Phase Locked LoopDesign

KyoungTae Kang, Kyusun Choi

Electrical Engineering

Computer Science and Engineering

CSE598A/EE597G Spring 2006

Frequency Synthesizer

General Synthesizer Issues

Frequency Spectrum

Settling Time (Lock Time)

PLL Components Circuits

PLL Components Circuits

Reference Circuit

PLL Components Circuits

PFD and Charge Pump

Spur!!

Phase Frequency Detector(1)

Phase Frequency Detector(2)

PFD and modified flip-flop

B.park, “A 1GHz, Low-Phase-Noise CMOS Frequency Synthesizer with Integrate LC VCO for Wireless Communications“, CICC 1998

Park, Byungha? GIT PhD. Samsung LSI, RF/Analog IC Group

New Modified flip-flop by KT

•Reduce signal path

•High speed

•10 Transistors

•Negative reset

•No oscillation

•Customized

D Flip-Flop

DFF Simulation Comparison

•Modifed FF by KT

•DFF

PFD Simulation(1)

PFD Simulation(2)

PFD Simulation(3)

PFD Output Stage-Charge Pump

Programmable

Charge Pump (Drain–s/w)

•My first Charge pump.

•Easy to design and understand how to work

•Spike Noise from net76 when U2 turn on

•High noise contribution!

•If you designed CP like this, you got fired!

Charge Pump (Source-s/w)

•Low charge sharing

•Low noise

•Suppression the Spur

Level?

Why? Cascode?

>High impedence

>Pole!!!

Charge Pump Simulation

CP_Drain

CP_Source

V(U/D)

I(U)

I(D)

Charge Pumps

Rhee, W., "Design of high performance CMOS charge pumps in phase locked loop", In Proc. ISCAS, 1999, Vol. 1, pp. 545-548

J. S. Lee, M. S. Keel, S. I. Lim, and S. Kim, “Charge pump with perfect current matching characteristics in phase-locked loops,” Electronics Letters, Vol. 36, No. 23, pp. 1907-1908, November 2000.

Loop Filter(1)

Loop Filter(2)

PLL Components Circuits

Differential Delay Cell-Single pass

Chan-Hong Park, Solid-State Circuits, 1999.

Differential Delay Cell-Multiple pass

Yalcin Alper Eken, Solid-State Circuits, 2004

Negative Skewed Delay Scheme:

Seog-Jun, Lee, ISSC, 1997

Single pass Ring OSC.

Multiple pass Ring OSC.

Which one is faster?

1. 3 stage single pass Ring OSC.

2. 5 stage multiple pass Ring OSC.

3 Stage-Single pass Ring OSC.

•220MHz~825MHz @ V(Ctrl)=1.65V~3.3V

3 Stage-Single pass Ring OSC.

5 Stage-Multiple pass Ring OSC.

•1.65GHz~2.5GHz @ V(Ctrl) 1.65V~3.3V

How to simulate Oscillator in Hspice?

.Option

Transient Step

Start-up time

Triggered Signal

Frequency Measure Tool: Cscope

PLL Components Circuits

Frequency Divider

•Input stage-high speed, low power, Following stages-High speed

•Differential type-Suppression Noise

•Input buffer is required

N=64 Divider Simulation

Input buffer

PLL Simulation

V(VCO)

V(Ref)

V(DiV)

V(Up)

V(Dn)

V(Ctrl)