Datasheet

LTC2977
8
2977fa
For more information www.linear.com/LTC2977
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
J
= 25°C. V
PWR
= V
IN_SNS
= 12V; V
DD33
, V
DD25
, REFP and REFM pins floating,
unless otherwise indicated. C
VDD33
= 100nF, C
VDD25
= 100nF and C
REF
= 100nF.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
f
WDI
Watchdog Interrupt Input Frequency
l
1 MHz
C
IN
Digital Input Capacitance 10 pF
Digital Input SHARE_CLK
V
IH
High Level Input Voltage
l
1.6 V
V
IL
Low Level Input Voltage
l
0.8 V
f
SHARE_CLK_IN
Input Frequency Operating Range
l
90 110 kHz
t
LOW
Assertion Low Time V
SHARE_CLK
< 0.8V
l
0.825 1.1 µs
t
RISE
Rise Time V
SHARE_CLK
< 0.8V to V
SHARE_CLK
> 1.6V
l
450 ns
I
LEAK
Input Leakage Current 0V ≤ V
SHARE_CLK
≤ V
DD33
+ 0.3V
l
±1 µA
C
IN
Input Capacitance 10 pF
Digital Outputs SDA, ALERTB, PWRGD, SHARE_CLK, FAULTB00, FAULTB01, FAULTB10, FAULTB11
V
OL
Digital Output Low Voltage I
SINK
= 3mA
l
0.4 V
f
SHARE_CLK_OUT
Output Frequency Operating Range 5.49kΩ Pull-Up to V
DD33
l
90 100 110 kHz
Digital Inputs ASEL0,ASEL1
V
IH
Input High Threshold Voltage
l
V
DD33
– 0.5 V
V
IL
Input Low Threshold Voltage
l
0.5 V
I
IH,IL
High, Low Input Current ASEL[1:0] = 0, V
DD33
l
±95 µA
I
IH, Z
Hi-Z Input Current
l
±24 µA
C
IN
Input Capacitance 10 pF
Serial Bus Timing Characteristics
f
SCL
Serial Clock Frequency (Note 8)
l
10 400 kHz
t
LOW
Serial Clock Low Period (Note 8)
l
1.3 µs
t
HIGH
Serial Clock High Period (Note 8)
l
0.6 µs
t
BUF
Bus Free Time Between Stop and Start
(Note 8)
l
1.3 µs
t
HD,STA
Start Condition Hold Time (Note 8)
l
600 ns
t
SU,STA
Start Condition Setup Time (Note 8)
l
600 ns
t
SU,STO
Stop Condition Setup Time (Note 8)
l
600 ns
t
HD,DAT
Data Hold Time (LTC2977 Receiving
Data) (Note 8)
l
0 ns
Data Hold Time (LTC2977 Transmitting
Data) (Note 8)
l
300 900 ns
t
SU,DAT
Data Setup Time (Note 8)
l
100 ns
t
SP
Pulse Width of Spike Suppressed
(Note 8)
98 ns
t
TIMEOUT_BUS
Time Allowed to Complete any PMBus
Command After Which Time SDA Will
Be Released and Command Terminated
Longer Timeout = 0
Longer Timeout = 1
l
l
25
200
35
280
ms
ms
Additional Digital T
iming Characteristics
t
OFF_MIN
Minimum Off Time for Any Channel 100 ms