IDT IDT8P79818NLGI Programmable low additive jitter 2:8 buffer with dividers and universal output Datasheet

Programmable Low Additive Jitter 2:8
Buffer with Dividers and Universal Outputs
8P79818
Datasheet
Description
Features
The device is intended to take 1 or 2 reference clocks, select
between them, using a pin or register selection and generate up to 8
outputs that may be the same as the reference frequency or
integer-divider versions of it.
▪ Two differential inputs support LVPECL, LVDS, HCSL or LVCMOS
reference clocks
— Accepts input frequencies ranging from 1PPS (1Hz) to
700MHz
▪ Select which of the two input clocks is to be used as the reference
clock for which divider via pin or register selection
— Switchover will not generate any runt clock pulses on the
output
▪ Generates eight differential outputs
or eight LVCMOS outputs, Bank A only
— Differential outputs selectable as LVPECL, LVDS, CML or
HCSL
— Differential outputs support frequencies from 1PPS to 700MHz
— LVCMOS outputs support frequencies from 1PPS to 200MHz
— LVCMOS outputs in the same pair may be inverted or in-phase
relative to one another
▪ Outputs arranged in 2 banks of 4 outputs each
— Each bank supports a separate power supply of 3.3V, 2.5V or
1.8V
— 1.5V output voltage is also supported for LVCMOS, Bank A
only
— One divider per output bank, supporting divide ratios of 2...511
or divider bypass
▪ Output enable control pin
— Output enable or disable will not cause any runt pulses
▪ Register programmable via I2C / SPI serial port
— Individual output enables, output type selection and output
power-down control bits supported
— Input mux selection control bit
▪ Core voltage supply of 3.3V, 2.5V or 1.8V
▪ -40°C to +85°C ambient operating temperature
▪ Lead-free (RoHS 6) packaging
The 8P79818 supports two output banks, each with its own divider
and power supply. All outputs in one bank would generate the same
output frequency, but each output can be individually controlled for
output type, output enable or even powered-off.
The device supports a serial port for configuration of the parameters
while in operation. The serial port can be selected to use the I2C or
SPI protocol. After power-up, all outputs will come up in LVDS mode
and may be programmed to other configurations over the serial port.
Outputs may be enabled or disabled under control of the OE input
pin.
The device can operate over the -40°C to +85°C temperature range.
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8P79818 Datasheet
Block Diagram
Figure 1: Block Diagram
Bank A
QA0
nQA0
DIV A
(2 to 511)
QA1
nQA1
CLK_SEL
PU
QA2
Div‐by‐1
nQA2
PD
CLK0
QA3
nQA3
nCLK0
PU/PD
Bank B
PD
CLK1
DIV B
(2 to 511)
nCLK1
PU/PD
OE
SCLK
PU
Div‐by‐1
PU
SDATA/SDI PU
QB0
nQB0
QB1
nQB1
QB2
nQB2
QB3
nQB3
Logic
SA0/nCS PU
nI2C/SPI
PD
8P79818 transistor count: 33,394
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8P79818 Datasheet
Pin Assignment
CLK0
nCLK0
VCC
SDATA/SDI
SCLK
VCC
nCLK1
CLK1
Figure 2: Pin Assignments for 5mm x 5mm 32-Lead VFQFN Package (Top View)
32
31
30
29
28
27
26
25
SDO
1
24
CLK_SEL
QA0
2
23
QB0
nQA0
3
22
nQB0
QA1
4
21
QB1
nQA1
5
20
nQB1
VCCOA
6
19
VCCOB
QA2
7
18
QB2
nQA2
8
17
nQB2
10
11
12
13
14
15
16
nI2C/SPI
VCC
SA0/nCS
OE
nQB3
QB3
QA3
9
nQA3
8P79818
Pin Description and Characteristic Tables
Table 1: Pin Description
Number
Name
Type[a]
1
SDO
Output
SPI mode data output signal. Unused in I2C mode.
2
QA0
Output
Positive differential clock output. Included in Bank A. Refer to Output Drivers section for details.
3
nQA0
Output
Negative differential clock output. Included in Bank A. Refer to Output Drivers section for details.
4
QA1
Output
Positive differential clock output. Included in Bank A. Refer to Output Drivers section for details.
5
nQA1
Output
Negative differential clock output. Included in Bank A. Refer to Output Drivers section for details.
6
VCCOA
Power
Output supply for output Bank A.
7
QA2
Output
Positive differential clock output. Included in Bank A. Refer to Output Drivers section for details.
8
nQA2
Output
Negative differential clock output. Included in Bank A. Refer to Output Drivers section for details.
9
QA3
Output
Positive differential clock output. Included in Bank A. Refer to Output Drivers section for details.
10
nQA3
Output
Negative differential clock output. Included in Bank A. Refer to Output Drivers section for details.
Description
Select protocol for serial port:
11
nI2C/SPI
Input (PD)
0 = I2C mode
1 = SPI mode
12
VCC
Power
13
SA0/nCS
Input (PU)
©2016 Integrated Device Technology, Inc.
Core logic supply.
SPI chip select input (active low) in SPI mode. Base address bit 0 in I2C mode.
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8P79818 Datasheet
Table 1: Pin Description (Cont.)
Master output enable control
14
OE
Input (PU)
0 = All outputs high-impedance
1 = All outputs enabled or disabled under control of register bits
15
nQB3
Output
Negative differential clock output. Included in Bank B. Refer to Output Drivers section for details.
16
QB3
Output
Positive differential clock output. Included in Bank B. Refer to Output Drivers section for details.
17
nQB2
Output
Negative differential clock output. Included in Bank B. Refer to Output Drivers section for details.
18
QB2
Output
Positive differential clock output. Included in Bank B. Refer to Output Drivers section for details.
19
VCCOB
Power
Output supply for output Bank B.
20
nQB1
Output
Negative differential clock output. Included in Bank B. Refer to Output Drivers section for details.
21
QB1
Output
Positive differential clock output. Included in Bank B. Refer to Output Drivers section for details.
22
nQB0
Output
Negative differential clock output. Included in Bank B. Refer to Output Drivers section for details.
23
QB0
Output
Positive differential clock output. Included in Bank B. Refer to Output Drivers section for details.
Input clock selection control pin. This pin may be disabled by register control, but if enabled
(default) its function is:
24
CLK_SEL
Input (PU)
25
CLK1
Input (PD)
26
nCLK1
Input (PU/ PD)
27
VCC
Power
28
SCLK
Input (PU)
29
SDATA/
SDI
Input/Output
(PU)
Input (PU)
30
VCC
Power
31
nCLK0
Input (PU/ PD)
32
CLK0
Input (PD)
Non-inverting differential clock input.
EP
VEE
Ground
Must be connected to ground (GND).
0 = CLK0 is selected
1 = CLK1 is selected
Non-inverting differential clock input.
Inverting differential clock input. VCC/2 when left floating (set by the internal pull-up and
pull-down resistors).
Core logic supply.
Serial port input clock for either SPI or I2C mode.
In I2C mode, this is the bi-directional data signal for the serial port
In SPI mode, this is the data input signal.
Core logic supply.
Inverting differential clock input. VCC/2 when left floating (set by the internal pull-up and
pull-down resistors).
a. Pull-up (PU) and pull-down (PD) resistors are indicated in parentheses. Pullup and Pulldown refer to internal input resistors. See Table 10,
DC Input/ Output Characteristics, for typical values.
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8P79818 Datasheet
Principles of Operation
Input Selection
The 8P79818 supports two input references: CLK0 and CLK1 that may be driven with differential or single-ended clock signals. Either or both
may be used as the source frequency for either output divider under control of the CLK_SEL input pin or under register control.
The CLK_SEL pin is the default selection mechanism and selects whether both dividers are driven by the CLK0, nCLK0 input (CLK_SEL =
Low) or by the CLK1, nCLK1 input (CLK_SEL = High).
If the user enables register control via the SEL_REG control bit, then there are 4 selection options available as shown in Table 2.
Table 2: Input Selection Register Control (SEL_REG = 1)
CLK_SEL [1:0]
Description
0
0
Divider A & B both driven from CLK0
0
1
Divider A driven from CLK1 &
Divider B driven from CLK0
1
0
Divider A driven from CLK0 &
Divider B driven from CLK1
1
1
Divider A & B both driven from CLK1
Output Dividers
Each bank of outputs has its own divider. All outputs in the same bank will be driven by that divider and so will all have the same frequency.
Divider A supplies the QA output bank and Divider B supplies the QB output bank. Each divider is capable of being driven by the same or a
different input frequency. Each divider can pass that input frequency directly to the outputs or to divide it by any integer from 2 up to 511.
Output Drivers
The QA[0:3] and QB[0:3] clock outputs are provided with register-controlled output drivers. By selecting the output drive type in the appropriate
register, any of these outputs can support LVCMOS, LVPECL, CML, HCSL or LVDS logic levels.
CML operation supports both a 400mV peak-peak swing and an 800mV peak-peak swing selection.
The operating voltage ranges of each output bank is determined by its independent output power pin (VCCOA or VCCOB). Output voltage levels
of 1.8V, 2.5V or 3.3V are supported for differential operation and LVCMOS operation. In addition, LVCMOS output operation supports 1.5V
VCCO.
A global OE input pin is provided. If the OE pin is negated (Low), then all outputs will be in a high-impedance state. If the OE pin is asserted
(High), then each output will behave as indicated by its individual register enable bit. Using the global OE pin to enable or disable outputs will
not result in any ‘runt’ clock pulses on the outputs.
Each output bank may be enabled or disabled using the SYNC_DISx register bit. Using these bits to enable or disable outputs will not result in
any ‘runt’ clock pulses on the outputs.
Individual outputs within a bank may be enabled or disabled using the DIS_Qxm register bits. These bits however may result in ‘runt’ pulses on
the outputs if the output is otherwise enabled, so it is recommended that the entire bank be disabled via the appropriate SYNC_DISx register
bit while an individual output is being enabled using the DIS_Qxm bit to avoid a possible ‘runt’ pulse on the output. If ‘runt’ pulses are not a
concern, then the DIS_Qxm bits may be used directly.
LVCMOS Operation
When a given output is configured to provide LVCMOS levels, then both the Q and nQ outputs will toggle at the selected output frequency. All
the previously described configuration and control apply equally to both outputs. Frequency, voltage levels and enable / disable status apply to
both the Q and nQ pins.
When configured as LVCMOS, the Q & nQ outputs can be selected to be phase-aligned with each other or inverted relative to one another.
Phase-aligned outputs will have increased simultaneous switching currents which can negatively affect phase noise performance and power
consumption. It is recommended that use of this selection be kept to a minimum.
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8P79818 Datasheet
Power-Saving Modes
To allow the device to consume the least power possible for a given application, the following functions are included under register control:
▪ Any unused output can be individually powered-off.
▪ If either bank is completely unused, all logic, including the dividers for that bank may be completely powered-off.
▪ Clock gating on logic that is not being used.
Device Start-up Behavior
The device will power-up with all outputs enabled in LVDS mode and all dividers bypassed.
Serial Control Port Description
Serial Control Port Configuration Description
The device has a serial control port capable of responding as a slave in an I2C or SPI compatible configuration, to allow access to any of the
internal registers for device programming or examination of internal status. All registers are configured to have default values. See the
specifics for each register for details. Selection of I2C versus SPI protocol will be done via the nI2C/SPI input pin.
SPI Mode Operation
SPI mode can be enabled via pin selection from power-up. The following information assumes SPI mode has been selected.
In a read operation (R/W bit is '1'), data on SDO will be clocked out on the falling edge of SCLK.
In a write operation (R/W bit is '0'), data on SDI will be clocked in on the rising edge of SCLK.
Figure 3: SPI Read Sequencing Diagram
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8P79818 Datasheet
During SPI Write operations, the user may continue to hold nCS low and provide further bytes of data for up to a total of 16 bytes in a single
block write. Data is written directly into the appropriate register as it is received.
Figure 4: SPI Write Sequencing Diagram
Figure 5: SPI Read/Write Timing Diagram
tpwh
tsu1
nCS
th1
tpwl
th2
tsu2
SCLK
SDI
R/W
A0
td2
td1
SDO
Hi‐Z
Hi‐Z
Table 3: Timing Characteristics in SPI Mode[a]
Symbol
Parameter
Min
Typ
Max
Unit
tpw
SCLK Period
20
ns
tpw1
SCLK Pulse Width Low
8
ns
tpw2
SCLK Pulse Width High
8
ns
tsu1
Valid nCS to SCLK Rising Setup Time
10
ns
th1
Valid nCS After Valid SCLK Hold Time (CLKE = 0/1)
10
ns
tsu2
Valid SDI to SCLK Rising Setup Time
5
ns
th2
Valid SDI after valid SCLK Hold Time
5
ns
td1
SCLK falling (rising in CLKE = 1 case) to Valid Data Delay Time
5
ns
td2
nCS rising edge to SDO High Impedance Delay Time
10
ns
tcsh
Time between Consecutive Read-Read or Read-Write Accesses
(nCS rising edge to nCS falling edge)
20
ns
a. Specifications guaranteed by design and characterization.
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8P79818 Datasheet
I2C Mode Operation
The I2C interface is designed to fully support v1.0 of the I2C specification for normal and fast mode operation. The device acts as a slave
device on the I2C bus at 100kHz or 400kHz using an address of 110110x (binary), where the value of ‘x’ is set by the SA0/nCS input pin. The
interface accepts byte-oriented block write and block read operations. One address byte specifies the register address of the byte position of
the first register to write or read. Data bytes (registers) are accessed in sequential order from the lowest to the highest byte (most significant
bit first). Read and write block transfers can be stopped after any complete byte transfer. During a write operation, data will be written to the
registers directly as each byte is received.
For full electrical I2C compliance, it is recommended to use external pull-up resistors for SDATA and SCLK. The internal pull-up resistors have
a size of 51k typical.
Figure 6: Slave Read and Write Cycle Sequencing
Current Read
S
Dev Addr + R
A
Data 0
A
Data 1
A
A
Data n
A
P
Sequential Read
S
Dev Addr + W
A
Offset Addr MSB
A
A
Offset Addr MSB
A
Sr
Dev Addr + R
A
Data 0
Data 1
A
A
Data 1
A
A
Data n
A
P
Sequential Write
S
Dev Addr + W
from master to slave
from slave to master
Data 0
A
A
Data n
A
P
S = start
Sr = repeated start
A = acknowledge
A = none acknowledge
P = stop
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8P79818 Datasheet
Register Descriptions
Table 4: Register Blocks
Register Ranges Offset (Hex)
Register Block Description
01
Device control
25
Bank A control
69
Bank B control
AB
Reserved
CF
Divide ratios
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8P79818 Datasheet
Table 5: Device Control Register Bit Field Locations
Address (Hex)
D7
0
CLKMODE
1
BKA_Vx
Bit Field Name
D6
D5
CLK_SEL[1:0]
BKB_Vx
Field Type
SYNC_DISA
D4
D3
D2
D1
D0
SEL_REG
Rsvd
Rsvd
Rsvd
DIV_SYNC
SYNC_DISB
PWR_DNA
PWR_DNB
DIS_DIVA
DIS_DIVB
Default Value
Description
Clock switchover mode selection:
CLKMODE
CLK_SEL[1:0]
R/W
R/W
0b
0 = Forced clock switch (may result in glitches as clocks switch)
1 = Glitch-less clock switch (may remain on original clock source if that
source is no longer toggling)
00b
Select which input clock is to be used as the reference clock. These bits are
only in effect when SEL_REG = 1:
00 = CLK0, nCLK0 input drives both Divider A & Divider B
01 = CLK1, nCLK1 input drives Divider A & CLK0, nCLK0 drives Divider B
10 = CLK0, nCLK0 input drives Divider A & CLK1, nCLK1 drives Divider B
11 = CLK1, nCLK1 input drives both Divider A & Divider B
SEL_REG
R/W
0b
Determines if input clock selection is to be performed by pin or register:
0 = CLK_SEL input pin controls reference selection mux
1 = CLK_SEL register bits controls reference selection mux
Rsvd
R/W

Reserved. Always write ‘0’ to this bit location. Read values are not defined.
Divider synchronization control:
DIV_SYNC
R/W
0b
0 = Dividers running normally
1 = Dividers in reset (output clocks halted)
1–>0 transition on this bit will synchronize the Bank A & Bank B output
dividers
Bank A voltage setting for optimal performance:
BKA_Vx
R/W
0b
0 = VCCOA is 3.3V
1 = VCCOA is 2.5V,1.8V, and 1.5V
Bank B voltage setting for optimal performance:
BKB_Vx
R/W
0b
0 = VCCOB is 3.3V
1 = VCCOB is 2.5V,1.8V
Glitch-free output enable bit for Bank A outputs:
SYNC_DISA
R/W
0b
0 = Outputs in Bank A are enabled glitch-lessly as indicated by their individual
DIS_QAm bits
1 = All outputs for Bank A are high-impedance
Glitch-free output enable bit for Bank B outputs:
SYNC_DISB
R/W
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0b
0 = Outputs in Bank B are enabled glitch-lessly as indicated by their individual
DIS_QBm bits
1 = All outputs for Bank B are high-impedance
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8P79818 Datasheet
Bit Field Name
Field Type
Default Value
Description
Power-down control for Bank A outputs:
PWR_DNA
R/W
0b
0 = All outputs for Bank A are powered (SYNC_DISA should be 1 when
powering-up the bank to prevent glitches on the output)
1 = All outputs in Bank A are powered-off
Power-down control for Bank B outputs:
PWR_DNB
R/W
0b
DIS_DIVA
R/W
0b
0 = All outputs for Bank B are powered (SYNC_DISB should be 1 when
powering-up the bank to prevent glitches on the output)
1 = All outputs in Bank B are powered-off
Power-down output divider for Bank A (DIVA must be set to 000h to bypass):
0 = Output divider for Bank A is powered
1 = Output divider for Bank A is powered-down
Power-down output divider for Bank B (DIVB must be set to 000h to bypass):
DIS_DIVB
R/W
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0b
0 = Output divider for Bank B is powered
1 = Output divider for Bank B is powered-down
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8P79818 Datasheet
Table 6: Bank A Control Register Bit Field Locations
Address (Hex)
D7
D6
2
D5
Rsvd
D4
D3
D2
D1
D0
TERM_A
QA_POL3
QA_POL2
QA_POL1
QA_POL0
3
Rsvd
MODE_QA3[2:0]
MODE_QA2[2:0]
4
Rsvd
MODE_QA1[2:0]
MODE_QA0[2:0]
5
DIS_QA3
Bit Field Name
TERM_A
DIS_QA2
Field Type
R/W
DIS_QA1
DIS_QA0
Rsvd
Default Value
Description
0b
Indicates termination used on Bank A outputs when HCSL mode is selected:
0 = 33/ 50
1 = 50
Output polarity selection for output pair nQAm, QAm in LVCMOS mode:
QA_POLm
MODE_QAm[2:0]
R/W
R/W
0h
010b
0 = nQAm pin is inverted relative to QAm pin when in LVCMOS mode
1 = nQAm and QAm pins are in-phase when in LVCMOS mode
Output driver mode of operation for output pair QAm, nQAm:
000 = high-impedance
001 = LVPECL
010 = LVDS (default)
011 = LVCMOS
100 = HCSL
101 = CML 400mV swing
110 = CML 800mV swing
111 = Reserved
Disable output pair QAm, nQAm:
DIS_QAm
R/W
0b
0 = Output pair QAm, nQAm is enabled (disable output bank using
SYNC_DISA to prevent runt pulses when enabling)
1 = Output pair QAm, nQAm is powered-down
Rsvd
R/W
©2016 Integrated Device Technology, Inc.

Reserved. Always write 0 to this bit location. Read values are not defined.
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8P79818 Datasheet
Table 7: Bank B Control Register Bit Field Locations
Address (Hex)
D7
D6
6
D5
Rsvd
D4
D3
D2
D1
D0
TERM_B
Rsvd
Rsvd
Rsvd
Rsvd
7
Rsvd
MODE_QB3[2:0]
MODE_QB2[2:0]
8
Rsvd
MODE_QB1[2:0]
MODE_QB0[2:0]
9
DIS_QB3
Bit Field Name
TERM_B
DIS_QB2
Field Type
R/W
DIS_QB1
DIS_QB0
Rsvd
Default Value
Description
0b
Indicates termination used on Bank B outputs when HCSL mode is selected:
0 = 33/ 50
1 = 50
Output driver mode of operation for output pair QBm, nQBm:
MODE_QBm[2:0]
R/W
010b
000 = high-impedance
001 = LVPECL
010 = LVDS (default)
011 = Rsvd
100 = HCSL
101 = CML 400mV swing
110 = CML 800mV swing
111 = Reserved
DIS_QBm
R/W
0b
Disable output pair QBm, nQBm:
0 = Output pair QBm, nQBm is enabled (disable output bank using
SYNC_DISB to prevent runt pulses when enabling)
1 = Output pair QBm, nQBm is powered-down
Rsvd
R/W

Reserved. Always write 0 to this bit location. Read values are not defined.
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8P79818 Datasheet
Table 8: Divide Ratio Register Field Locations
Address (Hex)
D7
D6
D5
D4
D3
C
DIVA[7:0]
D
DIVB[7:0]
E
D2
Rsvd
F
D1
D0
DIVB[8]
DIVA[8]
Rsvd
Bit Field Name
DIVA[8:0]
Field Type
R/W
Default Value
000h
Description
Divider ratio for Bank A outputs:
00h  01h = Bypass divider and pass reference clock directly to the Bank A
outputs
02h  1FFh = ratio to be used by the A divider is value written here. For
example writing a 4 in this field will results in a divide ratio of 4 being used.
Divider ratio for Bank B outputs:
DIVB[8:0]
R/W
000h
00h  01h = Bypass divider and pass reference clock directly to the Bank B
outputs
02h  1FFh = ratio to be used by the B divider is value written here. For
example writing a 4 in this field will results in a divide ratio of 4 being used.
Rsvd
R/W
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
Reserved. Always write 0 to this bit location. Read values are not defined.
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8P79818 Datasheet
Absolute Maximum Ratings
The absolute maximum ratings are stress ratings only. Stresses greater than those listed below can cause permanent damage to the device.
Functional operation of the 8P79818 at absolute maximum ratings is not implied. Exposure to absolute maximum rating conditions may affect
device reliability.
Table 9: Absolute Maximum Ratings
Item
Rating
Supply voltage, VCCX[a] to GND
3.6V
Inputs SCLK, SDATA/SDI, SA0/nCS, CLK_SEL, CLK0, nCLK0,
CLK1, nCLK1, OE, nI2C/SPI
0.5V to 3.6V
Outputs, IO QA[0:3], nQA[0:3], QB[0:3], nQB[0:3]
Continuous current
Surge current
40mA
60mA
Outputs, VO QA[0:3], nQA[0:3], QB[0:3], nQB[0:3]
0.5V to 3.6V
Outputs, VO SDO, SDATA/SDI
0.5V to 3.6V
Operating junction temperature
125°C
Storage temperature, TSTG
65°C to 150°C
Lead temperature (Soldering, 10s)
260°C
a. VCCx denotes VCC, VCCOA, or VCCOB.
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8P79818 Datasheet
DC Characteristics
Table 10: DC Input/ Output Characteristics
Symbol
Cin
Parameter
Test Conditions
Input capacitance
QA[0:3], nQA[0:3]
CML 400mV QB[0:3], nQB[0:3]
CPD
CML 800mV
Power
Bank A
dissipation LVCMOS
capacitance LVPECL
(per output)
LVDS
QA[0:3], nQA[0:3]
CML 400mV QB[0:3], nQB[0:3]
RPULLUP
Bank A
pF
1.2
pF
0.48
pF
0.44
pF
2.33
pF
1.4
pF
1.5
pF
0.53
pF
0.3
pF
2.1
pF
51
k
51
k
LVCMOS output type selected
VCCOA = 3.3V+5%
24

LVCMOS output type selected
VCCOA = 2.5V+5%
15

LVCMOS output type selected
VCCOA = 1.8V+5%
26

LVCMOS output type selected
VCCOA = 1.5V+5%
46

VCCOX[a] = 3.465V or 2.625V
VCCOA = 3.465V or 2.625V
VCCOX = 1.89V
VCCOA = 1.89V or 1.575V
Input pull-up resistor
Output impedance
QA[3:0], nQA[3:0]
Units
0.8
RPULLDOWN Input pull-down resistor
ROUT
Maximum
pF
CML 800mV
LVCMOS
Typical
0.5
LVPECL
LVDS
Minimum
a. VCCOx denotes VCCOA and VCCOB.
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Supply Voltage Characteristics
,
Table 11: Power Supply Characteristics, VCC = 3.3V ±5%, VEE = 0V, TA = -40°C to +85°C[a],
Symbol
VCC
VCCOA,
VCCOB
ICC
Parameter
Test Conditions
Minimum
Typical
[b], [c]
Maximum
Units
Core supply voltage
3.135
3.465
V
Output supply voltage
1.71
VCC
V
23
26
mA
DIV-by-1
157
177
mA
DIV A = DIV B = 2
125
140
mA
183
206
mA
Core supply current
ICCOA 
ICCOB
Output supply current
IEE
Power supply current
a. Internal dynamic switching current at maximum fOUT is included.
b. All outputs configured for LVEPCL logic levels and not terminated.
c. VCC  VCCOA and VCCOB.
Table 12: Power Supply Characteristics, VCC = 2.5V ±5%, VEE = 0V, TA = -40°C to +85°C[a],
Symbol
VCC
VCCOA,
VCCOB
ICC
Parameter
Test Conditions
Minimum
Typical
[b], [c]
Maximum
Units
Core supply voltage
2.375
2.625
V
Output supply voltage
1.71
VCC
V
18
20
mA
DIV-by-1
156
175
mA
DIV A = DIV B = 2
124
139
mA
177
199
mA
Core supply current
ICCOA 
ICCOB
Output supply current
IEE
Power supply current
a. Internal dynamic switching current at maximum fOUT is included.
b. All outputs configured for LVEPCL logic levels and not terminated.
c. VCC  VCCOA and VCCOB.
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Table 13: Power Supply Characteristics, VCC = 1.8V ±5%, VEE = 0V, TA = -40°C to +85°C[a],
Symbol
VCC
VCCOA,
VCCOB
ICC
Parameter
Test Conditions
Minimum
Typical
[b], [c]
Maximum
Units
Core supply voltage
1.71
1.89
V
Output supply voltage
1.71
VCC
V
14
16
mA
DIV-by-1
143
160
mA
DIV A = DIV B = 2
117
132
mA
161
181
mA
Core supply current
ICCOA 
ICCOB
Output supply current
IEE
Power supply current
a. Internal dynamic switching current at maximum fOUT is included.
b. All outputs configured for LVEPCL logic levels and not terminated.
c. VCC  VCCOA and VCCOB.
VCCOx[d] = 1.5V
VCCOx[d] = 1.5V  5%
LVCMOS
CML
LVPECL
LVDS
HCSL
LVCMOS
CML (400mV)
LVPECL
LVDS
HCSL
LVCMOS
CML (400mV)
LVCMOS
Units
Test Conditions
VCCOx[d] = 1.8V
HCSL
Bank B
output
supply
current
VCCOx[d] = 2.5V
LVDS
ICCOB
Bank A
output
supply
current
VCCOx[d] = 3.3V
LVPECL
ICCOA
Parameter[c]
Symbol
Table 14: Output Supply Current, VCC = 3.3V, 2.5V or 1.8V, VEE = 0V, TA = 25°C[a], [b]
VCC = 3.3V,
TA = 25°C
76
96
73
119
60
75
96
67
92
58
68
87
66
72
53
60
mA
VCC =
3.3V  5%,
TA = 85°C
88
114
87
149
70
88
113
85
111
67
80
104
78
86
63
71
mA
VCC = 3.3V,
TA = 25°C
76
96
73
119
60
75
96
67
92
58
68
87
66
72
53
60
mA
VCC = 3.3V,
TA = 85°C
88
114
87
149
70
88
113
85
111
67
80
104
78
86
63
71
mA
a. All outputs not terminated.
b. VCC  VCCOA and VCCOB.
c. Internal dynamic switching current at maximum fOUT is included.
d. VCCOx denotes VCCOA and VCCOB.
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8P79818 Datasheet
DC Electrical Characteristics
Table 15: LVCMOS/LVTTL Control / Status Signals DC Characteristics, VEE = 0V, TA = -40°C to +85°C
Symbol
VIH
VIL
IIH
IIL
VOH
Parameter
Test Conditions
Input high voltage
Input low voltage
SA0/nCS, SDATA/SDI,
SCLK, CLK_SEL, OE
Input
high current
nI2C/SPI
SA0/nCS, SDATA/SDI,
SCLK, CLK_SEL,OE
Input
low current
nI2C/SPI
Output
high voltage
SDATA/SDI, SDO
Minimum
Typical
Maximum
Units
VCC = 3.3V
2.20
VCC 0.3
V
VCC = 2.5V
1.85
VCC 0.3
V
VCC = 1.8V
1.25
VCC 0.3
V
VCC = 3.3V
–0.3
0.8
V
VCC = 2.5V
–0.3
0.7
V
VCC = 1.8V
–0.3
0.7
V
5
A
150
A
VCC = VIN = 3.465V, 2.625V or
1.89V
–150
A
–5
A
VCC = 3.3V ±5%, IOH = –5mA
2.6
V
VCC = 2.5V ±5%, IOH = –5mA
1.8
V
VCC = 3.465V, 2.625V or 1.89V,
VIN = 0V
VCC = 1.8V ±5%, IOH = –5mA
VOL
Output
low voltage
SDATA/SDI, SDO
V
VCC = 3.3V ±5% or 2.5V ±5% or
1.8V ±5%, IOL = 5mA
0.5
V
,
Table 16: Differential Input DC Characteristics, VCC = 3.3V±5%, 2.5V±5% or 1.8V±5%, VEE = 0V,
TA = -40°C to +85°C
Symbol
Parameter
Test Conditions
Minimum
Typical
Maximum
Units
150
A
IIH
Input
high current
CLKx, nCLKx[a] VCC = VIN = 3.465V or 2.625V
IIL
Input
low current
CLKx[a]
VCC = 3.465V or 2.625V, VIN = 0V
–5
A
nCLKx[a]
VCC = 3.465V or 2.625V, VIN = 0V
–150
A
VPP
VCMR
Peak-to-peak
voltage[b]
Common mode input voltage[b], [c]
0.15
1.3
V
0
VCC
V
a. CLKx denotes CLK0, CLK1. nCLKx denotes nCLK0, nCLK1.
b. VIL should not be less than –0.3V. VIH should not be higher than VCC.
c. Common mode voltage is defined as the cross-point.
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Table 17: LVPECL DC Characteristics, VCC = 3.3V±5%, 2.5V±5% or 1.8V±5%, VEE = 0V, TA = -40°C to +85°C
VCCOx[a] = 3.3V±5%
Symbol
Parameter
Min
Typ
VCCOx[a] = 2.5V±5%
Max
Min
Typ
VCCOx[a] = 1.8V±5%
Max
Min
Typ
Max
Units
VOH
Output
high voltage[b]
Qx,
nQx[c]
VCCOx 1.30
VCCOx 0.80
VCCOx 1.35
VCCOx 0.80
VCCOx 1.50
VCCOx 0.90
V
VOL
Output
low voltage
Qx,
nQx[c]
VCCOx 2.00
VCCOx 1.75
VCCOx 2.00
VCCOx 1.75
VEE
0.25
V
a. VCCOx denotes VCCOA and VCCOB.
b. Outputs terminated with 50 to VCCOx – 2V when VCCOx = 3.3V±5% or 2.5V±5%. Outputs terminated with 50 to ground when
VCCOx = 1.8V±5%.
c. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3. nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2, nQB3.
Table 18: LVDS DC Characteristics, VCC = 3.3V ±5%, 2.5V ±5% or 1.8V ±5%,
VCCOA = VCCOB = 3.3V ±5%, 2.5V ±5% or 1.8V ±5%, TA = -40°C to +85°C
Symbol
VOD
VOD
VOS
VOS
Parameter
Test Conditions
Differential output voltage
Qx, nQx[a]
VOD magnitude change
Qx, nQx[a]
[a]
Offset voltage
Qx, nQx
VOS magnitude change
Qx, nQx[a]
Minimum
Typical
Maximum
Units
480
mV
50
mV
1.375
V
50
mV
247
Terminated 100 across
Qx and nQx
1.125
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2, nQB3.
Table 19: CML (400mV Swing) DC Characteristics, VCC = 3.3V ±5%, 2.5V ±5% or 1.8V ±5%,
VCCOA = VCCOB = 3.3V ±5%, 2.5V ±5% or 1.8V ±5%, TA = -40°C to +85°C
Symbol
Parameter
VOH
Output high voltage
VOL
Output low voltage
VOUT
Output voltage swing
Test Conditions
Qx, nQx[a]
Qx, nQx[a]
Qx,
nQx[a]
Terminated with 50 to
VCCOx[b]
Minimum
Typical
Maximum
Units
VCCOx[b] – 0.10
VCCOx[b]
V
VCCOx[b] – 0.50
VCCOx[b] – 0.30
V
300
500
mV
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2, nQB3.
b. VCCOx denotes VCCOA and VCCOB.
Table 20: CML (800mV Swing) DC Characteristics, VCC = 3.3V ±5%, 2.5V ±5% or 1.8V ±5%, VCCOA = VCCOB =
3.3V ±5%, 2.5V ±5% or 1.8V ±5%, TA = -40°C to +85°C
Symbol
Parameter
Test Conditions
Qx, nQx[a]
VOH
Output high voltage
VOL
Output low voltage
Qx, nQx[a]
VOUT
Output voltage swing
Qx, nQx[a]
Terminated with 50 to
VCCOx[b]
Minimum
Typical
Maximum
Units
VCCOx[b] – 0.10
VCCOx
V
VCCOx[b] – 0.95
VCCOx[b] – 0.70
V
575
1000
mV
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2, nQB3.
b. VCCOx denotes VCCOA and VCCOB.
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8P79818 Datasheet
Table 21: LVCMOS Clock Outputs DC Characteristics, VCC = 3.3V±5%, 2.5V±5% or 1.8V±5%, VEE = 0V,
TA = -40°C to +85°C
Test
Conditions
Symbol
Parameter
VOH
Output high voltage
QAx, nQAx[a]
IOH = –8mA
VOL
Output low voltage
QAx, nQAx[a]
IOL = 8mA
VCCOA = 3.3V±5% VCCOA = 2.5V±5% VCCOA = 1.8V ±5% VCCOA = 1.5V ±5%
Min
Typ
Max
2.6
Min
Typ
Max
1.1
0.5
Min
Typ
Max
1.1
0.5
Min
Typ
Max
Units
1.1
V
0.5
0.5
V
a. QAm denotes QA0, QA1, QA2, QA3. nQAm denotes nQA0, nQA1, nQA2, nQA3.
Table 22: Input Frequency Characteristics, VCC = 3.3V±5%, 2.5V±5% or 1.8V±5%, TA = -40°C to +85°C
Symbol
fIN
idc
fSCLK
Parameter
Input frequency,
CLKx, nCLKx
Input duty
Test Conditions
Minimum
Maximum
LVPECL, LVDS,
HCSL, CML
1PPS
700MHz
LVCMOS
1PPS
200MHz
cycle[a]
Serial port clock SCLK
Typical
50
I2C operation
100
SPI operation
Units
%
400
kHz
50
MHz
a. Any deviation from a 50% duty cycle on the input may be reflected in the output duty cycle.
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AC Electrical Characteristics
Table 23: AC Characteristics, VCC = 3.3V ±5%, 2.5V ±5% or 1.8V ±5%,
VCCOA = VCCOB = 3.3V ±5%, 2.5V ±5% or 1.8V ±5%, TA = -40°C to +85°C
Parameter[a]
Symbol
Test Conditions
LVPECL, LVDS
fOUT
Output frequency
HCSL, CML[b]
LVCMOS
LVPECL
LVDS
tR / tF
Output rise and fall
times
odc
Bank skew[d], [e], [f]
Output
duty cycle[g]
VCCOx = 3.3V
20% to 80%
VCCOx[c] = 2.5V
20% to 80%
VCCOx[c] = 1.8V
20% to 80%
Maximum
Units
1PPS
700MHz
1PPS
200MHz
125
700
ps
125
550
ps
175
550
ps
20% to 80%
100
675
ps
CML, 800mV
20% to 80%
125
825
ps
200
800
ps
650
1300
ps
LVPECL
15
50
ps
LVDS
20
60
ps
CML
10
35
ps
HCSL
10
35
ps
LVCMOS
50
100
ps
VCCOA = 3.3V
20% to 80%
VCCOA = 2.5V
20% to 80%
VCCOA = 1.8V
20% to 80%
VCCOA = 1.5V
20% to 80%
LVPECL, LVDS,
HCSL, CML
Even divide ratios
45
50
55
%
LVPECL, LVDS,
HCSL, CML
Odd divide ratios / bypass
43
50
57
%
VCCOA = 3.3V,
2.5V, or 1.8V
Even divide ratios
45
50
55
%
LVCMOS
Odd divide ratios /
bypass
40
50
60
%
Even divide ratios
40
50
60
%
Odd divide ratios /
bypass
38
50
62
%
LVCMOS
MUXISOL
[c]
Typical
CML, 400mV
LVCMOS
tsk(b)
20% to 80%
Minimum
VCCOA = 1.5V
Mux isolation
156.25MHz, VSWING = 800mV
Noise floor
Offset >10MHz from156.25MHz carrier
61
dB
–154
dBc/Hz
a. 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 500lfpm. The device will meet specifications after thermal equilibrium
has been reached under these conditions.
b. CML denotes CML 400mV and CML 800mV, unless otherwise stated.
c. VCCOx denotes VCCOA and VCCOB.
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8P79818 Datasheet
d.
e.
f.
g.
This parameter is guaranteed by characterization. Not tested in production.
This parameter is defined in accordance with JEDEC Standard 65.
Defined as skew within a bank of outputs at the same supply voltage and with equal load conditions.
Measured using 50% duty cycle on input reference.
Table 24: HCSL AC Characteristics, VCC = 3.3V ±5%, 2.5V ±5% or 1.8V ±5%,
VCCOA = VCCOB = 3.3V ±5%, 2.5V ±5% or 1.8V ±5%, TA = -40°C to +85°C
Symbol
Parameter[a]
Test Conditions[b]
tSLEW
Rise/ fall edge rate[c]
VMAX
Absolute max. output voltage[d], [e]
VMIN
VCROSS
VCROSS
Absolute min. output voltage
[d], [f]
Total variation of VCROSS over all
edges[g], [i]
Typical
Maximum
Units
VCCOx = 3.3V or 2.5V
0.6
4
V/ns
VCCOx = 1.8V
0.45
4
V/ns
1150
mV
VCCOx = 3.3V, 2.5V, 1.8V
VCCOx = 3.3V, 2.5V, 1.8V
Absolute crossing voltage[g], [h]
Minimum
–150
mV
VCCOx = 3.3V, 2.5V, 1.8V
550
mV
VCCOx = 3.3V, 2.5V, 1.8V
140
mV
a. 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 500lfpm. The device will meet specifications after thermal
equilibrium has been reached under these conditions.
b. VCCOx denotes VCCOA and VCCOB.
c. Measured from –150mV to 150mV on the differential waveform (derived from Qx minus nQx). The signal must be monotonic through the
measurement region for rise and fall time. The 300mV measurement window is centered on the differential zero crossing.
d. Measurement taken from single ended waveform.
e. Defined as the maximum instantaneous voltage including overshoot.
f. Defined as the minimum instantaneous voltage including undershoot.
g. Measured at crossing point where the instantaneous voltage value of the rising edge of Qm equals the falling edge of nQm.
h. Refers to the total variation from the lowest crossing point to the highest, regardless of which edge is crossing. Refers to all crossing points
for this measurement.
i. Defined as the total variation of all crossing voltages of rising Qm and falling nQm, This is the maximum allowed variance in VCROSS for any
particular system.
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8P79818 Datasheet
Table 25: Additive Jitter, VCC = 3.3V, 2.5V or 1.8V, VCCOA = VCCOB = 3.3V, 2.5V, 1.8V or 1.5V
(1.5V only supported for LVCMOS outputs), TA = 25°C
Symbol
Test Conditions[a]
Parameter
fOUT =
156.25MHz
LVPECL
fOUT =
625MHz
fOUT =
156.25MHz
tjit(f)
RMS additive jitter
(random);
LVDS
fOUT =
625MHz
Integration range:
12kHz – 20MHz
fOUT =
156.25MHz
HCSL
fOUT =
625MHz
LVCMOS
fOUT =
156.25MHz
Typical
Maximum
Units
VCCOx[b] = 3.3V or 2.5V
77
92
fs
VCCOx[b] = 1.8V
90
117
fs
[b]
VCCOx = 3.3V or 2.5V
50
60
fs
VCCOx[b] = 1.8V
60
84
fs
[b] =
85
104
fs
VCCOx[b] = 1.8V
126
185
fs
VCCOx[b] = 3.3V or 2.5V
48
61
fs
57
84
fs
92
132
fs
VCCOx = 1.8V
92
133
fs
[b] =
61
73
fs
VCCOx[b] = 1.8V
67
93
fs
VCCOA = 3.3V or 2.5V
98
166
fs
VCCOA = 1.8V
128
204
fs
VCCOA = 1.5V
198
314
fs
VCCOx
VCCOx
[b] =
3.3V or 2.5V
1.8V
VCCOx[b] = 3.3V or 2.5V
[b]
VCCOx
3.3V or 2.5V
Minimum
a. All outputs configured for the specific output type, as shown in the table.
b. VCCOx denotes VCCOA and VCCOB.
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8P79818 Datasheet
Applications Information
Recommendations for Unused Input and Output Pins
Inputs:
CLK/nCLK Inputs
For applications not requiring the use of the differential input, both CLK and nCLK can be left floating. Though not required, but for additional
protection, a 1k resistor can be tied from CLK to ground.
LVCMOS Control Pins
All control pins have internal pullups and pulldowns; additional resistance is not required but can be added for additional protection. A 1k
resistor can be used.
Outputs:
LVCMOS Outputs
All unused LVCMOS outputs can be left floating. It is recommended that there is no trace attached.
LVPECL Outputs
All unused LVPECL outputs can be left floating. We recommend that there is no trace attached. Both sides of the differential output pair should
either be left floating or terminated.
LVDS Outputs
All unused LVDS output pairs can be either left floating or terminated with 100 across. If they are left floating, there should be no trace
attached.
Differential Outputs
All unused Differential outputs can be left floating. It is recommended that there is no trace attached.
Power Dissipation and Thermal Considerations
The 8P79818 is a multi-functional, high speed device that targets a wide variety of clock frequencies and applications. Since this device is
highly programmable with a broad range of features and functionality, the power consumption will vary as each of these features and functions
is enabled.
The 8P79818 device was designed and characterized to operate within the ambient industrial temperature range of -40°C to +85°C. The
ambient temperature represents the temperature around the device, not the junction temperature. When using the device in extreme cases,
such as maximum operating frequency and high ambient temperature, external air flow may be required in order to ensure a safe and reliable
junction temperature. Extreme care must be taken to avoid exceeding 125°C junction temperature.
The power calculation examples below were generated using a maximum ambient temperature and supply voltage. For many applications, the
power consumption will be much lower. Please contact IDT technical support for any concerns on calculating the power dissipation for your
own specific configuration.
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8P79818 Datasheet
Power Domains
The 8P79818 device has a number of separate power domains that can be independently enabled and disabled via register accesses (all
power supply pins must still be connected to a valid supply voltage). Figure 7 below indicates the individual domains and the associated power
pins.
Figure 7: 8P79818 Power Domains
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8P79818 Datasheet
Power Consumption Calculation
Determining total power consumption involves several steps:
1.Determine the power consumption using maximum current values for core voltage from Table 11, Table 12 and Table 13, Page 18 for the
appropriate case of how many dividers are enabled.
2.Determine the nominal power consumption of each enabled output path.
a. This consists of a base amount of power that is independent of operating frequency, as shown in Table 27 through Table 43 (depending
on the chosen output protocol).
b. Then there is a variable amount of power that is related to the output frequency. This can be determined by multiplying the output
frequency by the FQ_Factor shown in Table 27 through Table 43.
3.All of the above totals are then summed.
Example Calculations
Table 26: Example 1. Common Customer Configuration (3.3V Core Voltage)
Bank
Configuration
Frequency (MHz)
VCCO
Bank A
LVDS
125
3.3V
Bank B
LVDS
125
2.5V
▪
▪
▪
▪
▪
Core supply current, ICC = 24.7mA (max.)
Output supply current, Bank A = 0.06  125  71.615 = 79.115mA
Output supply current, Bank B = 0.06  125  71.615 = 79.115mA
Total device current = 24.7mA + 79.115mA  79.115mA = 182.93mA
Total device power = 3.465V  183.93mA = 633.934mW
With an ambient temperature of 85°C and no airflow, the junction temperature is:
TJ = 85°C  35.23°C/W  0.634W = 107.3°C
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Thermal Considerations
Once the total power consumption has been determined, it is necessary to calculate the maximum operating junction temperature for the device
under the environmental conditions it will operate in. Thermal conduction paths, air flow rate and ambient air temperature are factors that can
affect this. The thermal conduction path refers to whether heat is to be conducted away via a heat-sink, via airflow or via conduction into the
PCB through the device pads (including the ePAD). Thermal conduction data is provided for typical scenarios in Table 44, Page 30. Please
contact IDT for assistance in calculating results under other scenarios.
Current Consumption Data and Equations
Table 27: 3.3V LVDS Output Calculation Table
Table 30: 3.3V LVPECL Output Calculation Table
LVDS
FQ_Factor (mA/MHz),
per output
Base_Current (mA)
LVPECL
FQ_Factor (mA/MHz),
per output
Base_Current (mA)
Qx, nQx[a]
0.06
71.615
Qx, nQx[a]
0.05
53.475
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
Table 28: 2.5V LVDS Output Calculation Table
Table 31: 2.5V LVPECL Output Calculation Table
LVDS
FQ_Factor (mA/MHz),
per output
Base_Current (mA)
LVPECL
FQ_Factor (mA/MHz),
per output
Base_Current (mA)
Qx, nQx[a]
0.06
71.544
Qx, nQx[a]
0.04
20.874
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
Table 29: 1.8V LVDS Output Calculation Table
Table 32: 1.8V LVPECL Output Calculation Table
LVDS
FQ_Factor (mA/MHz),
per output
Base_Current (mA)
LVPECL
FQ_Factor (mA/MHz),
per output
Base_Current (mA)
Qx, nQx[a]
0.1
50.284
Qx, nQx[a]
0.04
19.962
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
Table 33: 3.3V HCSL Output Calculation Table
HCSL
FQ_Factor (mA/MHz),
per output
Base_Current (mA)
Qx, nQx[a]
0.05
54.911
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
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8P79818 Datasheet
Table 34: 3.3V CML Output (400mV) Calculation
Table
Table 39: 1.8V CML Output (800mV) Calculation
Table
CML
FQ_Factor (mA/MHz),
per output
Base_Current (mA)
CML
FQ_Factor (mA/MHz),
per output
Base_Current (mA)
Qx, nQx[a]
0.03
51.889
Qx, nQx[a]
0.02
47.334
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
Table 35: 2.5V CML Output (400mV) Calculation
Table
Table 40: 3.3V LVCMOS Output Calculation Table
LVCMOS
CML
FQ_Factor (mA/MHz),
per output
Base_Current (mA)
Qx, nQx[a]
0.02
49.220
Qx, nQx
LVCMOS
Qx,
Base_Current (mA)
Qx, nQx[a]
0.02
47.326
Base_Current (mA)
Qx, nQx[a]
0.02
51.474
Base_Current (mA)
Qx, nQx[a]
0.02
48.906
LVCMOS
Base_Current (mA)
Qx, nQx[a]
47.745
Table 43: 1.5V LVCMOS Output Calculation Table
LVCMOS
Qx,
nQx[a]
Base_Current (mA)
41.485
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
Table 38: 2.5V CML Output (800mV) Calculation
Table
FQ_Factor (mA/MHz),
per output
51.097
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
CML
Base_Current (mA)
Table 42: 1.8V LVCMOS Output Calculation Table
Table 37: 3.3V CML Output (800mV) Calculation
Table
FQ_Factor (mA/MHz),
per output
nQx[a]
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
CML
62.289
Table 41: 2.5V LVCMOS Output Calculation Table
Table 36: 1.8V CML Output (400mV) Calculation
Table
CML
Base_Current (mA)
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
FQ_Factor (mA/MHz),
per output
[a]
a. Qx denotes QA0, QA1, QA2, QA3, QB0, QB1, QB2, QB3.
nQx denotes nQA0, nQA1, nQA2, nQA3, nQB0, nQB1, nQB2,
nQB3.
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8P79818 Datasheet
Applying the values to the following equation will yield output current by frequency: (mA) = FQ_Factor  Frequency (MHz)  Base_Current
where:
Qx Current is the specific output current according to output type and frequency
FQ_Factor is used for calculating current increase due to output frequency
Base_Current is the base current for each output path independent of output frequency
The second step is to multiply the power dissipated by the thermal impedance to determine the maximum power gradient, using the following
equation:
TJ = TA  (JA  Pdtotal)
where:
TJ is the junction temperature (°C)
TA is the ambient temperature (°C)
JA is the thermal resistance value from Table 44, Page 30, dependent on ambient airflow (°C/W)
Pdtotal is the total power dissipation of the 8P79818 under usage conditions, including power dissipated due to loading (W)
Note that for LVPECL outputs the power dissipation through the load is assumed to be 27.95mW. When selecting LVCMOS outputs, power
dissipation through the load will vary based on a variety of factors including termination type and trace length. For these examples, power
dissipation through loading will be calculated using CPD (found in Table 10, Page 16) and output frequency:
PdOUT = CPD  fOUT  VCCO2
where:
Pdout is the power dissipation of the output (W)
CPD is the power dissipation capacitance (pF)
fOUT is the output frequency of the selected output (MHz)
VCCO is the voltage supplied to the appropriate output (V)
Table 44: JA vs. Air Flow Table for a 32-lead 5mm x 5mm VFQFN
JA vs. Air Flow
Meters per Second
Multi-Layer PCB, JEDEC Standard Test Boards
©2016 Integrated Device Technology, Inc.
0
1
2
35.23°C/W
31.6°C/W
30.0°C/W
30
December 19, 2016
8P79818 Datasheet
Package Drawings
www.IDT.com
IDT
Figure 8: Package Drawings
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8P79818 Datasheet
www.IDT.com
IDT
Figure 9: Package Drawings (Continued)
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8P79818 Datasheet
Marking Diagram
1. Line 1 is the prefix of the part number.
2. Line 2 and Line 3 is the part number.
3. Line 4 “YYWW$”
a. “YY” are the last digits of the year and “WW” is the work week that the part was assembled.
b. “$” denotes mark code.
Ordering Information
Table 45: Ordering Information
Part/Order Number
Marking
Package
Shipping Packaging
Temperature
8P79818NLGI
IDT8P79818NLGI
32-lead VFQFN, Lead Free
Tray
-40°C to +85°C
8P79818NLGI8
IDT8P79818NLGI
32-lead VFQFN, Lead Free
Tape & Reel
-40°C to +85°C
8P79818NLGI/W
IDT8P79818NLGI
32-lead VFQFN, Lead Free
Tape & Reel
-40°C to +85°C
Table 46: Pin 1 Orientation in Tape and Reel Packaging
Part Number Suffix
Pin 1 Orientation
Illustration
Correct Pin 1 ORIENTATION
NLGI8
CARRIER TAPE TOPSIDE
(Round Sprocket Holes)
Quadrant 1 (EIA-481-C)
USER DIRECTION OF FEED
Correct Pin 1 ORIENTATION
NLGI/W
CARRIER TAPE TOPSIDE
(Round Sprocket Holes)
Quadrant 2 (EIA-481-D)
USER DIRECTION OF FEED
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8P79818 Datasheet
Revision History
Revision Date
December 19, 2016
Description of Change
Initial datasheet.
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DISCLAIMER Integrated Device Technology, Inc. (IDT) reserves the right to modify the products and/or specifications described herein at any time, without notice, at IDT's sole discretion. Performance specifications and operating parameters of the described products are determined in an 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
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