1. A Floating-Gate Technology for Digital CMOS ProcessesV1 Cf
Creates a DC Measurement
of classic C-V curves C2 V2 C3
Vout V3
Vref V4 C4
Gain = DVout/ DVin
= - C1 / Cf
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2. Types of Integrated Capacitors
Double-Poly Capacitors
Well-Based MOS Capacitors
n-well + V -
Thin
oxide
n-well + V -
Thin
oxide

3. MOS Cap: CV Measurements5
4.5 4
3.5 3
2.5
Vref = 3.5V
Output voltage (V) 2
1.5
Vref = 3.0V 1
Vref = 2.5V
0.5
-1.5 -1
-0.5
0.5 1
Input voltage - Vref (V)

4. MOS Cap: CV Measurements4
Accumulation
3.5 3
Depletion
2.5
Capacitance (pF) 2
1.5 1
0.5
-1.5 -1
-0.5
0.5 1
Gate-to-well voltage (V)

5. MOS Capacitor FG Amplifiers5
Region 1
Vin
Vfg
Vdd
Vout Vt
4.5 4
Region 2
3.5
Output voltage (V) 3
2.5
Region where both capacitors
are acting as linear elements 2
1.5
1.5 2
2.5 3
3.5 4
4.5 5
Input voltage (V)

6. MOS Capacitor FG Transistor
10-5
Vdd
10-6
Vfg
Vin
10-7
10-8
Channel Current (A)
Iout
Sweep using two inputs: 39.6mV/e-fold
10-9
Vdd
10-10
Sweep using one input: 79.2mV/e-fold
Vfg
Vin
10-11
Vref
Iout
10-12 2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
Gate voltage (V)