Datasheet BAV70WT1 Datasheet (Motorola)

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SEMICONDUCTOR TECHNICAL DATA

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MAXIMUM RATINGS (TA = 25°C)

Rating Symbol Max Unit

Reverse Voltage V
Forward Current I
Peak Forward Surge Current I

THERMAL CHARACTERISTICS

Characteristic Symbol Max Unit

Total Device Dissipation FR–5 Board

TA = 25°C

Derate above 25°C
Thermal Resistance, Junction to Ambient
Total Device Dissipation

Alumina Substrate

Derate above 25°C
Thermal Resistance, Junction to Ambient
Junction and Storage Temperature TJ, T

(2)

TA = 25°C

(1)

DEVICE MARKING

A4

ELECTRICAL CHARACTERISTICS (T

Characteristic

A

OFF CHARACTERISTICS

Reverse Breakdown Voltage

(I

= 100 µAdc)

(BR)

Reverse Voltage Leakage Current

(VR = 70 Vdc)

(VR = 50 Vdc)
Diode Capacitance

(VR = 0, f = 1.0 MHz)
Forward Voltage

(IF = 1.0 mAdc)

(IF = 10 mAdc)

(IF = 50 mAdc)

(IF = 150 mAdc)
Reverse Recovery Time

(IF = IR = 10 mAdc, RL = 100 Ω, I
Forward Recovery Voltage

(IF = 10 mAdc, tr = 20 ns) (Figure 2)

1. FR–5 = 1.0  0.75  0.062 in.

2. Alumina = 0.4  0.3  0.024 in. 99.5% alumina.

R(REC)

R

F

FM(surge)

P

D

R

q

JA

P

D

R

q

JA

stg

= 25°C unless otherwise noted)

= 1.0 mAdc) (Figure 1)

3

CATHODE

70 Vdc
200 mAdc
500 mAdc

200

1.6

0.625 °C/W
300

2.4

417 °C/W

–55 to +150 °C



ANODE

1

2

mW

mW/°C

mW

mW/°C

Symbol Min Max Unit

V

(BR)

I

R1

I

R2

C

D

V

F

t

rr

V

RF

Motorola Preferred Device

3

1

2

CASE 419–02, STYLE 5

SC–70/SOT–323

70 — Vdc

—
—

— 1.5 pF

—
—
—
—

— 6.0 ns

— 1.75 V

5.0

100

715

855
1000
1250

µAdc
nAdc

mVdc

Thermal Clad is a trademark of the Bergquist Company

Preferred devices are Motorola recommended choices for future use and best overall value.

Motorola Small–Signal Transistors, FETs and Diodes Device Data

 Motorola, Inc. 1997

1

BAV70WT1

RS = 50

Ω

BAV70

SAMPLING

I

F

OSCILLOSCOPE

RL = 50

Ω

t

r

10%

V

R

90%

t

p

INPUT PULSE

I

+I

F

t

rr

OUTPUT PULSE

V

100

R

W

10% OF

Figure 1. Recovery Time Equivalent Test Circuit

1 K

RS = 50

Ω

Ω

BAV70

450

Ω

SAMPLING

OSCILLOSCOPE

RL = 50

Ω

I

V

90%

V

FR

10%

t

t

r

2

t

p

INPUT PULSE

Figure 2.

OUTPUT PULSE

t

Motorola Small–Signal Transistors, FETs and Diodes Device Data

BAV70WT1

100

10

1.0

, FORWARD CURRENT (mA)

F

I

0.1

0.2 0.4

TA = 85°C

TA = –40°C

0.6 0.8 1.0

VF, FORWARD VOLTAGE (VOLTS)

TA = 25°C

1.2

A)

µ

, REVERSE CURRENT (

R

I

0.001

10

1.0

0.1

0.01

0

10 20 30 40

TA = 150°C
TA = 125°C

TA = 85°C

TA = 55°C

TA = 25°C

VR, REVERSE VOLTAGE (VOLTS)

Figure 3. Forward V oltage Figure 4. Leakage Current

1.0

0.9

50

, DIODE CAPACITANCE (pF)

D

C

0.8

0.7

0.6
0

2468

VR, REVERSE VOLTAGE (VOLTS)

Figure 5. Capacitance

Motorola Small–Signal Transistors, FETs and Diodes Device Data

3

BAV70WT1

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

0.025

0.65

0.035

0.9

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 T
temperature of the die, R

θJA

device junction to ambient; and the operating temperature,
TA. Using the values provided on the data sheet, PD can be
calculated as follows.

PD =

The values for the equation are found in the maximum
ratings table on the data sheet. Substituting these values into

, the maximum rated junction

J(max)

, the thermal resistance from the

T

J(max)

R

θJA

– T

A

0.028

0.7

interface between the board and the package. With the
correct pad geometry, the packages will self align when
subjected to a solder reflow process.

0.025

0.65

0.075

1.9

inches

mm

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.

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.

4

Motorola Small–Signal Transistors, FETs and Diodes Device Data

SOLDER STENCIL GUIDELINES

BAV70WT1

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

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

200

150

100

STEP 1

PREHEA T

ZONE 1
“RAMP”

°

C

DESIRED CURVE FOR HIGH

MASS ASSEMBLIES

°

C

°

C

STEP 2

VENT

“SOAK”

150°C

100°C

STEP 3

HEATING

ZONES 2 & 5

“RAMP”

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.

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 6

STEP 4

HEATING

ZONES 3 & 6

“SOAK”

°

C

160

°

C

140

STEP 5

HEATING

ZONES 4 & 7

“SPIKE”

170°C

SOLDER IS LIQUID FOR

40 TO 80 SECONDS

(DEPENDING ON

MASS OF ASSEMBLY)

STEP 7

VENT

COOLING

205

°

TO 219°C

PEAK AT

SOLDER JOINT

DESIRED CURVE FOR LOW

°

C

50

TIME (3 TO 7 MINUTES TOTAL)

MASS ASSEMBLIES

Figure 6. T ypical Solder Heating Profile

Motorola Small–Signal Transistors, FETs and Diodes Device Data

T

MAX

5

BAV70WT1

0.05 (0.002)

P ACKAGE DIMENSIONS

A

L

NOTES:

3

S

12

V

B

D

G

R

C

H

N

K

J

CASE 419-02

1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.

2. CONTROLLING DIMENSION: INCH.

DIM MIN MAX MIN MAX

A 0.071 0.087 1.80 2.20
B 0.045 0.053 1.15 1.35
C 0.035 0.049 0.90 1.25

D 0.012 0.016 0.30 0.40
G 0.047 0.055 1.20 1.40
H 0.000 0.004 0.00 0.10
J 0.004 0.010 0.10 0.25
K 0.017 REF 0.425 REF
L 0.026 BSC 0.650 BSC
N 0.028 REF 0.700 REF
R 0.031 0.039 0.80 1.00
S 0.079 0.087 2.00 2.20
V 0.012 0.016 0.30 0.40

STYLE 5:

PIN 1. ANODE

MILLIMETERSINCHES

2. ANODE

3. CATHODE

ISSUE H

SC–70/SOT–323

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”
must be validated for each customer application by customer’s technical experts. Motorola does not convey any license under its patent rights nor the rights of
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applications intended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury
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Opportunity/Affirmative Action Employer.

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6

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Motorola Small–Signal Transistors, FETs and Diodes Device Data

Mfax is a trademark of Motorola, Inc.

BAV70WT1/D