Low Skew, 1:6 Crystal-to-LVCMOS
Fanout Buffer
83905-01
DATA SHEET
General Description
Features
The 83905-01 is a low skew, 1-to-6 LVCMOS Fanout Buffer. The low
impedance LVCMOS outputs are designed to drive 50 series or
parallel terminated transmission lines. The effective fanout can be
increased from 6 to 12 by utilizing the ability of the outputs to drive
two series terminated lines.
•
•
•
•
•
•
The 83905-01 is characterized at full 1.8V, 1.5V, and 1.2V, mixed
1.8V/1.5V, 1.8V/1.2V and 1.5V/1.2V output operating supply mode.
Guaranteed output skew characteristics along with the 1.2V output
capabilities makes the 83905-01 ideal for high performance, single
ended applications that also require a limited output voltage.
ENABLE2
XTAL_OUT
XTAL_IN
ENABLE1
nc
19
18
17
16
GND
1
15
BCLK5
GND
2
14
VDDO
BCLK0
3
13
BCLK4
VDDO
4
12
GND
BCLK1
5
11
GND
83905-01
BCLK2
9
VDD
8
Crystal Oscillator Interface
Crystal input frequency range: 10MHz to 40MHz
Output skew: 95ps (maximum)
RMS phase jitter @ 25MHz, (100Hz – 1MHz): 0.17ps (typical)
•
•
Synchronous output enables
•
•
0°C to 70°C ambient operating temperature
Power supply modes: Full 1.8V, 1.5V, 1.2V
Mixed 1.8V core/1.5V output operating supply
Mixed 1.8V core/1.2V output operating supply
Mixed 1.5V core/1.2V output operating supply
Available in lead-free (RoHS 6) package
Block Diagram
10
BCLK0
BCLK3
7
GND
GND
6
Outputs able to drive 12 series terminated lines
Noise Power
Offset
100Hz................. -115 dBc/Hz
1kHz ................... -138 dBc/Hz
10kHz ................. -154 dBc/Hz
100kHz ............... -160 dBc/Hz
Pin Assignments
20
Six LVCMOS outputs
BCLK1
XTAL_IN
20-pin, 4mm x 4mm VFQFN Package
BCLK2
XTAL_OUT
XTAL_OUT
1
16
XTAL_IN
ENABLE2
GND
2
15
3
14
ENABLE1
BCLK5
BCLK0
VDDO
BCLK1
GND
BCLK2
4
13
5
12
6
11
7
10
8
9
BCLK3
VDDO
BCLK4
GND
BCLK3
VDD
BCLK4
ENABLE 1
SYNCHRONIZE
BCLK5
ENABLE 2
SYNCHRONIZE
83905-01
16-pin, 4.4mm x 5.0mm TSSOP Package
83905-01 REVISION 1 05/01/15
1
©2015 Integrated Device Technology, Inc.
83905-01 DATA SHEET
Pin Descriptions and Characteristics
Table 1. Pin Descriptions
Name
Type
Description
XTAL_OUT
Output
Crystal oscillator interface.
XTAL_IN
Input
Crystal oscillator interface.
ENABLE1, ENABLE2
Input
Clock enable. LVCMOS/LVTTL interface levels. See Table 3.
BCLK0, BCLK1, BCLK2,
BCLK3, BCLK4, BCLK5
Output
Clock outputs. LVCMOS interface levels.
GND
Power
Power supply ground.
VDD
Power
Power supply pin.
VDDO
Power
Output supply pin.
nc
Unused
No connect.
Table 2. Pin Characteristics
Symbol
Parameter
CIN
Input Capacitance
CPD
Power Dissipation Capacitance
(per output)
ROUT
Test Conditions
ENABLE[2:1]
Output Impedance
Minimum
Typical
Maximum
Units
4
pF
VDDO = 2.0V
12
pF
VDDO = 1.6V
12
pF
VDDO = 1.26V
12
pF
VDDO = 1.8V ± 0.2V
17
VDDO = 1.5V ± 0.1V
18
VDDO = 1.2V ± 5%
24
Function Table
Table 3. Clock Enable Function Table
Control Inputs
Outputs
ENABLE 1
ENABLE2
BCLK[0:4]
BCLK5
0
0
LOW
LOW
0
1
LOW
Toggling
1
0
Toggling
LOW
1
1
Toggling
Toggling
BCLK5
BCLK[0:4]
ENABLE2
ENABLE1
Figure 1. Enable Timing Diagram
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
2
REVISION 1 05/01/15
83905-01 DATA SHEET
Absolute Maximum Ratings
NOTE: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These ratings are stress
specifications only. Functional operation of product at these conditions or any conditions beyond those listed in the DC Characteristics or AC
Characteristics is not implied. Exposure to absolute maximum rating conditions for extended periods may affect product reliability.
Item
Rating
Supply Voltage, VDD
4.6V
Inputs, VI
-0.5V to VDD + 0.5V
Input, VI Crystal Oscillator Input
0V to VDD
Outputs, VO
-0.5V to VDDO + 0.5V
Package Thermal Impedance, TJ
125C
Storage Temperature, TSTG
-65C to 150C
DC Electrical Characteristics
Table 4A. Power Supply DC Characteristics, VDD = VDDO = 1.8V ±0.2V, TA = 0°C to 70°C
Symbol
Parameter
Minimum
Typical
Maximum
Units
VDD
Power Supply Voltage
Test Conditions
1.6
1.8
2.0
V
VDDO
Output Supply Voltage
1.6
1.8
2.0
V
4
10
mA
1
mA
IDD; NOTE 1
Power Supply Current
ENABLE [1:2] = 00
IDDO; NOTE 1
Output Supply Current
ENABLE [1:2] = 00
NOTE 1: Measured with outputs unterminated, and XTAL_IN and XTAL_OUT floated.
Table 4B. Power Supply DC Characteristics, VDD = VDDO = 1.5V ±0.1V, TA = 0°C to 70°C
Symbol
Parameter
VDD
Test Conditions
Minimum
Typical
Maximum
Units
Power Supply Voltage
1.4
1.5
1.6
V
VDDO
Output Supply Voltage
1.4
1.5
1.6
V
IDD; NOTE 1
Power Supply Current
ENABLE [1:2] = 00
3
7
mA
IDDO; NOTE 1
Output Supply Current
ENABLE [1:2] = 00
1
mA
NOTE 1: Measured with outputs unterminated, and XTAL_IN and XTAL_OUT floated.
Table 4C. Power Supply DC Characteristics, VDD = VDDO = 1.2V ±5%, TA = 0°C to 70°C
Symbol
Parameter
VDD
Test Conditions
Minimum
Typical
Maximum
Units
Power Supply Voltage
1.14
1.2
1.26
V
VDDO
Output Supply Voltage
1.14
1.2
1.26
V
IDD; NOTE 1
Power Supply Current
ENABLE [1:2] = 00
2
6
mA
IDDO; NOTE 1
Output Supply Current
ENABLE [1:2] = 00
1
mA
NOTE 1: Measured with outputs unterminated, and XTAL_IN and XTAL_OUT floated.
REVISION 1 05/01/15
3
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
83905-01 DATA SHEET
Table 4D. Power Supply DC Characteristics, VDD = 1.8V ±0.2V, VDDO = 1.5V ±0.1V, TA = 0°C to 70°C
Symbol
Parameter
Minimum
Typical
Maximum
Units
VDD
Power Supply Voltage
Test Conditions
1.6
1.8
2.0
V
VDDO
Output Supply Voltage
1.4
1.5
1.6
V
IDD; NOTE 1
Power Supply Current
ENABLE [1:2] = 00
4
10
mA
IDDO; NOTE 1
Output Supply Current
ENABLE [1:2] = 00
1
mA
NOTE 1: Measured with outputs unterminated, and XTAL_IN and XTAL_OUT floated.
Table 4E. Power Supply DC Characteristics, VDD = 1.8V ±0.2V, VDDO = 1.2V ±5%, TA = 0°C to 70°C
Symbol
Parameter
VDD
Test Conditions
Minimum
Typical
Maximum
Units
Power Supply Voltage
1.6
1.8
2.0
V
VDDO
Output Supply Voltage
1.14
1.2
1.26
V
IDD; NOTE 1
Power Supply Current
ENABLE [1:2] = 00
4
10
mA
IDDO; NOTE 1
Output Supply Current
ENABLE [1:2] = 00
1
mA
NOTE 1: Measured with outputs unterminated, and XTAL_IN and XTAL_OUT floated.
Table 4F. Power Supply DC Characteristics, VDD = 1.5V ±0.1V, VDDO = 1.2V ±5%, TA = 0°C to 70°C
Symbol
Parameter
VDD
Test Conditions
Minimum
Typical
Maximum
Units
Power Supply Voltage
1.4
1.5
1.6
V
VDDO
Output Supply Voltage
1.14
1.2
1.26
V
IDD; NOTE 1
Power Supply Current
ENABLE [1:2] = 00
3
7
mA
IDDO; NOTE 1
Output Supply Current
ENABLE [1:2] = 00
1
mA
Maximum
Units
NOTE 1: Measured with outputs unterminated, and XTAL_IN and XTAL_OUT floated.
Table 4G. LVCMOS/LVTTL DC Characteristics, TA = 0°C to 70°C
Symbol
VIH
VIL
VOH
VOL
Parameter
Input High Voltage
Input Low Voltage
Output High Voltage;
NOTE 1
Output Low Voltage;
NOTE 1
Test Conditions
Minimum
Typical
VDD = 1.8V ± 0.2V
1.2
VDD + 0.3
V
VDD = 1.5V ± 0.1V
1.0
VDD + 0.3
V
VDD = 1.2V ± 5%
0.8
VDD + 0.3
V
VDD = 1.8V ± 0.2V
-0.3
0.4
V
VDD = 1.5V ± 0.1V
-0.3
0.3
V
VDD = 1.2V ± 5%
-0.3
0.2
V
VDDO = 1.8V ± 0.2V
0.7
V
VDDO = 1.5V ± 0.1V
0.7
V
VDDO = 1.2V ± 5%
0.7
V
VDDO = 1.8V ± 0.2V
0.4
V
VDDO = 1.5V ± 0.1V
0.4
V
VDDO = 1.2V ± 5%
0.4
V
NOTE 1: Outputs terminated with 50 to VDDO/2. See Parameter Measurement Information, Output Load Test Circuit diagrams.
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
4
REVISION 1 05/01/15
83905-01 DATA SHEET
Table 5. Crystal Characteristics
Parameter
Test Conditions
Minimum
Maximum
Units
40
MHz
Equivalent Series Resistance (ESR)
50
Shunt Capacitance
7
pF
12
18
pF
Typical
Mode of Oscillation
Typical
Fundamental
Frequency
10
Load Capacitance
AC Electrical Characteristics
Table 6A. AC Characteristics, VDD = VDDO = 1.8V ±0.2V, TA = 0°C to 70°C
Symbol
Parameter
Maximum
Units
Using External Crystal
Test Conditions
10
40
MHz
Using External Clock
Source NOTE 1
1
100
MHz
90
ps
fMAX
Output
Frequency
tsk(o)
Output Skew; NOTE 2, 3
tjit
RMS Phase Jitter (Random); NOTE 4
tR / tF
Output Rise/Fall Time
odc
Output Duty Cycle
tEN
Output Enable
Time; NOTE 5
tDIS
Output Disable
Time; NOTE 5
Minimum
25MHz, Integration Range:
100Hz – 1MHz
20% to 80%
0.17
300
ps
600
ps
58
%
ENABLE1
4
cycles
ENABLE2
4
cycles
ENABLE1
4
cycles
ENABLE2
4
cycles
42
50
NOTE: Electrical parameters are guaranteed over the specified ambient operating temperature range, which is established when the device is
mounted in a test socket with maintained transverse airflow greater than 500 lfpm. The device will meet specifications after thermal equilibrium
has been reached under these conditions.
All parameters measured at ƒ 40MHz using a crystal input unless noted otherwise. Outputs terminated with 50 to VDDO/2.
NOTE 1: XTAL_IN can be overdriven by an external source.
NOTE 2: Defined as skew between outputs at the same supply voltage and with equal load conditions. Measured at VDDO/2.
NOTE 3: This parameter is defined in accordance with JEDEC Standard 65.
NOTE 4: See phase noise plot.
NOTE 5: These parameters are guaranteed by design. Not tested in production.
REVISION 1 05/01/15
5
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
83905-01 DATA SHEET
Table 6B. AC Characteristics, VDD = VDDO = 1.5V ±0.1V, TA = 0°C to 70°C
Symbol
Parameter
Test Conditions
fMAX
Output
Frequency
tsk(o)
Output Skew; NOTE 2, 3
tjit
RMS Phase Jitter (Random)
tR / tF
Output Rise/Fall Time
odc
Output Duty Cycle
tEN
Output Enable
Time; NOTE 4
tDIS
Output Disable
Time; NOTE 4
Minimum
Typical
Maximum
Units
Using External Crystal
10
40
MHz
Using External Clock
Source; NOTE 1
1
100
MHz
90
ps
25MHz, Integration Range:
100Hz – 1MHz
20% to 80%
0.3
300
ps
650
ps
56
%
ENABLE1
4
cycles
ENABLE2
4
cycles
ENABLE1
4
cycles
ENABLE2
4
cycles
44
50
NOTE: Electrical parameters are guaranteed over the specified ambient operating temperature range, which is established when the device is
mounted in a test socket with maintained transverse airflow greater than 500 lfpm. The device will meet specifications after thermal equilibrium
has been reached under these conditions.
All parameters measured at ƒ 40MHz using a crystal input unless noted otherwise. Outputs terminated with 50 to VDDO/2.
NOTE 1: XTAL_IN can be overdriven by an external source.
NOTE 2: Defined as skew between outputs at the same supply voltage and with equal load conditions. Measured at VDDO/2.
NOTE 3: This parameter is defined in accordance with JEDEC Standard 65.
NOTE 4: These parameters are guaranteed by design. Not tested in production.
Table 6C. AC Characteristics, VDD = VDDO = 1.2V ±5%, TA = 0°C to 70°C
Symbol
Parameter
Test Conditions
fMAX
Output
Frequency
tsk(o)
Output Skew; NOTE 2, 3
tjit
RMS Phase Jitter (Random)
Typical
Maximum
Units
Using External Crystal
10
40
MHz
Using External Clock
Source; NOTE 1
1
100
MHz
90
ps
tR / tF
Output Rise/Fall Time
odc
Output Duty Cycle
tEN
Output Enable
Time; NOTE 4
Output Disable
Time; NOTE 4
tDIS
Minimum
25MHz, Integration Range:
100Hz – 1MHz
20% to 80%
0.7
350
ps
800
ps
56
%
ENABLE1
4
cycles
ENABLE2
4
cycles
ENABLE1
4
cycles
ENABLE2
4
cycles
44
50
NOTE: Electrical parameters are guaranteed over the specified ambient operating temperature range, which is established when the device is
mounted in a test socket with maintained transverse airflow greater than 500 lfpm. The device will meet specifications after thermal equilibrium
has been reached under these conditions.
All parameters measured at ƒ 40MHz using a crystal input unless noted otherwise. Outputs terminated with 50 to VDDO/2.
NOTE 1: XTAL_IN can be overdriven by an external source.
NOTE 2: Defined as skew between outputs at the same supply voltage and with equal load conditions. Measured at VDDO/2.
NOTE 3: This parameter is defined in accordance with JEDEC Standard 65.
NOTE 4: These parameters are guaranteed by design. Not tested in production.
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
6
REVISION 1 05/01/15
83905-01 DATA SHEET
Table 6D. AC Characteristics, VDD = 1.8V ±0.2V, VDDO = 1.5V ±0.1V, TA = 0°C to 70°C
Symbol
Parameter
Test Conditions
fMAX
Output
Frequency
tsk(o)
Output Skew; NOTE 2, 3
tjit
RMS Phase Jitter (Random)
tR / tF
Output Rise/Fall Time
odc
Output Duty Cycle
tEN
Output Enable
Time; NOTE 4
tDIS
Output Disable
Time; NOTE 4
Minimum
Typical
Maximum
Units
Using External Crystal
10
40
MHz
Using External Clock
Source; NOTE 1
1
100
MHz
90
ps
25MHz, Integration Range:
100Hz – 1MHz
20% to 80%
0.18
300
ps
650
ps
60
%
ENABLE1
4
cycles
ENABLE2
4
cycles
ENABLE1
4
cycles
ENABLE2
4
cycles
40
50
NOTE: Electrical parameters are guaranteed over the specified ambient operating temperature range, which is established when the device is
mounted in a test socket with maintained transverse airflow greater than 500 lfpm. The device will meet specifications after thermal equilibrium
has been reached under these conditions.
All parameters measured at ƒ 40MHz using a crystal input unless noted otherwise. Outputs terminated with 50 to VDDO/2.
NOTE 1: XTAL_IN can be overdriven by an external source.
NOTE 2: Defined as skew between outputs at the same supply voltage and with equal load conditions. Measured at VDDO/2.
NOTE 3: This parameter is defined in accordance with JEDEC Standard 65.
NOTE 4: These parameters are guaranteed by design. Not tested in production.
Table 6E. AC Characteristics, VDD = 1.8V ±0.2V, VDDO = 1.2V ±5%, TA = 0°C to 70°C
Symbol
Parameter
Test Conditions
fMAX
Output
Frequency
tsk(o)
Output Skew; NOTE 2, 3
tjit
RMS Phase Jitter (Random)
Typical
Maximum
Units
Using External Crystal
10
40
MHz
Using External Clock
Source; NOTE 1
1
100
MHz
95
ps
tR / tF
Output Rise/Fall Time
odc
Output Duty Cycle
tEN
Output Enable
Time; NOTE 4
Output Disable
Time; NOTE 4
tDIS
Minimum
25MHz, Integration Range:
100Hz – 1MHz
20% to 80%
0.2
350
ps
800
ps
58
%
ENABLE1
4
cycles
ENABLE2
4
cycles
ENABLE1
4
cycles
ENABLE2
4
cycles
42
50
NOTE: Electrical parameters are guaranteed over the specified ambient operating temperature range, which is established when the device is
mounted in a test socket with maintained transverse airflow greater than 500 lfpm. The device will meet specifications after thermal equilibrium
has been reached under these conditions.
All parameters measured at ƒ 40MHz using a crystal input unless noted otherwise. Outputs terminated with 50 to VDDO/2.
NOTE 1: XTAL_IN can be overdriven by an external source.
NOTE 2: Defined as skew between outputs at the same supply voltage and with equal load conditions. Measured at VDDO/2.
NOTE 3: This parameter is defined in accordance with JEDEC Standard 65.
NOTE 4: These parameters are guaranteed by design. Not tested in production.
REVISION 1 05/01/15
7
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
83905-01 DATA SHEET
Table 6F. AC Characteristics, VDD = 1.5V ±0.1V, VDDO = 1.2V ±5%, TA = 0°C to 70°C
Symbol
Parameter
Test Conditions
fMAX
Output
Frequency
tsk(o)
Output Skew; NOTE 2, 3
tjit
RMS Phase Jitter (Random)
tR / tF
Output Rise/Fall Time
odc
Output Duty Cycle
tEN
Output Enable
Time; NOTE 4
tDIS
Output Disable
Time; NOTE 4
Minimum
Typical
Maximum
Units
Using External Crystal
10
40
MHz
Using External Clock
Source; NOTE 1
1
100
MHz
90
ps
25MHz, Integration Range:
100Hz – 1MHz
20% to 80%
0.34
350
ps
800
ps
58
%
ENABLE1
4
cycles
ENABLE2
4
cycles
ENABLE1
4
cycles
ENABLE2
4
cycles
42
50
NOTE: Electrical parameters are guaranteed over the specified ambient operating temperature range, which is established when the device is
mounted in a test socket with maintained transverse airflow greater than 500 lfpm. The device will meet specifications after thermal equilibrium
has been reached under these conditions.
All parameters measured at ƒ 40MHz using a crystal input unless noted otherwise. Outputs terminated with 50 to VDDO/2.
NOTE 1: XTAL_IN can be overdriven by an external source.
NOTE 2: Defined as skew between outputs at the same supply voltage and with equal load conditions. Measured at VDDO/2.
NOTE 3: This parameter is defined in accordance with JEDEC Standard 65.
NOTE 4: These parameters are guaranteed by design. Not tested in production.
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
8
REVISION 1 05/01/15
83905-01 DATA SHEET
Noise Power (dBc/Hz)
Typical Phase Noise at 25MHz (1.8V Core, 1.8V Output)
Offset Frequency (Hz)
REVISION 1 05/01/15
9
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
83905-01 DATA SHEET
Parameter Measurement Information
0.75V±0.05V
0.9V±0.1V
SCOPE
VDD,
VDDO
SCOPE
VDD,
VDDO
Qx
Qx
GND
GND
-0.75V±0.05V
-0.9V±0.1V
1.5V Core/1.5V LVCMOS Output Load Test Circuit
1.8V Core/1.8V LVCMOS Output Load Test Circuit
1.05V±0.15V
0.6V±5%
0.75V±0.05V
SCOPE
VDD,
VDDO
SCOPE
VDD
VDDO
Qx
Qx
GND
GND
-0.75V±0.05V
-0.6V±5%
1.8V Core/1.5V LVCMOS Output Load Test Circuit
1.2V Core/1.2V LVCMOS Output Load Test Circuit
1.2V±0.2V
0.9V±0.07V
0.6V±5%
0.6V±5%
SCOPE
VDD
VDDO
SCOPE
VDD
VDDO
Qx
GND
GND
-0.6V±5%
-0.6V±5%
1.5V Core/1.2V LVCMOS Output Load Test Circuit
1.8V Core/1.2V LVCMOS Output Load Test Circuit
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
Qx
10
REVISION 1 05/01/15
83905-01 DATA SHEET
Parameter Measurement Information, continued
VDDO
2
BCLKx
VDDO
2
BCLKy
tsk(b)
RMS Phase Jitter
Output Skew
V
DDO
80%
80%
2
BCLK[0:5]
t PW
t
20%
20%
BCLK[0:5]
tR
tF
odc =
PERIOD
t PW
x 100%
t PERIOD
Output Duty Cycle/Pulse Width/Period
Output Rise/Fall Time
VDD
OEx
(High-level
enabling)
VDD/2
VDD/2
0V
tEN
Output BCLKx
(See Note)
tDIS
VOH
VDDO/2
VOL
Output Enable/Disable
REVISION 1 05/01/15
11
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
83905-01 DATA SHEET
Application Information
Recommendations for Unused Output Pins
Outputs:
LVCMOS Outputs
All unused LVCMOS output can be left floating. There should be no
trace attached.
Crystal Input Interface
The 83905-01 has been characterized with 18pF parallel resonant
crystals. The capacitor values, C1 and C2, shown in Figure 2 below
were determined using an 18pF parallel resonant crystal and were
chosen to minimize the ppm error. The optimum C1 and C2 values
can be slightly adjusted for different board layouts.
XTAL_IN
C1
15pF
X1
18pF Parallel Crystal
XTAL_OUT
C2
15pF
Figure 2. Crystal Input Interface
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
12
REVISION 1 05/01/15
83905-01 DATA SHEET
Overdriving the XTAL Interface
The XTAL_IN input can be overdriven by an LVCMOS driver or by one
side of a differential driver through an AC coupling capacitor. The
XTAL_OUT pin can be left floating. The amplitude of the input signal
should be between 500mV and 1.8V and the slew rate should not be
less than 0.2V/ns. For 3.3V LVCMOS inputs, the amplitude must be
reduced from full swing to at least half the swing in order to prevent
signal interference with the power rail and to reduce internal noise.
Figure 3A shows an example of the interface diagram for a high
speed 3.3V LVCMOS driver. This configuration requires that the sum
of the output impedance of the driver (Ro) and the series resistance
(Rs) equals the transmission line impedance. In addition, matched
termination at the crystal input will attenuate the signal in half. This
VCC
can be done in one of two ways. First, R1 and R2 in parallel should
equal the transmission line impedance. For most 50 applications,
R1 and R2 can be 100. This can also be accomplished by removing
R1 and changing R2 to 50. The values of the resistors can be
increased to reduce the loading for a slower and weaker LVCMOS
driver. Figure 3B shows an example of the interface diagram for an
LVPECL driver. This is a standard LVPECL termination with one side
of the driver feeding the XTAL_IN input. It is recommended that all
components in the schematics be placed in the layout. Though some
components might not be used, they can be utilized for debugging
purposes. The datasheet specifications are characterized and
guaranteed by using a quartz crystal as the input.
XTAL_OUT
R1
100
Ro
Rs
C1
Zo = 50 ohms
XTAL_IN
R2
100
Zo = Ro + Rs
.1uf
LVCMOS Driver
Figure 3A. General Diagram for LVCMOS Driver to XTAL Input Interface
XTAL_OUT
C2
Zo = 50 ohms
XTAL_IN
.1uf
Zo = 50 ohms
LVPECL Driver
R1
50
R2
50
R3
50
Figure 3B. General Diagram for LVPECL Driver to XTAL Input Interface
REVISION 1 05/01/15
13
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
83905-01 DATA SHEET
Schematic Example
Figure 4 shows an example of the 83905-01 application schematic.
In this example, the device is operated at VDD = VDDO = 1.8V. The
decoupling capacitors should be located as close as possible to the
power pin. The input is driven by an 18pF load resonant quartz
crystal. The tuning capacitors C1 and C2 are fairly accurate, but
minor adjustments might be required. For the LVCMOS output
drivers, two termination examples are shown in this schematic. For
additional termination examples, see LVCMOS Termination
Application Note.
VD DO = 1.8V
VDD = 1. 8V
R2
31
Z o = 50 Ohm
CL = 18 pf
C2
15pf
C1
15pF
LVCMO S
U1
EN ABLE 2
VDD O
1
2
3
4
5
6
7
8
XTAL_OUT
EN ABLE 2
GND
BC LK0
VD DO
BC LK1
GND
BC LK2
XTAL_IN
EN ABLE 1
BCLK5
VD DO
BCLK4
G ND
BCLK3
VDD
16
15
14
13
12
11
10
9
ENABLE 1
VDD
R3
100
Z o = 50 Ohm
R4
100
LVCMO S
VDD
C3
10uF
VDD O
C4
.1uF
C5
. 1uF
Optional Termination
C6
.1uF
Unused outputs can be left floating. There should be
no trace attached to unused outputs. Device
characterized and specification limits set with all
outputs terminated.
Figure 4. 83905-01 Schematic Layout
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
14
REVISION 1 05/01/15
83905-01 DATA SHEET
Power Considerations
This section provides information on power dissipation and junction temperature for the 83905-01.
Equations and example calculations are also provided.
1.
Power Dissipation.
The total power dissipation for the 83905-01 is the sum of the core power plus the analog power plus the power dissipated due to the load. The
following is the power dissipation for VDD = 1.8V + 0.2V = 2.0V, which gives worst case results.
•
Power (core)MAX = VDD_MAX * IDD = 2V * 10mA = 20mW
•
Output Impedance ROUT Power Dissipation due to Loading 50 to VDD/2
Output Current IOUT = VDD_MAX / [2 * (50 + ROUT)] = 2V / [2 * (50 + 17)] = 14.9mA
•
Power Dissipation on the ROUT per LVCMOS output
Power (ROUT) = ROUT * (IOUT)2 = 17 * (14.9mA)2 = 3.8mW per output
•
Total Power Dissipation on the ROUT
Total Power (ROUT) = 3.8mW * 6 = 22.8mW
Dynamic Power Dissipation at 100MHz
Power (100MHz) = CPD * Frequency * (VDD)2 = 12pF * 100MHz * (2V)2 = 4.8mW per output
Total Power (100MHz) = 4.8mW * 6 = 28.8mW
Total Power Dissipation
•
Total Power
= Power (core)MAX + Total Power (ROUT) + Total Power (100MHz)
= 20mW + 22.8mW + 28.8mW
= 71.6mW
2. Junction Temperature.
Junction temperature, Tj, is the temperature at the junction of the bond wire and bond pad and directly affects the reliability of the device. The
maximum recommended junction temperature is 125°C.
The equation for Tj is as follows: Tj = JA * Pd_total + TA
Tj = Junction Temperature
JA = Junction-to-Ambient Thermal Resistance
Pd_total = Total Device Power Dissipation (example calculation is in section 1 above)
TA = Ambient Temperature
In order to calculate junction temperature, the appropriate junction-to-ambient thermal resistance JA must be used. Assuming no air flow and
a multi-layer board, the appropriate value is 100.3°C/W per Table 7 below.
Therefore, Tj for an ambient temperature of 70°C with all outputs switching is:
70°C + 0.072W *100.3°C/W = 77.2°C. This is below the limit of 125°C.
This calculation is only an example. Tj will obviously vary depending on the number of loaded outputs, supply voltage, air flow and the type of
board (multi-layer).
Table 7. Thermal Resistance JA for 16-Lead TSSOP, Forced Convection
JA by Velocity
Meters per Second
Multi-Layer PCB, JEDEC Standard Test Boards
REVISION 1 05/01/15
0
1
2.5
100.3°C/W
96.0°C/W
93.9°C/W
15
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
83905-01 DATA SHEET
Reliability Information
Table 8A. JA vs. Air Flow Table for a 16-Lead TSSOP
JA vs. Air Flow
Meters per Second
Multi-Layer PCB, JEDEC Standard Test Boards
0
1
2.5
100.3°C/W
96.0°C/W
93.9°C/W
0
1
2.5
57.5°C/W
50.3°C/W
45.1°C/W
Table 8B. JA vs. Air Flow Table for a 20-Lead VFQFN
JA vs. Air Flow
Meters per Second
Multi-Layer PCB, JEDEC Standard Test Boards
Transistor Count
The transistor count for 83905-01: 505
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
16
REVISION 1 05/01/15
83905-01 DATA SHEET
16-Lead TSSOP Package Outline and Package Dimensions
Package Outline - G Suffix for 16-Lead TSSOP
Table 9A. Package Dimensions for 16-Lead TSSOP
All Dimensions in Millimeters
Symbol
Minimum
N
Maximum
16
A
1.20
A1
0.05
0.15
A2
0.80
1.05
b
0.19
0.30
c
0.09
0.20
D
4.90
5.10
E
E1
6.40 Basic
4.30
e
4.50
0.65 Basic
L
0.45
0.75
0°
8°
aaa
0.10
Reference Document: JEDEC Publication 95, MO-153
REVISION 1 05/01/15
17
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
83905-01 DATA SHEET
20-Lead VFQFN Package Outline and Package Dimensions
Package Outline - K Suffix for 20-Lead VFQFN
Table 9C. Package Dimensions for 20-Lead VFQFN
NOTE:
All Dimensions in Millimeters
Symbol
Minimum
Nom
Maximum
b
0.20
0.25
0.30
D
3.90
4.00
4.10
E
3.90
4.00
4.10
D2
1.95
2.10
2.25
E2
1.95
2.10
2.25
L
0.45
0.55
0.65
e
0.50 BSC
N
20
A
0.80
0.90
1.00
A1
0.00
0.02
0.05
A3
The drawing and dimension data originate from IDT package
outline drawing PSC-4170, rev03.
1. Dimensions and tolerances conform to ASME Y14.5M-1994
2. All dimensions are in millimeters. All angles are in degrees.
3. N is the total number of terminals.
4. All specifications comply with JEDEC MO-220.
0.2 REF
Reference Document: JEDEC Publication 95, MO-220
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
18
REVISION 1 05/01/15
83905-01 DATA SHEET
Ordering Information
Table 10. Ordering Information
Part/Order Number
Marking
Package
Shipping Packaging
Temperature
83905AG-01LF
3905A01L
16-Lead TSSOP, Lead-Free
Tube
0C to 70C
83905AG-01LFT
3905A01L
16-Lead TSSOP, Lead-Free
Tape & Reel
0C to 70C
83905AK-01LF
5A01L
20-Lead VFQFN, Lead-Free
Tray
0C to 70C
83905AK-01LFT
5A01L
20-Lead VFQFN, Lead-Free
Tape & Reel
0C to 70C
NOTE: Parts that are ordered with an "LF" suffix to the part number are the Pb-Free configuration and are RoHS compliant.
LOW SKEW, 1:6 CRYSTAL-TO-LVCMOS FANOUT BUFFER
19
REVISION 1 05/01/15
Corporate Headquarters
Sales
Tech Support
6024 Silver Creek Valley Road
San Jose, CA 95138 USA
1-800-345-7015 or 408-284-8200
Fax: 408-284-2775
www.IDT.com
email: clocks@idt.com
DISCLAIMER Integrated Device Technology, Inc. (IDT) and its subsidiaries reserve the right to modify the products and/or specifications described herein at any time and at IDT’s sole discretion. All information in
this document, including descriptions of product features and performance, is subject to change without notice. Performance specifications and the operating parameters of the described products are determined
in the independent state and are not guaranteed to perform the same way when installed in customer products. The information contained herein is provided without representation or warranty of any kind, whether
express or implied, including, but not limited to, the suitability of IDT’s products for any particular purpose, an implied warranty of merchantability, or non-infringement of the intellectual property rights of others. This
document is presented only as a guide and does not convey any license under intellectual property rights of IDT or any third parties.
IDT’s products are not intended for use in applications involving extreme environmental conditions or in life support systems or similar devices where the failure or malfunction of an IDT product can be reasonably
expected to significantly affect the health or safety of users. Anyone using an IDT product in such a manner does so at their own risk, absent an express, written agreement by IDT.
While the information presented herein has been checked for both accuracy and reliability, Integrated Device Technology (IDT) assumes no responsibility for either its use or for the infringement of any patents or
other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal commercial applications. Any other applications, such as
those requiring extended temperature ranges, high reliability or other extraordinary environmental requirements are not recommended without additional processing by IDT. IDT reserves the right to change any
circuitry or specifications without notice. IDT does not authorize or warrant any IDT product for use in life support devices or critical medical instruments.
Integrated Device Technology, IDT and the IDT logo are registered trademarks of IDT. Product specification subject to change without notice. Other trademarks and service marks used herein, including protected
names, logos and designs, are the property of IDT or their respective third party owners.
Copyright ©2015 Integrated Device Technology, Inc.. All rights reserved.