EP4CE6E22C8N Altera, EP4CE6E22C8N Datasheet - Page 88

• Manufacturer Part Number: EP4CE6E22C8N
• Description: IC CYCLONE IV FPGA 6K 144EQFP
• Manufacturer: Altera
• Series: CYCLONE® IV Er

Specifications of EP4CE6E22C8N

• Number Of Logic Elements/cells: 6272
• Number Of Labs/clbs: 392
• Total Ram Bits: 270000
• Number Of I /o: 91
• Voltage - Supply: 1.15 V ~ 1.25 V
• Mounting Type: Surface Mount
• Operating Temperature: 0°C ~ 85°C
• Package / Case: 144-EQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Number Of Gates: -
• Lead Free Status / Rohs Status: Compliant

5–26
Hardware Features
Clock Multiplication and Division
Cyclone IV Device Handbook, Volume 1
1
Cyclone IV PLLs support several features for general-purpose clock management.
This section discusses clock multiplication and division implementation,
phase shifting implementations, and programmable duty cycles.
Each Cyclone IV PLL provides clock synthesis for PLL output ports using
M/(N*post-scale counter) scaling factors. The input clock is divided by a pre-scale
factor, N, and is then multiplied by the M feedback factor. The control loop drives the
VCO to match f
divides down the high-frequency VCO. For multiple PLL outputs with different
frequencies, the VCO value is the least common multiple of the output frequencies
that meets its frequency specifications. For example, if output frequencies required
from one PLL are 33 and 66 MHz, the Quartus II software sets the VCO to 660 MHz
(the least common multiple of 33 and 66 MHz in the VCO range). Then, the post-scale
counters scale down the VCO frequency for each output port.
There is one pre-scale counter, N, and one multiply counter, M, per PLL, with a range
of 1 to 512 for both M and N. The N counter does not use duty cycle control because
the purpose of this counter is only to calculate frequency division. There are five
generic post-scale counters per PLL that can feed GCLKs or external clock outputs.
These post-scale counters range from 1 to 512 with a 50% duty cycle setting. The
post-scale counters range from 1 to 256 with any non-50% duty cycle setting. The sum
of the high/low count values chosen for a design selects the divide value for a given
counter.
The Quartus II software automatically chooses the appropriate scaling factors
according to the input frequency, multiplication, and division values entered into the
ALTPLL megafunction.
Phase alignment between output counters is determined using the t
specification.
IN
(M/N). Each output port has a unique post-scale counter that
Chapter 5: Clock Networks and PLLs in Cyclone IV Devices
© December 2010 Altera Corporation
PLL_PSERR
Hardware Features