MAX1537ETX Maxim Integrated, MAX1537ETX Datasheet - Page 13
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MAX1537ETX
Manufacturer Part Number
MAX1537ETX
Description
Current & Power Monitors & Regulators
Manufacturer
Maxim Integrated
Datasheet
1.MAX1537ETX-T.pdf
(38 pages)
MAX1533
High-Efficiency, 5x Output, Main Power-Supply
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1
2
3
4
5
6
7
8
9
PIN
MAX1537
10
11
1
2
3
4
5
6
7
8
9
______________________________________________________________________________________
PGDLY
Controllers for Notebook Computers
NAME
ADJA
ILIM3
ILIM5
FSEL
ONA
GND
ON5
ON3
REF
V
CC
Auxiliary Feedback Input. Connect a resistive voltage-divider from LDOA to analog
ground to adjust the auxiliary linear-regulator output voltage. ADJA regulates at 2V.
Connect ADJA to GND for nominal 12V output using internal feedback.
5V SMPS Enable Input. The 5V SMPS is enabled if ON5 is greater than the SMPS on
level and disabled if ON5 is less than the SMPS off level. If ON5 is connected to REF,
the 5V SMPS starts after the 3.3V SMPS reaches regulation (delay start). Drive ON5
below the clear fault level to reset the fault latches.
3.3V SMPS Enable Input. The 3.3V SMPS is enabled if ON3 is greater than the SMPS
on level and disabled if ON3 is less than the SMPS off level. If ON3 is connected to
REF, the 3.3V SMPS starts after the 5V SMPS reaches regulation (delay start). Drive
ON3 below the clear fault level to reset the fault latches.
LDOA Enable Input. When ONA is low, LDOA is high impedance and the secondary
winding control is off. When ONA is high, LDOA is on. Connect to LDO3, LDO5,
CSL3, CSL5, or other output for desired automatic startup sequencing.
Frequency-Select Input. This three-level logic input sets the controller’s switching
frequency. Connect to GND, REF, or V
frequencies:
V
3.3V SMPS Peak Current-Limit Threshold Adjustment. The current-limit threshold
defaults to 75mV if ILIM3 is connected to V
threshold across CSH3 and CSL3 is precisely 1/10th the voltage seen at ILIM3 over a
500mV to 2.0V range. The logic threshold for switchover to the 75mV default value is
approximately V
5V S M P S P eak C ur r ent- Li m i t Thr eshol d . The cur r ent- l i m i t thr eshol d d efaul ts to 75m V i f
and C S L5 i s p r eci sel y 1/10th the vol tag e seen at ILIM 5 over a 500m V to 2.0V r ang e. The
2.0V Reference Voltage Output. Bypass REF to analog ground with a 0.1µF or greater
ceramic capacitor. The reference can source up to 100µA for external loads. Loading
REF degrades output-voltage accuracy according to the REF load-regulation error.
The reference shuts down when SHDN is low.
Analog Supply Input. Connect to the system supply voltage (+4.5V to +5.5V) through
a series 20Ω resistor. Bypass V
capacitor.
Power-Good One-Shot Delay. Place a timing capacitor on PGDLY to delay PGOOD
going high. PGDLY has a 5µA pullup current and a 10Ω pulldown. The pulldown is
activated when power is not good. When power is good, the pulldown is shut off and
the 5µA pullup is activated. When PGDLY crosses REF, PGOOD is enabled.
ILIM 5 i s connected to V
l og i c thr eshol d for sw i tchover to the 75m V d efaul t val ue i s ap p r oxi m atel y V
Analog Ground. Connect the backside pad to GND.
CC
= 500kHz, REF = 300kHz, GND = 200kHz
CC
- 1V.
C C
. In ad j ustab l e m od e, the cur r ent- l i m i t thr eshol d acr oss C S H 5
CC
to analog ground with a 1µF or greater ceramic
FUNCTION
CC
to select the following typical switching
CC
. In adjustable mode, the current-limit
Pin Description
C C
- 1V .
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