Benthowave Instrument Inc.

BENTHOWAVE INSTRUMENT INC. Acoustic Transducer & System 

BII-5120 Series Power Amplifier: SONAR and HIFU Transducer

BII-5120 series power amplifiers can work as class AB linear amplifiers or Class D switching amplifiers. The SINE, Pulse and Square waveforms are acceptable to BII-5120 series. To achieve higher efficiency and higher power delivery to load, pulse or square waveform is recommended. Forced-air cooling by a fan is a must to cool down the amplifier in service of full power and continuous waveform.

Technical notes
The cable has adverse effects on the power amplifier performances in high frequency range. The longer the cable is, the worse the adverse effects is. If you use long cable or RF frequency in your project, you shall use an impedance matching unit which matches output impedance of the power amplifier with the characteristic impedance of the cable or load impedance such as 50 ohms RG58 coax and 50 ohms transducer load.

Suggested Application  
Image Sonar, HIFU Transducer
Underwater Sound Velocimeter/Sound Velocity Probe
Short Range Navigation, Inspection and Survey
Transmitting Array Shading
Object Avoidance/Tracking, Distance Gage
Low Power Underwater Wireless Communication
Modem FSK, PSK and Spread Spectrum System
Phantom Echo Generation
Phantom Generation of Clicks, Whistles and Pulse Trains
Audiogram Studies/Audiometry/Psychoacoustics
AEP/ABR Experiments on Aquatic Mammals
Bioacoustic and Biological Research (Whales/Dolphins)
Source Level Capability: 191+DI (dB)
Usable Frequency: up to 3 MHz, 29.5 dB Gain
Driving Reactive Load
Class AB Linear and Class D Switching Modes
Single DC Power Supply, Shut-down Low Power Mode
Small Size Available Fitting in ΦD1½" (38.1mm) Cylinder Housing
Related Products
BII-4000 Sonar Signal Generation
BII-6000 Impedance Matching & Tuning
Underwater Transducer: SONAR, HIFU...
BII-2100 Transmitting & Receiving Switch


Power Amplifier BII-5121 BII-5122
Application: 1. Burst SINE, Pulse and Square waveform.
2. Chirp/FM, Arbitrary Waveform
3. Spread Spectrum FSK and PSK Signals
4. Continuous Waveform
5. Marine Animal Sound, Clicks, Whistles and Pulse Trains
Duty Cycle ≤ 1%
1. Burst SINE/Pulse/Square waveform
2. Chirp/FM, Arbitrary Waveform
3. Spread Spectrum FSK and PSK Signals
Shut-down Control: Onboard ON/OFF Switch: Manually or Digitally Digital Output or Not Used
Size:  Round PCB ΦDxH=101.6x50.8 mm Rectangular PCB
Mounting:  4xΦD4.87mm through-holes 4xΦD3.2mm through-holes
Weight in Air:  200 grams  130 grams 
Cable:  6" or 0.15m wires 60 mm wires
Connector:  Wire Leads Wire Leads
Miscellaneous: BII-5120 Series Power Amplifier
Gain: 29.5 dB or 30
RMS Power Capability:
(Linear Mode)
45 W @ +12 VDC Power Supply
102 W @ +24 VDC Power Supply
176 W @ +35 VDC Power Supply
RMS Power Capability:
(Switching Mode)
72 W @ +12 VDC Power Supply
168 W @ +24 VDC Power Supply
256 W @ +32 VDC Power Supply
Minimum Load: 0.7 Ω @ +12VDC Power Supply
1.6 Ω @ +24 VDC Power Supply
2.8 Ω @ +32 or +35 VDC Power Supply
Shut-down Control Voltage: TTL/CMOS Compatible. Shut-down: Logic Low "0": 0 to +0.4 VDC; Active: Logic High "1": +0.8 to +5 VDC.
Power Bandwidth (-3dB): 200 Hz to 2 MHz
Usable Frequency: 200Hz to 3MHz
Maximum Output Level: Linear Mode: (Supply Voltage Vc -8) Vpp.   Vpp: Peak to Peak Voltage.
Switch Mode: (Supply Voltage Vc -2) Vpp.  Vpp: Peak to Peak Voltage.
Maximum Input Level: Linear Mode (SINE Waveform): Maximum Output Level/Gain or 2Vpp, whichever is less.
Switch Mode (Pulse and Square Waveform): TTL/CMOS Level or 5Vpp.
Input Impedance: 20 kΩ || 6 pF
Supply Voltage Vc: Linear Mode: +6 to +35 VDC
Switching Mode: +6 to +32 VDC
Quiescent Current: Active: 65 mA; Shut Down: 6 mA
Suggested DC Supply: Marine Battery, Automobile Battery, Fixed DC Linear Power Supply, Not Included.
DO NOT use variable power supply whose maximum supply voltage is higher than the above rated voltage.
DO NOT use switching mode DC power supply.
Operating Temperature: -40°C to 85°C
Storage Temperature: -50°C to 105°C
Technical Documents: Download BII-5120 specs.

BII-5121 PCB Size and Mounting Information

Power Amplifier

BII-5122 PCB Size and Mounting Information

Power Amplifier for Sonar Transducer Linear Power Amplifier

  Signal Wires' Color
IN+ Input Signal White
IN- Input Signal common Blue
COM Power Supply Common Black
+Vs Power Supply Positive Voltage Red
OUT- Negative Output Yellow
OUT+ Positive Output Blue
OUT COM Output Common Default: PCB Via Pad, BII does not solder wire.
ST-BY Shut Down Control Default: PCB Via Pad, BII does not solder wire.
ST-BY COM Shut Down Control Common Default: PCB Via Pad, BII does not solder wire.
SD Shut-down pin Default: PCB Via Pad, BII does not solder wire.
SW Shut-down pin Default: SW is wired to OFF
OFF Shut-down OFF pin Default: OFF is wired to SW
Default Factory-set: SW is wired to OFF, shut-down function is not available.
To use shut-down function:
1. Cut off the wire between SW and OFF
2. Solder a wire from SW to SD.
3. Solder wires to ST-BY and ST-BY COM respectively.

BII-5120 Series: Typical SPL (Sound Pressure Level) vs Frequency

Frequency (kHz) SPL (dB µPa*m) DUT (Device under Test)
200 216.0 to 217.5 3" Planar Transducer
300 218.4 to 221.0 3" Planar Transducer
420 218.8 to 220.3 2" Planar Transducer
600 219.4 to 221.0 1.5" Planar Transducer
1000 218.1 to 219.6 1" Planar Transducer
2000 221.1 to 222.6 1" Planar Transducer
3000 223.1 to 224.6 1" Planar Transducer

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