2.7Gbps, Low-Power SFP Laser Drivers
ELECTRICAL CHARACTERISTICS (continued)
(V
= +2.97V to +3.63V, T = -40°C to +85°C. Typical values at V
= +3.3V, I
= 20mA, I = 30mA, T = +25°C, unless
MOD A
CC
A
CC
BIAS
otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
1.30
1.30
MAX
1.39
1.39
UNITS
SAFETY FEATURES
TX_FAULT always occurs for V
1.38V, TX_FAULT never occurs for
≤ 1.22V
≥
≥
BC_MON
Excessive Bias-Current
Comparator Threshold Range
1.22
V
V
V
BC_MON
TX_FAULT always occurs for V
1.38V, TX_FAULT never occurs for
≤ 1.22V
PC_MON
Excessive MD-Current
Comparator Threshold Range
1.22
V
PC_MON
SFP TIMING REQUIREMENTS
Time from rising edge of TX_DISABLE to
TX_DISABLE Assert Time
t_off
t_on
I
= I
and I
= I
MODOFF
0.14
5
µs
BIAS
BIASOFF
MOD
(Note 4)
Time from falling edge
of TX_DISABLE to
C
= 2.7nF,
APC
1
ms
µs
MAX3735 (Note 4)
I
and I
at 95%
MOD
BIAS
TX_DISABLE Negate Time
of steady state when
TX_FAULT = 0 before
reset
MAX3735A
(Note 11)
600
Time from falling edge of TX_DISABLE to
and I at 95% of steady state when
TX_FAULT = 1 before reset (Note 4)
TX_DISABLE Negate Time
During FAULT Recovery
I
t_onFAULT
60
200
ms
BIAS
MOD
TX_FAULT Reset Time or Power-
On Time
From power-on or negation of TX_FAULT
using TX_DISABLE (Note 4)
t_init
60
200
50
5
ms
µs
µs
Time from fault to TX_FAULT on, C
≤
FAULT
TX_FAULT Assert Time
TX_DISABLE to Reset
t_fault
3.3
20pF, R
= 4.7kΩ (Note 4)
FAULT
Time TX_DISABLE must be held high to
reset TX_FAULT (Note 4)
Note 1: Specifications at -40°C are guaranteed by design and characterization. Dice are tested at T = +25°C only.
A
Note 2: Maximum value is specified at I
= 60mA, I
= 100mA.
MOD
BIAS
Note 3: TX_FAULT is an open-collector output and must be pulled up with a 4.7kΩ to 10kΩ resistor.
Note 4: Guaranteed by design and characterization.
Note 5:
V
CC
turn-on time must be ≤ 0.8s, DC-coupled interface.
Note 6: Gain stability is defined by the digital diagnostic document (SFF-8472, rev. 9.0) over temperature and supply variation.
Note 7: Assuming that the laser diode to photodiode transfer function does not change with temperature.
Note 8: Accuracy refers to part-to-part variation.
23
Note 9: Deterministic jitter is measured using a 2 - 1 PRBS or equivalent pattern.
Note 10: Broadband noise is filtered through the network as shown in Figure 3. One capacitor,
C < 0.47µF, and one 0603 ferrite bead or inductor can be added (optional). This supply voltage filtering reduces the hot-
plugging inrush current. The supply noise must be < 100mV
up to 2MHz.
P-P
Note 11: C
values chosen as shown in Table 4 (MAX3735A).
APC
4
_______________________________________________________________________________________