Philips PCK2509S Datasheet

INTEGRATED CIRCUITS

PCK2509S

50–150 MHz 1:9 SDRAM clock driver

Product specification 1999 Oct 19

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Philips Semiconductors Product specification

PCK2509S50–150 MHz 1:9 SDRAM clock driver

FEA TURES

•Phase-Locked Loop Clock distribution for PC100/PC133 SDRAM

applications

•Spread Spectrum clock compatible

•Operating frequency 50 to 150 MHz

•(t

phase error

– jitter) at 100 to133 MHz = ±50 ps

•Jitter (peak-peak) at 100 to 133 MHz = ± 80 ps

•Jitter (cycle-cycle) at 100 to 133 MHz = 65 ps

•Pin-to-pin skew < 200 ps

•Available in plastic 24-Pin TSSOP

•Distributes one clock input to one bank of ten outputs

•External Feedback (FBIN) terminal Is used to synchronize the

outputs to the clock input

•On-Chip series damping resistors

•No external RC network required

•Operates at 3.3 V

•Inputs compatible with 2.5 V and 3.3 V ranges

DESCRIPTION

The PCK2509S is a high-performance, low-skew, low-jitter, phase-locked loop (PLL) clock driver. It uses a PLLto precisely align, in both frequency and phase, the feedback (FBOUT) output to the clock (CLK) input signal. It is specifically designed for use with synchronous DRAMs. The PCK2509S operates at 3.3 V V input compatible with both 2.5 V and 3.3 V input voltage ranges. It also provides integrated series-damping resistors that make it ideal for driving point-to-point loads.

One bank of five outputs and one bank of four outputs provide nine low-skew, low-jitter copies of CLK. Output signal duty cycles are

and is

adjusted to 50 percent, independent of the duty cycle at CLK. Each bank of outputs can be enabled or disabled separately via the control (1G and 2G) inputs. When the G inputs are high, the outputs switch in phase and frequency with CLK; when the G inputs are low, the outputs are disabled to the logic–low state.

Unlike many products containing PLLs, the PCK2509S does not require external RC networks. The loop filter for the PLL is included on-chip, minimizing component count, board space, and cost.

Because it is based on PLL circuitry, the PCK2509S requires a stabilization time to achieve phase lock of the feedback signal to the reference signal. This stabilization time is required, following power up and application of a fixed-frequency, fixed-phase signal at CLK, and following any changes to the PLL reference or feedback signals. The PLL can be bypassed for test purposes by strapping AV

to ground.

The PCK2509S is characterized for operation from 0°C to +70°C.

PIN CONFIGURATION

AGND

1Y0

1Y1

1Y2

GND

1Y3

1Y4

12 13

FBOUT

CLK

24 23

2Y0

2Y1

GND

2Y2

2Y3 V

2G FBIN

SW00389

ORDERING INFORMA TION

PACKAGES TEMPERATURE RANGE ORDER CODE DRAWING NUMBER

24-Pin Plastic TSSOP 0°C to +70°C PCK2509S PW SOT355-1

1999 Oct 19 853–2180 22544

Philips Semiconductors Product specification

PCK2509S50–150 MHz 1:9 SDRAM clock driver

PIN DESCRIPTIONS

PIN NUMBER SYMBOL TYPE NAME, FUNCTION, and DIRECTION

1 AGND GND Analog ground. AGND provides the ground reference for the analog circuitry.

2, 10, 15, 22 V

3, 4, 5, 8, 9 1Y (0–4) OUT

6, 7, 18, 19 GND GND Ground

11 1G IN

12 FBOUT OUT

13 FBIN IN

14 2G IN

16, 17, 20, 21 2Y (0–3) OUT

23 AV

24 CLK IN

PWR Power supply

Clock outputs. These outputs provide low-skew copies of CLK. Output bank 1Y(0–4) is enabled via the1G input. These outputs can be disabled to a logic LOW state by de-asserting the 1G control input. Each output has an integrated 25 Ω series-damping resistor.

Output bank enable. 1G is the output enable for outputs 1Y(0–4). When 1G is LOW, outputs 1Y(0–4) are disabled to a logic LOW state. When 1G is HIGH, all outputs 1Y(0–4) are enabled and switch at the same frequency as CLK.

Feedback output. FBOUT is dedicated for external feedback. It switches at the same frequency as CLK. When externally wired to FBIN, FBOUT completes the feedback loop of the PLL. FBOUT has an integrated 25 Ω series-damping resistor.

Feedback input. FBIN provides the feedback signal to the internal PLL. FBIN must be hard-wired to FBOUT to complete the PLL. The integrated PLL synchronizes CLK and FBIN so that there is nominally zero phase error between CLK and FBIN.

Output bank enable. 2G is the output enable for outputs 2Y(0–3). When 2G is LOW, outputs 2Y(0–3) are disabled to a logic LOW state. When 2G is HIGH, all outputs 2Y(0–3) are enabled and switch at the same frequency as CLK.

Clock outputs. These outputs provide low-skew copies of CLK. Output bank 2Y(0–3) is enabled via the 2G input. These outputs can be disabled to a logic LOW state by de-asserting the 2G control input. Each output has an integrated 25 Ω series-damping resistor.

Analog power supply. AVCC provides the power reference for the analog circuitry. In addition,

PWR

AVCC can be used to bypass the PLL for test purposes. When AVCC is strapped to ground, PLL is bypassed and CLK is buffered directly to the device outputs.

Clock input. CLK provides the clock signal to be distributed by the PCK2509S clock driver. CLK is used to provide the reference signal to the integrated PLL that generates the clock output signals. CLK must have a fixed frequency and fixed phase for the PLL to obtain phase lock. Once the circuit is powered up and a valid CLK signal is applied, a stabilization time is required for the PLL to phase lock the feedback signal to its reference signal.

FUNCTION TABLE

INPUTS OUTPUTS

1G 2G CLK 1Y (0–4) 2Y (0–3) FBOUT

X X L L L L L L H L L H L H H L H H H L H H L H H H H H H H

1999 Oct 19

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