1997 Nov 13
2
Philips Semiconductors
Product specification
VHF variable capacitance diode
BB178
FEATURES
Excellent linearity
Excellent matching to 2% DMA
Ultra small plastic SMD package
C28: 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 performance is
achieved by gliding matching and a
direct matching assembly procedure.
PINNING
PIN
DESCRIPTION
1
cathode
2
anode
Fig.1 Simplified outline
(SOD523; SC-79) and symbol.
handbook, 2 columns
1
2
MBK441
8
Marking code: 8.
Orientation of marking code as shown.
Cathode side indicated by a bar.
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134).
ELECTRICAL CHARACTERISTICS
T
j
= 25
C unless otherwise specified.
SYMBOL
PARAMETER
CONDITIONS
MIN.
MAX.
UNIT
V
R
continuous reverse voltage
-
32
V
V
RM
peak reverse voltage
in series with a 10 k
resistor
-
35
V
I
F
continuous forward current
-
20
mA
T
stg
storage temperature
-
55
+150
C
T
j
operating junction temperature
-
55
+125
C
SYMBOL
PARAMETER
CONDITIONS
MIN.
TYP.
MAX.
UNIT
I
R
reverse current
V
R
= 30 V; see Fig.3
-
-
10
nA
V
R
= 30 V; T
j
= 85
C; see Fig.3
-
-
200
nA
r
s
diode series resistance
f = 100 MHz;
V
R
is the value at which C
d
= 30 pF
-
0.65
0.8
C
d
diode capacitance
V
R
= 1 V; f = 1 MHz; see Figs 2 and 4
34.65
-
42.35
pF
V
R
= 28 V; f = 1 MHz; see Figs 2 and 4 2.361
-
2.754
pF
capacitance ratio
f = 1 MHz
-
1.3
-
capacitance ratio
f = 1 MHz
13.5
-
-
capacitance ratio
f = 1 MHz
-
1.08
-
capacitance matching
V
R
= 1 to 28 V; in a sequence of 15
diodes (gliding)
-
-
2
%
C
d 1V
(
)
C
d 2V
(
)
------------------
C
d 1V
(
)
C
d 28V
(
)
--------------------
C
d 25V
(
)
C
d 28V
(
)
--------------------
C
d
C
d
----------
1997 Nov 13
3
Philips Semiconductors
Product specification
VHF variable capacitance diode
BB178
GRAPHICAL DATA
Fig.2 Diode capacitance as a function of reverse voltage; typical values.
f = 1 MHz; T
j
= 25
C
.
handbook, full pagewidth
0
50
MBK438
10
2
10
1
10
-
1
10
20
30
40
Cd
(pF)
V
R
(V)
Fig.3
Reverse current as a function of junction
temperature; maximum values.
handbook, halfpage
100
0
10
MLC816
10
2
10
3
50
IR
(nA)
T ( C)
j
o
Fig.4
Temperature coefficient of diode
capacitance as a function of reverse
voltage; typical values.
handbook, halfpage
MLC815
1
10
10
2
10
3
10
4
10
5
10
1
(K
-
1
)
V (V)
R
d
TC
T
j
= 0 to 85
C.
1997 Nov 13
4
Philips Semiconductors
Product specification
VHF variable capacitance diode
BB178
PACKAGE OUTLINE
REFERENCES
OUTLINE
VERSION
EUROPEAN
PROJECTION
ISSUE DATE
IEC
JEDEC
EIAJ
SOD523
SC-79
98-11-25
Plastic surface mounted package; 2 leads
SOD523
0
0.5
1 mm
scale
D
1
2
HE
E
bp
A
c
v
M
A
A
UNIT
bp
c
D
E
v
mm
0.35
0.25
0.2
0.1
0.15
0.9
0.7
1.3
1.1
A
0.7
0.5
HE
1.7
1.5
DIMENSIONS (mm are the original dimensions)
Note
1. The marking bar indicates the cathode.
(1)
1997 Nov 13
5
Philips Semiconductors
Product specification
VHF variable capacitance diode
BB178
DEFINITIONS
LIFE SUPPORT APPLICATIONS
These products are not designed for use in life support appliances, devices, or systems where malfunction of these
products can reasonably be expected to result in personal injury. Philips customers using or selling these products for
use in such applications do so at their own risk and agree to fully indemnify Philips for any damages resulting from such
improper use or sale.
Data sheet status
Objective specification
This data sheet contains target or goal specifications for product development.
Preliminary specification
This data sheet contains preliminary data; supplementary data may be published later.
Product specification
This data sheet contains final product specifications.
Limiting values
Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). Stress above one or
more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation
of the device at these or at any other conditions above those given in the Characteristics sections of the specification
is not implied. Exposure to limiting values for extended periods may affect device reliability.
Application information
Where application information is given, it is advisory and does not form part of the specification.
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