ICS9214DGLFT IDT, Integrated Device Technology Inc, ICS9214DGLFT Datasheet - Page 11

• Manufacturer Part Number: ICS9214DGLFT
• Description: IC CLOCK GEN RAMBUS XDR 28-TSSOP
• Manufacturer: IDT, Integrated Device Technology Inc
• Type: Direct RAMbus Clock Generatorr

Specifications of ICS9214DGLFT

• Input: Clock
• Output: Clock
• Frequency - Max: 500MHz
• Voltage - Supply: 2.375 V ~ 2.625 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 28-TSSOP
• Frequency-max: 500MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 9214DGLFT

Clock Output Drivers
Figure 2 shows the clock driver equivalent circuit. The differential driver produces a specified voltage swing on the channel
by switching the currents going into ODCLK_T and ODCLK_C. The external resistor R
current. The minimum current is zero.
The voltage at the IREFY pin, V
flowing through R
The driver output characteristics are defined together with the external resistors, R
specified at the measurement points indicated in Figure 2. Table 5 shows example values for the resistors.
R
secondary reflections. Z
estimated by:
Pull-up resistor R
shows the resistor values for establishing and effective source termination impedance of 49.2 Ohms to match a 50 Ohm
channel. The termination voltages are 2.5 V for V
= 54.9 Ohms and R
0809G—08/02/08
1
, R
2
, and R
Integrated
Circuit
Systems, Inc.
3
CLK_INC
CLK_INT
and the clock driver output impedance, Z
RC
T
terminates the transmission line at the load to minimize clock signal reflection signal reflections. Table 5
RC
. So, the output low current can be estimated as I
= 200 Ohms can be used to match a 28 Ohm channel.
Table 5. Example Resistor Values and Termination Voltages for a 50 Ohm Channel
OUT
Symbol
Notes:
R
V
R
R
R
R
V
RC
TS
Input
Figure 1. Differential and single-ended reference clock inputs
T
T
1
2
3
is specified as 1000 Ohms, minimum to accomplish this. The effective impedance can be
IREFY
a. Differential input
(1000R
1 A different set of resistors is used in Figure 2 when testing
Clock Generator
for maximum output current of the clock driver (I
These resistors are: R
R
, is by design equal to 1 V nominally, and the driver current is seven times the current
T
XDR
=28Ω, R
Source termination voltage
1
/(1000+R
Swing control resistor
Termination resistor
Termination resistor
Termination resistor
Termination resistor
Termination voltage
Parameter
RC
TS
= 147Ω
and 1.2 V for V
1
)+R2) R
CLK_INT
OUT
1
3
11
, must match the impedance of the channel, Z
Supply Voltage
/(1000R
= 34Ω, R
T
. The resistor values R1 = 38.3 Ohms, R
OL
1
/(1000+R
Value
39.2
66.5
93.1
49.9
2
VTH
200
2.5
1.2
= 7/ R
= 31.8Ω, R
RC
Input
1
b. Single-ended input
.
)+R
Tolerance
1
, R
Clock Generator
+/- 1%
+/- 1%
+/- 1%
+/- 1%
+/- 1%
+/-5%
+/-5%
2
3
2
RC
+R
, and R
= 48.7Ω,
OLABS
XDR
at the IREFY pin sets the maximum
3
)
).
3
. The output clock signals are
Unit
Ω
Ω
Ω
Ω
Ω
V
V
1
2
= 19.1 Ohms, R
CH
ICS9214
, to minimize
3