]
Output Frequency：f[MHz]
●Reference data
(BU2374FV－Recommended Oscillation Range, Frequency - Frequency Sensitivity)
Recommended Oscillation Range”H”
15
10
Recommended Oscillation Range”L”
5
2.0
2.2
2.4
2.6
2.8
Resistor:Rbias[KO]
3.0
Fig.34 Bias Resistance
– Recommended Oscillation Range
(VDD=3.3V, Select=”L”)
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40
35
30
25
20
15
10
5
0
0
0
45
2.0
2.2
2.4
2.6
2.8
Resistor:Rbias[KO]
3.0
Fig.35 Bias Resistance
– Recommended Oscillation Range
(VDD=3.3V, Select=”H”)
7/18
35
40
45
50
55
60
Frequency: f[MHz]
Fig.36 Output Frequency
- Frequency Sensitivity
(VDD=3.3V, Select=”L”)
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
●Reference data
(BU2373FV－VCO Free-run Output Characteristics)
1V/div
1V/div
10dB/div
RBW:30kHz
VBW:30kHz
100kHz/div
Fig.37 Spectrum Waveform
(VDD=3.0V,Select=”L”,Output=50MHz)
5nsec/div
Fig.38 Output Waveform
(VDD=3.0V,Select=”L”,Output=50MHz)
500psec/div
Fig.39 Period-Jitter Waveform
(VDD=3.0V,Select=”L”,Output=50MHz)
5nsec/div
100kHz/div
Fig40 Spectrum Waveform
(VDD=3.3V,Select=”L”,Output=50MHz)
1V/div
1V/div
10dB/div
RBW:30kHz
VBW:30kHz
Fig.41 Output Waveform
(VDD=3.3V, Select=”L”, Output=50MHz)
500psec/div
Fig.42 Period-Jitter Waveform
(VDD=3.3V,Select =”L”, Output=50MHz)
1V/div
1V/div
10dB/div
RBW:30kHz
VBW:30kHz
100kHz/div
Fig.43 Spectrum Waveform
(VDD=5.0V,Select=”L”,Output=75MHz)
500psec/div
2nsec/div
Fig.44 Output Waveform
(VDD=5.0V,Select=”L”,Output=75MHz)
Fig.45 Period-Jitter Waveform
(VDD=5.0V,Select=”L”,Output=75MHz)
●Reference data
(BU2374FV－VCO Free-run Output Characteristics)
1V/div
1V/div
10dB/div
RBW:30kHz
VBW:30kHz
100kHz/div
Fig.46 Spectrum Waveform
(VDD=3.3V,Select=”L”,Output=50MHz)
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5nsec/div
Fig.47 Output Waveform
(VDD=3.3V,Select=”L”,Output=50MHz)
8/18
500psec/div
Fig.48 Period-Jitter Waveform
(VDD=3.3V,Select=”L”,Output=50MHz)
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
●Block diagram
(BU2373FV)
2PIN：SELECT
Through
or 1/2
Level
Shifter
13PIN：BIAS
ＶＣＯ
12PIN：VCO_IN
3PIN：VCO_OUT
14:VCO_VDD
2:SELECT
13:BIAS
3:VCO_OUT
4:FIN_A
5:FIN_B
BU2373FV
SSOP-B14
1:LOGIC_VDD
4PIN：FIN_A
12:VCO_IN
11:VCO_GND
5PIN：FIN_B
10:VCO_INHIBIT
6:PFD_OUT
9:PFD_INHIBIT
7:LOGIC_GND
8:TEST
10PIN：VCO_INHIBIT
Pmos Gate
Phase
Detector
6PIN：PFD_OUT
Nmos Gate
9PIN：PFD_INHIBIT
Fig.49
(BU2374FV)
2PIN：SELECT
1:LOGIC_VDD
3:VCO_OUT
4:FIN_A
5:FIN_B
14:VCO_VDD
BU2374FV
SSOP-B14
2:SELECT
Through
or 1/4
Level
Shifter
13PIN：BIAS
ＶＣＯ
12PIN：VCO_IN
3PIN：VCO_OUT
13:BIAS
12:VCO_IN
11:VCO_GND
4PIN：FIN_A
10:VCO_INHIBIT
6:PFD_OUT
9:PFD_INHIBIT
7:LOGIC_GND
8:TEST
5PIN：FIN_B
10PIN：VCO_INHIBIT
Pmos Gate
Phase
Detector
6PIN：PFD_OUT
Nmos Gate
9PIN：PFD_INHIBIT
Fig.50
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© 2011 ROHM Co., Ltd. All rights reserved.
9/18
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
●Pin assignment function
PIN NO.
PIN name
1
LOGIC_VDD
2
SELECT
3
VCO_OUT
4
FIN-A
5
FIN-B
6
PFD_OUT
7
8
9
10
Function
Power supply for the internal Logic and the VCO output,
which should be separated from power supply for the VCO_VDD (analog block).
VCO output frequency dividing mode selection pin.
H: Frequency dividing output, L: Through output
VCO output pin. If the VCO_INHIBIT is set to “H”, the VCO_OUT will be fixed to L.
Reference frequency input pin
VCO block frequency dividing input pin,
which inputs after the VCO output frequency is divided through the external counter.
Phase comparator output pin. If the PFD_INHIBIT is set to “H”,
the PFD_OUT will be set to Hi-Z output.
LOGIC_GND GND for the internal Logic and the VCO output
Test mode pin, which is normally used with set to OPEN or fixed to L.
Equipped with Pull-down resistor.
Phase comparator inhibit control pin.
PFD_INHIBIT
If the PFD_INHIBIT is set to “H”, the PFD_OUT will be set to Hi-Z output.
VCO inhibit control pin.
VCO_INHIBIT
If the VCO_INHIBIT is set to “H”, the VCO_OUT will be fixed to L output.
TEST
11
VCO_GND
12
VCO_IN
13
BIAS
14
VCO_VDD
GND for VCO (Analog block GND)
VCO control pin, to which loop filter output
for the PLL system is connected due to frequency control on normal system.
Bias current setting pin for the shift of VCO oscillation range.
A resistor is connected to the VCO_VDD for the control of bias current.
VDD for VCO (power supply for analog block)
●Example of application circuit
Please separate completely the bypass capacitor between an analog power supply and
GND from a digital power supply and GND. Please insert an about 0.01µF bypass
capacitor near the pin as much as possible.
1
LOGIC_VDD
2
SELECT
3
VCO_OUT
VCO_VDD
14
BIAS
13
VCO_IN
12
Please adjust so that the voltage of VCO_IN
is set to 1/2VDD.
H:VCO_OUT divide
recommend a lug lead filter.
L：VCO_OUT normal
R2
C1
1/N
Divider
R1
C2
4
FIN_A
VCO_GND
11
5
FIN_B
VCO_INHIBIT
10
H:VCO_OUT disable
L:VCO_OUT enable
H:PFD_OUT disable
6
PFD_OUT
PFD_INHIBIT
9
L:PFD_OUT enable
7
LOGIC_GND
TEST
8
The bypass capacitor between a digital power supply and GND should set aside
an analog power supply and GND. Please insert an about 0.01uF bypass
capacitor near the pin as much as possible.
Fig.51
*
*
It is recommended to use bypass capacitors of good high-frequency characteristics.
It is recommended to apply power supply in the LOGIC_VDD and LOGIC_GND circuits for the SELECT. PFD_INHIBIT, and VCO_INHIBIT control pins.
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© 2011 ROHM Co., Ltd. All rights reserved.
10/18
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
●Description of operations
VCO Block
Our VCO block consists of ring oscillators using 5-step reverse Amp. Setting the 2PIN: SELECT to “H” makes it possible to
set the system to output frequency dividing mode. (The frequency is divided to 1/2 on the BU2373FV, while 1/4 on the
BU2374FV.) 50% of the frequency is guaranteed even to the duty at this time.
Furthermore, setting the 10Pin: VCO_INHIBIT to “H” makes it possible to set the system to power-down mode. While in
power-down mode, the VCO_OUT output is fixed to “L”, thus achieving reduction in Analog consumption current
approximately by 80%.
In addition, through the adjustment of external resistance value for the BIAS terminal on 13Pin, the fine adjustment of
output frequency can be made.
(VCO I/O Characteristics)
frequency
(MHz)
It is possible to adjust
center frequency with biasresistor
0
Fig.52
VCO_IN (V)
* The VCO built in the BU2373FV has been designed to provide the lowest frequency sensitivity when using the VCO_IN
at about VDD/2. To make use of the VCO, it is recommended to adjust the BIAS resistance so that the voltage of the
VCO_IN will reach VDD/2.
(Configuration of VCO Block)
VCOIN
Bias
Level
Shifter
block
VCO_INHIBIT
L
1/2
VCO_OUT
1/2
H
SELECT
Fig.53
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© 2011 ROHM Co., Ltd. All rights reserved.
11/18
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
Phase Comparator
Our phase comparator is of rising edge detection type. This phase comparator shows the characteristics shown below.
(1) The phase comparator outputs an error pulse (UP signal) after the rising edge is detected at the FIN-A until the
rising edge is detected at the FIN-B, and then it is reset.
(2) The phase comparator outputs an error pulse (DOWN signal) after the rising edge is detected at the FIN-B until the
rising edge is detected at the FIN-A, and then it is reset.
Furthermore, setting the 9Pin: PFD_INHIBIT to “H” makes it possible to set the system to power-down mode. While in
power-down mode, the PFD_OUT outputs high impedance. In other words, it is brought to reset state with the Logic power
supply. (A leak current of 1 A or less is guaranteed.)
(I/O Characteristics of Phase Comparator)
FIN-A
FIN-B
PFD_OUT
Fig.54
Upper：FIN_A
Upper：FIN_A
Middle：FIN_B
Lower：PFD_OUT
1V/div
1V/div
1V/div
●Reference data
(Common to BU2373FV & BU2374FV – Phase Comparator I/O Waveform)
50µsec/div
Fig.55 UP Signal Output
(VDD=3.3V, FIN_A > FIN_B)
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© 2011 ROHM Co., Ltd. All rights reserved.
Middle：FIN_B
Lower：PFD_OUT
Upper：FIN_A
50µsec/div
Middle：FIN_B
50µsec/div
Lower：PFD_OUT
Fig.56 No Error Signal Output
(VDD=3.3V, FIN_A = FIN_B)
12/18
Fig.57 DOWN Signal Output
(VDD=3.3V, FIN_A < FIN_B)
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
(Functioning of PLL System)
In order to configure the stable PLL system, the following section describes the functional principle, open loop
characteristics, and closed loop characteristics by block shown in the Block Diagram below.
PLL System Block Diagram
FIN-A
θi
FIN-B
θo
Phase-comparator
Kp
LPF
VCO
F(s)
Kv/s
VCO_OUT
1/N
Divider
Fig.58
①
Phase Comparator
The phase comparator shows the characteristics shown in figure below. Assuming that the Gain is Kp,
Kp=(VOHVOL)/4(V/rad)
②
VCO (Voltage Controlled Oscillator)
The VCO shows the characteristics shown in figure below.
Assuming that the Gain is Kv, Kv=2   (fmax-fmin)/(Vmax-Vmin)(rad/s/V)
frequency
(MHz)
VOH
fmax
-2π
0
2π
fmin
VOL
0
Fig.59 Phase Comparator Characteristics
③
Vmin
Vmax
VCO_IN (V)
Fig.60 VCO Characteristics
LPF (Lag-Lead Filter)
Calculate the Gain of the lag-lead filter. It is recommended to use the filter having the pattern shown below.
R2
PDOUT
VCOIN
R1
C2
C1
Fig.61
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13/18
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
For the lag-lead filter afore-mentioned, assuming that C1  C2 (C2 is used at a value approx. 10 times as high as C1),
break this filter into two portions as shown below to facilitate the calculation, thus proceeding with the calculation.
(1)
(2)
R2
R2
R1
R1
C1
C2
Fig.62 LPF Portion ①
Fig.63 LPF Portion ②
In the case of (1) above,
1
S・C2
1
R1+R2+
S・C2
R1+
VOUT
F(s) =
=
VIN
2
2
S・C2・R1+1
S・C2・(R1+R2)+1
=
2
1+ω ・C2 ・R1
2
1+｛ω・C2・(R1+R2) ｝
| F(jω) | =
(S=jω)
-1
(ω=2πf)
-1
φ(ω) = tan （ω・C2・R1）-tan ｛ω・C2・（R1+R2) ｝
・By the expression above, the Gain and the Phase are given as shown in graphs below.
<Phase>
<Gain>
Gain(dB)
φ
fC1
fC2
f
-6dB/oct
π/4
π/2
20log{R1/(R1+R2)}
fC1
f
fC2
Fig.64 (Fig.62) Frequency  Gain Characteristics
fC1
=
1
2π
×
1
fc2 =
C2・（R1+R2)
,
Fig.65 (Fig.62) Frequency  Phase Characteristics
1
2π
×
1
C2・R1
In the case of (2) above,
VOUT
F(s) =
=
VIN
R1
R1
R1+R2
1+S・C1・R1
=
R1
R1・R2
R2+
S・C1・
R1+R2
1+S・C1・R1
(S=jω)
+1
2
| F(jω) | =
R1
2
(R1+R2)
φ( ω ) =
2
2
R1 ・R2
1+ω ・C1 ・
(R1+R2)2
2
2
(ω=2πf)
R1・R2
-1
｝
-tan ｛ω・C1・
（R1+R2)
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© 2011 ROHM Co., Ltd. All rights reserved.
14/18
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
・By the expression aforementioned, the Gain and the Phase are given as shown in graphs below.
<Phase>
<Gain>
Gain(dB)
φ
fC3
20log{R1/(R1+R2)}
f
-6dB/oct
π/4
π/2
f
fC3
Fig.66 (Fig.63) Frequency  Gain Characteristics
1
fC3 = 2
×
π
Fig.67 (Fig.63) Frequency  Phase Characteristics
R1+R2
C1・R1・R2
By combining (1) and (2), finding the Gain and the Phase of the lag-lead filter,
F(s) =
VOUT
VIN
1+S・C2・R1
=
× ｛1+ S・C1・
｛1+S・C2・(R1+R2)｝
R1・R2
R1+R2
(S=jω)
｝
The gain and the Phase are given as shown below, respectively.
G2
G1×G3
Gain=20・log｛
｝
2
,
2
G1=
1+C2 ・(R1+R2) ・(2πf)
G2=
1+C2 ・R1 ・(2πf)
G3=
2
2
2
2
1+C1 ・R1 ・
Phase=θ2-θ1-θ3
2
2
1
2
2 ・(2πf)
(R1+R2)
-1
,
θ1= -tan ｛2πf・C2・（R1+R2)｝
,
θ2= tan （2πf・C2・R1）
,
R1・R2
-1
｝
θ3= -tan ｛2πf・C1・
（R1+R2)
-1
<Phase>
<Gain>
Gain(dB)
φ
fC1
-6dB/oct
fC2
fC3
f
π/4
20log{R1/(R1+R2)}
π/2
fC1
fC2
fC3
f
Fig.68 (Fig.61) Frequency  Gain Characteristics
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© 2011 ROHM Co., Ltd. All rights reserved.
Fig.69 (Fig.61) Frequency  Phase Characteristics
15/18
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
・Where, find the Gain for the open loop of PLL system. Assuming that the transfer function is H(s),
Kv
1
H(s)= Kp×F(s)×
×
S
N
Kp×
G0=
Kv
S
×
1
N
N
Kp×Kv
S×
2
2πf×N
Kp×Kv
PLL-Gain=20・log｛
1
=
,
G2
G1×G3×G0
-1
θ0=
｝
-tan (2πf・
,
N
Kp×Kv
π
2
Phase=-θ0+θ2-θ1-θ3
<Phase>
<Gain>
Gain(dB)
) =
φ
fC1
fC2
fC3
f
π/2
fC1
fC2
fC3
f
π
Fig.71 (Fig.58) Frequency  Phase Characteristics
Fig.70 (Fig.58) Frequency  Gain Characteristics
If, by the expression above, the LPF constant is selected so that a phase margin of 45 or more is secured when the
Gain for the open loop becomes 0 dB, the PLL system will stably function.
Note)
・As to the jitters, the TYP values vary with the substrate, power supply, output loads, noises, and others. Besides, for the
use of the BU2373FV or the BU2374FV, the operating margin should be thoroughly checked.
・The Analog power supply and the Logic power supply should be separated from each other so that noises generated with
the Logic power supply have no adverse influences on the Analog power one.
・Bypass capacitors between the power supply and GND should be mounted as close as possible.
・Power to control pins (i.e., VCO_INHIBIT, PFD_INHIBIT and SELECT) should be supplied from the logic power supply.
・In order to configure the PLL system, the LPF GND should be connected to the Analog GND and mounted in the
proximity of the VCO_IN.
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16/18
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
●Notes for use
(1) Absolute Maximum Ratings
An excess in the absolute maximum ratings, such as applied voltage (VDD or VIN), operating temperature range (Topr),
etc., can break down devices, thus making impossible to identify breaking mode such as a short circuit or an open circuit.
If any special mode exceeding the absolute maximum ratings is assumed, consideration should be given to take physical
safety measures including the use of fuses, etc.
(2) Recommended operating conditions
These conditions represent a range within which characteristics can be provided approximately as expected. The
electrical characteristics are guaranteed under the conditions of each parameter.
(3) Reverse connection of power supply connector
The reverse connection of power supply connector can break down ICs. Take protective measures against the breakdown
due to the reverse connection, such as mounting an external diode between the power supply and the IC’s power supply
terminal.
(4) Power supply line
Design PCB pattern to provide low impedance for the wiring between the power supply and the GND lines.
In this regard, for the digital block power supply and the analog block power supply, even though these power supplies has
the same level of potential, separate the power supply pattern for the digital block from that for the analog block, thus
suppressing the diffraction of digital noises to the analog block power supply resulting from impedance common to the
wiring patterns. For the GND line, give consideration to design the patterns in a similar manner.
Furthermore, for all power supply terminals to ICs, mount a capacitor between the power supply and the GND terminal. At
the same time, in order to use an electrolytic capacitor, thoroughly check to be sure the characteristics of the capacitor to
be used present no problem including the occurrence of capacity dropout at a low temperature, thus determining the
constant.
(5) GND voltage
Make setting of the potential of the GND terminal so that it will be maintained at the minimum in any operating state.
Furthermore, check to be sure no terminals are at a potential lower than the GND voltage including an actual electric
transient.
(6) Short circuit between terminals and erroneous mounting
In order to mount ICs on a set PCB, pay thorough attention to the direction and offset of the ICs. Erroneous mounting can
break down the ICs. Furthermore, if a short circuit occurs due to foreign matters entering between terminals or between
the terminal and the power supply or the GND terminal, the ICs can break down.
(7) Operation in strong electromagnetic field
Be noted that using ICs in the strong electromagnetic field can malfunction them.
(8) Inspection with set PCB
On the inspection with the set PCB, if a capacitor is connected to a low-impedance IC terminal, the IC can suffer stress.
Therefore, be sure to discharge from the set PCB by each process. Furthermore, in order to mount or dismount the set
PCB to/from the jig for the inspection process, be sure to turn OFF the power supply and then mount the set PCB to the jig.
After the completion of the inspection, be sure to turn OFF the power supply and then dismount it from the jig. In addition,
for protection against static electricity, establish a ground for the assembly process and pay thorough attention to the
transportation and the storage of the set PCB.
(9) Input terminals
In terms of the construction of IC, parasitic elements are inevitably formed in relation to potential. The operation of the
parasitic element can cause interference with circuit operation, thus resulting in a malfunction and then breakdown of the
input terminal. Therefore, pay thorough attention not to handle the input terminals, such as to apply to the input terminals a
voltage lower than the GND respectively, so that any parasitic element will operate. Furthermore, do not apply a voltage to
the input terminals when no power supply voltage is applied to the IC. In addition, even if the power supply voltage is
applied, apply to the input terminals a voltage lower than the power supply voltage or within the guaranteed value of
electrical characteristics.
(10) Ground wiring pattern
If small-signal GND and large-current GND are provided, It will be recommended to separate the large-current GND
pattern from the small-signal GND pattern and establish a single ground at the reference point of the set PCB so that
resistance to the wiring pattern and voltage fluctuations due to a large current will cause no fluctuations in voltages of the
small-signal GND. Pay attention not to cause fluctuations in the GND wiring pattern of external parts as well.
(11) External capacitor
In order to use a ceramic capacitor as the external capacitor, determine the constant with consideration given to a
degradation in the nominal capacitance due to DC bias and changes in the capacitance due to temperature, etc.
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17/18
2011.08 - Rev.B
Technical Note
BU2373FV,BU2374FV
●Ordering part number
B
U
2
Part No.
3
7
F
3
Part No.
2373
2374
V
-
Package
F: SSOP-B14
E
2
Packaging and forming specification
E2: Embossed tape and reel
SSOP-B14
<Tape and Reel information>
5.0 ± 0.2
8
0.3Min.
4.4 ± 0.2
6.4 ± 0.3
14
1
Tape
Embossed carrier tape
Quantity
2500pcs
Direction
of feed
E2
The direction is the 1pin of product is at the upper left when you hold
( reel on the left hand and you pull out the tape on the right hand
)
7
0.10
1.15 ± 0.1
0.15 ± 0.1
0.65
0.1
0.22 ± 0.1
1pin
(Unit : mm)
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© 2011 ROHM Co., Ltd. All rights reserved.
Reel
18/18
Direction of feed
∗ Order quantity needs to be multiple of the minimum quantity.
2011.08 - Rev.B
Notice
Notes
No copying or reproduction of this document, in part or in whole, is permitted without the
consent of ROHM Co.,Ltd.
The content specified herein is subject to change for improvement without notice.
The content specified herein is for the purpose of introducing ROHM's products (hereinafter
"Products"). If you wish to use any such Product, please be sure to refer to the specifications,
which can be obtained from ROHM upon request.
Examples of application circuits, circuit constants and any other information contained herein
illustrate the standard usage and operations of the Products. The peripheral conditions must
be taken into account when designing circuits for mass production.
Great care was taken in ensuring the accuracy of the information specified in this document.
However, should you incur any damage arising from any inaccuracy or misprint of such
information, ROHM shall bear no responsibility for such damage.
The technical information specified herein is intended only to show the typical functions of and
examples of application circuits for the Products. ROHM does not grant you, explicitly or
implicitly, any license to use or exercise intellectual property or other rights held by ROHM and
other parties. ROHM shall bear no responsibility whatsoever for any dispute arising from the
use of such technical information.
The Products specified in this document are intended to be used with general-use electronic
equipment or devices (such as audio visual equipment, office-automation equipment, communication devices, electronic appliances and amusement devices).
The Products specified in this document are not designed to be radiation tolerant.
While ROHM always makes efforts to enhance the quality and reliability of its Products, a
Product may fail or malfunction for a variety of reasons.
Please be sure to implement in your equipment using the Products safety measures to guard
against the possibility of physical injury, fire or any other damage caused in the event of the
failure of any Product, such as derating, redundancy, fire control and fail-safe designs. ROHM
shall bear no responsibility whatsoever for your use of any Product outside of the prescribed
scope or not in accordance with the instruction manual.
The Products are not designed or manufactured to be used with any equipment, device or
system which requires an extremely high level of reliability the failure or malfunction of which
may result in a direct threat to human life or create a risk of human injury (such as a medical
instrument, transportation equipment, aerospace machinery, nuclear-reactor controller, fuelcontroller or other safety device). ROHM shall bear no responsibility in any way for use of any
of the Products for the above special purposes. If a Product is intended to be used for any
such special purpose, please contact a ROHM sales representative before purchasing.
If you intend to export or ship overseas any Product or technology specified herein that may
be controlled under the Foreign Exchange and the Foreign Trade Law, you will be required to
obtain a license or permit under the Law.
Thank you for your accessing to ROHM product informations.
More detail product informations and catalogs are available, please contact us.
ROHM Customer Support System
http://www.rohm.com/contact/
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R1120A