Cypress Semiconductor CY2292FI, CY2292F, CY2291FI, CY2291F Datasheet

CY2291

Three-PLL General Purpose

EPROM Programmable Clock Generator

Features Benefits
Three integrated phase-locked loops
EPROM programmability
Factory-programmable (CY2291) or field-programmable

(CY2291F) device options
Low-skew, low-jitter, high-accuracy outputs
Power-management options (Shutdown, OE, Suspend)
Frequency select option
Smooth slewing on CPUCLK
Configurable 3.3V or 5V operation
20-pin SOIC Package

Selector Guide

Part Number Outputs Input Frequency Range Output Frequency Range Specifics

CY2291 8 10 MHz–25 MHz (external crysta l)

1 MHz–30 MHz (reference clock)

CY2291I 8 10 MHz–25 MHz (external crysta l)

1 MHz–30 MHz (reference clock)

CY2291F 8 10 MHz–25 MHz (external crysta l)

1 MHz–30 MHz (reference clock)

CY2291FI 8 10 MHz–25 MHz (external crysta l)

1 MHz–30 MHz (reference clock)

Generates up to 3 custom fr equencies from external sources
Easy customizati on and fast turnaround
Programming support av ailable for all opportunities

Meets critical industry standard timing requirements
Supports low-power applications
8 user-selectable frequencies on CPU PLL
Allows downstream PLLs to stay locked on CPUCLK output
Enables applic ation compatibil it y
Industry-standard packaging saves on board space

76.923 kHz–100 MHz (5V)

76.923 kHz–80 MHz (3.3V)

76.923 kHz–90 MHz (5V)

76.923 kHz–66.6 MHz (3.3V)

76.923 kHz–90 MHz (5V)

76.923 kHz–66.6 MHz (3.3V)

76.923 kHz–80 MHz (5V)

76.923 kHz–60.0 MHz (3.3V)

Fac tory Prog rammable
Commercial Temperature

Fac tory Prog rammable
Industrial Temperature

Field Programmable

Commercial Temperature

Field Programmable

Industrial Temperature

Logic Block Diagram

32XIN
32XOUT
XTALIN

XTALOUT

S0
S1

S2/SUSPEND

SHUTDOWN

OE

OSC.

OSC. XBUF

CPLL

(8 BIT)

UPLL

(10 BIT)

SPLL

(8 BIT)

/

/1,2,4

/1,2,4,8

/1,2,3,4,5,6
/8,10,12,13
/20,24,26,40
/48,52,96,104

/2,3,4

CONFIG
EPROM

MUX

32K

CPUCLK

CLKA

CLKB

CLKC

CLKD

CLKF

Cypress Semiconductor Corporation

• 3901 North First Street • San Jose • CA 95134 • 408-943-2600
June 14, 2000, rev. **

CY2291

Pin Configurations

CY2291

20-pin SOIC

32K

CLKC

V

DD

GND

XBUF
CLKD

1
2
3
4
5
6
7
8

9
10

20
19
18
17
16

15
14

13
12
11

32XIN
V

BATT

SHUTDOWN

S2/SUSPEND
V

DD

S1
S0

CLKF
CLKA
CLKB

/OE

32XOUT

XTALIN

XTALOUT

CPUCLK

Pin Summary

Name Pin Number Description

32XOUT 1 32.768 kHz crystal feedback.
32K 2 32.768 kHz output (always active if V
CLKC 3 Configurable clock output C.
V

DD

4, 16 Voltage supply.
GND 5 G round.
XTALIN
XTALOUT

[1]

[1, 2]

6 Reference crystal input or external referen ce clock input.

7 Reference crystal feedbac k.
XBUF 8 Buffered reference clock output.
CLKD 9 Configurable clock output D.
CPUCLK 10 CPU frequency clock output.
CLKB 11 Configurable clock output B.
CLKA 12 Configurable clock out put A.
CLKF 13 Configurable clock output F.
S0 14 CPU clock select input, bit 0.
S1 15 CPU clock select input, bit 1.
S2/SUSPEND 17 CPU clock selec t i nput, bit 2. Optionally enables suspend feature when LOW.
SHUTDOWN/OE 18 Places outputs in three-state

places outputs in three-state

V

BATT

19 Battery supply for 32.768-kHz circuit.

[4]

condition and shuts do wn chip when LO W . Optionally, only

[4]

condition and does not shut down chip when LOW.

32XIN 20 32.768-kHz crystal input.

Notes:

1. For best accuracy, use a parallel-resonant crystal, C

2. Float XTALOUT pin if XTALIN is driven by reference clock (as opposed to crystal).

3. Please refer to application note “Understanding the CY2291, CY2292 and CY2295” for more information.

4. The CY2291 has weak pull-downs on all outputs (except 32K). Hence, when a three-state condition is forced on the outputs, the output pins are pulled LOW.

≈ 17 pF or 18 pF.

LOAD

is present).

BATT

[3]

2

CY2291

Operation

The CY2291 is a third-generation family of clock generators.
The CY2291 is upwardl y compatible with the industry standard
ICD2023 and ICD2028 and cont inue s the ir trad itio n by pro vid­ing a high level of customizable feat ures to meet the diverse
clock generation needs of modern motherboards and other
synchronous systems.

All parts provide a highly configurable set of clocks for PC
motherboard applications. Each of the four configurable clock
outputs (CLKA–CLKD) can be as si gned 1 of 3 0 freq uencies i n
any combination. Multiple outputs configured for the same or

[3]

related
providing on-chip buffering for heavily loaded signals.

The CY2291 can be config ured f or either 5V or 3.3 V operation.
The internal ROM t abl es use EPROM techno log y, allowing ful l
customization of output frequencies. The reference oscillator
has been designed for 10-MHz to 25-MHz crystals, providing
additional f le xi bility. No ext ernal componen ts are requir ed wit h
this crystal. Alternatively, an external reference clock of fre­quency between 1 MHz and 30 MHz can be used. Customers
using the 32-kHz oscil lator shoul d connect a 10-MΩ resist or i n
parallel with the 32-kHz crystal.

frequencies will have low (<500 ps) skew, in effect

Output Configuration

The CY2291 has five independ ent frequency sources on-c hip.
These are the 32-kHz oscillator, the reference oscillator, and
three Phase-Locked Loops (PLLs). Each PLL has a specific
function. The System PLL (SPLL) driv es the CLKF output and
provides fix e d outpu t frequen cies on the confi gur abl e outputs .
The SPLL offers the most output frequency divider options.
The CPU PLL (CPLL) is controlled by the select inputs
(S0–S2) to provide eight user-selectable frequencies with
smooth slewing between frequencies. The Utility PLL (UPLL)
provides the most accurate cloc k. It is often used fo r misce lla­neous frequenci es not provi ded by the other freque ncy sourc­es.

All configurations are EPROM programmable , providing short
sample and p roduction le ad times . Pl ease ref er to the appli ca­tion note “Understanding the CY22 91, CY2292, and CY2295”
for information on configuri ng the part.

Pow er Saving Featur es

The SHUTDOWN/OE input three-states the outputs when
pulled LOW (the 32-kHz cloc k output is not affec ted). If syst em

shutdown is enabled, a LOW on this pin also shuts off the
PLLs, co unters, the refer ence oscillat or, and all other active
components. Th e r esult ing cu rr ent on the V
than 50 µA (for Commercial Temp. or 100 µA for Industrial
Temp.) plus 15 µA max. for the 32-kHz subsystem and is typ­ically 10 µA. After lea ving shutdown mode , the PLLs will have
to re-lock. All outputs except 32K have a weak pull-down so
that the outputs do not float when three-stated.

The S2/SUSPEND input can be configured to shut down a
customizabl e set of output s and/ or PLLs , when LO W. All PLLs
and any of the outputs e xcept 32K can be shut off in n early any
combin a tion. Th e o n ly limita tio n is that if a PLL i s s hu t o ff, a l l
outputs derived from it must also be shut off. Suspending a
PLL shuts off all associated logic, while suspending an output
simply for ces a three-state condi ti on.

The CPUCLK can slew (transition) smoot hly between 8 MHz
and the maximum output frequency (100 MHz at 5V/80 MHz
at 3.3V for Commercial Temp. parts or 90 M Hz at 5V/66. 6 MHz
at 3.3V for Industrial Temp. and for field-programmed parts).
This feature is extremely useful in “Green” PC and laptop ap­plications, where reducing the frequency of operation can re­sult in considerab le pow er savi ngs . This feat ure meets all 486
and Pent ium® processor slewing requirements .

[3]

pins will be less

DD

[4]

CyClocks™ Software

CyClocks is an ea sy-to- use applic ation that allo ws y ou to con ­figure any one o f the EPR OM pr ogra mmabl e c lock s offered by
Cypress. You may spec ify t he inpu t fre quency, PLL and output
frequencies, and differ ent functional options. Please note the
output frequency ranges in this data sheet when specifying
them in CyClocks to ensure that you stay within the limits.
CyClocks also has a powe r calculat ion f eat ure that allo ws you
to see the power consumption of your specific configuration.
You can download a copy of CyClocks for free on Cypress’s
website at www.cypress. com .

Cypress FTG Programmer

The Cypress Frequency Timing Generator (FTG) Program­mers is a portable programmer designed to custom program
our family of EPROM Field Progr ammable Cloc k Devices . The
FTG program mers conn ect to a PC s erial port and all ow users
of CyClocks software to quickly and easily prog ram any of t he
CY2291F, CY2292F, CY2071AF, and CY2907F devices. The
ordering code for th e Cypress FTG Programmer is CY3670.

3

Maximum Ratings

CY2291

(Abov e which the useful lif e m ay be impaired. For user guide­lines, not tested.)

Suppl y Voltage............ ... ......... .......... .......... .. . –0.5V to +7.0V

DC Input Voltage............................................ –0.5V to +7.0V

Storage Temperature ............................. ....–65°C to +1 5 0°C

Operating Conditions

[5]

Max. Soldering T emperature (10 sec)..........................260°C

Junction Temperature...................................................150°C

Pack age Power Dissipation................................... ...750 mW

Static Discharge Voltage.............................................>

2000V

(per MIL-STD-883, Method 3015)

Parameter Description Part N umbers Min. Ma x. Unit

V
V
V
T

C
C
f

REF

A

DD
DD
BATT

LOAD
LOAD

Supply Voltage, 5.0V operation All 4.5 5.5 V
Supply Voltage, 3.3V operation All 3.0 3.6 V
Battery Backup Voltage All 2.0 5.5 V
Commercial Operating Temperature, Ambient CY2291/CY2291F 0 +70
Industrial Operating Temperature, Ambient CY2291I/CY2291FI

−40

+85
Max. Load Capacitance 5.0V Operation All 25 pF
Max. Load Capacitance 3.3V Operation All 15 pF
External Reference Crystal All 10.0 25.0 MHz
External Referen ce Clock

[6, 7, 8 ]

All 1 30 MHz

Electrical Characteristics, Commercial 5.0V

Parameter Description Conditions Min. Typ. Max. Unit

V

OH

V

OL

V

OH–32

V

OL–32

V

IH

V

IL

I

IH

I

IL

I

OZ

I

DD

I

DDS

I

BATT

Notes:

5. Electrical parameters are guaranteed by design with these operating conditions, unless otherwise noted.

6. External input reference clock must have a duty cycle between 40% and 60%, measured at V

7. Please refer to application note “Crystal Oscillator Topics” for information on AC-coupling the external input reference clock.

8. The oscillator circuit is optimized for a crystal reference and for external reference clocks up to 20 MHz. For external reference clocks above 20 MHz, it is
recommended that a 150Ω pull-up resistor to V

9. Xtal inputs have CMOS thresholds.

10. Load = Max., VIN = 0V or VDD, Typical (–104) configuration, CPUCLK = 66 MHz. Other configurations will vary. Power can be approximated by the following
formula (multiply by 0.65 for 3V operation): IDD=10+0.06•(F

HIGH-Level Output Voltage IOH = 4.0 mA 2.4 V
LOW-Level Output Voltage IOL = 4.0 mA 0.4 V

32.768-kHz HIGH-Level
Output Voltage

32.768-kHz LOW-Level

IOH = 0.5 mA V

BATT

0.5

IOL = 0.5 mA 0.4 V

Output Voltage
HIGH-Level Input Voltage
LOW-Level Input Voltage

[9]

Except crystal pins 2.0 V

[9]

Except crystal pins 0.8 V
Input HIGH Current VIN = VDD–0.5V <1 10
Input LOW Current VIN = +0.5V <1 10
Output Leakage Current Three-state outputs 250
VDD Supply Current

[10]

VDD = VDD Max., 5V operati on 75 100 mA
Commercial

VDD Powe r Supply Current
in Shutdown Mode

V

Power Supply

BATT

Current

[10]

Shutdown active,

excluding V

V

BATT

be connected to the Xout pin.

DD

BATT

= 3.0V 5 15

CPLL+FUPLL

+2•F

CY2291/CY2291F 10 50

/2.

DD

)+0.27•(F

SPLL

CLKA+FCLKB+FCLKC+FCLKD+FCPUCLK+FCLKF+FXBUF

).

°C
°C

V

µA
µA
µA

µA

µA

4