CAV424 Datasheet, PDF (8/16 Pages) List of Unclassifed Manufacturers – Converter IC for Capacitive Signals

CAV424 - C/U transducer IC
with adjustable output voltage
The overall transfer function (9) is accrued from equations (5) and (6). It becomes evident
that the output signal is a function of capacitors C_M and C_R, of oscillator frequency f_OSC and
of the integrator charging currents I_CM and I_CR.
U_LPOUT
V_M 2,5V
C_M
C_{M Min}
C_{M Max}
C_M
Figure 6: Output signal V_LPOUT with C_M > C_R referenced to ground
A voltage is provided (9) as an output variable which is relative to the average voltage V_M. As this is
ratiometric to the supply voltage, in effect a differential ratiometric output signal is obtained.
R R _CX
CM
R_OSC
7
CAV424
T Sensor
12
C_OSC
Reference
oscillator
16
C_R
14
C_M
Integrator 1
Integrator 2
10
R_CR
2
3
1
11
Current reference
6
Signal conditioning
5
15
13 4
V_CC
C_VM
V_M
V_DIFF
V_LPout
C_RL1
R R _L1
L2
C_{L 1}
C_L2
R_L3 R_A
R_B
GND
Figure 7: Functional diagram for CAV424 (with charging currents I_CM
and I_CR constant)
Analog Microelectronics GmbH
An der Fahrt 13, D – 55124 Mainz
Phone: [phone]
Fax: [phone]
Internet:
http://www.analogmicro.de
Email: [e-mail]
July 2007 - Rev 1.2 - Page 8/16