PWRDWN
Driving PWRDWN low puts the outputs in high imped-
ance, stops the PLL, and reduces supply current to
50µA or less. Driving PWRDWN high drives the outputs
low until the PLL locks. The outputs of two deserializers
can be bused to form a 2:1 mux with the outputs con-
trolled by PWRDWN. Wait 100ns between disabling one
deserializer (driving PWRDWN low) and enabling the
second one (driving PWRDWN high) to avoid con-
tention of the bused outputs.
Input Clock and PLL Lock Time
There is no required timing sequence for the applica-
tion or reapplication of the parallel rate clock (RxCLK
IN) relative to PWRDWN, or to a power-supply ramp for
proper PLL lock. The PLL lock time is set by an internal
counter. The maximum time to lock is 32,800 clock
periods. Power and clock should be stable to meet the
lock time specification. When the PLL is locking, the
outputs are low.
Power-Supply Bypassing
There are separate on-chip power domains for digital
circuits, outputs, PLL, and LVDS inputs. Bypass each
V
CC
, V
CCO
, PLL V
CC
, and LVDS V
CC
pin with high-fre-
quency, surface-mount ceramic 0.1µF and 0.001µF
capacitors in parallel as close to the device as possi-
ble, with the smallest value capacitor closest to the
supply pin.
Cables and Connectors
Interconnect for LVDS typically has a differential imped-
ance of 100Ω. Use cables and connectors that have
matched differential impedance to minimize impedance
discontinuities.
Twisted-pair and shielded twisted-pair cables offer
superior signal quality compared to ribbon cable and
tend to generate less EMI due to magnetic field cancel-
ing effects. Balanced cables pick up noise as common
mode, which is rejected by the LVDS receiver.
Board Layout
Keep the LVTTL/LVCMOS outputs and LVDS input sig-
nals separated to prevent crosstalk. A four-layer printed-
circuit board (PCB) with separate layers for power,
ground, LVDS inputs, and digital signals is recom-
mended.
ESD Protection
The MAX9210/MAX9214/MAX9220/MAX9222 ESD toler-
ance is rated for IEC 61000-4-2, Human Body Model and
ISO 10605 standards. IEC 61000-4-2 and ISO 10605
specify ESD tolerance for electronic systems. The IEC
61000-4-2 discharge components are C
S
= 150pF and
R
D
= 330Ω (Figure 14). For IEC 61000-4-2, the LVDS
inputs are rated for ±8kV Contact Discharge and ±15kV
Air Discharge. The Human Body Model discharge com-
ponents are C
S
= 100pF and R
D
= 1.5kΩ (Figure 15). For
the Human Body Model, all pins are rated for ±5kV
Contact Discharge. The ISO 10605 discharge compo-
nents are C
S
= 330pF and R
D
= 2kΩ (Figure 16). For ISO
10605, the LVDS inputs are rated for ±8kV Contact
Discharge and ±25kV Air Discharge.
5V Tolerant Input
PWRDWN is 5V tolerant and is internally pulled down to
GND. DCB/NC is not 5V tolerant. The input voltage
range for DCB/NC is nominally ground to V
CC
.
Normally, DCB/NC is connected to V
CC
or ground.
