Bcd To Decimal Decoder 1820-1047; Voltage Regulator 1826-0010; Voltage Regulator 1826-0016; Operational Amplifier 1826-0021 - HP 5340A Operating And Service Manual

Model 5340A
Theory of Operation

4-87. BCD to Decimal Decoder 1820-1047

The 1820-1047 is a low power version of the 1820-0214. Power dissipation is typically
4-88.
70 milliwatts.

4-89. Voltage Regulator 1826-0010

4-89. The outline drawing and equivalent circuit for the 1826-0010 are shown in Figure 4-38. The
regulator consists of a current source, a voltage reference amplifier, a n error amplifier, a current
limiter, and a series pass transistor. The current source, Zener diode, and voltage reference
amplifier provide a constant 7.2 volt reference output (Vref) for the non-inverting input of the
difference amplifier. The inverting input of the difference amplifier senses the power supply
output voltage through a n external voltage divider. An example of operation is as follows. If
the power supply output voltage decreases, the voltage a t the inverting input (pin 2) also
decreases. This drives the error amplifier output to bias the series pass transistor to decrease its
impedance. When the impedance of the series pass transistor decreases, the output voltage tends
to increase to regulate the output. The frequency compensation input prevents high frequency
oscillations.
TEMPERATURE
COMPENSATED
NON INVERT1

4-91. Voltage Regulator 1826-0016

4-92. The 1826-0016 (Figure 4-39) is a negative regulator. Operation is similar to the 1826-0010.

4-93. Operational Amplifier 1826-0021

4-94. The 1826-0021 (Figure 4-40) is a n operational amplifier internally connected as a unity-
gain non-inverting amplifier. Pins 1 and 8 allow for offset balancing.
I
4-28
Figure 4-38. Voltage Regulator 1826-0010
FREQUENCY
COMPENSATION
SERIES PASS
TRANS ISTO
ERROR CURRENT
AMPLIFIER LIMITER
CURRENT
LIMIT
CURRENT FREQUENCY
INVERTING
INPUT
NON INVERTING INPUT 3
NOTE: PIN 5 CONNECTED TO CASE