BAV70WT1-D - ON Semiconductor

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/°C

Thermal Resistance, Junction to Ambient RJA 0.625 °C/W

Total Device Dissipation

Alumina Substrate(2) TA = 25°C

Derate above 25°C

PD300

2.4

mW/°C

Thermal Resistance, Junction to Ambient RJA 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 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.

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

CATHODE

ANODE

BAV70WT1

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Figure 1. Recovery Time Equivalent Test Circuit

ure 2.

RS = 50 Ω

BAV70

SAMPLING

OSCILLOSCOPE

RL = 50 Ω

trtp

10%

90%

INPUT PULSE

+IFtrr OUTPUT PULSE

10%OF VR

100

RS = 50 Ω

BAV70 SAMPLING

OSCILLOSCOPE

RL = 50 Ω

1 KΩ450 Ω

90%

10%

trtp

INPUT PULSE

VFR

OUTPUT PULSE t

BAV70WT1

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100

0.2 0.4

VF, FORWARD VOLTAGE (VOLTS)

0.6 0.8 1.0 1.2

1.0

0.1

TA = 85°C

VR, REVERSE VOLTAGE (VOLTS)

1.0

0.1

0.01

0.001

10 20 30 40 50

1.0

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.

inches

0.035

0.9

0.075

0.7

1.9

0.028

0.65

0.025

0.65

0.025

BAV70WT1

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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.

BAV70WT1

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PACKAGE DIMENSIONS

CASE 419–04

ISSUE L

SC–70 (SOT–323)

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

BAV70WT1

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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

purpose, nor does SCILLC 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 special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC 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. SCILLC does not convey any license under its patent rights nor the rights of others.

SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications

intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or

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alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer.

PUBLICATION ORDERING INFORMATION

JAPAN: ON Semiconductor, Japan Customer Focus Center

4–32–1 Nishi–Gotanda, Shinagawa–ku, Tokyo, Japan 141–0031

Phone: 81–3–5740–2700

Email: r14525@onsemi.com

ON Semiconductor Website: http://onsemi.com

For additional information, please contact your local

Sales Representative.

BAV70WT1/D

Thermal Clad is a trademark of the Bergquist Company.

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