Datasheet
4 ______________________________________________________________________________________
MAX3946
1Gbps to 11.3Gbps, SFP+ Laser Driver
with Laser Impedance Mismatch Tolerance
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +2.85V to +3.63V, T
A
= -40°C to +85°C, and Figure 1. Guaranteed by design and characterization from T
A
= -40°C to +95°C.
Typical values are at V
CC
= +3.3V, I
BIAS
= 60mA, I
MOD
= 40mA, 25I differential output load, and T
A
= +25°C, unless otherwise
noted.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Random Jitter RJ
10mA P I
MOD
P 80mA, output differential
load = 25I (Note 2)
0.19 0.55 ps
RMS
Differential Output Return Loss SDD22
Part powered on, f P 5GHz
8
dB
Part powered on, f P 10GHz
6
SAFETY FEATURES
Threshold Voltage at BMAX V
BMAX
FAULT always occurs for V
BMAX
R 1.3V,
FAULT never occurs for V
BMAX
< 1.1V
(Note 2, Figure 1)
1.1 1.2 1.3 V
Threshold Voltage at BIAS V
BIAS
FAULT never occurs for V
BIAS
R 0.57V,
FAULT always occurs for V
BIAS
< 0.44V
0.44 0.48 0.57 V
Threshold Voltage at BMON V
BMON
Warning always occurs for V
BMON
R
V
CC
- 0.5V, warning never occurs for
V
BMON
< V
CC
- 0.7V
V
CC
-
0.7
V
CC
-
0.6
V
CC
-
0.5
V
SFP TIMING REQUIREMENTS
DISABLE Assert Time t
_OFF
Time from rising edge of DISABLE input
signal to I
BIAS
< I
BIAS-OFF
and I
MOD
<
I
MOD-OFF
0.05 1
Fs
DISABLE Negate Time t
_ON
Time from falling edge of DISABLE to I
BIAS
and I
MOD
at 90% of steady state
0.5 5
Fs
FAULT Reset Time of Power-On
Time
t
_INIT
Time from power-on or negation of FAULT
using DISABLE
50 200
Fs
FAULT Reset Time t
_FAULT
Time from fault to FAULT on, C
FAULT
P
20pF, R
FAULT
= 4.7kI
0.5 2
Fs
DISABLE to Reset
Time DISABLE must be held high to reset
FAULT
0.5
Fs
BIAS CURRENT DAC
Full-Scale Current I
BIAS-FS
SET_IBIAS[8:1] = HxFF 80 100 mA
LSB Size 190
FA
Integral Nonlinearity INL
5mA P I
BIAS
P 80mA
±0.5
%FS
Differential Nonlinearity DNL
5mA P I
BIAS
P 80mA, guaranteed mono-
tonic at 8-bit resolution SET_IBIAS[8:1]
±0.5
LSB
MODULATION CURRENT DAC (25I DIFFERENTIAL LOAD)
Full-Scale Current I
MOD-FS
SET_IMOD[8:1] = HxFF 80 105 mA
LSB Size 200
FA
Integral Nonlinearity INL
10mA P I
MOD
P 80mA Q1
%FS
Differential Nonlinearity DNL
10mA P I
MOD
P 80mA, guaranteed mono-
tonic at 9-bit resolution SET_IMOD[8:0]
Q0.5
LSB