MMBT3904WT1-D - ON Semiconductor

 Semiconductor Components Industries, LLC, 2002

May, 2002 – Rev. 3 1Publication Order Number:

MMBT3904WT1/D

MMBT3904WT1, NPN

MMBT3906WT1, PNP

General Purpose

Transistors

NPN and PNP Silicon

These transistors are designed for general purpose amplifier

applications. They are housed in the SOT–323/SC–70 package which

is designed for low power surface mount applications.

MAXIMUM RATINGS

Rating Symbol Value Unit

Collector–Emitter Voltage

MMBT3904WT1

MMBT3906WT1

VCEO 40

–40

Vdc

Collector–Base Voltage

MMBT3904WT1

MMBT3906WT1

VCBO 60

–40

Vdc

Emitter–Base V oltage

MMBT3904WT1

MMBT3906WT1

VEBO 6.0

–5.0

Vdc

Collector Current – Continuous

MMBT3904WT1

MMBT3906WT1

IC200

–200

mAdc

THERMAL CHARACTERISTICS

Characteristic Symbol Max Unit

Total Device Dissipation (Note 1)

TA = 25°CPD150 mW

Thermal Resistance,

Junction to Ambient RJA 833 °C/W

Junction and Storage Temperature TJ, Tstg –55 to +150 °C

1. Device mounted on FR4 glass epoxy printed circuit board using the minimum

recommended footprint.

Device Package Shipping

ORDERING INFORMATION

MMBT3904WT1 SC–70

SC–70/SOT–323

CASE 419

STYLE 3

3000/Tape & Reel

MARKING DIAGRAM

AM M

AM = Specific Device Code

2A = Specific Device Code

M = Date Code

COLLECTOR

BASE

EMITTER

http://onsemi.com

MMBT3906WT1 SC–70 3000/Tape & Reel

2A M

MMBT3904WT1 MMBT3906WT1

MMBT3904WT1, NPN MMBT3906WT1, PNP

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ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise noted)

Characteristic Symbol Min Max Unit

OFF CHARACTERISTICS

Collector–Emitter Breakdown Voltage (Note 2)

(IC = 1.0 mAdc, IB = 0) MMBT3904WT1

(IC = –1.0 mAdc, IB = 0) MMBT3906WT1

V(BR)CEO 40

–40 –

–

Vdc

Collector–Base Breakdown Voltage

(IC = 10 Adc, IE = 0) MMBT3904WT1

(IC = –10 Adc, IE = 0) MMBT3906WT1

V(BR)CBO 60

–40 –

–

Vdc

Emitter–Base Breakdown Voltage

(IE = 10 Adc, IC = 0) MMBT3904WT1

(IE = –10 Adc, IC = 0) MMBT3906WT1

V(BR)EBO 6.0

–5.0 –

–

Vdc

Base Cutoff Current

(VCE = 30 Vdc, VEB = 3.0 Vdc) MMBT3904WT1

(VCE = –30 Vdc, VEB = –3.0 Vdc) MMBT3906WT1

IBL –

–50

nAdc

Collector Cutoff Current

(VCE = 30 Vdc, VEB = 3.0 Vdc) MMBT3904WT1

(VCE = –30 Vdc, VEB = –3.0 Vdc) MMBT3906WT1

ICEX –

–50

nAdc

ON CHARACTERISTICS (Note 2)

DC Current Gain

(IC = 0.1 mAdc, VCE = 1.0 Vdc) MMBT3904WT1

(IC = 1.0 mAdc, VCE = 1.0 Vdc)

(IC = 10 mAdc, VCE = 1.0 Vdc)

(IC = 50 mAdc, VCE = 1.0 Vdc)

(IC = 100 mAdc, VCE = 1.0 Vdc)

(IC = –0.1 mAdc, VCE = –1.0 Vdc) MMBT3906WT1

(IC = –1.0 mAdc, VCE = –1.0 Vdc)

(IC = –10 mAdc, VCE = –1.0 Vdc)

(IC = –50 mAdc, VCE = –1.0 Vdc)

(IC = –100 mAdc, VCE = –1.0 Vdc)

hFE 40

100

–

300

–

300

–

Collector–Emitter Saturation Voltage

(IC = 10 mAdc, IB = 1.0 mAdc) MMBT3904WT1

(IC = 50 mAdc, IB = 5.0 mAdc)

(IC = –10 mAdc, IB = –1.0 mAdc) MMBT3906WT1

(IC = –50 mAdc, IB = –5.0 mAdc)

VCE(sat) –

–

0.2

0.3

–0.25

–0.4

Vdc

Base–Emitter Saturation Voltage

(IC = 10 mAdc, IB = 1.0 mAdc) MMBT3904WT1

(IC = 50 mAdc, IB = 5.0 mAdc)

(IC = –10 mAdc, IB = –1.0 mAdc) MMBT3906WT1

(IC = –50 mAdc, IB = –5.0 mAdc)

VBE(sat) 0.65

–

–0.65

–

0.85

0.95

–0.85

–0.95

Vdc

2. Pulse Test: Pulse Width  300 s; Duty Cycle  2.0%.

MMBT3904WT1, NPN MMBT3906WT1, PNP

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ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise noted) (Continued)

Characteristic Symbol Min Max Unit

SMALL–SIGNAL CHARACTERISTICS

Current–Gain – Bandwidth Product

(IC = 10 mAdc, VCE = 20 Vdc, f = 100 MHz) MMBT3904WT1

(IC = –10 mAdc, VCE = –20 Vdc, f = 100 MHz) MMBT3906WT1

fT300

250 –

–

MHz

Output Capacitance

(VCB = 5.0 Vdc, IE = 0, f = 1.0 MHz) MMBT3904WT1

(VCB = –5.0 Vdc, IE = 0, f = 1.0 MHz) MMBT3906WT1

Cobo –

–4.0

4.5

Input Capacitance

(VEB = 0.5 Vdc, IC = 0, f = 1.0 MHz) MMBT3904WT1

(VEB = –0.5 Vdc, IC = 0, f = 1.0 MHz) MMBT3906WT1

Cibo –

–8.0

10.0

Input Impedance

(VCE = 10 Vdc, IC = 1.0 mAdc, f = 1.0 kHz) MMBT3904WT1

(VCE = –10 Vdc, IC = –1.0 mAdc, f = 1.0 kHz) MMBT3906WT1

hie 1.0

2.0 10

k Ω

Voltage Feedback Ratio

(VCE = 10 Vdc, IC = 1.0 mAdc, f = 1.0 kHz) MMBT3904WT1

(VCE = –10 Vdc, IC = –1.0 mAdc, f = 1.0 kHz) MMBT3906WT1

hre 0.5

0.1 8.0

X 10–4

Small–Signal Current Gain

(VCE = 10 Vdc, IC = 1.0 mAdc, f = 1.0 kHz) MMBT3904WT1

(VCE = –10 Vdc, IC = –1.0 mAdc, f = 1.0 kHz) MMBT3906WT1

hfe 100

100 400

400

–

Output Admittance

(VCE = 10 Vdc, IC = 1.0 mAdc, f = 1.0 kHz) MMBT3904WT1

(VCE = –10 Vdc, IC = –1.0 mAdc, f = 1.0 kHz) MMBT3906WT1

hoe 1.0

3.0 40

mhos

Noise Figure

(VCE = 5.0 Vdc, IC = 100 Adc, RS = 1.0 k Ω, f = 1.0 kHz) MMBT3904WT1

(VCE = –5.0 Vdc, IC = –100 Adc, RS = 1.0 k Ω, f = 1.0 kHz) MMBT3906WT1

NF –

–5.0

4.0

SWITCHING CHARACTERISTICS

Characteristic Condition Symbol Min Max Unit

Delay Time (VCC = 3.0 Vdc, VBE = –0.5 Vdc) MMBT3904WT1

(VCC = –3.0 Vdc, VBE = 0.5 Vdc) MMBT3906WT1 td–

–35

35 ns

Rise Time (IC = 10 mAdc, IB1 = 1.0 mAdc) MMBT3904WT1

(IC = –10 mAdc, IB1 = –1.0 mAdc) MMBT3906WT1 tr–

–35

Storage Time (VCC = 3.0 Vdc, IC = 10 mAdc) MMBT3904WT1

(VCC = –3.0 Vdc, IC = –10 mAdc) MMBT3906WT1 ts–

–200

225 ns

Fall Time (IB1 = IB2 = 1.0 mAdc) MMBT3904WT1

(IB1 = IB2 = –1.0 mAdc) MMBT3906WT1 tf–

–50

MMBT3904WT1

Figure 1. Delay and Rise Time

Equivalent Test Circuit Figure 2. Storage and Fall Time

Equivalent Test Circuit

+3 V

275

10 k

1N916 CS < 4 pF*

+3 V

275

10 k

CS < 4 pF*

< 1 ns

-0.5 V

+10.9 V

300 ns

DUTY CYCLE = 2%

< 1 ns

-9.1 V

+10.9 V

DUTY CYCLE = 2%

10 < t1 < 500 s

* Total shunt capacitance of test jig and connectors

MMBT3904WT1, NPN MMBT3906WT1, PNP

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MMBT3904WT1

TYPICAL TRANSIENT CHARACTERISTICS

Figure 3. Turn–On Time

IC, COLLECTOR CURRENT (mA)

100

200

300

500

Figure 4. Rise Time

IC, COLLECTOR CURRENT (mA)

TIME (ns)

1.0 2.0 3.0 10 20 70

5100

t , RISE TIME (ns)

Figure 5. Storage Time

IC, COLLECTOR CURRENT (mA)

Figure 6. Fall Time

IC, COLLECTOR CURRENT (mA)

5.0 7.0 30 50 200

100

200

300

500

1.0 2.0 3.0 10 20 70

5100

5.0 7.0 30 50 200

100

200

300

500

1.0 2.0 3.0 10 20 70

5100

5.0 7.0 30 50 200

100

200

300

500

1.0 2.0 3.0 10 20 70

5100

5.0 7.0 30 50 200

t , FALL TIME (ns)

t , STORAGE TIME (ns)

′

VCC = 40 V

IC/IB = 10

VCC = 40 V

IB1 = IB2

IC/IB = 20

IC/IB = 10

tr @ VCC = 3.0 V

td @ VOB = 0 V

40 V

15 V

2.0 V

IC/IB = 10

IC/IB = 20

IC/IB = 10

IC/IB = 20

t′s = ts - 1/8 tf

IB1 = IB2

MMBT3904WT1 MMBT3904WT1

TJ = 25°C

TJ = 125°C

MMBT3904WT1, NPN MMBT3906WT1, PNP

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MMBT3904WT1

TYPICAL AUDIO SMALL–SIGNAL CHARACTERISTICS

NOISE FIGURE VARIATIONS

(VCE = 5.0 Vdc, TA = 25°C, Bandwidth = 1.0 Hz)

Figure 7. Noise Figure

f, FREQUENCY (kHz)

0.1

Figure 8. Noise Figure

RS, SOURCE RESISTANCE (k OHMS)

NF, NOISE FIGURE (dB)

1.0 2.0 4.0 10 20 40

0.2 0.4

0100

0.1 1.0 2.0 4.0 10 20 40

0.2 0.4 100

NF, NOISE FIGURE (dB)

f = 1.0 kHz IC = 1.0 mA

IC = 0.5 mA

IC = 50 A

IC = 100 A

SOURCE RESISTANCE = 200 

IC = 1.0 mA

SOURCE RESISTANCE = 200 

IC = 0.5 mA

SOURCE RESISTANCE = 500 

IC = 100 A

SOURCE RESISTANCE = 1.0 k

IC = 50 A

MMBT3904WT1 MMBT3904WT1

h PARAMETERS

(VCE = 10 Vdc, f = 1.0 kHz, TA = 25°C)

Figure 9. Current Gain

IC, COLLECTOR CURRENT (mA)

100

200

300

Figure 10. Output Admittance

IC, COLLECTOR CURRENT (mA)

h , CURRENT GAIN

h , OUTPUT ADMITTANCE ( mhos)

Figure 11. Input Impedance

IC, COLLECTOR CURRENT (mA)

Figure 12. Voltage Feedback Ratio

IC, COLLECTOR CURRENT (mA)

100

2.0

3.0

5.0

7.0

1.0

0.1 0.2 1.0 2.0 5.0

0.5

0.3 0.5 3.0

0.7

2.0

5.0

1.0

0.2

0.5

h , VOLTAGE FEEDBACK RATIO (X 10 )

h , INPUT IMPEDANCE (k OHMS)

0.1 0.2 1.0 2.0 5.0 10

0.3 0.5 3.0

0.1 0.2 1.0 2.0 5.0 10

0.3 0.5 3.0

0.1 0.2 1.0 2.0 5.0 10

0.3 0.5 3.0



-4

MMBT3904WT1 MMBT3904WT1

MMBT3904WT1, NPN MMBT3906WT1, PNP

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MMBT3904WT1

TYPICAL STATIC CHARACTERISTICS

Figure 13. DC Current Gain

IC, COLLECTOR CURRENT (mA)

0.3

0.5

0.7

1.0

2.0

0.2

0.1

h , DC CURRENT GAIN (NORMALIZED)

0.5 2.0 3.0 10 50 70

0.2 0.3

0.1 100

1.00.7 200

30205.0 7.0

VCE = 1.0 V

TJ = +125°C

+25°C

-55°C

MMBT3904WT1

Figure 14. Collector Saturation Region

IB, BASE CURRENT (mA)

0.4

0.6

0.8

1.0

0.2

0.1

V , COLLECTOR EMITTER VOLTAGE (VOLTS)

0.5 2.0 3.0 100.2 0.3

01.00.7 5.0 7.0

IC = 1.0 mA

TJ = 25°C

0.070.050.030.020.01

10 mA 30 mA 100 mA

MMBT3904WT1

Figure 15. “ON” Voltages

IC, COLLECTOR CURRENT (mA)

0.4

0.6

0.8

1.0

1.2

0.2

Figure 16. Temperature Coefficients

IC, COLLECTOR CURRENT (mA)

V, VOLTAGE (VOLTS)

1.0 2.0 5.0 10 20 50

0100

-0.5

0.5

1.0

0 60 80 120 140 160 180

20 40 100

COEFFICIENT (mV/ C)

200

-1.0

-1.5

-2.0

200

TJ = 25°C

VBE(sat) @ IC/IB =10

VCE(sat) @ IC/IB =10

VBE @ VCE =1.0 V

+25°C TO +125°C

-55°C TO +25°C

+25°C TO +125°C

-55°C TO +25°C

VC FOR VCE(sat)

VB FOR VBE(sat)

MMBT3904WT1 MMBT3904WT1

MMBT3904WT1, NPN MMBT3906WT1, PNP

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MMBT3904WT1

Figure 17. Capacitance

REVERSE BIAS VOLTAGE (VOLTS)

2.0

3.0

5.0

7.0

1.0

0.1

CAPACITANCE (pF)

1.0 2.0 3.0 5.0 7.0 10 20 30 40

0.2 0.3 0.5 0.7

Cibo

Cobo

TJ = 25°C

TJ = 125°C

MMBT3904WT1

MMBT3904WT1, NPN MMBT3906WT1, PNP

http://onsemi.com

MMBT3906WT1

Figure 18. Delay and Rise Time

Equivalent Test Circuit Figure 19. Storage and Fall Time

Equivalent Test Circuit

3 V

275

10 k

1N916 CS < 4 pF*

3 V

275

10 k

CS < 4 pF*

< 1 ns

+10.6 V 300 ns

DUTY CYCLE = 2%

< 1 ns

+9.1 V

10.9 V

DUTY CYCLE = 2%

10 < t1 < 500 s

* Total shunt capacitance of test jig and connectors

TYPICAL TRANSIENT CHARACTERISTICS

TJ = 25°C

TJ = 125°C

Figure 20. Turn–On Time

IC, COLLECTOR CURRENT (mA)

100

200

300

500

TIME (ns)

1.0 2.0 3.0 10 20 70

5100

5.0 7.0 30 50 200

IC/IB = 10

tr @ VCC = 3.0 V

td @ VOB = 0 V

40 V

15 V

2.0 V

MMBT3906WT1

Figure 21. Fall Time

IC, COLLECTOR CURRENT (mA)

100

200

300

500

1.0 2.0 3.0 10 20 70

5100

5.0 7.0 30 50 200

t , FALL TIME (ns)

VCC = 40 V

IB1 = IB2

IC/IB = 20

IC/IB = 10

MMBT3906WT1

TYPICAL AUDIO SMALL–SIGNAL CHARACTERISTICS

NOISE FIGURE VARIATIONS

(VCE = –5.0 Vdc, TA = 25°C, Bandwidth = 1.0 Hz)

f = 1.0 kHz IC = 1.0 mA

IC = 0.5 mA

IC = 50 A

IC = 100 A

SOURCE RESISTANCE = 200 

IC = 1.0 mA

SOURCE RESISTANCE = 200 

IC = 0.5 mA

SOURCE RESISTANCE = 2.0 k

IC = 100 A

SOURCE RESISTANCE = 2.0 k

IC = 50 A

Figure 22.

f, FREQUENCY (kHz)

1.0

2.0

3.0

4.0

5.0

0.1

Figure 23.

RS, SOURCE RESISTANCE (kΩ)

NF, NOISE FIGURE (dB)

1.0 2.0 4.0 10 20 40

0.2 0.4

100

4.0

6.0

8.0

2.0

0.1 1.0 2.0 4.0 10 20 40

0.2 0.4 100

NF, NOISE FIGURE (dB)

MMBT3906WT1 MMBT3906WT1

MMBT3904WT1, NPN MMBT3906WT1, PNP

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MMBT3906WT1

h PARAMETERS

hfe, CURRENT GAIN

Figure 24. Current Gain

IC, COLLECTOR CURRENT (mA)

100

200

300

Figure 25. Output Admittance

IC, COLLECTOR CURRENT (mA)

h , OUTPUT ADMITTANCE ( mhos)

Figure 26. Input Impedance

IC, COLLECTOR CURRENT (mA)

Figure 27. Voltage Feedback Ratio

IC, COLLECTOR CURRENT (mA)

100

2.0

3.0

5.0

7.0

1.0

0.1 0.2 1.0 2.0 5.0

0.5

0.7

2.0

5.0

1.0

0.2

0.5

h , VOLTAGE FEEDBACK RATIO (X 10 )

h , INPUT IMPEDANCE (k

0.1 0.2 1.0 2.0 5.0 10

0.5

0.1 0.2 1.0 2.0 5.0 10

0.5

7.0

5.0

0.1 0.2 1.0 2.0 5.0 10

0.5



-4

(VCE = –10 Vdc, f = 1.0 kHz, TA = 25°C)

Ω)

MMBT3906WT1 MMBT3906WT1

0.3 0.7 3.0 7.0 0.3 0.7 3.0 7.0

0.3

0.7

3.0

7.0

0.3 0.7 3.0 7.0 0.3 0.7 3.0 7.0

MMBT3904WT1, NPN MMBT3906WT1, PNP

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MMBT3906WT1

STATIC CHARACTERISTICS

Figure 28. DC Current Gain

IC, COLLECTOR CURRENT (mA)

0.3

0.5

0.7

1.0

2.0

0.2

0.1

h , DC CURRENT GAIN (NORMALIZED)

0.5 2.0 3.0 10 50 70

0.2 0.3

0.1

100

1.00.7 200

30205.0 7.0

VCE = 1.0 V

TJ = +125°C

+25°C

-55°C

MMBT3906WT1

Figure 29. Collector Saturation Region

IB, BASE CURRENT (mA)

0.4

0.6

0.8

1.0

0.2

0.1

V , COLLECTOR EMITTER VOLTAGE (VOLTS)

0.5 2.0 3.0 100.2 0.3

01.00.7 5.0 7.0

IC = 1.0 mA

TJ = 25°C

0.070.050.030.020.01

10 mA 30 mA 100 mA

MMBT3906WT1

Figure 30. “ON” Voltages

IC, COLLECTOR CURRENT (mA)

0.4

0.6

0.8

1.0

0.2

Figure 31. Temperature Coefficients

IC, COLLECTOR CURRENT (mA)

V, VOLTAGE (VOLTS)

1.0 2.0 5.0 10 20 50

100

-0.5

0.5

1.0

0 60 80 120 140 160 180

20 40 100 200

-1.0

-1.5

-2.0

200

TJ = 25°CVBE(sat) @ IC/IB = 10

VCE(sat) @ IC/IB = 10

VBE @ VCE = 1.0 V +25°C TO +125°C

-55°C TO +25°C

+25°C TO +125°C

-55°C TO +25°C

VC FOR VCE(sat)

VS FOR VBE(sat)

V, TEMPERATURE COEFFICIENTS (mV/ C)°θ

MMBT3906WT1 MMBT3906WT1

MMBT3904WT1, NPN MMBT3906WT1, PNP

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MMBT3906WT1

Cibo

Cobo

Figure 32. Capacitance

REVERSE BIAS VOLTAGE (VOLTS)

2.0

3.0

5.0

7.0

1.0

0.1

CAPACITANCE (pF)

1.0 2.0 3.0 5.0 7.0 10 20 30 40

0.2 0.3 0.5 0.7

TJ = 25°C

TJ = 125°C

MMBT3906WT1

MMBT3904WT1, NPN MMBT3906WT1, PNP

http://onsemi.com

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

MMBT3904WT1, NPN MMBT3906WT1, PNP

http://onsemi.com

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 33. 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 to the next. Figure 33 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.

MMBT3904WT1, NPN MMBT3906WT1, PNP

http://onsemi.com

PACKAGE DIMENSIONS

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 3:

PIN 1. BASE

2. EMITTER

3. COLLECTOR

SC–70/SOT–323

CASE 419–04

ISSUE L

MMBT3904WT1, NPN MMBT3906WT1, PNP

http://onsemi.com

Notes

MMBT3904WT1, NPN MMBT3906WT1, PNP

http://onsemi.com

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