LESHAN RADIO COMPANY, LTD.
VHF variable capacitance diode
BB 178
FEATURES
· Excellent linearity
· Excellent matching to 2% DMA
· Ultra small plastic SMD package
· C 28: 2.6 pF; ratio: 15
· Very low series resistance.
APPLICATIONS
· Electronic tuning in VHF television
tuners, band B up to 460 MHz
· Voltage controlled oscillators(VCO).
DESCRIPTION
The BB178 is a planar technology variable
capacitance diode, in a SOD523 (SC-79)
package. The excellent matching perfor-
mance is achieved by gliding matching and
a direct matching assembly procedure.
1
2
SOD523 SC-79
MARKING CODE:8
8
MAX.
32
35
20
+150
+125
UNIT
V
V
mA
°C
°C
MAX.
–
–
0.65
–
–
1.3
–
1.08
–
TYP.
10
200
0.8
42.35
2.754
–
–
–
2
%
nA
nA
Ω
pF
pF
1
CATHODE
2
ANODE
1
2
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134).
SYMBOL
V
R
V
RM
I
F
T
stg
T
j
PARAMETER
continuous reverse voltage
peak reverse voltage
continuous forward current
storage temperature
operating junction temperature
CONDITIONS
in series with a 10 kΩ resistor
MIN.
–
–
–
–55
–55
ELECTRICAL CHARACTERISTICS
T
j
=25°C unless otherwise specified.
SYMBOL
I
R
r
s
C
d
C
d(1V)
C
d(2V)
C
d(1V)
C
d(28V)
C
d(25V)
C
d(28V)
∆C
d
C
d
PARAMETER
reverse current
diode series resistance
diode capacitance
CONDITIONS
V
R
= 30 V; see Fig.2
V
R
= 30 V; T
j
=85°C; see Fig.2
f = 100 MHz;
V
R
is the value at which Cd =30 pF
V
R
= 1 V; f = 1 MHz; see Figs 1and 3
V
R
= 28 V; f = 1 MHz; see Figs 1and 3
f = 1 MHz
f = 1 MHz
f = 1 MHz
V
R
= 1 to 28 V; in a sequence of 15
diodes(gliding)
MIN.
–
–
–
34.65
2.361
–
13.5
–
–
UNIT
capacitance ratio
capacitance ratio
capacitance ratio
capacitance matching
BB178–1/2
LESHAN RADIO COMPANY, LTD.
BB 178
50
40
C
d
( pF )
30
20
f = 1 MHz; T
j
=25°C
10
0
10
–1
1
10
10
2
V
R
( V )
Fig.1 Diode capacitance as a function of reverse voltage; typical values.
10
3
10
–3
I
R
(nA)
TC
d
( K
-1
)
10
2
10
–4
T
j
= 0 to 85 °C.
10
0
50
100
10
–5
10
–1
1
10
T
j
( °C )
V
R
( V )
Fig.2 Reverse current as a function of junction
temperature; maximum values.
Fig.3 Temperature coefficient of diode capacitance as a function of
reverse voltage; typical values.
BB178–2/2
Embedded System
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