SC4905A/B
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Unless otherwise specified, V
DD
= 12V, V
IN
= 48V, R
OSC
= 499k, C
OSC
= 220pF, R
T
= 280k, R
M
= 2k, R
B
= 8.25k, C
VDD
= 0.1uF, Ta = Tj = -40 to 105 °C.
Parameter
Sync/CLOCK (Cont.)
Sync Frequency
(1)
Test Conditions
Min
Typ
Max
Unit
1.2 *F
OSC
Hz
Current Limit Section
Input Bias Current
Current Limit Threshold
Propagation Delay, ILIM to OUT
(1)
VREF Section
VREF (A version)
VREF (B version)
VDD UVLO Section (A version)
Start Threshold
Hysteresis
VDD UVLO Section (B version)
Start Threshold
Hysteresis
Pulse Width Modulator Section
FB Input current
Minimum Duty Cycle
Maximum Duty Cycle
PWM Gain
(1)
Propagation Delay, PWM to OUT
(1)
Output
Output VSAT Low
Output VSAT High
Rise Time
Fall Time
(1)
(1)
0
170
50mV Overdrive
200
35
-2
230
µA
mV
ns
0 - 5mA
0 - 5mA
-3%
-3%
4
5
+3%
+3%
V
V
4.1
4.4
200
4.6
300
V
mV
11
11.6
3.6
12
4
V
V
V
FB
= 0V to Vref
V
FB
< 500mV
V
DMAX
= V
FF
, V
FB
= Vref
V
FF
= 3.6
95
27.5
75
1
0
uA
%
%
%/V
ns
I
OUT
= 1mA
I
OUT
= 1mA
C
OUT
= 20pF
C
OUT
= 20pF
VREF - 0.5
10
10
500
mV
V
ns
ns
(1)
Note 1: Guaranteed by design. Not 100% tested in production.
2006 Semtech Corp.
3
www.semtech.com
SEMTECH [ SEMTECH CORPORATION ]
