Question

R1 Iref= 2mA +5V 2.5k L 151 R2 DAC0808 2.5k R3 Vout HI + 15PF 15V = V2 Figure 2: DAC conversion circuit

Answer 1

1) For this question it is not possible to sketch or shown here connect the circuit using pspice, Itspice

so, thats why i am skipping this question and moving ahead

2)In this question digita or binary input given and i hvve to measure analog output volatge.

DAC0808 IC is used in applications where a digital to analog conversion is required, The chip used to be popular a decade ago and its applications used to be many but at present there are many modern IC which can perform DAC with higher resolution, speed and efficiency.

So this device is mainly used for reference and beginner applications and nothing more.

For advance applications microcontroller with DAC feature or DAC IC with serial interface is preferred at present.

Pin configuration :- DAC0808 is a sixteen pin device and description for each pin is given below

Pin

Name

Description

1	NC	No connection
2	GND	Ground
3	VEE	Negative power supply
4	IO	Output signal pin
5	A1	Digital input bit 1 (Most Significant Bit)
6	A2	Digital input bit 2
7	A3	Digital input bit 3
8	A4	Digital input bit 4
9	A5	Digital input bit 5
10	A6	Digital input bit 6
11	A7	Digital input bit 7
12	A8	Digital input bit 8 (Least Significant Bit)
13	VCC	Positive power supply
14	VREF+	Positive reference voltage
15	VREF-	Negative reference voltage
16	COMPENSATION	Compensation capacitor pin

The device takes in parallel 8 bit data from a microcontroller or microprocessor and converts that data in to analog signal at the output, And the analog output from DAC is a current quantity and this needed to be converted in to voltage parameter for using in application easily.

So to convert the current parameter in to voltage parameter we will use op-amp circuit as shown in circuit diagram. .

The output analog voltage from op-amp is in linear relation with input digital value and hence DAC conversion with DAC0808 is achieved. Similarly you can also use other application circuits for DAC0808 given in the datashee

TABLE-2

BINARY INPUT	MEASURE ANALOG OUTPUT
00000001	-0.625
00000010	-1.250
00000011	-1.875
00000100	-2.500
00001000	-5.000
00010000	-10.000
00100000	-20.000
01000000	-40.000
10000000	-80.000
11111111	-159.37