MIC502 Micrel Semiconductor, MIC502 Datasheet - Page 5

• Manufacturer Part Number: MIC502
• Description: Fan Management IC Advance Information
• Manufacturer: Micrel Semiconductor

Note H. At power-on, the startup timer forces OUT on for 64 PWM cycles of the internal timebase (t
Note I.
Note J.
Note K. PWM duty-cycle is 100% (OUT constantly on) anytime V
Note L.
Note M. /OTF is deasserted when V
Note N. Duty-cycle follows V
Note O. All functions cease when V
May 1999
MIC502
V
V
V
V
V
T1
T2
OUT
OTF
DD
0.7V
0.3V
0.3V
dead stop.
The PWM duty-cycle follows the higher of V
The PWM duty-cycle follows V
/OTF is asserted anytime V
normal operation continues. (Both V
V
V
V
V
V
V
V
V
0V
SLP
V
0V
0V
0V
DD
DD
DD
OH
OH
DD
OT
OL
OL
IH
IL
H
t
STARTUP
100%
T1
until V
40%
T1
T1
T1
T1
< V
> V
I
Figure 2. MIC502 Typical Power-Up System Behavior
T1
falls below V
< V
IL
as it increases.
OT
40%
; this occurs regardless of the state of V
t
T2
PWM
. (The fan continues to run at 100% duty-cycle.)
T1
60%
, at which time V
and V
OT
T1
T2
; duty-cycle once again follows V
and V
J
must be below V
60%
T2,
T2
K
in the case, V
T1
becomes the controlling input signal. Note that V
> V
PWM(max)
L
167
SLP
to active sleep mode.)
100%
T1
.
.
T2
.
T1
M
.
PWM
). This insures that the fan will start from a
N
30%
T1
30%
is below V
O
SLP
0%
but above V
100%
PWM
Range
20%
0%
Output
Duty Cycle
MIC502
IH
Micrel
; so