ECRI Microelectronics

HCA1-100 High-Precision Charge Amplifier

Features:
Connected with capacitive sensor

Gain: 1~100mV/pC adjustable
High charge/voltage accuracy: ≤0.5%
Good low frequency characteristic
-3dB bandwidth: 0.3Hz~300kHz
Volume is 25×20×5.5mm3, hybrid integrated metal airtight package case
Quality class: commercial, industrial, military and aerospace class
Operating temperature range: 0~70℃, -40~85℃, -55~85℃, -55~125℃


1.Keywords of HCA1-100 High-Precision Charge Amplifier:

Charge, amplifier, high-precision, shock, acceleration

2.Description of HCA1-100 High-Precision Charge Amplifier:

HCA1-100 high-precision charge amplifier is a type of charge amplifier designed for accurate shock and acceleration measurement, and combined with it is a capacitive piezoelectric sensor. According to the principle of charge amplifier, it is very easy to achieve connection with long cable without affecting its accuracy, this is an advantage of charge amplifier over high-resistance voltage amplifier. By adopting metal case airtight package, it is also very easy to achieve signal shielding and noise reduction. Moreover, the internally interconnecting medium adopts ceramic wafer, the input impedance can be higher than that of PCB medium board, making the low-frequency response of electric circuit reach as low as 0.3Hz. The product has small volume and light weight, its main indexes reach or exceed the level of charge amplifier for general instrument such as LC0601, YE5850, HXC2102 etc., and complies with military standard on reliability.

3.Application of HCA1-100 High-Precision Charge Amplifier:

Measurement of shock, vibration and pressure
Measurement of slow varying acceleration

4.Schematic block diagram of HCA1-100 High-Precision Charge Amplifier

hca1-100-high-precision-charge-amplifier
HCA1-100 high-precision charge amplifier is divided into two stages, the first stage is for charge/voltage conversion with A1 as the core, the gains is fixed at 1mV/pC, which is equivalent to HCA2 hybrid integrated charge amplifier of our company; the second stage RA is externally connected adjustable resistance, which makes total gain of the circuit continuously adjustable in the range of 1~100.
Ca in the circuit is the self capacitor of sensor Q, Cc is the cable capacitor for connection and Ci is the input capacitor of circuit module. From the principle of charge amplifier, it can be derived that the gain of the first stage is V1=Q/Cf, where Q is the quantity of electric charge of the sensor. So it can be seen that V1 is independent of Ca, Cc, Ci etc., this is the reason that the charge amplifier adapts to signal measurement of high-sensitivity sensor.

5.Pin designation of HCA1-100 High-Precision Charge Amplifier

The module is of DIL construction.

6.Pins of the circuit are as follows of HCA1-100 High-Precision Charge Amplifier:

hca1-100-high-precision-charge-amplifier
Bottom view

Pin

Symbol

Meaning

Pin

Symbol

Meaning

1

IN

Charge input

9

OUT

Output

2

GND

Ground

10

J1

External resistance

3

NOP

Blank

11

NOP

Blank

4

NOP

Blank

12

+15V

Positive power source

5

NOP

Blank

13

GND

Ground

6

OUT1

Stage 1 output of charge/voltage conversion

14

-15V

Negative power source

7

GND

Ground

15

NOP

Blank

8

NOP

Blank

16

NOP

Blank


7.Electric performance of circuit of HCA1-100 High-Precision Charge Amplifier

Table 1  Electric characteristics

Characteristics

Symbol

Condition

(Unless otherwise specified,

VCC=15±0.1V

VEE=-15±0.1V

-55℃≤TA≤125℃)

Limit value

Unit

Min.

Max.

Input charge range

Q


0.05

10,000

pC

Preamplifier stage gain1)

A1


0.995

1.005


Bandwidth (-3dB)

f

The gain is 1.

0.32

300,000

Hz

Max. output voltage

Vmax


11.5

-

V

Gain accuracy

Ac


-

0.5

%

Harmonic distortion

α


-

0.5

%

Adjustable range of gain

Avar

R is externally connected2)

1

500


Notes:
1) The output of preamplifier stage is phase reversed
2) Resistance R is externally connected between pin 9 and 10 to control the gain; second stage inside the module is a noninverting amplifier and the gain of next stage is

8.Characteristic curve of HCA1-100 High-Precision Charge Amplifier

hca1-100-high-precision-charge-amplifier

Amplitude-frequency characteristic at gain of 1mV/pC

hca1-100-high-precision-charge-amplifier

Amplitude-frequency characteristic at gain of 500mV/pC

9.Application block diagram of HCA1-100 High-Precision Charge Amplifier

hca1-100-high-precision-charge-amplifier

10.External dimensions of HCA1-100 High-Precision Charge Amplifier


hca1-100-high-precision-charge-amplifier
The type of package and performance indexes of the circuit can be adjusted and customized according to customer’s demand.

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