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
9
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
S1S2
DIV
2
BUSCLK
S0
V
DD
GND
CLK
CLKB
GND
V
DD
S2
XOUT
V
DDP
ON00NormalCLKCLKBXIN divided by 2
ON11NormalCLKCLKBXIN divided by 2
ON01TestDivided by 2Divided by 2XIN divided by 2
ON10TestDivided by 4Divided by 4XIN divided by 2
0 V00TestXINXIN (invert)XIN divided by 2
0 V11TestXINXIN (invert)XIN divided by 2
0 V01TestXIN divided by 2XIN (invert) divided by 2XIN divided by 2
0 V10TestXIN divided by 4XIN (invert) divided by 4XIN 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.
S1S2MODECLKCLKBLCLK
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
016
1 or Open64/3
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
NAMENO.
CLK13OOutput clock, connect to Rambus channel
CLKB12OOutput clock (complement), connect to Rambus channel
GNDP, GNDL,
GND
LCLK6OLVCMOS output, 1/2 of crystal frequency
S0, S1, S216, 8, 9ILVTTL level logic select terminal for function selection
V
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
PW1400 mW11 mW/°C740 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
MINNOMMAXUNIT
Supply voltage, V
LCLK supply voltage, V
p
Input frequency at crystal input14.0625 18.75MHz
nput capacitance
Operating free-air temperature, T
†
Capacitance measured at f = 1 MHz, dc bias = 0.9 V, and VAC < 100 mV
Figure 3. Short-Term Cycle-to-Cycle Jitter over 2, 3, 4, or 6 Cycles
CLK
CLKB
t
(cycle)
tjL = | t
(cycle), max
– t
(cycle), min
| over 10000 consecutive cycles
Figure 4. Long-Term Jitter
6
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
CDCR61A
DIRECT RAMBUS CLOCK GENERATOR – LITE
SCAS626 – FEBRUARY 2000
PARAMETER MEASUREMENT INFORMATION
CLK
CLK
CLKB
Duty cycle error (t
CLK
CLKB
CLKB
Duty cycle (tDC) = (t
t
pW+/t(cycle)
(cycle)
)
t
pW+
Figure 5. Output Duty Cycle
t
pW+(i)
DC,ERR
) = t
t
(cycle)
pW+(i)
– t
pW+(i+1)
t
(cycle)
Figure 6. Duty Cycle Error (Cycle-to-Cycle)
Figure 7. Crossing-Point Voltage
t
pW+(i+1)
V
O(X)+
V
O(X), nom
V
O(X)–
1.8 V
LCLK
10 pF
120 Ω
120 Ω
20%
t
r
80%
t
f
V
OH
V
OL
Figure 8. LCLK Test Load Circuit and Voltage Waveform for CLK/CLKB and LCLK
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
7
CDCR61A
ООООООО
DIRECT RAMBUS CLOCK GENERATOR – LITE
SCAS626 – FEBRUARY 2000
PARAMETER MEASUREMENT INFORMATION
VDD, V
CLK/CLKB
LCLK
DDP
t
(cj)
, or
S0
t
(STL)
Figure 9. PLL Frequency Transition Timing
t
(cj10)
Figure 10. LCLK Jitter
8
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
CDCR61A
DIRECT RAMBUS CLOCK GENERATOR – LITE
SCAS626 – FEBRUARY 2000
MECHANICAL DATA
PW (R-PDSO-G**) PLASTIC SMALL-OUTLINE P ACKAGE
14 PIN SHOWN
0,65
14
1
1,20 MAX
0,30
0,19
8
6,60
4,50
4,30
6,20
7
A
0,15
0,05
M
0,10
Seating Plane
0,10
0,15 NOM
Gage Plane
0,25
0°–8°
0,75
0,50
PINS **
DIM
A MAX
A MIN
NOTES: A. All linear dimensions are in millimeters.
B. This drawing is subject to change without notice.
C. Body dimensions do not include mold flash or protrusion not to exceed 0,15.
D. Falls within JEDEC MO-153
8
3,10
2,90
14
5,10
4,90
16
5,10
20
6,60
6,404,90
24
7,90
7,70
28
9,80
9,60
4040064/E 08/96
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
9
IMPORTANT NOTICE
T exas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those
pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty . Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
CERTAIN APPLICA TIONS USING SEMICONDUCT OR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF
DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL
APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR
WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER
CRITICAL APPLICA TIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERST OOD TO
BE FULLY AT THE CUSTOMER’S RISK.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI’s publication of information regarding any third
party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.
Copyright 2000, Texas Instruments Incorporated
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