Document
B9940L
2.5V or 3.3V, 200-MHz, 1:18 Clock Distribution Buffer
Features
• • • • • • 200-MHz clock support LVPECL or LVCMOS/LVTTL clock input LVCMOS/LVTTL compatible inputs 18 clock outputs: drive up to 36 clock lines 150-ps max. output-to-output skew Dual- or single-supply operation: — 3.3V core and 3.3V outputs — 3.3V core and 2.5V outputs — 2.5V core and 2.5V outputs • Pin-compatible with MPC940L • Industrial temperature range: -40°C to 85°C • 32-pin LQFP package
Description
The B9940L is a low-voltage clock distribution buffer with the capability to select either a differential LVPECL- or an LVCMOS/LVTTL-compatible input clock. The two clock sources can be used to provide for a test clock as well as the primary system clock. All other control inputs are LVCMOS/LVTTL compatible. The eighteen outputs are 2.5V or 3.3V compatible and can drive two series-terminated 50Ω transmission lines. With this capability the B9940L has an effective fan-out of 1:36. Low output-to-output skews make the B9940L an ideal clock distribution buffer for nested clock trees in the most demanding of synchronous systems.
Block Diagram
Pin Configuration
VDDC
32
31
30
29
28
27
26
25
VSS
Q0
Q1
Q2
Q3
Q4
Q5
VDD PECL_CLK PECL_CLK# TCLK TCLK_SEL 0 1
VDDC
18
Q0-Q17
VSS VSS TCLK T C LK _S E L P E C L _C L K P E C L_ C LK # VDD VDDC
1 2 3 4 5 6 7 8 9
B9940L
10 11 12 13 14 15 16
24 23 22 21 20 19 18 17
Q6 Q7 Q8 VDD Q9 Q 10 Q 11 VSS
Q17
Q16
Q15
Q14
Q13
VSS
Q12
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Cypress Semiconductor Corporation Document #: 38-07105 Rev. *C
•
3901 North First Street
•
San Jose, CA 95134 • 408-943-2600 Revised December 26, 2002
VDDC
B9940L
Pin Description[1]
Pin 5 6 3 Name PECL_CLK PECL_CLK# TCLK VDDC PWR I/O I, PU PECL Input Clock I, PD PECL Input Clock I, PD External Reference/Test Clock Input O Clock Outputs Description
9, 10, 11, 13, Q(17:0) 14, 15, 18, 19, 20, 22, 23, 24, 26, 27, 28, 30, 31, 32 4 8, 16, 29 7, 21 TCLK_SEL VDDC VDD
I, PD Clock Select Input. When LOW, PECL clock is selected and when HIGH TCLK is selected. 3.3V or 2.5V Power Supply for Output Clock Buffers 3.3V or 2.5V Power Supply Common Ground
1, 2, 12, 17, 25 VSS
Note: 1. PD = internal pull-down, PU = internal pull-up.
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Document #: 38-07105 Rev. *C
Page 2 of 5
B9940L
Maximum Ratings[2]
Maximum Input Voltage Relative to VSS: ............ VSS – 0.3V Maximum Input Voltage Relative to VDD: ............. VDD + 0.3V Storage Temperature: ................................–65°C to + 150°C Operating Temperature: ................................ –40°C to +85°C Maximum ESD protection ............................................... 2 kV Maximum Power Supply: ................................................5.5V Maximum Input Current: ............................................±20 mA This device contains circuitry to protect the inputs against damage due to high static voltages or electric field; however, precautions should be taken to avoid application of any voltage higher than the maximum rated voltages to this circuit. For proper operation, Vin and Vout should be constrained to the range: VSS < (Vin or Vout) < VDD. Unused inputs must always be tied to an appropriate logic voltage level (either VSS or VDD).
DC Parameters VDD = 3.3V ±5% or 2.5V ±5%, VDDC = 3.3V ±5% or 2.5V ±5%, TA = –40°C to +85°C
Parameter VIL VIH IIL IIH VPP VCMR VOL VOH IDDQ Zout Cin Description Input Low Voltage Input High Voltage Input Low Current[3] Input High Current[3] Peak-to-Peak Input Voltage PECL_CLK Common Mode PECL_CLK Range[4] VDD = 3.3V VDD = 2.5V IOL = 20 mA IOH = –20 mA, VDDC = 3.3V IOH = –20 mA, VDDC = 2.5V Quiescent Supply Current Output Impedance Input Capacitance VDD = 3.3V VDD = 2.5V Conditions All other inputs All other inputs Min. VSS 2.0 – – 500 VDD – 1.4 VDD – 1.0 – 2.4 1.8 – 9 11 – Typ. – – – – – – – – – – 2 14 18 4
[6]
Max. 0.8 VDD –200 200 1000 VDD – 0.6 VDD – 0.6 0.5 – – 5 19 26 –
Unit V V µA µA mV V V V V V mA Ω pF
Output Low Voltage[5] Output High Voltage[5]
AC Parameters VDD = 3.3V ±5% or 2.5V ±5%, VDDC = 3.3V ±5% or 2.5V ±5%, TA = –40°C to +85°C
Parameter Fmax tPD tPD FoutDC Tskew Tskew(pp) Description Maximum Input Frequency PECL_CLK to Q Delay
[7, 9]
Conditions VDD = 3.3V VDD = 2.5V VDD = 3.3V VDD = 2.5V Measured at VDD/2 VDD = 3.3V, Fin = 150 MHz VDD = 2.5V, Fin = 150 MHz PECL, VDDC = 3.3V
Min. – 2.0 2.6 1.8 2.3 45 – – –
Typ. – 3.5 4.0 3.3 3.8 – – – –
Max. 200 4.0 5.2 3.8 4.4 55 150 200 1.4
Units MHz ns ns % ps ns
TTL_CLK to Q Delay[7, 9] Output Duty Cycle[7, 8, 9] Output-to-Output Skew[7, 9] Part-to-Part Skew[10]
– – 2.2 PECL, VDDC = 2.5V Notes: www.DataSheet4U.com 2. The voltage on any input or I/O pin cannot exceed the power pin during power-up. Power suppl sequencing is NOT required. 3. Inputs have pull-up/pull-down resistors that effect input current. 4. The VCMR is the difference from the most positive side of the differential input signal. Normal operation is obtained when the “High” input is wit.