Rainbow Electronics MAX5971B - Manual (Page 6)

6 ______________________________________________________________________________________
MAX5971B
Single-Port, 40W, IEEE 802.3af/at,
PSE Controller with I 2 C
Note 2: This device is production tested at T
A = +25°C. Limits to T A
= -40°C to +85°C are guaranteed by design.
Note 3: Default thresholds are set by the classification result in auto mode. The thresholds are manually software programmable
through the ICUT Register (R2Ah[2:0]). If ILIM1 and ILIM2 are both unconnected, Class 5 detection is disabled. See the
Class 5 PD Classification section and Table 3 for details and settings.
Note 4: Default value. The AC load-disconnect threshold can be programmed through the AC_TH register (R23h[2:0]).
Note 5: Default value. The load-disconnect time, tDISC can be programmed through the TDISC register (R16h[1:0]).
Note 6: R
DOK
= (V
OUT2
- V
OUT1
)/(I
DET2
- I
DET1
). V
OUT1
, V
OUT2
, I
DET2
, and I
DET1
represent the voltage at OUT and the current at
DET during phase 1 and 2 of the detection, respectively.
Note 7: If Class 5 is enabled, this value is the classification current threshold from Class 4 to Class 5.
Note 8: Default values. The startup, fault, and restart timers can be programmed through the TSTART (R16h[5:4]), TFAULT
(R16h[3:2]), and RSRT (R16h[7:6]) registers, respectively.
Note 9: Guaranteed by design. Not subject to production testing.
ELECTRICAL CHARACTERISTICS (continued)
(V AGND - V EE = 32V to 60V, T A = -40NC to +85NC, all voltages are referenced to V EE , unless otherwise noted. Typical values are at
V AGND - V EE = +54V, T A = +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
ADC PERFORMANCE (Power-On Mode)
Resolution 9 Bits
Range 1.507 A
LSB Step Size 2.95 mA
Gain Error
T
A
= +25NC 2
%
T A = -40NC to +85NC 4
ADC Absolute Accuracy I OUT = 400mA 130 136 142 LSB
Integral Nonlinearity INL 0.3 1.7 LSB
Differential Nonlinearity DNL 0.3 1.7 LSB
TIMING CHARACTERISTICS (For 2-Wire Fast Mode)
Serial Clock Frequency
f
SCL
400 kHz
Bus Free Time Between a STOP
and START Condition
tBUF 1.3 µs
Hold Time for a START Condition t HD,STA 0.6 µs
Low Period of the SCL Clock t LOW 1.3 µs
High Period of the SCL Clock t HIGH 0.6 µs
Setup Time for a Repeated
START Condition (Sr)
t SU,STA 0.6 µs
Data Hold Time t HD,DAT 0 150 ns
Data in Setup Time t SU,DAT 100 ns
Rise Time of Both SDA and SCL
Signals, Receiving
t R (Note 9)
20 +
0.1C B
300 ns
Fall Time of SDA Transmitting t F (Note 9) 250 ns
Setup Time for STOP Condition t SU,STO 0.6 µs
Capacitive Load for Each
Bus Line
C B (Note 9) 400 pF
Pulse Width of Spike Suppressed t SP (Note 9) 50 ns