2N4856A/4857A/4858A
Vishay Siliconix
N-Channel JFETs
PRODUCT SUMMARY
Part
Number
2N4856A
2N4857A
2N4858A
V
GS(off)
(V)
–4 to –10
–2 to –6
–0.8 to –4
V
(BR)GSS
Min (V)
–40
–40
–40
I
DSS
Min
(mA)
50
20
8
r
DS(on)
Max
(W)
25
40
60
I
D(off)
Typ
(pA)
5
5
5
t
ON
Typ
(ns)
4
4
4
FEATURES
D
Low On-Resistance: 2N4856A
<25
W
D
Fast Switching—t
ON
: 4 ns
D
High Off-Isolation—I
D(off)
: 5 pA
D
Low Capacitance: 3 pF
D
Low Insertion Loss
BENEFITS
D
D
D
D
D
Low Error Voltage
High-Speed Analog Circuit Performance
Negligible “Off-Error,” Excellent Accuracy
Good Frequency Response
Eliminates Additional Buffering
APPLICATIONS
D
D
D
D
D
Analog Switches
Choppers
Sample-and-Hold
Normally “On” Switches
Current Limiters
DESCRIPTION
The 2N4856A/4857A/4858A all-purpose JFET analog
switches offer low on-resistance, low capacitance, good
isolation, and fast switching.
Hermetically-sealed TO-206AA (TO-18) packaging allows full
military processing (see Military Information). For similar
products in TO-226AA (TO-92) and SOT-23 packages, see the
J/SST111 series data sheet. For similar duals, see the
2N5564/5565/5566 data sheet.
TO-206AA
(TO-18)
S
1
2
D
Top View
3
G and Case
Document Number: 70243
S-04028—Rev. D, 04-Jun-01
www.vishay.com
7-1
2N4856A/4857A/4858A
Vishay Siliconix
ABSOLUTE MAXIMUM RATINGS
Gate-Drain, Gate-Source Voltage : (2N4856A-58A) . . . . . . . . . . . . . . . –40 V
Gate Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 mA
Lead Temperature (
1
/
16
” from case for 10 seconds) . . . . . . . . . . . . . . 300
_C
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65 to 200_C
Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . –55 to 200_C
Power Dissipation
a
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.8 W
Notes
a.
Derate 10 mW/_C for T
C
> 25_C
SPECIFICATIONS (T
A
= 25_C UNLESS OTHERWISE NOTED)
Limits
2N4856A
2N4857A
2N4858A
Parameter
Static
Gate-Source
Breakdown Voltage
Gate-Source Cutoff Voltage
Saturation Drain Current
b
Gate Reverse Current
Gate Operating Current
c
Drain Cutoff Current
Symbol
Test Conditions
Typ
a
Min
Max
Min
Max
Min
Max
Unit
V
(BR)GSS
V
GS(off)
I
DSS
I
GSS
I
G
I
D(off)
I
G
= –1
mA
, V
DS
= 0 V
V
DS
= 15 V, I
D
= 0.5 nA
V
DS
= 15 V, V
GS
= 0 V
V
GS
= –20 V, V
DS
= 0 V
T
A
= 150_C
V
DG
= 15 V, I
D
= 10 mA
V
DS
= 15 V, V
GS
= –10 V
T
A
= 150_C
I
D
= 5 mA
–55
–40
–4
50
–10
–40
–2
20
–250
–500
–6
100
–250
–500
–40
V
–0.8
8
–4
80
–250
–500
mA
pA
nA
pA
nA
–5
–13
–5
5
13
0.25
0.35
0.5
250
500
250
500
250
500
0.5
Drain-Source On-Voltage
V
DS(on)
V
GS
= 0 V
I
D
= 10 mA
I
D
= 20 mA
0.5
0.75
25
40
60
V
Drain-Source On-Resistance
c
Gate-Source Forward Voltage
c
r
DS(on)
V
GS(F)
V
GS
= 0 V, I
D
= 1 mA
I
G
= 1 mA , V
DS
= 0 V
0.7
W
V
Dynamic
Common-Source
Forward Transconductance
c
Common-Source
Output Conductance
c
Drain-Source On-Resistance
Common-Source
Input Capacitance
Common-Source
Reverse Transfer Capacitance
Equivalent Input
Noise Voltage
c
g
fs
g
os
r
ds(on)
C
iss
C
rss
e
n
V
DS
= 0 V, V
GS
= –10 V
f = 1 MHz
V
DS
= 20 V, I
D
= 1 mA
f = 1 kHz
6
25
25
7
3
3
10
4
40
10
3.5
60
10
pF
3.5
nV⁄
√Hz
mS
mS
W
V
GS
= 0 V, I
D
= 0 mA
f = 1 kHz
V
DS
= 10 V, I
D
= 10 mA
f = 1 kHz
Switching
t
d(on)
Turn-On Time
Turn-Off Time
t
r
t
OFF
V
DD
= 10 V, V
GSH
= 0 V
See Switching Circuit
2
2
12
5
3
20
6
4
40
8
8
80
NCB
ns
Notes
a. Typical values are for DESIGN AID ONLY, not guaranteed nor subject to production testing.
b. Pulse test: PW
v100
ms
duty cycle
v10%.
c. This parameter not registered with JEDEC.
www.vishay.com
7-2
Document Number: 70243
S-04028—Rev. D, 04-Jun-01
2N4856A/4857A/4858A
Vishay Siliconix
TYPICAL CHARACTERISTICS (T
A
= 25_C UNLESS OTHERWISE NOTED)
On-Resistance and Drain Current
vs. Gate-Source Cutoff Voltage
r
DS
@ I
D
= 1 mA, V
GS
= 0
I
DSS
@ V
DS
= 20 V, V
GS
= 0
80
I
DSS
120
160
100
r
DS(on)
– Drain-Source On-Resistance (
Ω )
200
r
DS(on)
– Drain-Source On-Resistance (
Ω )
I
DSS
– Saturation Drain Current (mA)
100
On-Resistance vs. Drain Current
T
A
= 25_C
80
V
GS(off)
= –2 V
60
60
r
DS
40
80
40
–4 V
–8 V
20
40
20
0
0
–2
–4
–6
–8
V
GS(off)
– Gate-Source Cutoff Voltage (V)
–10
0
0
1
10
I
D
– Drain Current (mA)
100
On-Resistance vs. Temperature
200
r
DS(on)
– Drain-Source On-Resistance (
Ω )
I
D
= 1 mA
r
DS
changes X 0.7%/_C
160
Switching Time (ns)
4
5
Turn-On Switching
t
r
approximately independent of I
D
V
DG
= 5 V, R
G
= 50 W
V
GS(L)
= –10 V
t
r
t
d(on)
@
I
D
= 12 mA
2
120
3
80
V
GS(off)
= –2 V
–4 V
40
–8 V
0
–55 –35
–15
5
25
45
65
85
105
125
T
A
– Temperature (_C)
1
t
d(on)
@
I
D
= 3 mA
0
0
–2
–4
–6
–8
–10
V
GS(off)
– Gate-Source Cutoff Voltage (V)
Turn-Off Switching
30
t
d(off)
independent of device V
GS(off)
V
DG
= 5 V, V
GS(L)
= –10 V
24
Switching Time (ns)
Capacitance (pF)
24
30
Capacitance vs. Gate-Source Voltage
f = 1 MHz
18
t
f
12
t
d(off)
6
V
GS(off)
= –8 V
0
0
2
4
V
GS(off)
= –2 V
18
12
C
iss
@ V
DS
= 0 V
6
C
rss
@ V
DS
= 0 V
0
6
8
10
0
–4
–8
–12
–16
–20
I
D
– Drain Current (mA)
Document Number: 70243
S-04028—Rev. D, 04-Jun-01
V
GS
– Gate-Source Voltage (V)
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7-3
2N4856A/4857A/4858A
Vishay Siliconix
TYPICAL CHARACTERISTICS (T
A
= 25_C UNLESS OTHERWISE NOTED)
Noise Voltage vs. Frequency
100
V
DG
= 10 V
g
fs
– Forward Transconductance (mS)
40
Hz
Forward Transconductance and Output Conductance
vs. Gate-Source Cutoff Voltage
50
g
fs
and g
os
@ V
DS
= 20 V
V
GS
= 0 V, f = kHz
500
gos – Output Conductance (µS)
400
g
os
300
en – Noise Voltage nV /
30
g
fs
10
I
D
= 1 mA
20
200
I
D
= 10 mA
10
100
1
10
100
1k
f – Frequency (Hz)
10 k
100 k
0
0
–4
–6
–8
V
GS(off)
– Gate-Source Cutoff Voltage (V)
–2
–10
0
10 nA
Gate Leakage Current
I
GSS
@ 25_C
100
Common-Gate Input Admittance
V
DG
= 10 V
I
D
= 10 mA
T
A
= 25_C
1 nA
I
G
– Gate Leakage
T
A
= 125_C
I
D
= 10 mA
g
ig
100 pA
1 mA
(mS)
1 mA
10
b
ig
10 pA
T
A
= 25_C
1 pA
10 mA
I
GSS
@ 25_C
1
I
G(on)
@ I
D
0.1 pA
0
6
12
18
24
30
0.1
100
200
500
1000
V
DG
– Drain-Gate Voltage (V)
f – Frequency (MHz)
Common-Gate Forward Admittance
100
V
DG
= 10 V
I
D
= 10 mA
T
A
= 25_C
–g
fg
10
(mS)
(mS)
g
fg
b
fg
1
10
Common-Gate Reverse Admittance
V
DG
= 10 V
I
D
= 10 mA
T
A
= 25_C
–b
rg
+g
rg
–g
rg
0.1
1
0.1
100
200
500
f – Frequency (MHz)
1000
0.01
100
200
500
f – Frequency (MHz)
1000
www.vishay.com
7-4
Document Number: 70243
S-04028—Rev. D, 04-Jun-01
2N4856A/4857A/4858A
Vishay Siliconix
TYPICAL CHARACTERISTICS (T
A
= 25_C UNLESS OTHERWISE NOTED)
Common-Gate Output Admittance
100
V
DG
= 10 V
I
D
= 10 mA
T
A
= 25_C
I
D
– Drain Current (mA)
b
og
10
(mS)
20
V
GS(off)
= –2 V
16
Output Characteristics
12
V
GS
= 0 V
–0.2 V
–0.4 V
g
og
1
8
–0.6 V
–0.8 V
4
–1.0 V
–1.2 V
0.1
100
200
500
1000
0
0
0.2
0.4
0.6
0.8
1.0
f – Frequency (MHz)
V
DS
– Drain-Source Voltage (V)
Output Characteristics
40
V
GS(off)
= –4 V
32
I
D
– Drain Current (mA)
I
D
– Drain Current (mA)
40
50
Output Characteristics
V
GS(off)
= –8 V
–1 V
V
GS
= 0 V
30
–2 V
–3 V
20
–4 V
–5 V
–6 V
–3.0 V
0
0
0.2
0.4
0.6
0.8
1.0
0
0
0.2
0.4
0.6
0.8
1.0
24
V
GS
= 0 V
–0.5 V
–1.0 V
16
–1.5 V
–2.0 V
8
–2.5 V
10
V
DS
– Drain-Source Voltage (V)
V
DS
– Drain-Source Voltage (V)
V
DD
SWITCHING TIME TEST CIRCUIT
2N4856A
V
GS(L)
R
L
*
I
D(on)
*Non-inductive
–10 V
464
W
20 mA
R
L
OUT
V
GS(H)
V
GS(L)
1 κΩ
51 Ω
2N4857A
–6 V
953
W
10 mA
2N4858A
–4 V
1910
W
5 mA
INPUT PULSE
Rise Time < 1 ns
Fall Time < 1 ns
Pulse Width 100 ns
PRF 1 MHz
Document Number: 70243
S-04028—Rev. D, 04-Jun-01
SAMPLING SCOPE
Rise Time 0.4 ns
Input Resistance 10 MW
Input Capacitance 1.5 pF
V
IN
Scope
51 Ω
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7-5
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