Rainbow Electronics MAX1635 - Manual (Page 6)

__________________________________________________________________________Pin Description
MAX1630–MAX1635
Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
6 _______________________________________________________________________________________
____________________________________Typical Operating Characteristics (continued)
(Circuit of Figure 1, 3A Table 1 components, T A = +25°C, unless otherwise noted.)
1000
0.1
0.1 10 1000 100
SWITCHING FREQUENCY
vs. LOAD CURRENT
10
1
100
MAX1630/35-10
LOAD CURRENT (mA)
SWITCHING FREQUENCY (kHz)
1
+5V, V
IN
= 15V
+3.3V, V IN = 15V
+3.3V, V IN = 6V
+5V, V IN = 6V
5.00
4.90
50 60
VL REGULATOR OUTPUT VOLTAGE
vs. OUTPUT CURRENT
4.98 MAX 1630/35-11
OUTPUT CURRENT (mA)
VL OUTPUT VOLTAGE (V)
0
4.94
4.92
30 40
4.96
10 20
V IN = 15V
ON3 = ON5 = 0V
2.510
2.480
2.485
5 6
REF OUTPUT VOLTAGE
vs. OUTPUT CURRENT
2.505
MAX 1630/35-12
OUTPUT CURRENT (mA)
REF OUTPUT VOLTAGE (V)
0
2.495
2.490
3 4
2.500
1 2
V IN = 15V
ON3 = ON5 = 0V
2ms/div
START-UP WAVEFORMS
RUN
5V/div
3.3V OUTPUT
2V/div
TIME
5V/div
5V OUTPUT
5V/div
SEQ = VL, 0.015 µ F CAPACITOR ON-TIME
MAX1630/35-13
Feedback Input for the 3.3V SMPS; regulates at FB3 = REF (approx. 2.5V) in adjustable mode. FB3 is a
Dual Mode input that also selects the 3.3V fixed output voltage setting when tied to GND. Connect FB3
to a resistor divider for adjustable-output mode.
FB3 3
12V/120mA Linear Regulator Output. Input supply comes from V DD . Bypass 12OUT to GND with
1µF minimum.
12OUT
(MAX1630/
32/33/35)
Current-Sense Input. Also serves as the feedback input in fixed-output mode. CSL3 2
FUNCTION NAME PIN
Logic-Control Input for secondary feedback. Selects the PWM that uses a transformer and secondary
feedback signal (SECFB):
STEER = GND: 3.3V SMPS uses transformer
STEER = VL: 5V SMPS uses transformer
STEER
(MAX1631/
MAX1634)
Current-Sense Input for the 3.3V SMPS. Current-limit level is 100mV referred to CSL3. CSH3 1
4