Characterization of a CMOS cell library for low-voltage operation

Department of Electrical and Computer Engineering

Jia Yao

Low-power and Low-voltage

Pavg = Pdyn + Pstatic Pdyn = Ptran + Pshort-circuit Ptran = α * C * Vdd 2 * f Pshort-circuit = Isc * Vdd

CMOS: dynamic power

Reduction of the power supply voltage is the most efficient way to reduce the power consumption.

Concentration

Study TSMC 0.18um standard cell library Design basic CMOS cells in Hspice and run

simulation Apply supply voltage from high to low to

observe the influence of lowering Vdd Collect data and arrive to conclusion

Basic Parameters

The environment temperature : 25 ℃ Input pulse T=24ns, and the width of input pulse is 12ns,

so the frequency is 41.6MHz. Input slew : 0.03ns Channel length L=0.2um Width Wn=2um, Wp=2.4um Nmos:VTH0 = 0.3725327

Pmos: VTH0 = -0.3948389

Calculation

Vdd/2

Vdd

Vdd/2

Vdd/2 Vdd/2

tphl tplh

Vdd

1. Gate Delay

Vdd

Gate Delay= (tphl+ tplh)/2

For two or more inputs gate, calculate delay separately.

Vdd/2 Vdd/2

Vdd/2 Vdd/2

tphl tplh

A

BY

Without and with outloading

A

BY’

Vdd

in

out

Y

Calculation

※ Average power and Peak power

※ For two or more inputs, calculate power

separately, keep only one signal changing at

one time.

※ Without and with outloading

2. Power Calculation

2.5v 2.0v 1.8v 1.5v 1.2v 1.0v 0.8v 0.5vA→Y↓

(ns) 0.0092

0.019

0.0113

0.021

0.0126

0.023

0.0151

0.026

0.0189

0.033

0.0240

0.042

0.0377

0.068

0.7660

1.266

A→Y↑

(ns)0.015

0.030

0.018

0.036

0.019

0.039

0.023

0.048

0.031

0.065

0.043

0.092

0.081

0.176

2.420

5.036

Delay

(ns)

0.012

0.025

0.015

0.029

0.016

0.031

0.019

0.037

0.025

0.049

0.034

0.067

0.059

0.122

1.593

3.151

Avg Power

(uW/Mhz)0.0558

0.1975

0.0357

0.1224

0.0293

0.0981

0.0210

0.0674

0.0149

0.0429

0.0109

0.0297

0.0074

0.0188

0.0029

0.0064

Peak

Power(uW/Mhz)

49.63776.98

32.29

48.76

25.32

39.73

17.76

26.83

13.48

15.09

9.71

8.40

4.62

3.23

0.14

0.09

Power-Delay

Product

(e-17)

0.0682

0.489

0.0519

0.350

0.0465

0.305

0.0400

0.248

0.0371

0.209

0.0367

0.200

0.0439

0.299

0.4714

2.020

Inverter

delay

-0.5

0

0.5

1

1.5

2

0 1 2 3

v

ns

avg power and peak power

0

10

20

30

40

50

60

0 1 2 3

v

uW/M

HZ

Power-Delay Product

power-delay product

0

0.1

0.2

0.3

0.4

0.5

0 1 2 3

v

e-1

7

Comparison : with and without outloading

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

0 1 2 30

0.05

0.1

0.15

0.2

0.25

0 1 2 3

0

10

20

30

40

50

60

70

80

90

0 1 2 3

Delay Avg Power

Peak Power

0

0.5

1

1.5

2

2.5

0 1 2 3

Power-Delay Product

Nand2

2.5v 2.0v 1.8v 1.5v 1.2v 1.0v 0.8v 0.5vA→Y↓

(ns) 0.016

0.029

0.018

0.033

0.020

0.035

0.023

0.042

0.031

0.055

0.040

0.077

0.083

0.143

2.4

2.987

A→Y↑

(ns)0.018

0.034

0.021

0.040

0.023

0.044

0.028

0.054

0.038

0.073

0.055

0.104

0.107

0.196

3.280

5.392

Delay

(ns)

0.017

0.031

0.020

0.036

0.021

0.040

0.026

0.048

0.035

0.064

0.048

0.090

0.095

0.170

2.842

4.190

Avg Power

(uW/Mhz)0.0789

0.2290

0.0504

0.1404

0.0412

0.1120

0.0293

0.0764

0.0195

0.0483

0.0132

0.0333

0.0094

0.0209

0.0036

0.0066

Peak

Power(uW/Mhz)

48.25

63.32

30.81

38.17

24.71

29.62

17.66

18.27

10.18

9.08

5.51

4.50

1.90

1.46

0.09

0.11

Power-Delay

Product

(e-16)

0.0134

0.0719

0.0099

0.0511

0.0088

0.0445

0.0075

0.0364

0.0068

0.0310

0.0063

0.0301

0.0089

0.0354

0.1029

0.2760

2.5v 2.0v 1.8v 1.5v 1.2v 1.0v 0.8v 0.5vB→Y↓

(ns) 0.019

0.032

0.022

0.036

0.024

0.039

0.029

0.046

0.037

0.061

0.053

0.083

0.096

0.015

2.383

3.762

B→Y↑

(ns)0.025

0.041

0.030

0.049

0.033

0.054

0.041

0.066

0.058

0.089

0.082

0.125

0.152

0.230

3.989

6.091

Delay

(ns)

0.022

0.036

0.026

0.043

0.029

0.047

0.035

0.056

0.047

0.075

0.068

0.104

0.124

0.122

3.168

4.927

Avg Power

(uW/Mhz)0.1190

0.2903

0.7660

0.1779

0.0625

0.1420

0.0442

0.0964

0.0284

0.0604

0.0202

0.0413

0.0126

0.0255

0.0035

0.0063

Peak

Power(uW/Mhz)

57.80

64.08

36.44

38.32

28.99

29.34

17.92

18.02

9.40

8.54

6.04

6.04

2.93

2.93

0.05

0.05

Power-Delay

Product

(e-16)

0.0257

0.105

0.0198

0.0756

0.0178

0.0664

0.0155

0.0543

0.0134

0.0454

0.0136

0.0429

0.0156

0.0312

0.1115

0.3108

Comparison : with and without outloading

-1

0

1

2

3

4

5

0 0.5 1 1.5 2 2.5 30

0.05

0.1

0.15

0.2

0.25

0 0.5 1 1.5 2 2.5 3

0

10

20

30

40

50

60

70

0 0.5 1 1.5 2 2.5 3

0

0.05

0.1

0.15

0.2

0.25

0.3

0 0.5 1 1.5 2 2.5 3

Delay Avg Power

Peak Power Power-Delay Product

NOR2

2.5v 2.0v 1.8v 1.5v 1.2v 1.0v 0.8v 0.5vA→Y↓

(ns) 0.013

0.022

0.015

0.024

0.016

0.026

0.018

0.029

0.023

0.036

0.029

0.047

0.047

0.075

1.005

1.660

A→Y↑

(ns)0.027

0.06

0.032

0.07

0.037

0.08

0.047

0.100

0.067

0.14

0.011

0.22

0.242

0.45

7.938

11.96

Delay

(ns)

0.020

0.041

0.024

0.049

0.026

0.053

0.033

0.065

0.045

0.090

0.020

0.131

0.145

0.264

4.471

6.812

Avg Power

(uW/Mhz)0.0775

0.2298

0.0500

0.1399

0.04098

0.1108

0.0294

0.0745

0.0189

0.0465

0.0139

0.0319

0.0091

0.0201

0.0034

0.0054

Peak

Power(uW/Mhz)

64.91

83.87

42.72

54.07

33.62

43.32

24.49

28.59

16.20

15.69

10.36

8.62

4.50

3.32

0.12

1.13

Power-Delay

Product

(e-16)

0.0154

0.0940

0.0119

0.0679

0.0108

0.0592

0.0096

0.0487

0.0085

0.0420

0.0028

0.0420

0.0133

0.0530

0.1532

0.3658

2.5v 2.0v 1.8v 1.5v 1.2v 1.0v 0.8v 0.5vB→Y↓

(ns) 0.015

0.024

0.017

0.027

0.018

0.028

0.021

0.032

0.026

0.040

0.034

0.051

0.055

0.082

1.104

1.762

B→Y↑

(ns)0.032

0.07

0.040

0.08

0.045

0.09

0.058

0.11

0.083

0.15

0.125

0.22

0.256

0.44

7.141

11.75

Delay

(ns)

0.024

0.045

0.029

0.053

0.032

0.058

0.039

0.071

0.055

0.096

0.079

0.136

0.155

0.262

4.122

0.6756

Avg Power

(uW/Mhz)0.100

0.2505

0.0647

0.1526

0.0524

0.1209

0.0368

0.0810

0.0235

0.0500

0.0162

0.0399

0.0101

0.0209

0.0033

0.0054

Peak

Power(uW/Mhz)

70.48

85.80

45.92

54.08

37.06

42.85

26.05

27.65

15.04

14.75

8.52

7.93

3.30

2.96

0.05

0.07

Power-Delay

Product

(e-16)

0.0240

0.1124

0.0186

0.0812

0.0166

0.0706

0.0145

0.0573

0.0129

0.0478

0.0129

0.0460

0.0156

0.0548

0.1349

0.3630

-1

0

1

2

3

4

5

6

7

8

0 0.5 1 1.5 2 2.5 3

0

0.05

0.1

0.15

0.2

0.25

0 0.5 1 1.5 2 2.5 3

0

1020

3040

5060

7080

90

0 0.5 1 1.5 2 2.5 3

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 0.5 1 1.5 2 2.5 3

Comparison : with and without outloading

Delay Avg Power

Peak Power Power-Delay Product

Review

Around 1 V

With and without outloading

Separate calculation

Reference

1. Class notes and slides from ELEC6270 by Dr. Agrawal

2. TSMC 0.18 um standard cell library data book

3. Hspice user guide

4. Boarh,M.; Owens, R.M.and Irwin, M.J, “Transistor sizing

For low power CMOS circuits’’ IEEE Trans. On Computer-

Aided Design of Integrated Circuits and System, vol.15,

pp.665-671, 1996