TEXAS INSTRUMENTS CDCR61A Technical data

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CDCR61A

DIRECT RAMBUS CLOCK GENERATOR – LITE

SCAS626 – FEBRUARY 2000

D

400-MHz Differential Clock Source for
Direct Rambus Memory Systems for an
800-MHz Data Transfer Rate

D

Operates From Two (3.3-V and 1.80-V)
Power Supplies With 180 mW (Typ) at 400
MHz Total

D

Packaged in a Thin Shrink Small-Outline
Package (PW)

D

External Crystal Required for Input

V

DDP

GNDP

XOUT

XIN

V

DDL

LCLK

GNDL

S1

PW PACKAGE

(TOP VIEW)

1
2
3
4
5
6
7
8

16
15
14
13
12
11
10

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description

The Direct Rambus clock generator – lite (DRCG-Lite) is an independent crystal clock generator. It performs
clock multiplication using PLL, sourced by an internal crystal oscillator. It provides one dif ferential, high-speed
Rambus channel compatible output pair. Also, one single-ended output is available to deliver 1/2 of the crystal
frequency. The Rambus channel operates at up to 400 MHz with an option to select 300 MHz as well. The
desired crystal is a 18.75-MHz crystal in a series resonance fundamental application.

The CDCR61A is characterized for operation over free-air temperatures of 0°C to 85°C.

functional block diagram

XTAL

XIN

OSC

S0

PLL

V

DDP

S1 S2

DIV

2

BUSCLK

S0
V

DD

GND
CLK
CLKB
GND
V

DD

S2

XOUT

V

DDP

ON 0 0 Normal CLK CLKB XIN divided by 2
ON 1 1 Normal CLK CLKB XIN divided by 2
ON 0 1 Test Divided by 2 Divided by 2 XIN divided by 2
ON 1 0 Test Divided by 4 Divided by 4 XIN divided by 2
0 V 0 0 Test XIN XIN (invert) XIN divided by 2
0 V 1 1 Test XIN XIN (invert) XIN divided by 2
0 V 0 1 Test XIN divided by 2 XIN (invert) divided by 2 XIN divided by 2
0 V 1 0 Test XIN divided by 4 XIN (invert) divided by 4 XIN divided by 2

Direct Rambus and Rambus are trademarks of Rambus Inc.

PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.

S1 S2 MODE CLK CLKB LCLK

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

/2

BUSCLK FREQUENCY SETTINGS

S0

0 16

1 or Open 64/3

FUNCTION TABLE

M (PLL MULTIPLIER)

Copyright  2000, Texas Instruments Incorporated

LCLK

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

1

CDCR61A

I/O

DESCRIPTION

DIRECT RAMBUS CLOCK GENERATOR – LITE

SCAS626 – FEBRUARY 2000

Terminal Functions

TERMINAL

NAME NO.

CLK 13 O Output clock, connect to Rambus channel
CLKB 12 O Output clock (complement), connect to Rambus channel
GNDP, GNDL,

GND
LCLK 6 O LVCMOS output, 1/2 of crystal frequency
S0, S1, S2 16, 8, 9 I LVTTL level logic select terminal for function selection
V

DD

V

DDP

V

DDL

XIN 4 I Reference crystal input
XOUT 3 O Reference crystal feedback

2, 7,

11, 14

10, 15 Power supply, 3.3 V

1 Power supply for PLL, 3.3 V (0 V for Test mode)
5 Power supply for LCLK, 1.8 V

Ground

absolute maximum ratings over operating free-air temperature (unless otherwise noted)

Supply voltage range, VDD or V
Supply voltage range, V
Input voltage range,V

(see Note 1) –0.5 V to 4 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DDL

, at any input terminal –0.5 V to VDD + 0.5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I

Output voltage range, VO, at any output terminal (CLK, CLKB) –0.5 V to V
Output voltage range, VO, at any output terminal (LCLK) –0.5 V to V

(see Note 1) –0.5 V to 4 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DDP

†

DD

DDL

+ 0.5 V. . . . . . . . . . . . . . . . . . . .

+ 0.5 V. . . . . . . . . . . . . . . . . . . . . . . .

ESD rating (MIL-STD 883C, Method 3015) > 2 kV, Machine Model >200 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Continuous total power dissipation see Dissipation Rating Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operating free-air temperature range, T
Storage temperature range, T

–65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

stg

0°C to 85°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A

Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds 260°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

†

Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

NOTE 1: All voltage values are with respect to the GND terminals.

DISSIPATION RATING TABLE

PACKAGE

PW 1400 mW 11 mW/°C 740 mW

‡

This is the inverse of the junction-to-ambient thermal resistance when board-mounted and with
no air flow.

TA ≤ 25°C

POWER RATING

DERATING FACTOR

ABOVE TA = 25°C

‡

POWER RATING

TA = 85°C

2

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Low-level input voltage, V

V

High-level input voltage, V

V

Internal pullup resistance

kΩ

Low-level output current, I

mA

High-level output current, I

mA

I

(CMOS), C

†

pF

CDCR61A

DIRECT RAMBUS CLOCK GENERATOR – LITE

SCAS626 – FEBRUARY 2000

recommended operating conditions

MIN NOM MAX UNIT

Supply voltage, V
LCLK supply voltage, V

p

Input frequency at crystal input 14.0625 18.75 MHz

nput capacitance

Operating free-air temperature, T

†

Capacitance measured at f = 1 MHz, dc bias = 0.9 V, and VAC < 100 mV

DD

DDL

p

p

p

p

p

IL

IH

OL

OH

I

A

S0 0.35×V
S1, S2 0.35×V
S0 0.65×V
S1, S2 0.65×V
S0 10 55 100
S1, S2 90 145 250
CLK, CLKB 16
LCLK 10
CLK, CLKB –16
LCLK –10

S0, S1, S2 2.5
XIN, XOUT 20

3 3.3 3.6 V

1.7 1.8 2.1 V
DD

DD

DD
DD

0 85 °C

p

timing requirements

MIN MAX UNIT

Clock cycle time, t
Input slew rate, SR 0.5 4 V/ns
State transition latency (V

(cycle)

or S0 to CLKs – normal mode), t

DDX

(STL)

2.5 3.7 ns

3 ms

crystal specifications

MIN MAX UNIT

Frequency 14.0625 18.75 MHz
Frequency tolerance (at 25°C ±3°C) –15 15 ppm
Equivalent resistance (CL = 10 pF) 100 Ω
Temperature drift (–10°C to 75°C) 10 ppm
Drive level 0.01 1500 µW
Motional inductance 20.7 25.3 mH
Insulation resistance 500 MΩ
Spurious attenuation ratio (at frequency ±500 kHz) 3 dB
Overtone spurious 8 dB

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

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