ST LF351 Operation Manual
Wide bandwidth single JFET operational amplifiers
8
6
5
7
Features
■ Internally adjustable input offset voltage
■ Low power consumption
■ Wide common-mode (up to V
differential voltage range
■ Low input bias and offset current
■ Output short-circuit protection
■ High input impedance JFET input stage
■ Internal frequency compensation
■ Latch up free operation
■ High slew rate 16 V/µs (typical)
Description
CC
+
) and
LF351
N
DIP8
(Plastic package)
D
SO-8
(Plastic micro package)
These circuits are high speed JFET input single
operational amplifiers incorporating well matched,
high voltage JFET and bipolar transistors in a
monolithic integrated circui t.
The devices feature high slew rates, low input
bias and offset currents, and low offset voltage
temperature coefficient.
Pin connections
(top view)
1
2
3
4
1 - Offset null 1
2 - Inverting input
3 - Non-inverting input
-
4 - V
CC
5 - Offset null 2
6 - Output
+
7 - V
CC
8 - N.C.
April 2008 Rev 2 1/14
www.st.com
14
Schematics LF351
1 Schematics
Figure 1. Schematic diagram
V
CC
Non-inverting
input
input
Inverting
1.3k
V
CC
Offset Null1 Offset Null2
1.3k
35k
W
100
W
200
W
100
30k
8.2k
W
100
35k
Output
Figure 2. Input offset voltage null circuit
2/14
LF351 Absolute maximum ratings and operating conditions
2 Absolute maximum ratings and operating conditions
Table 1. Absolute maximum ratings
Symbol Parameter Value Unit
(2)
(1)
(7)
(3)
(6)
(5)
(8)
(4)
CC
(4)
+
and V
CC
±18 V
±15 V
±30 V
125
°C/W
85
40
°C/W
41
Infinite
500 V
200 V
1.5 kV
-
.
V
CC
V
i
V
id
Supply voltage
Input voltage
Differential input voltage
Thermal resistance junction to ambient
R
thja
SO-8
DIP8
Thermal resistance junction to case
R
thjc
SO-8
DIP8
Output short-circuit duration
T
stg
Storage temperature range -65 to +150 °C
HBM: human body model
ESD
MM: machine model
CDM: charged device model
1. All voltage values, except differential voltage, are with respect to the zero reference level (ground) of the supply voltages
where the zero reference level is the midpoint between V
2. The magnitude of the input voltage must never exceed the magnitude of the supply voltage or 15 volts, whichever is less.
3. Differential voltages are the non-inverting input terminal with respect to the inverting input terminal.
4. Short-circuits can cause excessive heating and destructive dissipation. Values are typical.
5. The output may be shorted to ground or to either supply. Temperature and/or supply voltages must be limited to ensure
that the dissipation rating is not exceeded
6. Human body model: A 100 pF capacitor is charged to the specified voltage, then discharged through a 1.5 kΩ resistor
between two pins of the device. This is done for all couples of connected pin combinations while the other pins are floating.
7. Machine model: A 200 pF capacitor is charged to the specified voltage, then discharged directly between two pins of the
device with no external series resistor (internal resistor < 5 Ω). This is done for all couples of connected pin combinations
while the other pins are floating.
8. Charged device model: all pins and the package are charged together to the specified voltage and then discharged directly
to the ground through only one pin. This is done for all pins.
Table 2. Operating conditions
Symbol Parameter LF151 LF251 LF351 Unit
T
V
oper
Supply voltage 6 to 32 V
CC
Operating free-air temperature range -55 to +125 -40 to +105 0 to +70 °C
3/14
Electrical characteristics LF351
3 Electrical characteristics
Table 3. Electrical characteristics at VCC = ±15 V, T
= +25°C (unless otherwise specified)
amb
Symbol Parameter Min. Typ. Max. Unit
V
io
DV
I
io
I
ib
A
vd
SVR
I
CC
V
icm
CMR
I
OS
Input offset voltage (Rs = 10kΩ)
≤ T
≤ T
≤ T
amb
amb
amb
≤ T
≤ T
≤ T
max
max
(1)
max
(1)
T
min
Input offset voltage drift 10 µV/°C
io
Input offset current
T
min
Input bias current
T
min
Large signal voltage gain (RL = 2kΩ, Vo = ±10V)
T
≤ T
≤ T
amb
amb
≤ T
≤ T
max
max
= 10kΩ)
S
min
Supply voltage rejection ratio (R
T
min
Supply current, no load
≤ T
T
min
amb
≤ T
max
Input common mode voltage range
Common mode rejection ratio (RS = 10kΩ)
T
≤ T
amb
≤ T
max
min
Output short-circuit current
T
≤ T
amb
≤ T
max
min
310
5 100
20 200
5025200
808086
1.4 3.4
±11 +15
-12
707086
101040 60
13
4
20
V/mV
3.4
60
Output voltage swing
RL = 2kΩ
= 10kΩ
R
±V
opp
L
≤ T
T
min
amb
≤ T
max
RL = 2kΩ
= 10kΩ
R
L
SR Slew rate, V
Rise time, Vi = 20mV, RL = 2kΩ, CL = 100pF, unity gain 0.1 µs
t
r
K
Overshoot, Vi = 20mV, RL = 2kΩ, CL = 100pF, unity gain 10 %
ov
= 10V, RL = 2kΩ, CL = 100pF, unity gain 12 16 V/µs
i
GBP Gain bandwidth product, f = 100kHz, V
Input resistance 10
R
i
THD
Total harmonic distortion
f= 1kHz, A
Equivalent input noise voltage
e
n
R
S
= 20dB, RL= 2kΩ, CL=100pF, Vo=2V
v
= 100Ω, f = 1KHz
= 10mV, RL = 2kΩ, CL = 100pF 2.5 4 MHz
in
pp
10
12
12
13.5
10
12
12
0.01 %
15
∅m Phase margin 45 Degrees
mV
pA
nA
pA
nA
dB
mA
V
dB
mA
V
Ω
nV
----------- Hz
1. The input bias currents are junction leakage currents which approximately double for every 10°C increase in the junction
temperature.
4/14
LF351 Electrical characteristics
Figure 3. Maximum peak-to-peak output
voltage versus frequency
Figure 5. Maximum peak-to-peak output
voltage versus frequency
Figure 4. Maximum peak-to-peak output
voltage versus frequency
Figure 6. Maximum peak-to-peak output
voltage versus free air temp.
Figure 7. Maximum peak-to-peak output
voltage versus load resistance
Figure 8. Maximum peak-to-peak output
voltage versus supply vo ltage
5/14
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