
Application
UHF low noise amplifier
Features
• Excellent low noise characteristics.
Fmin = 0.83 dB Typ. (3 V, 10 mA, 2 GHz)
• High associated gain.
Ga = 17 dB Typ. (3 V, 10 mA, 2 GHz)
• High voltage.
VDS = 6 or more voltage.
• Small package. (CMPAK-4)
2SK2685
GaAs HEMT
ADE-208-400
1st. Edition
Outline
CMPAK–4
2
3
1
4
1. Source
2. Gate
3. Source
4. Drain

2SK2685
Absolute Maximum Ratings (Ta = 25°C)
Item Symbol Ratings Unit
Drain to source voltage V
Gate to source voltage V
Gate to drain voltage V
Drain current I
DSS
GSO
GDO
D
Channel power dissipation Pch 100 mW
Channel temperature Tch 125 °C
Storage temperature Tstg –55 to +125 °C
Attention: This device is very sensitive to electro static discharge.
It is recommended to adopt appropriate cautions when handling this transistor.
Electrical Characteristics (Ta = 25°C)
Item Symbol Min Typ Max Unit Test conditions
Gate to source leak current I
Gate to source cutoff voltage V
Drain current I
GSS
GS(off)
DSS
Forward transfer admittance |yfs| 40 60 — mS VDS = 3 V, ID = 10 mA,
Associated gain Ga — 17.0 — dB VDS = 3 V, ID = 10 mA,
Associated gain Ga — 15.2 — dB VDS = 3 V, ID = 3 mA,
Associated gain Ga 16 21.4 — dB VDS = 3 V, ID = 10 mA,
Associated gain Ga — 19.7 — dB VDS = 3 V, ID = 3 mA,
Minimum noise figure Fmin — 0.83 — dB VDS = 3 V, ID = 10 mA,
Minimum noise figure Fmin — 1.08 — dB VDS = 3 V, ID = 3 mA,
Minimum noise figure Fmin — 0.52 1.0 dB VDS = 3 V, ID = 10 mA,
Minimum noise figure Fmin — 0.74 — dB VDS = 3 V, ID = 3 mA,
Note: Marking is “ZT–”.
— — –20 µAVGS = –6 V, VDS = 0
–0.3 — –2.0 V VDS = 3 V, ID = 100 µA
35 50 70 mA VDS = 3 V, VGS = 0
6V
–6 V
–7 V
20 mA
(Pulse Test)
f = 1 kHz
f = 2 GHz
f = 2 GHz
f = 900 MHz
f = 900 MHz
f = 2 GHz
f = 2 GHz
f = 900 MHz
f = 900 MHz
2

2SK2685
Maximum Channel Power
Dissipation Curve
200
150
100
50
Channel Power Dissipation Pch (mW)
0 20015010050
Ambient Temperature Ta (°C)
Typical Transfer Characteristics
100
80
VDS = 3 V
Pulse Test
20
Typical Output Characteristics
–0.4 V
16
(mA)
D
12
8
–0.3 V
–0.1 V
–0.5 V
Pulse Test
–0.6 V
–0.7 V
Drain Current I
4
–0.8 V
VGS = –0.9 V
0 12345
Drain to Source Voltage V
DS
(V)
Forward Transfer Admittance vs.
Gate to Source Voltage
100
VDS = 3 V
Pulse Test
80
(mA)
D
60
40
Drain Current I
20
–2.0
–1.6 –1.2 –0.8 –0.4 0
Gate to Source Voltage V
GS
(V)
60
40
20
Forward Transfer Admittance yfs (mS)
0
–2.0 –1.6 –1.2 –0.8 –0.4 0
Gate to Source Voltage V
GS
(V)
3