1
2
3
4
5
J5
PRI_P
1
2
3
4
5
J6
PRI_N
AC_PRI_P
VDD_Plane
0402
0
R31
0402
0
R32
0402
49.9
R35
DNP
0402
49.9
R38
DNP
LOOP FILTER LAYOUT NOTES:
- Use sufficient clearance on these noise-sensitive nodes (traces, vias, TPs) from dynamic signals
and power planes/traces.
- Connect loop filter caps to clean analog ground return path back to DUT.
PRIREF_P
PRIREF_N
PRIMARY REF INPUT
SECONDARY REF INPUT
LOOP FILTER "C2" CAP SELECTION
CRYSTAL INPUT
CRYSTAL LAYOUT REQUIREMENTS:
*** PLACEMENT ***
- CRITICAL: Minimize PCB trace and Pad parasitic cap <0.9pF (each leg of XTAL t o DUT pin)
- Place XTAL as close as possible to DUT on Top side with short traces.
- Try to match lengths from each XTAL pin (XA/XB) to DUT pin (SECREF_P/N).
*** SHIELDING / ISOLATION ***
- XA/SECREF_P and XB/SECREF_N traces should be separated and kept away from other traces.
- Avoid routing below the XTAL pads and use plane cutouts below XTAL pads to minimize parasitic capacitance.
SCL
SDA
GPIO1
GPIO0
GPIO5
GPIO4
PDN
GPIO2
GPIO3
RSEL
HW_CTRL
PRIREF_P
PRIREF_N
SECREF_P
SECREF_N
OUT0_P
OUT0_N
OUT1_P
OUT1_N
OUT2_P
OUT2_N
OUT3_P
OUT3_N
OUT4_P
OUT4_N
OUT5_P
OUT5_N
OUT6_P
OUT6_N
OUT7_P
OUT7_N
C_PLL1
C_PLL2
LF2
C_DIG
LF1
STAT0
STAT1
1
3
4
2
G
G
50MHz
3.2x0.55x2.5mm
Y1
7M50072001
LMK033x8 DUT
VDDDIG
VDDIN
VDDPLL1
VDDPLL2
VDDO5
VDDO4
VDDO23
VDDO01
VDDO7
VDDO6
DUT LAYOUT NOTES:
*** THERMAL REQUIREMENTS ***
- LMK03328 thermal vias: Use 6x6 via array with 0.3mm hole, 0.5mm via diameter, 0.8mm via pitch,
1 oz. copper plating.
- Remove soldermask on bottom thermal pad to expose copper.
- Use Ground flood on all layers (except split power plane) and DUT thermal vias using solid
connection (no thermal relief) to all ground layers.
AC_PRI_N
PRI_P
PRI_N
0.1µF
0402
C54
3
4
S1C
LF1
2
5
S1B
LF1
1
6
S1A
LF1
USER NOTE:
"C2" Loop Filter Cap Selection Switches
Pos A: C2 = 3300 pF --- Integer-mode LBW
Pos B: C2 = 0.033 uF --- Fractional-mode LBW
Pos C: C2 = 22 uF --- Narrow LBW (< 1 kHz)
1
2
3
JP15
VT PRI
Resistor
0
0402
C49
Resistor
0
0402
C50
R_SEC_P
R_SEC_N
1
2
3
4
5
J7
SEC_P
1
2
3
4
5
J8
SEC_N
AC_SEC_P
VDD_Plane
0402
0
R29
0402
0
R30
0402
49.9
R33
0402
49.9
R34
AC_SEC_N
SEC_P
SEC_N
0.1µF
0402
C53
1
2
3
JP16
VT SEC
0.1µF
0402
C51
0.1µF
0402
C52
0402
0
R36
DNP
0402
0
R37
DNP
0402
0
R40
0402
0
R41
XA
XB
SECREF_P
SECREF_N
Overlap 0R pads on
SECREF nets
50-ohm single-ended RF traces
Place close DUT pins
Place close to XTAL on top side
LF1
0
R42
3
4
S2C
LF2
2
5
S2B
LF2
1
6
S2A
LF2
LF2
0
R43
0.033µF
C64
0.033µF
C65
CLOCK INPUT (PRIREF_P,/ _N, SECREF_P/_N) LAYOUT REQUIREMENTS:
*** CONTROLLED IMPEDANCE ***
- Route as 50-ohm (+/-5% tol.) controlled-impedance single-ended RF traces from SMA center pin to DUT pin
- Place component pads directly on RF traces (no stubs), match 50-ohm trace width to SMA center pad, and use 50-ohm Zo via structures.
*** LENGTH / SKEW MATCHING ***
- Match input path length WITHIN pair from DUT to SMA pins (minimize intra-pair skew).
*** SHIELDING / ISOLATION ***
- Use ground shielding on routing layers with sufficient clearance to not affect controlled impedance of RF traces.
- Use ground stitching vias with 100 mil spacing around RF traces to connect together GND shielding on all layers.
- Use sufficient clearance between OUT# paths, as well as from other dynamic signal paths.
- Avoid crossing Digital signal/return paths with REF input signal/return paths; if unavoidable, cross at a 90 deg. angle
Add Surface-Mount GND pad on top
side near Test Point.
SECREF_P
SECREF_N
4.32k
R25
4.32k
R27
LABEL SW = PLL1 C2
LABEL SW POSITIONS:
A = INT-N
B = FRAC-N
C = NARROW
LABEL JP PINS:
1 = VB1
2 = VT1
3 = GND
LABEL JP PINS:
1 = VB2
2 = VT2
3 = GND
LABEL SW = PLL2 C2
LABEL SW POSITIONS:
A = INT-N
B = FRAC-N
C = NARROW
10µF
C57
10µF
C56
10µF
C55
Place Caps close DUT pins
3300pF
C67
22µF
C63
22µF
C62
3300pF
C66
TP20
LF1
DNP
TP21
LF2
DNP
STATUS0
1
STATUS1
2
CAP_DIG
3
VDD_DIG
4
VDD_IN
5
PRIREF_P
6
PRIREF_N
7
REFSEL
8
HW_SW_CTRL
9
SECREF_P
10
SECREF_N
11
GPIO0
12
PDN
13
OUT0_P
14
OUT0_N
15
OUT1_N
16
OUT1_P
17
VDDO_01
18
VDDO_23
19
OUT2_P
20
OUT2_N
21
OUT3_N
22
OUT3_P
23
GPIO1
24
SDA
25
SCL
26
VDD_PLL2
27
CAP_PLL2
28
LF2
29
GPIO2
30
GPIO3
31
LF1
34
CAP_PLL1
35
VDD_PLL1
36
GPIO4
32
GPIO5
33
VDDO_4
37
OUT4_N
38
OUT4_P
39
VDDO_5
40
OUT5_N
41
OUT5_P
42
VDDO_6
43
OUT6_N
44
OUT6_P
45
VDDO_7
46
OUT7_N
47
OUT7_P
48
PAD
49
U5
LMK03328RHSR
1pF
C58
DNP
1pF
C59
DNP
3000pF
C61
DNP
3000pF
C60
DNP
2.49k
R26
2.49k
R28
VT_SEC
VT_PRI
SH15_1-2
SH16_1-2
50-ohm single-ended RF traces
USER NOTE:
By default, PRIREF SMA ports are DC-coupled to DUT inputs with programable on-chip termination.
USER NOTE:
By default, the onboard crystal (Y1) is connected to the SECREF inputs of the DUT. To use the SECREF SMA ports, depop
R40/R41 and short R36/R37 to bypass the crystal. SECREF SMA ports are AC-coupled to external termination/biasing
(on-chip termination disabled).
EVM Schematic
35
SNAU184 – August 2015
LMK03328EVM User’s Guide
Copyright © 2015, Texas Instruments Incorporated