FAN5235 Datasheet, PDF (5/15 Pages) Fairchild Semiconductor – System Electronics Regulator for Mobile PCs

FAN5235
Operating Conditions (Continued)
Recommended Operating Conditions Unless Noted Refers to Block Diagrams
Parameter
12V Regulator (Continued)
On Output, V_5V-Always-V_GS
Off Output, V_GS
Ramp Amplitude, pk-pk
Error Amplifier GBW
Under Voltage Shut Down
Over Voltage Shut Down
Min Duty Cycle
Max Duty Cycle
5V and 3.3V Always
Bypass Switch rdson
Linear Regulator Accuracy
Rated Output Current
Over-current Limit
Under-voltage Threshold
Reference
Internal Reference Accuracy
Control Functions
SDWN Off Voltage Max.
SDWN On Voltage Min.
Over-temperature Shutdown, t_j
Over-temperature Hysteresis
PGOOD Threshold
PGOOD Sink Current
PGOOD leakage
+5V Analog Softstart
+3.3V Analog Softstart
Soft Start Current
PGOOD Min Pulse Width
Conditions
Min. Typ. Max. Units
I = 10µA
I = 10µA
2µs delay
Measured at VFB₁₂
(By design)
100
mV
100
mV
2
V
1
MHz
70
76
80
%V_O
115
%V_O
0
%
32
33
34
%
1.3
1.5
Ω
5.6 to 24V, 0 to 50mA,
-3.3
5V Main On or Off
2
%
I_3.3 + I₅
2µs delay
0
50
mA
100
180
mA
2µs delay
70
75
80
%
0-70°C
-1
1
%
800
mV
3
V
150
°C
25
°C
PWM Buck Converters
-14
-11
-8.5 %V_O1
-4
mA
1
µA
Css=100nF
65
msec
Css=100nF
65
msec
5
µA
Note 2
5
10
µs
Notes
1. The minimum input voltage does not include voltage drop in the source supply due to source resistance. It is operating voltage
for static load conditions. To get acceptable load transient performance, the input voltage required will be much higher, in the
7.5 to 8.5 volt range or even higher depending on the severity of dynamic load, source impedance and input and output
capacitance and inductor values. The user should thoroughly test the performance at minimum input voltage using intended
component values and transient loading.
2. Min/Max specifications are guaranteed by design.
REV. 1.3.3 1/3/02
5