LM346N National Semiconductor, LM346N Datasheet - Page 8

• Manufacturer Part Number: LM346N
• Description: IC OP AMP PROGRAM QUAD 16-DIP
• Manufacturer: National Semiconductor

Specifications of LM346N

• Amplifier Type: General Purpose
• Number Of Circuits: 4
• Slew Rate: 0.4 V/µs
• Gain Bandwidth Product: 1.2MHz
• Current - Input Bias: 50nA
• Voltage - Input Offset: 500µV
• Current - Supply: 1.4mA
• Current - Output / Channel: 20mA
• Voltage - Supply, Single/dual (±): 3 V ~ 36 V, ±1.5 V ~ 18 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 16-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Output Type: -
• -3db Bandwidth: -
• Other names: *LM346N; LM346; LM346NNS

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Application Hints
Avoid reversing the power supply polarity; the device will fail.
COMMON-MODE INPUT VOLTAGE
The negative common-mode voltage limit is one diode drop
above the negative supply voltage. Exceeding this limit on
either input will result in an output phase reversal. The
positive common-mode limit is typically 1V below the posi-
tive supply voltage. No output phase reversal will occur if this
limit is exceeded by either input.
OUTPUT VOLTAGE SWING VS I
For a desired output voltage swing the value of the minimum
load depends on the positive and negative output current
capability of the op amp. The maximum available positive
output current, (I
whereas the negative output current (I
I
INPUT CAPACITANCE
The input capacitance, C
pF; any stray capacitance, C
layout) will add to C
applied, an additional pole is added to the open loop fre-
quency response of the device. For instance with resistive
feedback (Figure 2), this pole occurs at
C
beyond the expected −3 dB frequency corner of the closed
loop gain of the amplifier; if not, place a lead capacitor in the
feedback such that the time constant of this capacitor and
the resistance it parallels is equal to the R
R
TEMPERATURE EFFECT ON THE GBW
The GBW (gain bandwidth product), of the LM146 is directly
proportional to I
lute temperature. When using resistors to set the bias cur-
SET
S
I
). Make sure that this pole occurs at least 2 octaves
is the input resistance of the circuit.
. Figure 1 illustrates the above.
FIGURE 1. Output Current Limit vs I
SET
CL+
IN
and inversely proportional to the abso-
), of the device increases with I
. When resistive or active feedback is
FIGURE 2.
IN
, of the LM146 is approximately 2
S
, (due to external circuit circuit
SET
CL−
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00565409
1
⁄
) is independent of
2
I
(C
π (R1||R2) (C
S
+ C
SET
IN
), where
IN
SET
+
8
rent, I
increasing temperature. Compensation can be provided by
creating an I
(see typical applications).
ISOLATION BETWEEN AMPLIFIERS
The LM146 die is isothermally layed out such that crosstalk
between all 4 amplifiers is in excess of −105 dB (DC).
Optimum isolation (better than −110 dB) occurs between
amplifiers A and D, B and C; that is, if amplifier A dissipates
power on its output stage, amplifier D is the one which will be
affected the least, and vice versa. Same argument holds for
amplifiers B and C.
LM146 TYPICAL PERFORMANCE SUMMARY
The LM146 typical behaviour is shown in Figure 3. The
device is fully predictable. As the set current, I
the speed, the bias current, and the supply current increase
while the noise power decreases proportionally and the V
remains constant. The usable GBW range of the op amp is
10 kHz to 3.5−4 MHz.
Low Power Supply Operation: The quad op amp operates
down to
biased through programmable current sources, no degrada-
tion of the device speed will occur.
SPEED VS POWER CONSUMPTION
LM146 vs LM4250 (single programmable). Through Figure
4, we observe that the LM146’s power consumption has
been optimized for GBW products above 200 kHz, whereas
the LM4250 will reach a GBW of no more than 300 kHz. For
GBW products below 200 kHz, the LM4250 will consume
less power.
SET
FIGURE 3. LM146 Typical Characteristics
, of the device, the GBW product will decrease with
±
1.3V supply. Also, since the internal circuitry is
SET
current directly proportional to temperature
SET
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, increases,
OS -