Datasheet

MAX3645
+2.97V to +5.5V, 125Mbps to 200Mbps Limiting
Amplifier with Loss-of-Signal Detector
_______________________________________________________________________________________ 3
Note 1: Between sensitivity and overload, the output amplitude is >95% of the fully limited amplitude and all AC specifications are met.
Note 2: Guaranteed by design and characterization.
Note 3: Noise is derived from BER measurement.
Note 4: The data input transition time is controlled by a 4th-order Bessel filter with f
-3dB
= 0.75 × data rate.
Note 5: PWD = [(width of wider pulse) - (width of narrower pulse)] / 2, measured with 155Mbps 0011 pattern.
Note 6: All LOS specifications are measured using a 155Mbps 2
23
- 1 PRBS pattern.
Note 7: The signal at the input is switched between two amplitudes, SIGNAL_ON and SIGNAL_OFF, as shown in Figure 1.
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +2.97V to +5.5V, PECL outputs are terminated with 50Ω to V
CC
- 2V, R
TH
= 100Ω, C
AZ
= 0.1µF, C
SD
= 1nF, T
A
= -40°C to
+85°C. Typical values are at V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.)
PARAMETER
SYM B O L
CONDITIONS
MIN
TYP
MAX
UNITS
TRANSFER CHARACTERISTICS
Bandwidth Gain = 60dB 150
250
MHz
C
AZ
= open
500
Low-Frequency Cutoff
C
AZ
= 0.1µF 0.5
kHz
LOSS-OF-SIGNAL SPECIFICATIONS (Notes 2, 4, 6)
LOS Sensitivity Range 0Ω ≤ R
TH
≤ 2kΩ 220
mV
P-P
LOS Hysteresis 10log (V
DEASSERT
/V
ASSERT
) 1.4 2 dB
LOS Assert/Deassert Time (Note 7) 2.3
80.0
µs
R
TH
= 0Ω, low setting 0.5 0.9 1.3
R
TH
= 1kΩ, medium setting 4.8 6.6 8.3LOS Assert Level
R
TH
= 2kΩ, high setting 12 17 22
mV
P-P
R
TH
= 0Ω, low setting 1.1 1.5 1.9
R
TH
= 1kΩ, medium setting 8.0
10.8 13.5
LOS Deassert Level
R
TH
= 2kΩ, high setting 20 28 36
mV
P-P
Signal-Dectect Filter Resistance R
SD
Pin 7 14 20 26 kΩ
Figure 1. Signal Levels for LOS Assert/Deassert Time
Measurement
TIME
V
IN
MAXIMUM DEASSERT LEVEL
1dB
6dB MAXIMUM POWER-DETECT WINDOW
SIGNAL ON
SIGNAL OFF
MINIMUM ASSERT LEVEL
0V