Dual Switching Diode
MAXIMUM RATINGS (TA = 25°C)
Rating Symbol Max Unit
Reverse Voltage VR70 Vdc
Forward Current IF200 mAdc
Peak Forward Surge Current IFM(surge) 500 mAdc
THERMAL CHARACTERISTICS
Characteristic Symbol Max Unit
Total Device Dissipation FR–5 Board(1)
TA = 25°C
Derate above 25°C
PD200
1.6
mW
mW/°C
Thermal Resistance, Junction to Ambient RJA 0.625 °C/W
Total Device Dissipation
Alumina Substrate(2) TA = 25°C
Derate above 25°C
PD300
2.4
mW
mW/°C
Thermal Resistance, Junction to Ambient RJA 417 °C/W
Junction and Storage Temperature TJ, Tstg –55 to +150 °C
DEVICE MARKING
BAV70WT1 = A4
ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise noted)
Characteristic Symbol Min Max Unit
OFF CHARACTERISTICS
Reverse Breakdown Voltage
(I(BR) = 100 µAdc) V(BR) 70 Vdc
Reverse Voltage Leakage Current (Note 3)
(VR = 70 Vdc)
(VR = 50 Vdc) IR
IR
5.0
100 µAdc
nAdc
Diode Capacitance
(VR = 0, f = 1.0 MHz) CD 1.5 pF
Forward Voltage
(IF = 1.0 mAdc)
(IF = 10 mAdc)
(IF = 50 mAdc)
(IF = 150 mAdc)
VF
715
855
1000
1250
mVdc
Reverse Recovery Time
(IF = IR = 10 mAdc, RL = 100 , IR(REC) = 1.0 mAdc) (Figure 1) trr 6.0 ns
Forward Recovery Voltage
(IF = 10 mAdc, tr = 20 ns) (Figure 2) VRF 1.75 V
1. FR–5 = 1.0 0.75 0.062 in.
2. Alumina = 0.4 0.3 0.024 in. 99.5% alumina.
3. For each individual diode while the second diode is unbiased.
Preferred devices are ON Semiconductor recommended choices for future use and best overall value.
ON Semiconductor
Semiconductor Components Industries, LLC, 2001
November, 2001 – Rev. 2 1Publication Order Number:
BAV70WT1/D
BAV70WT1
ON Semiconductor Preferred Device
CASE 419–04, STYLE 5
SC–70/SOT–323
12
3
3
CATHODE
ANODE
1
2
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Figure 1. Recovery Time Equivalent Test Circuit
Fi
g
ure 2.
RS = 50
BAV70
IF
SAMPLING
OSCILLOSCOPE
RL = 50
trtp
I
10%
90%
VR
INPUT PULSE
+IFtrr OUTPUT PULSE
10%OF VR
100
RS = 50
BAV70 SAMPLING
OSCILLOSCOPE
RL = 50
1 K450
90%
10%
t
trtp
INPUT PULSE
V
VFR
OUTPUT PULSE t
I
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100
0.2 0.4
VF, FORWARD VOLTAGE (VOLTS)
0.6 0.8 1.0 1.2
10
1.0
0.1
TA = 85°C
10
0
VR, REVERSE VOLTAGE (VOLTS)
1.0
0.1
0.01
0.001
10 20 30 40 50
1.0
0
VR, REVERSE VOLTAGE (VOLTS)
0.9
0.8
0.7
0.6
CD, DIODE CAPACITANCE (pF)
2468
IF, FORWARD CURRENT (mA)
Figure 3. Forward Voltage Figure 4. Leakage Current
Figure 5. Capacitance
TA = -40°C
TA = 25°C
TA = 150°C
TA = 125°C
TA = 85°C
TA = 55°C
TA = 25°C
IR, REVERSE CURRENT (µA)
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PD = TJ(max) – TA
RθJA
PD = 150°C – 25°C
0.625°C/W = 200 milliwatts
The soldering temperature and time should not exceed
260°C for more than 10 seconds.
When shifting from preheating to soldering, the
maximum temperature gradient should be 5°C or less.
After soldering has been completed, the device should
be allowed to cool naturally for at least three minutes.
Gradual cooling should be used as the use of forced
cooling will increase the temperature gradient and
result in latent failure due to mechanical stress.
Mechanical stress or shock should not be applied dur-
ing cooling
* Soldering a device without preheating can cause exces-
sive thermal shock and stress which can result in damage
to the device.
INFORMATION FOR USING THE SC–70/SOT–323 SURFACE MOUNT PACKAGE
MINIMUM RECOMMENDED FOOTPRINT FOR SURFACE MOUNTED APPLICATIONS
Surface mount board layout is a critical portion of the total
design. The footprint for the semiconductor packages must
be the correct size to insure proper solder connection
SC–70/SOT–323 POWER DISSIPATION
The power dissipation of the SC–70/SOT–323 is a func-
tion of the pad size. This can vary from the minimum pad
size for soldering to the pad size given for maximum power
dissipation. Power dissipation for a surface mount device
is determined by TJ(max), the maximum rated junction tem-
perature of the die, RθJA, the thermal resistance from the
device junction to ambient; and the operating temperature,
TA. Using the values provided on the data sheet, PD can be
calculated as follows.
The values for the equation are found in the maximum
ratings table on the data sheet. Substituting these values into
the equation for an ambient temperature TA of 25°C, one
can calculate the power dissipation of the device which in
this case is 200 milliwatts.
The 0.625°C/W assumes the use of the recommended
footprint on a glass epoxy printed circuit board to achieve
a power dissipation of 200 milliwatts. Another alternative
would be to use a ceramic substrate or an aluminum core
board such as Thermal Clad. Using a board material such
as Thermal Clad, a higher power dissipation of 300 milli-
watts can be achieved using the same footprint.
interface between the board and the package. With the
correct pad geometry, the packages will self align when
subjected to a solder reflow process.
SOLDERING PRECAUTIONS
The melting temperature of solder is higher than the rated
temperature of the device. When the entire device is heated
to a high temperature, failure to complete soldering within
a short time could result in device failure. Therefore, the
following items should always be observed in order to
minimize the thermal stress to which the devices are
subjected.
Always preheat the device.
The delta temperature between the preheat and
soldering should be 100°C or less.*
When preheating and soldering, the temperature of the
leads and the case must not exceed the maximum
temperature ratings as shown on the data sheet. When
using infrared heating with the reflow soldering
method, the difference should be a maximum of 10°C.
mm
inches
0.035
0.9
0.075
0.7
1.9
0.028
0.65
0.025
0.65
0.025
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STEP 1
PREHEAT
ZONE 1
RAMP"
STEP 2
VENT
SOAK"
STEP 3
HEATING
ZONES 2 & 5
RAMP"
STEP 4
HEATING
ZONES 3 & 6
SOAK"
STEP 5
HEATING
ZONES 4 & 7
SPIKE"
STEP 6
VENT
STEP 7
COOLING
200°C
150°C
100°C
50°C
TIME (3 TO 7 MINUTES TOTAL) TMAX
SOLDER IS LIQUID FOR
40 TO 80 SECONDS
(DEPENDING ON
MASS OF ASSEMBLY)
205° TO 219°C
PEAK AT
SOLDER JOINT
DESIRED CURVE FOR LOW
MASS ASSEMBLIES
100°C
150°C
160°C
140°C
Figure 6. Typical Solder Heating Profile
DESIRED CURVE FOR HIGH
MASS ASSEMBLIES
170°C
For any given circuit board, there will be a group of
control settings that will give the desired heat pattern. The
operator must set temperatures for several heating zones,
and a figure for belt speed. Taken together, these control
settings make up a heating “profile” for that particular
circuit board. On machines controlled by a computer, the
computer remembers these profiles from one operating
session t o the next. Figure 7 shows a typical heating profile
for use when soldering a surface mount device to a printed
circuit board. This profile will vary among soldering
systems but it is a good starting point. Factors that can
affect the profile include the type of soldering system in
use, density and types of components on the board, type of
solder used, and the type of board or substrate material
being used. This profile shows temperature versus time.
SOLDER STENCIL GUIDELINES
Prior to placing surface mount components onto a printed
circuit board, solder paste must be applied to the pads. A
solder stencil is required to screen the optimum amount of
solder paste onto the footprint. The stencil is made of brass
or stainless steel with a typical thickness of 0.008 inches.
The stencil opening size for the surface mounted package
should be the same as the pad size on the printed circuit
board, i.e., a 1:1 registration.
TYPICAL SOLDER HEATING PROFILE
The line on the graph shows the actual temperature that
might be experienced on the surface of a test board at or
near a central solder joint. The two profiles are based on a
high density and a low density board. The Vitronics
SMD310 convection/infrared reflow soldering system was
used to generate this profile. The type of solder used was
62/36/2 Tin Lead Silver with a melting point between
177–189°C. When this type of furnace is used for solder
reflow work, the circuit boards and solder joints tend to
heat first. The components on the board are then heated by
conduction. The circuit board, because i t has a lar ge surface
area, absorbs the thermal energy more efficiently, then
distributes this energy to the components. Because of this
effect, the main body of a component may be up to 30
degrees cooler than the adjacent solder joints.
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PACKAGE DIMENSIONS
CASE 419–04
ISSUE L
SC–70 (SOT–323)
CN
AL
D
G
SB
H
J
K
3
12
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
DIM MIN MAX MIN MAX
MILLIMETERSINCHES
A0.071 0.087 1.80 2.20
B0.045 0.053 1.15 1.35
C0.032 0.040 0.80 1.00
D0.012 0.016 0.30 0.40
G0.047 0.055 1.20 1.40
H0.000 0.004 0.00 0.10
J0.004 0.010 0.10 0.25
K0.017 REF 0.425 REF
L0.026 BSC 0.650 BSC
N0.028 REF 0.700 REF
S0.079 0.095 2.00 2.40
0.05 (0.002)
STYLE 5:
PIN 1. ANODE
2. ANODE
3. CATHODE
BAV70WT1
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Notes
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without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular
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including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or
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BAV70WT1/D
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