1
Motorola Small–Signal Transistors, FETs and Diodes Device Data
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 R
q
JA 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 R
q
JA 417 °C/W
Junction and Storage Temperature TJ, Tstg –55 to +150 °C
DEVICE MARKING
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 V oltage Leakage Current
(VR = 70 Vdc)
(VR = 50 Vdc) IR1
IR2 —
—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 Ω, 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.
Thermal Clad is a trademark of the Bergquist Company
Preferred devices are Motorola recommended choices for future use and best overall value.
Order this document
by BAV70WT1/D
SEMICONDUCTOR TECHNICAL DATA
Motorola Preferred Device
CASE 419–02, STYLE 5
SC–70/SOT–323
12
3
Motorola, Inc. 1997
3
CATHODE
ANODE
1
2
BAV70WT1
2 Motorola Small–Signal Transistors, FETs and Diodes Device Data
Figure 1. Recovery Time Equivalent Test Circuit
Figure 2.
RS = 50
Ω
BAV70
IF
SAMPLING
OSCILLOSCOPE
RL = 50
Ω
trtp
I
10%
90%
VRINPUT PULSE
+IFtrr OUTPUT PULSE
10% OF VR
100
W
RS = 50
Ω
BAV70 SAMPLING
OSCILLOSCOPE
RL = 50
Ω
1 K
Ω
450
Ω
90%
10%
t
trtp
INPUT PULSE
V
VFR
OUTPUT PULSE t
I
BAV70WT1
3
Motorola Small–Signal Transistors, FETs and Diodes Device Data
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
0VR, REVERSE VOLTAGE (VOL TS)
1.0
0.1
0.01
0.001 10 20 30 40 50
1.0
0VR, REVERSE VOLTAGE (VOL TS)
0.9
0.8
0.7
0.6
CD, DIODE CAPACITANCE (pF)
2468
I
F
, 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 (
µ
A)
BAV70WT1
4 Motorola Small–Signal Transistors, FETs and Diodes Device Data
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
interface between the board and the package. With the
correct pad geometry, the packages will self align when
subjected to a solder reflow process.
mm
inches
0.035
0.9
0.075
0.7
1.9
0.028
0.65
0.025
0.65
0.025
SC–70/SOT–323 POWER DISSIPATION
The power dissipation of the SC–70/SOT–323 is a function
of the collector 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
temperature 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.
PD = TJ(max) – TA
RθJA
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 T A of 25°C, one can
calculate the power dissipation of the device which in this
case is 200 milliwatts.
PD = 150°C – 25°C
0.625°C/W = 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 power dissipation of 300 milliwatts can be
achieved using the same footprint.
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.
•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 during
cooling
* Soldering a device without preheating can cause excessive
thermal shock and stress which can result in damage to the
device.
BAV70WT1
5
Motorola Small–Signal Transistors, FETs and Diodes Device Data
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
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 to the
next. Figure 6 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. 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 it has a large 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.
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 T OTAL) 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
°
C160
°
C
140
°
C
Figure 6. Typical Solder Heating Profile
DESIRED CURVE FOR HIGH
MASS ASSEMBLIES 170
°
C
BAV70WT1
6 Motorola Small–Signal Transistors, FETs and Diodes Device Data
PACKAGE DIMENSIONS
CASE 419-02
ISSUE H
SC–70/SOT–323
CRN
AL
D
G
V
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
C0.035 0.049 0.90 1.25
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
R0.031 0.039 0.80 1.00
S0.079 0.087 2.00 2.20
V0.012 0.016 0.30 0.40
0.05 (0.002)
STYLE 5:
PIN 1. ANODE
2. ANODE
3. CATHODE
Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding
the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and
specifically disclaims any and all liability, including without limitation consequential or incidental damages. “T ypical” parameters which may be provided in Motorola
data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals”
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BAV70WT1/D
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