Manual
MAX3795
1Gbps to 4.25Gbps Multirate VCSEL Driver
with Diagnostic Monitors
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +2.97V to +3.63V, T
A
= -40°C to +85°C. Typical values are at V
CC
= +3.3V, TC1 and TC2 are shorted, PEAKSET open, T
A
=
+25°C, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
- 40°C to + 85° C
8.4
15.6
Deterministic Jitter DJ
5m A ≤ I
M OD
≤ 15m A,
4.25G b p s, K28.5 ( N otes 2, 5)
+100°C
12.7
ps
P-P
APC closed loop 0.5
Random Jitter RJ
APC open loop (Note 2) 0.5 0.9
ps
RMS
SAFETY FEATURES (see the Typical Operating Characteristics)
High-Current Fault Threshold V
BMTH
V
BIASMON
> V
BMTH
causes a fault 0.7 0.8 0.9 V
V
BIAS
Fault Threshold V
BTH
V
BIAS
referenced to V
CC
-0.250 -0.2 -0.150
V
Power-Monitor Fault Threshold V
PMTH
V
PWRMON
> V
PMTH
causes a fault 0.7 0.8 0.9 V
TX Disable Time t_
OFF
Time from rising edge of TX_DISABLE to
I
BIAS
= I
BIAS_OFF
and I
MOD
= I
MOD_OFF
(Note 2)
1.8 5 µs
TX Disable Negate Time t_
ON
Time from rising edge of TX_DISABLE to
I
BIAS
and I
MOD
at 99% of steady state
(Note 2)
55 500 µs
Fault Reset Time t_
INIT
1
Time to set V
FAULT
= low after power-on or
after rising edge of TX_DISABLE (Note 2)
60 200 ms
Power-On Time t_
INIT
2
Time after power-on to transmitter-on with
TX_DISABLE low (Note 2)
60 200 ms
Fault Assert Time
t_
FAULT
Time from fault occurrence to V
FAULT
=
high; C
FAULT
< 20pF, R
FAULT
= 4.7kΩ
(Note 2)
1.4 50 µs
Fault Delay Time
t_
FLTDLY
Time from fault to I
BIAS
= I
BIAS_OFF
and
I
MOD
= I
MOD_OFF
; measured with a
continuously occurring fault (Note 2)
15µs
TX_DISABLE Reset
t_
RESET
Time TX_DISABLE must be held high to
reset FAULT (Note 2)
1µs
Note 1: Supply current measurements exclude I
BIAS
from the total current.
Note 2: AC characteristics guaranteed by design and characterization.
Note 3: Measured by applying a pattern that contains 20µs of K28.5, followed by 5µs of zeros, then 20µs of K28.5, followed by 5µs
of ones. Data rate is equal to 2.5Gbps, with inputs filtered using 1.8GHz Bessel filters.
Note 4: Variation of bias monitor gain for any single part over the range of V
CC
, temperature, 3mA < I
BIAS
< 15mA.
Note 5: Deterministic jitter measured at 4.25Gbps with a K28.5 pattern (00111110101100000101).