LM611IM National Semiconductor, LM611IM Datasheet - Page 12

• Manufacturer Part Number: LM611IM
• Description: Operational Amplifier (Op-Amp) IC
• Manufacturer: National Semiconductor

Specifications of LM611IM

• No. Of Amplifiers: 1
• Slew Rate: 0.7V/µs
• No. Of Pins: 14
• Operating Temperature Range: -40°C To +85°C
• Peak Reflow Compatible (260 C): No
• Leaded Process Compatible: No
• Amplifier Type: Operational
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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Application Information
Connecting a resistor across Cathode-to-FEEDBACK cre-
ates a 0 TC current source, but a range of TCs may be syn-
thesized.
I = Vr/R1 = 1.24/R1
FIGURE 9. Current Source is Programmed by R1
Voltage Across R1 and R2 to be Proportional
FIGURE 8. Diode in Series with R1 Causes
FIGURE 10. Proportional-to-Absolute-
to Absolute Temperature (PTAT)
Temperature Current Source
DS009221-23
DS009221-22
DS009221-21
(Continued)
12
Hysteresis
The reference voltage depends, slightly, on the thermal his-
tory
vary — always check the data sheet for any given device. Do
not assume that no specification means no hysteresis.
OPERATIONAL AMPLIFIER
The amp or the reference may be biased in any way with no
effect on the other, except when a substrate diode conducts
(see Guaranteed Electrical Characteristics Note 1). The amp
may have inputs outside the common-mode range, may be
operated as a comparator, or have all terminals floating with
no effect on the reference (tying inverting input to output and
non-inverting input to V
Choosing operating points that cause oscillation, such as
driving too large a capacitive load, is best avoided.
Op Amp Output Stage
The op amp, like the LM124 series, has a flexible and rela-
tively wide-swing output stage. There are simple rules to op-
timize output swing, reduce cross-over distortion, and opti-
mize capacitive drive capability:
1. Output Swing: Unloaded, the 42 µA pull-down will bring
2. Cross-over Distortion: The LM611 has lower cross-over
3. Capacitive Drive: Limited by the output pole caused by
Op Amp Input Stage
The lateral PNP input transistors, unlike those of most op
amps, have BV
voltage. Also, they have no diode clamps to the positive sup-
ply nor across the inputs. These features make the inputs
look like high impedances to input sources producing large
differential and common-mode voltages.
the output within 300 mV of V
ture range. If more than 42 µA is required, a resistor from
output to V
proved slightly if the load can be tied to V
poorer sinking open-loop voltage gain.
distortion (a 1 V
LM124), and increased slew rate as shown in the char-
acteristic curves. A resistor pull-up or pull-down will force
class-A operation with only the PNP or NPN output tran-
sistor conducting, eliminating cross-over distortion.
the output resistance driving capacitive loads, a
pull-down resistor conducting 1 mA or more reduces the
output stage NPN r
the current limit 25 . 200 pF may then be driven without
oscillation.
of
FIGURE 11. Negative −TC Current Source
the
−
EBO
die.
will help. Swing across any load may be im-
equal to the absolute maximum supply
Competitive
BE
e
until the output resistance is that of
−
deadband versus 3 V
on unused amp is preferred).
DS009221-24
−
over the military tempera-
micro-power
+
, at the cost of
BE
products
for the