IC CTRLR PWM STP-DN TRIPL 32WQFN

MAX15048ETJ+

Manufacturer Part NumberMAX15048ETJ+
DescriptionIC CTRLR PWM STP-DN TRIPL 32WQFN
ManufacturerMaxim Integrated Products
MAX15048ETJ+ datasheet
 


Specifications of MAX15048ETJ+

ApplicationsPower Supply Controller, SequencerVoltage - Supply4.7 V ~ 23 V
Current - Supply6mAOperating Temperature-40°C ~ 85°C
Mounting TypeSurface MountPackage / Case32-WQFN Exposed Pad
Number Of Outputs3Output Voltage5 V
Input Voltage4.7 V to 23 VSupply Current6 mA
Switching Frequency200 KHzMounting StyleSMD/SMT
Maximum Operating Temperature+ 85 CMinimum Operating Temperature- 40 C
Lead Free Status / RoHS StatusLead free / RoHS CompliantVoltage - Input-
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Triple-Output Buck Controllers
with Tracking/Sequencing
Below are equations that define the power modulator:
V
IN
=
G
MOD(DC)
V
RAMP
1
=
f
LC
2
π ×
L C
×
=
f
ZERO, ESR
π ×
2
ESR C
ESR
f
=
ZERO, ESL
2
π ×
The switching frequency is programmable between
200kHz and 1.2MHz using an external resistor at RT.
Typically, the crossover frequency (f
frequency when the system’s closed-loop gain is equal
to unity, crosses the 0dB axis, and should be set at or
below 1/10 the switching frequency (f
closed-loop response.
The MAX15048/MAX15049 provide an internal transcon-
ductance amplifier with its inverting input and its output
available to the user for external frequency compensation.
The flexibility of external compensation for each con-
verter offers wide selection of output-filtering components,
40
20
0
-20
-40
-60
-80
Figure 4a. Power Modulator Gain and Phase Response (Large, Bulk C
22
_____________________________________________________________________________________
especially the output capacitor. For cost-sensitive appli-
cations, use aluminum electrolytic capacitors; for space-
sensitive applications, use low ESR tantalum or multilayer
ceramic chip (MLCC) capacitors at the output. The higher
switching frequencies of the MAX15048/MAX15049 allow
the use of MLCC as the primary filter capacitor(s).
First, select the passive and active power compo-
OUT
nents that meet the application’s output ripple, compo-
nent size, and component cost requirements. Second,
choose the small-signal compensation components to
1
achieve the desired closed-loop frequency response
×
OUT
and phase margin as outlined below.
The power modulator’s LC lowpass filter exhibits a vari-
ESL
ety of responses, depending on the value of L and C
(and their parasitics).
One such response is shown in Figure 4a. In this exam-
ple, the power modulator’s uncompensated crossover
), which is the
CO
is approximately 1/6 the desired crossover frequency,
f
. Note also, the uncompensated rolloff through 0dB
CO
plane follows the double-pole, -40dB/decade slope and
/10) for stable,
SW
approaches 180° of phase shift, indicative of a poten-
tially unstable system. Together with the inherent 180° of
phase delay in the negative feedback system, this can
lead to near 360°, or “positive” feedback—an unstable
system.
f
LC
|G
| ASYMPTOTE
MOD
|G
|
MOD
f
ZERO, ESR
< G
MOD
f
ZERO, ESL
FREQUENCY (Hz)
)
OUT
Closed-Loop Response and Compensation
of Voltage-Mode Regulators
90
45
0
-45
-90
-135
-180