
3
Precision Edge
SY89531L
Micrel, Inc.
M9999-010808
hbwhelp@micrel.com or (408) 955-1690
PIN DESCRIPTION
Power
Pin Number
Pin Name
Pin Function
60, 61
V
CC_Logic
Power for Core Logic: Connect to 3.3V supply. 3.3V power pins are not internally
connected on the die, and must be connected together on the PCB.
62
V
CCA
Power for PLL: Connect to “quiet” 3.3V supply. 3.3V power pins are not internally
connected on the die, and must be connected together on the PCB.
55
V
CCOA
Power for Output Drivers: Connect all V
CCOA and VCCOC pins to 3.3V supply and VCCOB
30, 31, 50
V
CCOB
pins to 1.8V supply.
21
V
CCOC
9, 25, 63, 29
GND
Ground: Exposed pad must be soldered to a ground plane.
(exposed pad)
Configuration
Pin Number
Pin Name
Pin Function
4
VCO_SEL
LVTTL/CMOS Compatible Input: Selects between internal or external VCO. For
external VCO, leave floating. Default condition is logic HIGH. Internal 25k
pull-up.
When tied LOW, internal VCO is selected.
7
LOOP REF
Analog Input/Output: Provides the reference voltage for PLL loop filter.
8
LOOP FILTER
Analog Input/Output: Provides the loop filter for PLL. See
“External Loop Filter
Considerations” for loop filter values.
13,14,15,16
M (3:0)
LVTTL/CMOS Compatible Input: Used to change the PLL feedback divider. Internal 25k
pull-up. M0 = LSB. Default is logic HIGH. See
“Feedback Divide Select” table.
22, 23, 24
FSEL_C (2:0)
LVTTL/CMOS Compatible Input: Bank C post divide select. Internal 25k
pull-up.
Default is logic HIGH. See
“Post-Divide Frequency Select” table. FSEL_C0 = LSB.
26, 27, 28
FSEL_B (2:0)
LVTTL/CMOS Compatible Input: Bank B post divide select. Internal 25k
pull-up.
Default is logic HIGH. See
“Post-Divide Frequency Select” table. FSEL_B0 = LSB.
56, 57, 58
FSEL_A (2:0)
LVTTL/CMOS Compatible Input: Bank A post divide select. Internal 25k
pull-up.
Default is logic HIGH. See
“Post-Divide Frequency Select” table. FSEL_A0 = LSB.
59
OUT_SYNC
Banks A, B, C Output Synchronous Control: (LVTTL/CMOS compatible). Internal 25k
pull-up. After any bank has been programmed, toggle with a HIGH-LOW-HIGH
pulse to resynchronize all output banks.
Input/Output
Pin Number
Pin Name
Pin Function
1, 2, 3
NC
No Connect: Leave floating.
10, 11
XTAL2, XTAL1
Crystal Input. Directly connect a series resonant crystal across inputs.
12
VBB_REF
Reference Output Voltage. Used for single-ended input. Maximum sink/source
current = 0.5mA.
5, 6
/EXT_VCO,
Differential “Any In” Compatible Input Pair. Allows for external VCO connection. The “Any
EXT_VCO
In” input structure accepts many popular logic types. See
“Input Interface for ExtVCO Pins”
section for interface diagrams. Can leave unconnected if using internal VCO.
51, 52, 53, 54
QA1 to QA0
Bank A 100k LVPECL Output Drivers: Output frequency is controlled by FSEL_A
(0:2). Terminate outputs with 50
to V
CC –2V. See “Output Termination
Recommendations” section.
32–49
QB8 to QB0
Bank B Output Drivers: Differential HSTL outputs. See
“Output Termination Recommendations”
section. Output frequency is controlled by FSEL_B (0:2).
17, 18, 19, 20
QC1 to QC0
Bank C 100k LVPECL Output Drivers: Output frequency is controlled by FSEL_C (0:2).
Terminate outputs with 50
to V
CC–2V. See “Output Termination Recommendations” section.
64
NC
No Connect: Leave floating.