LM359M National Semiconductor, LM359M Datasheet - Page 9

• Manufacturer Part Number: LM359M
• Description: IC AMP DUAL PROG CUR MODE 14SOIC
• Manufacturer: National Semiconductor

Specifications of LM359M

• Amplifier Type: General Purpose
• Number Of Circuits: 2
• Slew Rate: 60 V/µs
• Gain Bandwidth Product: 400MHz
• Current - Input Bias: 8µA
• Current - Supply: 18.5mA
• Current - Output / Channel: 40mA
• Voltage - Supply, Single/dual (±): 5 V ~ 22 V, ±2.5 V ~ 11 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Output Type: -
• -3db Bandwidth: -
• Voltage - Input Offset: -
• Other names: *LM359M

Application Hints
The input set current I
into pin 8. A resistor from pin 8 to V
I
tics of the LM359 as it directly sets the total input stage
current of the amplifiers which determines the maximum
slew rate, the frequency of the open loop dominant pole, the
input resistance of the (−) input and the biasing current I
All of these parameters are significant in wide band amplifier
design. The input stage current is approximately 3 times
I
approximations for these AC parameters are:
where C
pin (pin 3 or pin 13) to ground, A
open loop voltage gain in V/V and an ambient temperature of
25˚C is assumed (KT/q = 26 mV and β
controls the DC input bias current by the expression:
which is important for DC biasing considerations.
The total device supply current (for both amplifiers) is also a
direct function of the set currents and can be approximated
by:
with each set current programmed by individual resistors.
SET(IN)
SET(IN)
FIGURE 7. Establishing the Input Set Current
and by using this relationship the following first order
is most significant in controlling the AC characteris-
comp
I
supply
is the total capacitance from the compensation
. 27 x I
SET(IN)
SET(OUT)
is equal to the current flowing
(Continued)
VOL
+ 11 x I
+
sets this current to be:
typ
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is the low frequency
= 150). I
SET(IN)
SET(IN)
b
also
(−).
9
PROGRAMMING WITH A SINGLE RESISTOR
Operating current programming may also be accomplished
using only one resistor by letting I
programming current is now referred to as I
created by connecting a resistor from pin 1 to pin 8 (Figure
8).
I
This configuration does not affect any of the internal set
current dependent parameters differently than previously
discussed except the total supply current which is now equal
to:
Care must be taken when using resistors to program the set
current to prevent significantly increasing the supply voltage
above the value used to determine the set current. This
would cause an increase in total supply current due to the
resulting increase in set current and the maximum device
power dissipation could be exceeded. The set resistor val-
ue(s) should be adjusted for the new supply voltage.
One method to avoid this is to use an adjustable current
source which has voltage compliance to generate the set
current as shown in Figure 9.
This circuit allows I
supply voltage range of the LM359 which also improves
power supply ripple rejection as illustrated in the Typical
Performance Characteristics. It should be noted, however,
that the current through the LM334 as shown will change
linearly with temperature but this can be compensated for
(see LM334 data sheet).
SET(IN)
FIGURE 8. Single Resistor Programming of I
FIGURE 9. Current Source Programming of I
= I
SET(OUT)
= I
SET
SET
I
supply
to remain constant over the entire
. 37 x I
SET(IN)
SET
equal I
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SET(OUT)
SET
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and it is
SET
SET
. The