MMBT4401LT1
SMALL−SIGNAL CHARACTERISTICS
NOISE FIGURE
V
CE
= 10 Vdc, T
A
= 25°C; Bandwidth = 1.0 Hz
10
8.0
NF, NOISE FIGURE (dB)
I
C
= 1.0 mA, R
S
= 150
W
I
C
= 500
mA,
R
S
= 200
W
I
C
= 100
mA,
R
S
= 2.0 kW
I
C
= 50
mA,
R
S
= 4.0 kW
R
S
= OPTIMUM
RS =
SOURCE
RS =
RESISTANCE
10
f = 1.0 kHz
8.0
NF, NOISE FIGURE (dB)
I
C
= 50
mA
I
C
= 100
mA
I
C
= 500
mA
I
C
= 1.0 mA
6.0
6.0
4.0
2.0
0
0.01 0.02 0.05 0.1 0.2 0.5 1.0 2.0 5.0
f, FREQUENCY (kHz)
4.0
2.0
0
10
20
50
100
50
100 200
500 1.0 k 2.0 k 5.0 k 10 k 20 k
R
S
, SOURCE RESISTANCE (OHMS)
50 k 100 k
Figure 9. Frequency Effects
Figure 10. Source Resistance Effects
h PARAMETERS
V
CE
= 10 Vdc, f = 1.0 kHz, T
A
= 25°C
This group of graphs illustrates the relationship between h
fe
and other “h” parameters for this series of transistors. To obtain
these curves, a high−gain and a low−gain unit were selected from the MMBT4401LT1 lines, and the same units were used to
develop the correspondingly numbered curves on each graph.
300
hie , INPUT IMPEDANCE (OHMS)
200
hfe , CURRENT GAIN
50 k
20 k
10 k
5.0 k
MMBT4401LT1 UNIT 1
MMBT4401LT1 UNIT 2
100
70
50
30
20
0.1
MMBT4401LT1 UNIT 1
MMBT4401LT1 UNIT 2
2.0 k
1.0 k
500
0.1
0.2
0.3
0.5 0.7
1.0
2.0
3.0
5.0 7.0 10
0.2
0.3
0.5 0.7 1.0
2.0
3.0
5.0 7.0 10
I
C
, COLLECTOR CURRENT (mA)
I
C
, COLLECTOR CURRENT (mA)
Figure 11. Current Gain
h re , VOLTAGE FEEDBACK RATIO (X 10
−4
)
10
hoe, OUTPUT ADMITTANCE (
m
mhos)
7.0
5.0
3.0
2.0
1.0
0.7
0.5
0.3
0.2
0.1
0.2
0.3
0.5 0.7 1.0
2.0
3.0
5.0 7.0 10
100
50
20
10
5.0
2.0
1.0
0.1
Figure 12. Input Impedance
MMBT4401LT1 UNIT 1
MMBT4401LT1 UNIT 2
MMBT4401LT1 UNIT 1
MMBT4401LT1 UNIT 2
0.2
0.3
0.5 0.7 1.0
2.0 3.0
5.0 7.0 10
I
C
, COLLECTOR CURRENT (mA)
I
C
, COLLECTOR CURRENT (mA)
Figure 13. Voltage Feedback Ratio
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5
Figure 14. Output Admittance
ONSEMI [ ON SEMICONDUCTOR ]
