Fluke 5720A service manual ±PA Supplies Digital Control

Contents (continued)

2-49.	Decoding and Timing Circuitry	2-28
2-50.	Control Display Circuitry	2-29
2-51.	Output Display Circuitry	2-30
2-52.	Keyboard Scanner Circuitry	2-31
2-53.	Knob Encoder Circuitry	2-31
2-54.	Led Circuitry	2-32
2-55.	Keyboard Assembly (A1)	2-32
2-56. Analog Section Detailed Circuit Description		2-33
2-57.	Filter/PA Supply (A18), Low-voltage Filter/Regulator Section	2-33
2-58.	Unregulated OSC Supplies	2-34
2-59.	Unregulated LH Supplies	2-34
2-60.	Unregulated S Supplies	2-34
2-61.	Triac Circuit	2-34
2-62.	FR1 Supplies	2-34
2-63.	Unregulated FR1 Supply	2-34
2-64.	FR2 Supplies	2-35
2-65.	Filter/PA Supply (A18), Power Amplifier Output Supply Section .	2-35
2-66.	±PA Supplies Digital Control	2-35
2-67.	±250V and ±500V Supplies	2-37
2-68.	+PA and -PA Supplies	2-37
2-69.	±PA Supply Current Limit	2-37
2-70.	Regulator/Guard Crossing Assembly (A17)	2-38
2-71.	Voltage Regulator Circuitry	2-38
2-72.	Regulated OSC Supplies	2-38
2-73.	Regulated LH Supplies	2-39
2-74.	Regulated S Supplies	2-39
2-75.	FR1 Supply	2-40
2-76.	FR2 Supply	2-40
2-77.	Guarded Digital Control Circuitry	2-41
2-87.	Switch Matrix Assembly (A8)	2-43
2-88.	Switch Matrix Digital Control	2-44
2-89.	Switch Matrix Operation: 11V DC and 22V DC Ranges	2-46
2-90.	Switch Matrix Operation: 2.2V AC and 22V AC Ranges	2-48
2-91.	Switch Matrix Operation: 220V AC and DC Ranges	2-48
2-92.	Switch Matrix Operation: 2.2V DC Range	2-51
2-93.	Calibration of the 2.2V Range	2-53
2-94.	Switch Matrix Operation: 220 mV DC Range	2-53
2-95.	Switch Matrix Operation: 220 mV AC Range	2-56
2-96.	Switch Matrix Operation: 2.2 mV and 22 mV AC Ranges	2-56
2-97.	Calibration of the mV Ranges	2-56
2-98.	Internal CAL Zero Amplifier	2-59
2-99.	Switch Matrix 5725A Amplifier Interface	2-61
2-100.	DAC Assembly (A11)	2-61
2-101.	Basic DAC Theory of Operation	2-61
2-102.	DAC Assembly Digital Control	2-64
2-103.	DAC Assembly Reference Circuitry	2-64
2-104.	Duty-Cycle Control Circuit	2-65
2-105.	DAC Filter Circuit	2-66
2-106.	DAC Output Stage	2-66
2-107.	Sense Current Cancellation Circuit	2-67
2-108.	Linearity Control Circuit	2-67
2-109.	Negative Offset Circuit	2-68
2-110.	DAC Output Switching	2-68
2-111.	DAC Buffered Reference Sip	2-68
2-112.	Calibration Hardware	2-69

iii