ASM3P2184A - Alliance Semiconductor

November 2003 ASM3P2184A

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.

LCD Panel EMI Reduction IC

Features

 FCC approved method of EMI attenuation.

 Provides up to 15dB EMI reduction.

 Generates a 1X low EMI spread spectrum clock of

the input frequency.

 Input frequency range: 6MHz to 70 MHz.

 Internal loop filter minimizes external components

and board space.

 Spread option: Center Spread.

 2 spread frequency deviation selections:

o ±0.625% or ±1.875%

 Low inherent cycle-to-cycle jitter.

 3.3V operating voltage range.

 Low power CMOS design.

 Supports notebook VGA and other LCD timing

controller applications.

 Product available for industrial temperature range.

 Available in 8-pin SOIC and TSSOP.

Product Description

The ASM3P2184A is a versatile spread spectrum

frequency modulators designed specifically for a wide

range of input clock frequencies from 6MHz to 70MHz.

(Refer Input Frequency and Modulation Rate Table). The

ASM3P2184A can generate an EMI reduced clock from

an OSC or a system generated clock. The

ASM3P2184A offers a Center Spread clock with 2

percentage deviations; ±0.625% and ±1.675%.

The ASM3P2184A reduces electromagnetic interference

(EMI) at the clock source, allowing system wide reduction

of EMI of down stream clock and data dependent

signals. The ASM3P2184A 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 ASM3P2184A uses the most efficient and optimized

modulation profile approved by the FCC and is

implemented in a proprietary all digital method.

The ASM3P2184A 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’.

Applications

The ASM3P2184A is targeted towards EMI management

for memory and LVDS interfaces in mobile graphic

chipsets and high-speed digital applications such as PC

peripheral devices, consumer electronics, and embedded

controller systems.

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4 5

XIN

XOUT

GND

SS% ModOUT

VDD

FS0

FS1

ASM3P2184A

Block Diagram

Pin Configuration

VSS

XIN Crystal

Oscillator

Frequency

Divider

Feedback

Divider

Modulation

Phase

Detector Loop

Filter VCO Output

Divider

MODOUT

PLL

VDD

SS%

FS0 FS1

XOUT

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Pin Description

Pin# Pin Name Type Description

1 XIN I

Crystal connection or external frequency input. This pin has dual functions.

It can be connected to either an external crystal or an external reference

clock.

2 XOUT I

Crystal connection. Input connection for an external crystal. If using an

external reference, this pin must be left unconnected.

3 GND P Ground to entire chip.

4 SS% I

Spread range select. Digital logic input used to select frequency deviation

(Refer Spread Deviation S election Table). This pin has an internal pull-up

resistor.

5 ModOUT O Spread spectrum low EMI output.

6 VDD P Power supply for the entire chip (3.3V).

7 FS0 I

Frequency range select. Digital logic input used to select frequency range

(Refer Input Frequency and Modulation Rate Table). This pin has an internal

pull-up resistor.

8 FS1 I

Frequency range select. Digital logic input used to select frequency range

(Refer Input Frequency and Modulation Rate Table). This pin has an internal

pull-up resistor.

Input Frequency and Modulation Rate Table

FS1 (pin 8) FS0 (pin 7) Frequency Range

0 0 6 MHz to 13 MHz

0 1 12 MHz to 25 MHz

1 0 18 MHz to 35 MHz

1 1 40 MHz to 70 MHz

Spread Deviation Selection Table

Part Number SS% (pin 4) Spread Deviation (%)

0 ± 0.625

ASM3P2184A

1 ± 1.875

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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 Characteris tics

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 - - -35 µA

IIH Input high current - - 35 µA

IXOL XOUT Output low current

(@ 0.4V, VDD = 3.3V) - TBD - mA

IXOH XOUT Output high current

(@ 2.5V, VDD = 3.3V) - TBD - mA

VOL Output low voltage (VDD = 3.3V, IOL = 20mA) - - 0.4 V

VOH Output high voltage (VDD = 3.3V, IOH = 20mA) 2.5 - - V

ICC Dynamic supply current

Normal mode (3.3V and 10pF loading) 8.46 12 17.78 mA

IDD Static supply current

Standby mode 0.6 mA

VDD Operating voltage 2.7 3.3 3.7 V

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

ZOUT Clock out impedance - 50 - Ω

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AC Electrical Characteris tics

Symbol Parameter Min Typ Max Unit

XIN Input frequency 6 - 70 MHz

ModOUT Output frequency 6 - 70 MHz

tLH* Output rise time (measured at 0.8V to 2.0V) 0.7 0.9 1.1 ns

tHL* Output fall time (measured at 2.0V to 0.8V) 0.6 0.8 1.0 ns

tJC Jitter (cycle to cycle) - - 200 ps

TD Output duty cycle 45 50 55 %

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

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Package Information

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

 0° 8° 0° 8°

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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°

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Ordering Information

Ordering Code Package Name Package Type

ASM3P2184A-08ST 8-Pin SOIC Tube

ASM3P2184A-08SR 8-Pin SOIC Tape and Reel

ASM3P2184A-08TT 8-Pin TSSOP Tube

ASM3P2184A-08TR 8-Pin TSSOP Tape and Reel

ASM3P2184A-08-TR

OR - SOT23/T/R ST – SOIC, TUBE

TT – TSSOP, TUBE SR - SOIC, T/R

TR – TSSOP, T/R QR – QFN, T/R

QT - QFN, TUBE VT – TVSOP, TUBE

BT - BGA, TUBE VR – TVSOP, T/R

BR – BGA, T/R JR – SSOP, T/R

JT - SSOP, TUBE

PIN COUNT

X = Automotive I = Industrial P or n/c = Commercial

1 – reserved 6 – power management

2 - Non PLL based 7 – power management

3 – EMI Reduction 8 – power management

4 – DDR support products 9 – Hi performance

–

STD Zero Dela

Buffe

0 - reserved

Alliance Semiconductor Mixed Signal Product

PART NUMBER

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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: ASM3P2184A

Document Version: v1.0