Krohn-Hite 7620 User manual

7620 OPERATI
Model 7620
DC to 1MHz General Purpose
Wideband Power Amplifier
OPERATING MANUAL
Date: 3/5/20 Revision 1.0
Serial No. ___________________________
15 Jonathan Drive, Unit 4 Brockton, MA 02301-5566 U.S.A.
Tel: [phone]; Fax: [phone]
Email: [email protected]
Service: [email protected] www.krohn-hite.com
Copyright © 2020 Krohn-Hite Corporation
All rights reserved. Contents of this publication may not be reproduced in any form
without the written permission from Krohn-Hite Corporation

7620 OPERATING MANUAL TABLE OF CONTENTS
REV 1.0 i
TABLE OF CONTENTS
SECTION 1 PRODUCT DESCRIPTION AND SPECIFICATIONS...............................1
1.1 PRODUCT DESCRIPTION................................................................................1
1.2 PRODUCT SPECIFICATIONS...........................................................................2
1.2.1 OUTPUT......................................................................................................2
1.2.2 INPUT..........................................................................................................3
1.2.3 GENERAL ...................................................................................................4
1.3 REMOTE COMMUNICATION OPTIONS...........................................................4
1.4 OPTIONAL ACCESSORIES..............................................................................4
SECTION 2 OPERATION............................................................................................5
2.1 INTRODUCTION................................................................................................5
2.2 POWER REQUIREMENTS................................................................................5
2.3 INITIAL POWER-UP SEQUENCE.....................................................................5
2.4 INITIAL FUNCTIONAL TEST.............................................................................6
2.5 FRONT PANEL..................................................................................................7
2.5.1 KEYS...........................................................................................................7
2.5.2 LED INDICATORS ......................................................................................7
2.5.3 FRONT PANEL SELF-TEST.......................................................................7
2.5.4 POWER SWITCH........................................................................................8
2.5.5 INPUT CONNECTORS ...............................................................................8
2.5.6 OUTPUT CONNECTORS ...........................................................................8
2.6 REAR PANEL ....................................................................................................9
2.6.1 AC POWER RECEPTACLE (LINE).............................................................9
2.6.2 AC LINE FUSE............................................................................................9
2.6.3 AC LINE SWITCHES.................................................................................10
2.6.4 CHASSIS/FLOATING GROUND SWITCH................................................10
2.6.5 REMOTE COMMUNICATIONS PORT......................................................10
2.7 MENU ..............................................................................................................11
2.7.1 INPUT CONFIGURATION.........................................................................12
2.7.2 INPUT COUPLING....................................................................................13
2.7.3 AGA (AUTOMATIC GAIN ADJUST)..........................................................14
2.7.4 SAVE SETUP............................................................................................15

TABLE OF CONTENTS 7620 OPERATING MANUAL
ii REV 1.0
2.7.5 RECALL SETUP........................................................................................15
2.7.6 REMOTE ADDRESS (GPIB/LAN).............................................................16
2.7.7 DEVICE INFORMATION...........................................................................17
2.7.8 SOUND......................................................................................................18
2.7.9 EXIT...........................................................................................................18
2.8 DC OFFSET.....................................................................................................19
2.9 OUTPUT GAIN.................................................................................................20
2.10 GAIN RANGE ...............................................................................................21
2.11 PREVIOUS SETTING (ENTER) KEY...........................................................22
2.12 HEATSINK TEMPERATURE MONITOR......................................................23
2.13 AVERAGE CURRENT MONITOR................................................................23
2.14 OUTPUT VOLTAGE MONITOR ...................................................................24
2.15 DEFAULT SETTINGS...................................................................................25
SECTION 3 REMOTE COMMUNICATION................................................................27
3.1INTRODUCTION..............................................................................................27
3.2 GPIB/IEEE-488 SETUP ...................................................................................27
3.3 GPIB/IEEE-488 INTERFACE COMMANDS.....................................................27
3.4 REMOTE PROGRAMMING COMMANDS.......................................................29
3.5 LAN (LOCAL AREA NETWORK) SETUP........................................................31
3.5.1 NETWORK CONNECTION.......................................................................31
3.5.2 DIRECT PC CONNECTION......................................................................31
3.5.3 FIND UNIT’S IP ADDRESS .......................................................................32
3.5.4 SET A STATIC IP ADDRESS....................................................................34
3.6 LAN COMMUNICATION..................................................................................35
3.7 USB SETUP.....................................................................................................36
3.8 USB COMMUNICATION..................................................................................37
SECTION 4 INCOMING ACCEPTANCE....................................................................39
4.1 INTRODUCTION..............................................................................................39
4.2 REQUIRED TEST EQUIPMENT......................................................................39
4.3 FRONT PANEL SELF-TEST............................................................................39
4.4 DC OFFSET AND PEAK VOLTS DISPLAY CHECK .......................................40
4.5 SQUARE WAVE BROADBANDING CHECK...................................................40

7620 OPERATING MANUAL TABLE OF CONTENTS
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4.6 SQUARE WAVE RISE AND FALL TIME CHECK............................................41
4.7 SLEW RATE CHECK.......................................................................................41
4.8 GAIN CALIBRATION CHECK..........................................................................42
4.9 FREQUENCY RESPONSE CHECK ................................................................43
4.10 1K LOAD MAXIMUM POWER......................................................................43
4.11 DISTORTION CHECK..................................................................................44
SECTION 5 SERVICE AND WARRANTY..................................................................45
5.1 SERVICE .........................................................................................................45
5.2 WARRANTY.....................................................................................................45
5.3 CLAIM FOR DAMAGE IN SHIPMENT TO PURCHASER................................45
5.4 SHIPPING TO KROHN-HITE FOR REPAIR OR CALIBRATION.....................46

SAFETY PRECAUTIONS 7620 OPERATING MANUAL
iv REV 1.0
SAFETY PRECAUTIONS
The following general safety precautions must be observed during all phases of operation,
service, and repair. Failure to comply with these precautions or with specific warnings elsewhere
in this manual violate safety standards of design, manufacture and intended use of this
instrument. Krohn-Hite assumes no liability for the customer’s failure to comply with these
requirements. For the correct and safe use of this instrument, operating and service personnel
must follow generally accepted safety procedures.
HIGH VOLTAGE WARNING
Potentially lethal voltages may be present on the instrument’s output terminals. Please observe
all safety precautions when operating this instrument.
POWER SOURCE
The 7620 is designed to operate from a 105Vrms to 240Vrms AC source. The protective ground
connection, provided by the grounding conductor in the power cord, is essential for safe
operation. Refer to section 2.2 for complete power requirements and section 2.3 to configure the
power input.
PROPER FUSE
To avoid damage to the 7620 or to prevent a fire hazard, use the correct fuse for the line voltage
selected. Refer to section 2.6.2 for proper fuse rating.
ENVIRONMENTAL WARNING
Do not operate the instrument in the presence of flammable gases or fumes. Do not operate the
instrument in damp, wet or dusty environments. Operation of this instrument in such
environments constitutes a safety hazard.
DO NOT REMOVE COVER
Operating personnel must not remove the instrument covers. Only qualified maintenance
personnel following proper safety precautions may remove the cover. To avoid injuries, always
disconnect the AC line cord and disconnect all cables and equipment from the input and output
terminals before removing the covers.
DO NOT SUBSTITUTE PARTS OR MODIFY INSTRUMENT
To avoid damaging the instrument, causing injuring or creating unsafe conditions, do not install
substitute parts or perform any unauthorized modifications. For service and repairs contact
Krohn-Hite.
DO NOT OPERATE A DAMAGED INSTRUMENT
Do not operate the instrument if it is damaged. Disconnect the AC line cord and disconnect all
cables and equipment from the input and output terminals. For service and repairs contact
Krohn-Hite.

7620 OPERATING MANUAL SECTION 1
REV 1.0 1
SECTION 1 PRODUCT DESCRIPTION AND
SPECIFICATIONS
1.1 PRODUCT DESCRIPTION
The 7620 wideband power amplifier offers extended output power and voltage
capabilities with low distortion, using the latest in hybrid power operational amplifier
technology. This makes the 7620 suitable for a broad array of applications.
With two inputs, both non-inverted and inverted, the unit is configurable for either single-
end or differential operation. A maximum input voltage of ±200V, AC or DC, and a
frequency range from DC to 1MHz, allows for a wide range of input signals.
Additionally, the two outputs, either non-inverted or inverted, provide a maximum
voltage of ±200V and 200mA (34W maximum).
The instrument is operated either using the local front panel controls and menu driven
configuration, or remotely through the standard GPIB port, or optional LAN or USB
connections.
Features include DC offset, 0V to ±200V in 0.1V increments, and three selectable gain
ranges X5, X25 and X125 with incremental output gain control, as well as, an automatic
gain adjustment setting with clipping control. These settings are controlled in real-time
using the front panel buttons or remotely and all active settings are shown on the two-line
display.
In addition, the unit continuously monitors and displays the heatsink temperature, output
peak voltage and average output current to warn of any potential issues. Warnings are
triggered to alert the user of the problem condition and to prevent damage to equipment.
The unit is equipped with ten unique memory locations used to store pre-configured
setups and a recall function to quickly restore the unit to a previous configuration.
All the information needed to operate this instrument is contained in this manual. For
application specific information or other questions, please contact Krohn-Hite.

SECTION 1 7620 OPERATING MANUAL
2 REV 1.0
1.2 PRODUCT SPECIFICATIONS
1.2.1 OUTPUT
Note: All values are measured from each output to GND.
Frequency Range: DC to 1MHz
Power:
o1kΩ Load:
17Wrms (34W DC) (DC to 500kHz)
5Wrms (500kHz to 1MHz)
o600Ω Load:
4Wrms (9W DC) (DC to 100Hz)
9Wrms (100Hz to 1MHz)
Voltage:
oNo Load to 10kΩ:
±200Vpeak (141Vrms)
o1kΩ Load:
±200Vpeak (141Vrms) AC or DC (DC to 200kHz)
±160Vpeak (113Vrms) AC (200kHz to 500kHz)
±106Vpeak (75rms) AC (500kHz to 1MHz)
o600Ω Load:
±113Vpeak (80Vrms) (100Hz to 1MHz)
±73Vpeak (52Vrms) (DC to 100Hz)
Current: 910Ω load ±200mApeak (141mArms) (DC to 500kHz)
Frequency Response:
o±0.5dB DC to 1MHz
Harmonic Distortion:
o0.02% (typical), 0.05% (max)
Voltage Gain Ranges:
oX5: X0.0 to X5.0 (X0.1 increments)
oX25: X0.0 to X25.0 (X0.5 increments)
oX125: X0.0 to X125 (X1.0 increments)
Step Accuracy: ±0.1dB plus frequency response specification
Stability: < 0.001dB change for each 10% change in line voltage.
Dynamic Range: > 70dB
Hum and Noise (2MHz bandwidth): referred to output, < 20mVrms
Phase Shift: A input 0° ±1°, -B input, 180° ±1° dc to 10kHz
increasing linearly 60° lagging at 1MHz. (Inverted output relative
to non-inverted) 180°, –0.3° at 10kHz; 180°, –3° at 100kHz; 180°,
–20° at 1MHz.

7620 OPERATING MANUAL SECTION 1
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Square wave Response:
oRise/Fall Time: 200ns to 100Vp-p
oSlew Rate: > 500V/µs, 400Vp-p
Regulation: < 0.1% with no load to 1kΩ (DC to 10kHz), rising to
2% at 1MHz.
DC Coupling:
oDC Level: Nominal zero volts; vs. temperature, 2mV/°C.
oDC Offset Control (no load): 0V to ±200V.
oDC Level Stability
Vs. Line: < 1mV for each 10% change in line voltage
Vs. Temperature: < 0.01%/°C or 2mV/°C (whichever is
greater)
Internal Impedance:
o< 0.5Ω (DC to 10kHz)
o5Ω (10kHz to 100kHz)
o20Ω (100kHz to 1MHz)
1.2.2 INPUT
Configurations:
oA (Single-Ended, Non-Inverted)
o-B (Single-Ended, Inverted)
oA–B (Differential)
Maximum Voltage: ±200VDC (referenced to ground)
Maximum Common Mode:
oX5 range: ±200Vpeak
oX25 range: ±40Vpeak
oX125 range: ±8Vpeak
Common Mode Rejection:
o70dB: DC to 200Hz (at max gain setting)
o60dB: 200Hz to 1kHz (at max gain setting)
o40dB: 1kHz to 10kHz (at max gain setting)
o20dB: 10kHz to 1MHz (at max gain setting)
Note: Improves to < 80dB at lower gain settings.
Sensitivity: ±1.6V peak
Coupling: Direct (DC) or capacitive (AC) with low frequency
cutoff of approximately 1Hz
Impedance: 1 MΩ in parallel with 30pF

SECTION 1 7620 OPERATING MANUAL
4 REV 1.0
1.2.3 GENERAL
Temperature Range: 0°C to 45°C.
Power Requirements: 120V or 240V, 50Hz-400Hz, 200W
Dimensions: 14” W (35.6cm) x 13.64” L (34.6cm) x 3.5” H (8.9 cm)
4” H (10.2 cm) with feet installed
Weight: 12.8 lbs. (5.81 kg.)
1.3 REMOTE COMMUNICATION OPTIONS
The standard 7620 is equipped with a GPIB/IEEE-488 remote communications port. An
optional LAN or USB option is also available. Please specify which option you prefer
when placing your order.
IEEE-COM (standard) - 24-Pin, Female Connector
LAN-COM (optional) –RJ45 Connector
USB-COM (optional) –Mini Type B 5-Pin Connector
1.4 OPTIONAL ACCESSORIES
RK-314: Rack Mount Kit (for mounting the 7620 into a standard 19" rack)
CAB-10: GPIB Cable with Connectors (2 meters)
CAB-11: GPIB Cable with Connectors (1 meter)
CAB-018: Cable, Multi-Stacking Double Banana Plug
CAB-025: BNC Cable (3 Feet)
7620EXT: One Year Extended Warranty