Datasheet

MAX3735/MAX3735A
2.7Gbps, Low-Power SFP Laser Drivers
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +2.97V to +3.63V, T
A
= -40°C to +85°C. Typical values at V
CC
= +3.3V, I
BIAS
= 20mA, I
MOD
= 30mA, T
A
= +25°C, unless
otherwise noted.) (Note 1)
Note 1: Specifications at -40°C are guaranteed by design and characterization. Dice are tested at T
A
= +25°C only.
Note 2: Maximum value is specified at I
MOD
= 60mA, I
BIAS
= 100mA.
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.
Note 9: Deterministic jitter is measured using a 2
23
- 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
P-P
up to 2MHz.
Note 11: C
APC
values chosen as shown in Table 4 (MAX3735A).
PARAMETER SYM B O L CONDITIONS MIN TYP MAX UNITS
SAFETY FEATURES
Excessive Bias-Current
Comparator Threshold Range
TX_FAULT always occurs for V
BC_MON
≥
1.38V, TX_FAULT never occurs for
V
BC_MON
≤ 1.22V
1.22 1.30 1.39 V
Excessive MD-Current
Comparator Threshold Range
TX_FAULT always occurs for V
PC_MON
≥
1.38V, TX_FAULT never occurs for
V
PC_MON
≤ 1.22V
1.22 1.30 1.39 V
SFP TIMING REQUIREMENTS
TX_DISABLE Assert Time t_off
Time from rising edge of TX_DISABLE to
I
BIAS
= I
BIASOFF
and I
MOD
= I
MODOFF
(Note 4)
0.14 5 µs
C
APC
= 2.7nF,
MAX3735 (Note 4)
1ms
TX_DISABLE Negate Time t_on
Time from falling edge
of TX_DISABLE to
I
BIAS
and I
MOD
at 95%
of steady state when
TX_FAULT = 0 before
reset
MAX3735A
(Note 11)
600 µs
TX_DISABLE Negate Time
During FAULT Recovery
t_onFAULT
Time from falling edge of TX_DISABLE to
I
BIAS
and I
MOD
at 95% of steady state when
TX_FAULT = 1 before reset (Note 4)
60 200 ms
TX_FAULT Reset Time or Power-
On Time
t_init
From power-on or negation of TX_FAULT
using TX_DISABLE (Note 4)
60 200 ms
TX_FAULT Assert Time t_fault
Time from fault to TX_FAULT on, C
FAULT
≤
20pF, R
FAULT
= 4.7kΩ (Note 4)
3.3 50 µs
TX_DISABLE to Reset
Time TX_DISABLE must be held high to
reset TX_FAULT (Note 4)
5µs