L1817BF-08TR - Alliance Semiconductor

October 2003 P1817A/B

rev 1.0

Alliance Semiconductor

2575, Augustine Drive • Santa Clara, CA • Tel: 408.855.4900 • Fax: 408.855.4999 • www.alsc.com

Notice: The information in this document is subject to change without notice.

Low-Power Mobile VGA EMI Reduction IC

Features

 FCC approved method of EMI attenuation.

 Generates a low EMI spread spectrum clock of the

input frequency.

 Optimized for frequency range from:

o P1817A – 20 to 30MHz. Operation

o P1817B – 10 to 20MHz Operation

 Internal loop filter minimizes external components

and board space.

 Two selectable spread ranges.

 Low inherent cycle-to-cycle jitter.

 3.3V or 5V operating voltage range.

 TTL or CMOS compatible outputs.

 Ultra-low power CMOS design.

 3.17mA @3.3V, 10MHz | 6.20mA@5.0V, 10MHz

 4.28mA @3.3V, 14MHz | 7.50mA @5.0V, 14MHz

 5.50mA @3.3V, 20MHz | 9.50mA @5.0V, 20MHz

 Supports notebook VGA and other LCD timing

controller applications.

 SSON pin for Spread Spectrum On/Off and

Standby Mode controls.

 Available in 8-pin SOIC and TSSOP.

Product Description

The P1817 is a versatile spread spectrum frequency

modulator designed specifically for input clock frequencies.

The P1817 reduces electromagnetic interference (EMI) at

the clock source, allowing system wide reduction of EMI of

down stream clock and data dependent signals. The P1817

allows significant system cost savings by reducing the

number of circuit board layers ferrite beads, shielding and

other passive components that are traditionally required to

pass EMI regulations.

The P1817 modulates the output of a single PLL in order to

“spread” the bandwidth of a synthesized clock, and more

importantly, decreases the peak amplitudes of its

harmonics. This results in significantly lower system EMI

compared to the typical narrow band signal produced by

oscillators and most frequency generators. Lowering EMI

by increasing a signal’s bandwidth is called ‘spread

spectrum clock generation’.

The P1817 uses the most efficient and optimized

modulation profile approved by the FCC and is

implemented in a proprietary all digital method.

Applications

The P1817 is targeted towards notebook VGA chip and

other displays using an LVDS interface, PC peripheral

devices, and embedded systems.

Block Diagram

VSS

XIN

XOUT

Crystal

Oscillator

Frequency

Divider

Feedback

Divider

Modulation

Phase

Detector

Loop

Filter VCO Output

Divider

ModOUT

PLL

VDD

SSON

SR0

Ref

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Notice: The information in this document is subject to change without notice.

ModOUT

4 5

P1817A/B

XIN /CLKIN

VSS

SR0

SSON/SBM

REF

VDD

XOUT

Pin Configuration

Pin Description

Pin# Pin Name Type Description

1 XIN/CLKIN I

Connect to externally generated clock signal. To put the part into standby

mode, disable the input clock signal to this pin and pull SSON/SBM (pin 4)

low. Refer Standby Mode Selection Table.

2 VSS P Ground Connection. Connect to system ground.

3 SR0 I

Digital logic input used to select Spreading Range. Refer Spread Spectrum

Selection Table. This pin has an internal pull-up resistor.

4 SSON/SBM I Spread Spectrum On/Off and standby mode control. Refer Standby Mode

Selection Table.

5 ModOUT O

Spread spectrum clock output or reference output. Refer Standby Mode

Selection Table.

6 REF O Reference output.

7 VDD P Connect to +3.3V or 5.0V.

8 XOUT O Connect to crystal. No connect if externally generated clock signal is used.

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Notice: The information in this document is subject to change without notice.

Standby Mode Selection

CLKIN SSON/SBM Spread

Spectrum ModOUT PLL Mode

Disabled 0 N/A Disabled Disabled Standby

Disabled 1 N/A Disabled Free Running Free Running

Enabled 0 Off Reference Disabled Buffer out

Enabled 1 On Normal Normal Normal

Spread Range Selection, VDD = 5V

CLKIN frequency SR0 Spreading Range Modulation Rate

1 ± 1.5%

10 MHz 0 ± 1.9%

1 ± 1.36%

14.318MHz 0 ± 1.64%

1 ± 1.3%

15MHz 0 ± 1.5%

1 ± 0.95%

20MHz 0 ± 1.125%

(CLKIN/10) * 20.83KHz

Spread Range Selection, VDD = 3.3V

CLKIN frequency SR0 Spreading Range Modulation Rate

1 ± 1.5%

10 MHz 0 ± 1.65%

1 ± 1.4%

14.318MHz 0 ± 1.7%

1 ± 1.37%

15MHz 0 ± 1.63%

1 ± 1.1%

20MHz 0 ± 1.28%

(CLKIN/10) * 20.83KHz

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Notice: The information in this document is subject to change without notice.

Schematic for Notebook VGA Application

1. To set the P1817 to standby mode, disable the input clock (pin 1 CLKIN), and pull pin 4 SSON/SBM low.

VDD

Ferrite

Bead

0.1µF

0Ω

CLKIN/

XIN

VSS

SR0

SSON/

SBM ModOUT

REF

VDD

XOUT

Use either pull-up or pull-down

resistors with 0Ω.

Pull pin 4 low to turn Spread Spectrum

off and enable Standby Mode1.

10 to 20 MHz and 20 to 32 MHz EMI

reduced clock output.

P1817A/B

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Notice: The information in this document is subject to change without notice.

Absolute Maximum Ratings

Symbol Parameter Rating Unit

VDD, VIN Voltage on any pin with respect to GND -0.5 to + 7.0 V

TSTG Storage temperature -65 to +125 °C

TA Operating temperature 0 to 70 °C

Note: These are stress ratings only and functional operation is not implied. Exposure to absolute maximum

ratings for extended periods may affect device reliability.

DC Electrical Characteristics

Symbol Parameter Min Typ Max Unit

VIL Input low voltage GND – 0.3 - 0.8 V

VIH Input high voltage 2.0 - VDD + 0.3 V

IIL Input low current (pull-up resistors on inputs SR0 and

SSON/SBM) - - -35 µA

IIH Input high current (pull-down resistor on input SSON#) - - 35 µA

@ 0.4V, VDD = 3.3V - 3 -

IXOL X

OUT output low current @ 0.4V, VDD = 5.0V - 20 - mA

@ 2.5V, VDD = 3.3V - 3 -

IXOH X

OUT output high current @ 4.5V, VDD = 5.0V - 20 - mA

VDD =3.3V, IOL = 20mA - - 0.4

VOL Output low voltage VDD =5.0V, IOL = 20mA - - - V

VDD =3.3V, IOH = 20mA 2.5 - -

VOH Output high voltage VDD =5.0V, IOH = 20mA 4.5 - - V

Normal Mode fIN-min f

IN-typ f

IN-max

3.3V and 10pF loading 3.2 - 7.0

ICC Dynamic supply current

normal mode 5.0V and 10pF loading 6.2 - 13.6

IDD Static supply current standby mode - 0.6 - mA

VDD Operating voltage 2.7 3.3 5.5 V

tON Power up time (first locked clock cycle after power up) - 0.18 - mS

ZOUT Clock output impedance - 50 - Ω

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Notice: The information in this document is subject to change without notice.

AC Electrical Characteristics

Symbol Parameter Min Typ Max Unit

fIN Input frequency (See device type P1817A or P1817B). 10 - 32 MHz

fOUT Output frequency (See device type P1817A or P1817B). 10 - 32 MHz

Measured at 0.8V to 2.0V 0.7 0.9 1.1 ns

tLH* Output rise time Measured at 1.2V to 3.75V - 0.75 - ns

Measured at 0.8V to 2.0V 0.6 0.8 1.0 ns

tHL* Output fall time Measured at 1.2V to 3.75V - 0.75 - ns

tJC Jitter (cycle to cycle) - - 360 ps

tD Output duty cycle 45 50 55 %

*tLH and tHL are measured into a capacitive load of 15pF

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Notice: The information in this document is subject to change without notice.

Package Information

Mechanical Package Outline 8-Pin SOIC

Symbol Dimensions in inches Dimensions in millimeters

Min Max Min Max

A 0.057 0.071 1.45 1.80

A1 0.004 0.010 0.10 0.25

A2 0.053 0.069 1.35 1.75

B 0.012 0.020 0.31 0.51

C 0.004 0.01 0.10 0.25

D 0.186 0.202 4.72 5.12

E 0.148 0.164 3.75 4.15

e 0.050 BSC 1.27 BSC

H 0.224 0.248 5.70 6.30

L 0.012 0.028 0.30 0.70

θ 0° 8° 0° 8°

Note: Controlling dimensions are millimeters

SOIC – 0.074 grams unit weight

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Notice: The information in this document is subject to change without notice.

Mechanical Package Outline 8-Pin TSSOP

Dimensions in inches Dimensions in millimeters

Symbol Min Max Min Max

A 0.047 1.10

A1 0.002 0.006 0.05 0.15

A2 0.031 0.041 0.80 1.05

B 0.007 0.012 0.19 0.30

C 0.004 0.008 0.09 0.20

D 0.114 0.122 2.90 3.10

E 0.169 0.177 4.30 4.50

e 0.026 BSC 0.65 BSC

H 0.244 0.260 6.20 6.60

L 0.018 0.030 0.45 0.75

θ 0° 8° 0° 8°

Note: Controlling dimensions are millimeters

TSSOP – 0.034 grams unit weight

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Notice: The information in this document is subject to change without notice.

Ordering Codes

Part Number Marking

Input

Frequency

(MHz)

Package Type Pb

Free

Qty per

reel

Temperature

(°C)

P1817A-08ST P1817A 20-32 8-pin SOIC, tube No 0 to 70

P1817AF-08ST P1817AF 20-32 8-pin SOIC, tube Yes 0 to 70

I1817A-08SR I1817A 20-32 8-pin SOIC, tape & reel No 2500 -20 to 85

I1817BF-08TR I1817BF 10-20 8-pin SOIC, tape & reel Yes 2500 -20 to 85

Device Ordering Information

X1817X X- 08 XX

Licensed under US patent Nos 5,488,627 and 5,631,920.

Preliminary datasheet. Specification subject to change without notice.

OR - SOT23/T/R SR - SOIC, T/R

TT – TSSOP, TUBE QR – QFN, T/R

TR - TSSOP, T/R QT - QFN, TUBE

VT – TVSOP, TUBE BT - BGA, TUBE

VR – TVSOP, T/R BR – BGA, T/R

ST – SOIC, TUBE

F = Pb FREE

DEVICE NUMBER

Flow:

P = Commercial Temperature Range (0°C to 70°C)

I = Industrial Tem

erature Ran

(

-25°C to 85°C

)

Pin Count

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Notice: The information in this document is subject to change without notice.

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Alliance Semiconductor Corporation

2595, Augustine Drive,

Santa Clara, CA 95054

Tel# 408-855-4900

Fax: 408-855-4999

www.alsc.com

Preliminary Information

Part Number: P1817A/B

Document Version: v1.0