AN24

Application Note 24
Issue 2 January 1996
An Introduction to the SM-8 Package
Mike Townson
Introduction
Over recent years the benefits for
companies to move to surface mount
technology has lead to significant
growth in the component industry. The
requirements on the component
suppliers is to provide either smaller
components or components containing
more than one device. The aim being to
reduce PCB size and the number of
component placements, thus reducing
overall costs. Zetex is expanding it’s
range of surface mount packages to
meet these demands. The first in this
new series of packages to be introduced
is the SM-8.
What is SM-8?
The SM-8 package has evolved from the
industry standard SOT223 surface
mount package. The development of a
new lead frame, whilst maintaining the
physical outline of the standard
package, effectively gives two
trans istors in a package initially
designed for one. Figure 1 illustrates the
package.
Figure 1
The SM-8 package.
Package Construction
The SM-8 is an eight pin device that can
be configured in two ways due to
different lead frame options. Both frame
options enable two totally independent
devices to be assembled into the same
package.
The first frame option has eight
independent pins enabling two devices
that require four connections to be
assembled in the package, for example
two high side drivers, such as the Zetex
ZHD100 BiMos switch.
The second frame option has two sets of
two pins connected internally,
effectively allowing the assembly of two
devices requiring three connections, for
AN 24 - 1
Application Note 24
Issue 2 January 1996
The thermal capability of the package
depends somewhat on the devices that
are assembled within it, and will be
detailed for each device assembly on the
appropriate datasheet. However for
illustrative purposes, the dual Bipolar
transistor ZDT1048 device is used here
as an example. Figures 2 and 3 show the
transient and DC thermal resistance
response for the ZDT1048 device, when
one and two devices are powered
respectively, and show DC values of
thermal resistance of 55.6 and 45.5°C/W.
This leads to a package power handling
capability of 2.75W at an ambient
temperature of 25°C, when both devices
are turned on equally. If the circuit
operation is such that only one of the
devices is on at once, then the capable
dissipation is 2.25W. The data for the
above was derived from thermal
resistance measurements with the
package mounted on a standard FR4
PCB with a copper area of 2 inches
square. As with any surface mount
component, the actual thermal
resistance achieved depends on many
The latter is particularly effective in
dissipating heat as the internal copper
traces encourage lateral heat flow within
the board, therefore possibly increasing
the area from which the heat is
dissipated. Figure 4 shows how the
thermal resistance varies with single
copper sided FR4 PCB area.
D=1(D.C.)
t1
50
40
D=t1
tP
120
Thermal Resistance ( C/W)
Thermal Capability
Single device on
56
Thermal Resistance ( C/W)
The body of the device is a moulded
epoxy and the leads are tin/lead plated.
The dimensions of the package and
pinout detail for transistors is provided
in Appendix A.
factors including the board area, the
board material, proximity of passive and
other components, and whether the
board is single, double sided or
multi-layer.
tP
D=0.5
30
D=0.2
D=0.1
D=0.05
20
10
Single Pulse
0
100µ
1m
10m
100m
10
1
100
Pulse Width (Sec)
100
80
20
1
10
PCB Area (square inches)
Electrical Specification
D=1(D.C.)
t1
40
D=t1
tP
30
tP
D=0.5
20
D=0.2
D=0.1
D=0.05
10
Single Pulse
0
100µ
1m
10m
100m
1
10
100
Pulse Width (Sec)
Transient Thermal Resistance
Figure 3
Transient Thermal Resistance Curves for
the ZDT1048 - Both Devices on.
AN 24 - 2
Overall the SM-8 package offers Zetex
and it’s customers the flexibility to
provide innovative and cost effective
circuit solutions.
Applications
Figure 4
Thermal Resistance vs PCB Area (Single
Copper Layer on FR4).
Both devices on
46
The product range is still in its infancy.
New products are being introduced on a
gradual basis as new opportunities are
identified. An introductory range has
been generated to demonstrate the
options that are available to design
engineers, This includes dual NPN or
PNP transistors, NPN and PNP
combinations, MOSFET combinations,
dual high side drivers, and various
Linear IC combinations.
40
0.1
Figure 2
Transient Thermal Resistance Curves for
the ZDT1048 - Single Device on.
Product Range
Future developments will include dual
IGBTs, and linear ICs/discrete
component combinations.
60
0
Transient Thermal Resistance
Thermal Resistance ( C/W)
example two Bipolar transistors or
MOSFETs. The two common pins are
internally connected to the frame onto
which the transistor die is attached, and
through which the collector or drain
connection is made. This provides a low
thermal resistance, and therefore allows
a good transfer of heat away from the
semiconductor chip through the frame,
and onto the board or substrate.
Application Note 24
Issue 2 January 1996
Theoretically any combination of two
chips from the Zetex range of
components can be assembled in the
SM-8 package, however, commercial
i m p l i c a t i o n s w i l l b e t a k e n i n to
consideration before introduction. This
gives a potential current handling
capability up to 5 Amps continuous with
20 Amps pulsed and voltages ranging
from 10 to 450 Volts. Appendix B
reproduces a datasheet for one of the
dual transistor products - the ZDT1048.
This devic e has been developed
specifically for service within LCD
Backlight Inverters.
For discrete component combinations
the opportunities will lie in designs
using push pull circuits, half or full
bridges, Royer converters or high side
drivers. These can be found in such
applications as compact fluorescent
bal lasts , eme rge ncy lighting, LCD
backlighting, motor drives and siren
drivers.
As an example of how the SM-8 package
can transform a product, Figure 5 shows
how Mitel Semiconductors have been
able to reduce the size of their SLIC
hybrid (part # MH88615) by replacing 4
SOT223 packaged devices with 2 SM-8s.
The SLIC (Subscriber Line Interface
Card) provides a complete interface
between a switching system and a
subscriber loop.
AN 24 - 3
Application Note 24
Issue 2 January 1996
The thermal capability of the package
depends somewhat on the devices that
are assembled within it, and will be
detailed for each device assembly on the
appropriate datasheet. However for
illustrative purposes, the dual Bipolar
transistor ZDT1048 device is used here
as an example. Figures 2 and 3 show the
transient and DC thermal resistance
response for the ZDT1048 device, when
one and two devices are powered
respectively, and show DC values of
thermal resistance of 55.6 and 45.5°C/W.
This leads to a package power handling
capability of 2.75W at an ambient
temperature of 25°C, when both devices
are turned on equally. If the circuit
operation is such that only one of the
devices is on at once, then the capable
dissipation is 2.25W. The data for the
above was derived from thermal
resistance measurements with the
package mounted on a standard FR4
PCB with a copper area of 2 inches
square. As with any surface mount
component, the actual thermal
resistance achieved depends on many
The latter is particularly effective in
dissipating heat as the internal copper
traces encourage lateral heat flow within
the board, therefore possibly increasing
the area from which the heat is
dissipated. Figure 4 shows how the
thermal resistance varies with single
copper sided FR4 PCB area.
D=1(D.C.)
t1
50
40
D=t1
tP
120
Thermal Resistance ( C/W)
Thermal Capability
Single device on
56
Thermal Resistance ( C/W)
The body of the device is a moulded
epoxy and the leads are tin/lead plated.
The dimensions of the package and
pinout detail for transistors is provided
in Appendix A.
factors including the board area, the
board material, proximity of passive and
other components, and whether the
board is single, double sided or
multi-layer.
tP
D=0.5
30
D=0.2
D=0.1
D=0.05
20
10
Single Pulse
0
100µ
1m
10m
100m
10
1
100
Pulse Width (Sec)
100
80
20
1
10
PCB Area (square inches)
Electrical Specification
D=1(D.C.)
t1
40
D=t1
tP
30
tP
D=0.5
20
D=0.2
D=0.1
D=0.05
10
Single Pulse
0
100µ
1m
10m
100m
1
10
100
Pulse Width (Sec)
Transient Thermal Resistance
Figure 3
Transient Thermal Resistance Curves for
the ZDT1048 - Both Devices on.
AN 24 - 2
Overall the SM-8 package offers Zetex
and it’s customers the flexibility to
provide innovative and cost effective
circuit solutions.
Applications
Figure 4
Thermal Resistance vs PCB Area (Single
Copper Layer on FR4).
Both devices on
46
The product range is still in its infancy.
New products are being introduced on a
gradual basis as new opportunities are
identified. An introductory range has
been generated to demonstrate the
options that are available to design
engineers, This includes dual NPN or
PNP transistors, NPN and PNP
combinations, MOSFET combinations,
dual high side drivers, and various
Linear IC combinations.
40
0.1
Figure 2
Transient Thermal Resistance Curves for
the ZDT1048 - Single Device on.
Product Range
Future developments will include dual
IGBTs, and linear ICs/discrete
component combinations.
60
0
Transient Thermal Resistance
Thermal Resistance ( C/W)
example two Bipolar transistors or
MOSFETs. The two common pins are
internally connected to the frame onto
which the transistor die is attached, and
through which the collector or drain
connection is made. This provides a low
thermal resistance, and therefore allows
a good transfer of heat away from the
semiconductor chip through the frame,
and onto the board or substrate.
Application Note 24
Issue 2 January 1996
Theoretically any combination of two
chips from the Zetex range of
components can be assembled in the
SM-8 package, however, commercial
i m p l i c a t i o n s w i l l b e t a k e n i n to
consideration before introduction. This
gives a potential current handling
capability up to 5 Amps continuous with
20 Amps pulsed and voltages ranging
from 10 to 450 Volts. Appendix B
reproduces a datasheet for one of the
dual transistor products - the ZDT1048.
This devic e has been developed
specifically for service within LCD
Backlight Inverters.
For discrete component combinations
the opportunities will lie in designs
using push pull circuits, half or full
bridges, Royer converters or high side
drivers. These can be found in such
applications as compact fluorescent
bal lasts , eme rge ncy lighting, LCD
backlighting, motor drives and siren
drivers.
As an example of how the SM-8 package
can transform a product, Figure 5 shows
how Mitel Semiconductors have been
able to reduce the size of their SLIC
hybrid (part # MH88615) by replacing 4
SOT223 packaged devices with 2 SM-8s.
The SLIC (Subscriber Line Interface
Card) provides a complete interface
between a switching system and a
subscriber loop.
AN 24 - 3
Application Note 24
Issue 2 January 1996
Figure 5
Mitel SLIC Hybrid using SM-8 Dual
transistors.
Future Developments
Evaluation is ongoing of suitable four
chip assemblies including a ’H’-Bridge
configuration (4 transistors), an
anti-parallel diode protected half-bridge
(2 transistors and 2 diodes) and Schottky
diode bridges. Plans are already
underway to develop an 8 lead version
of the smaller SOT23 package, again
with the aim of offering two independent
devices in one package. This part will be
called the SSM-8, and it is expected that
u s i n g v a r i a n t s o f th e S u p e r S O T
geometry will enable the package to
house two 15V devices, individually
capable of conducting up to 3A
continuous, and 12A under pulsed
conditions.
AN 24 - 4
Application Note 24
Issue 2 January 1996
Appendix A
Dimensional and Pinout details
He
A
PIN
NUMBER
BIPOLARS
MOSFETS
1
E2
S2
2
B2
G2
3
E1
S1
4
B1
G1
5
C1
D1
6
C1
D1
7
C2
D2
8
C2
D2
4
3
2
8
e1
1
D
e2
5
6
A1
7
b
E
o
45°
c
Pinout details for dual Bipolar
and MOSFET products.
Lp
3
Dim
Millimetres
Min
A
A1
–
0.02
Max
Min
Typ
Max
–
1.7
–
–
0.067
–
0.1
0.0008
–
0.004
–
0.028
–
c
0.24
–
0.32
0.009
–
0.013
D
6.3
–
6.7
0.248
–
0.264
E
3.3
–
3.7
b
–
Typ
Inches
0.7
–
0.130
–
0.145
e1
–
4.59
–
–
0.180
–
e2
–
1.53
–
–
0.060
–
He
6.7
–
7.3
0.264
–
0.287
Lp
0.9
–
–
0.035
–
–
α
–
–
15°
–
–
15°
β
–
10°
–
–
10°
–
Dimensional detail.
AN 24 - 5
Application Note 24
Issue 2 January 1996
Appendix B
Sample Datasheet
ELECTRICAL CHARACTERISTICS (at Tamb = 25°C unless otherwise
stated).
SM-8 DUAL NPN MEDIUM POWER
HIGH GAIN TRANSISTORS
ZDT1048
ISSUE 2 - FEBRUARY 1996
C1
B1
C1
E1
C2
B2
C2
E2
SM-8
(8 LEAD SOT223)
PARTMARKING DETAIL – T1048
ABSOLUTE MAXIMUM RATINGS.
PARAMETER
SYMBOL
VALUE
UNIT
V
V
Collector-Base Voltage
VCBO
50
Collector-Emitter Voltage
VCEO
17.5
Emitter-Base Voltage
VEBO
5
V
Peak Pulse Current
ICM
20
A
Continuous Collector Current
IC
5
A
Base Current
IB
500
mA
Operating and Storage Temperature Range
Tj:Tstg
-55 to +150
°C
THERMAL CHARACTERISTICS
PARAMETER
SYMBOL
Total Power Dissipation at T amb = 25°C*
Any single die “on”
Both die “on” equally
Ptot
Derate above 25°C*
Any single die “on”
Both die “on” equally
Thermal Resistance - Junction to Ambient*
Any single die “on”
Both die “on” equally
VALUE
UNIT
2.25
2.75
W
W
18
22
mW/ °C
mW/ °C
55.6
45.5
°C/ W
°C/ W
* The power which can be dissipated assuming the device is mounted in a typical manner on a
PCB with copper equal to 2 inches square.
AN 24 - 6
Application Note 24
Issue 2 January 1996
PARAMETER
SYMBOL MIN.
TYP.
UNIT
CONDITIONS.
Collector-Base
Breakdown Voltage
V (BR)CBO 50
85
V
IC=100µA
Collector-Emitter
Breakdown Voltage
VCES
50
85
V
IC=100µA
Collector-Emitter
Breakdown Voltage
VCEO
17.5
24
V
IC=10mA
Collector-Emitter
Breakdown Voltage
VCEV
50
85
V
IC=100µA, VEB=1V
Emitter-Base
Breakdown Voltage
V(BR)EBO 5
8.7
V
IE=100µA
Collector Cutoff Current
ICBO
0.3
10
nA
VCB=35V
Emitter Cutoff Current
I EBO
0.3
10
nA
VEB=4V
Collector Emitter Cutoff
Current
ICES
0.3
10
nA
VCES=35V
Collector-Emitter
Saturation Voltage
VCE(sat)
27
55
120
200
200
45
75
160
240
300
mV
mV
mV
mV
mV
IC=0.5A, IB=10mA*
IC=1A, IB=10mA*
IC=2A, IB=10mA*
IC=5A, IB=100mA*
IC=5A, IB=50mA*
Base-Emitter
Saturation Voltage
VBE(sat)
1000
1100
mV
IC=5A, IB=100mA*
Base-Emitter Turn-On
Voltage
VBE(on)
900
1000
mV
IC=5A, VCE=2V*
Static Forward Current
Transfer Ratio
hFE
280
300
300
250
50
440
450
450
300
80
Transition Frequency
fT
150
Output Capacitance
Cobo
60
ton
toff
Switching Times
MAX.
IC=10mA, VCE=2V*
IC=0.5A, VCE=2V*
IC=1A, VCE=2V*
IC=5A, VCE=2V*
IC=20A, V CE=2V*
1200
MHz
IC=50mA, VCE=10V
f=50MHz
pF
VCB=10V, f=1MHz
120
ns
IC=4A, IB=40mA,
VCC=10V
250
ns
IC=4A, IB=±40mA,
VCC=10V
80
*Measured under pulsed conditions. Pulse width=300µs. Duty cycle ≤ 2%
AN 24 - 7
Application Note 24
Issue 2 January 1996
Appendix B
Sample Datasheet
ELECTRICAL CHARACTERISTICS (at Tamb = 25°C unless otherwise
stated).
SM-8 DUAL NPN MEDIUM POWER
HIGH GAIN TRANSISTORS
ZDT1048
ISSUE 2 - FEBRUARY 1996
C1
B1
C1
E1
C2
B2
C2
E2
SM-8
(8 LEAD SOT223)
PARTMARKING DETAIL – T1048
ABSOLUTE MAXIMUM RATINGS.
PARAMETER
SYMBOL
VALUE
UNIT
V
V
Collector-Base Voltage
VCBO
50
Collector-Emitter Voltage
VCEO
17.5
Emitter-Base Voltage
VEBO
5
V
Peak Pulse Current
ICM
20
A
Continuous Collector Current
IC
5
A
Base Current
IB
500
mA
Operating and Storage Temperature Range
Tj:Tstg
-55 to +150
°C
THERMAL CHARACTERISTICS
PARAMETER
SYMBOL
Total Power Dissipation at T amb = 25°C*
Any single die “on”
Both die “on” equally
Ptot
Derate above 25°C*
Any single die “on”
Both die “on” equally
Thermal Resistance - Junction to Ambient*
Any single die “on”
Both die “on” equally
VALUE
UNIT
2.25
2.75
W
W
18
22
mW/ °C
mW/ °C
55.6
45.5
°C/ W
°C/ W
* The power which can be dissipated assuming the device is mounted in a typical manner on a
PCB with copper equal to 2 inches square.
AN 24 - 6
Application Note 24
Issue 2 January 1996
PARAMETER
SYMBOL MIN.
TYP.
UNIT
CONDITIONS.
Collector-Base
Breakdown Voltage
V (BR)CBO 50
85
V
IC=100µA
Collector-Emitter
Breakdown Voltage
VCES
50
85
V
IC=100µA
Collector-Emitter
Breakdown Voltage
VCEO
17.5
24
V
IC=10mA
Collector-Emitter
Breakdown Voltage
VCEV
50
85
V
IC=100µA, VEB=1V
Emitter-Base
Breakdown Voltage
V(BR)EBO 5
8.7
V
IE=100µA
Collector Cutoff Current
ICBO
0.3
10
nA
VCB=35V
Emitter Cutoff Current
I EBO
0.3
10
nA
VEB=4V
Collector Emitter Cutoff
Current
ICES
0.3
10
nA
VCES=35V
Collector-Emitter
Saturation Voltage
VCE(sat)
27
55
120
200
200
45
75
160
240
300
mV
mV
mV
mV
mV
IC=0.5A, IB=10mA*
IC=1A, IB=10mA*
IC=2A, IB=10mA*
IC=5A, IB=100mA*
IC=5A, IB=50mA*
Base-Emitter
Saturation Voltage
VBE(sat)
1000
1100
mV
IC=5A, IB=100mA*
Base-Emitter Turn-On
Voltage
VBE(on)
900
1000
mV
IC=5A, VCE=2V*
Static Forward Current
Transfer Ratio
hFE
280
300
300
250
50
440
450
450
300
80
Transition Frequency
fT
150
Output Capacitance
Cobo
60
ton
toff
Switching Times
MAX.
IC=10mA, VCE=2V*
IC=0.5A, VCE=2V*
IC=1A, VCE=2V*
IC=5A, VCE=2V*
IC=20A, V CE=2V*
1200
MHz
IC=50mA, VCE=10V
f=50MHz
pF
VCB=10V, f=1MHz
120
ns
IC=4A, IB=40mA,
VCC=10V
250
ns
IC=4A, IB=±40mA,
VCC=10V
80
*Measured under pulsed conditions. Pulse width=300µs. Duty cycle ≤ 2%
AN 24 - 7
Application Note 24
Issue 2 January 1996
TYPICAL CHARACTERISTICS
0.8
0.8
+25°C
0.6
VCE(sat) - (V)
VCE(sat) - (V)
0.6
IC/IB=100
IC/IB=50
IC/IB=100
IC/IB=200
0.4
0.2
1mA
10mA 100mA
1A
10A
0.4
-55°C
+25°C
+100°C
+175°C
0.2
1mA
100A
10mA 100mA
IC-Collector Current
1.4
1.2
+25°C
1.0 +25°C
VBE(sat) - (V)
Hfe - Typical Gain
IC/IB=100
+100°C
400
-55°C
300
200
0.8
-55°C
+100°C
+175°C
0.6
0.4
0.2
100
1mA
10mA 100mA
1A
10A
1mA
100A
10mA 100mA
100
-55°C
1.0 +25°C
+100°C
0.8 +175°C
0.6
0.4
0.2
1A
10A
100A
IC - Collector Current (A)
1.2 VCE=2V
10mA 100mA
10A
100A
VBE(sat) v Ic
hFE v IC
1mA
1A
IC-Collector Current
IC-Collector Current
VBE(on) -(V)
100A
VCE(sat) v IC
700 VCE=2V
500
10A
IC-Collector Current
VCE(sat) v IC
600
1A
Single Pulse Test Tamb=25C
10
1
0.1
0.01
10mV
DC
1s
100ms
10ms
1ms
100us
100mV
1V
10V
IC-Collector Current
VCE - Collector Voltage
VBE(on) v IC
Safe Operating Area
AN 24 - 8
100V
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