Datenblatt-pdf.com


MAX5090C Schematic ( PDF Datasheet ) - Maxim Integrated Products

Teilenummer MAX5090C
Beschreibung High-Efficiency MAXPower Step-Down DC-DC Converters
Hersteller Maxim Integrated Products
Logo Maxim Integrated Products Logo 




Gesamt 17 Seiten
MAX5090C Datasheet, Funktion
19-3872; Rev 0; 3/06
EVAALVUAAILTAIOBNLEKIT
2A, 76V, High-Efficiency
MAXPower Step-Down DC-DC Converters
General Description
The MAX5090A/B/C easy-to-use, high-efficiency, high-
voltage step-down DC-DC converters operate from an
input voltage up to 76V, and consume only 310µA qui-
escent current at no load. This pulse-width-modulated
(PWM) converter operates at a fixed 127kHz switching
frequency at heavy loads, and automatically switches
to pulse-skipping mode to provide low quiescent cur-
rent and high efficiency at light loads. The MAX5090
includes internal frequency compensation simplifying
circuit implementation. The device can also be syn-
www.DcahtraoSnhiezeetd4Uw.ciothmexternal system clock frequency in a
noise-sensitive application. The MAX5090 uses an
internal low on-resistance and a high-voltage DMOS
transistor to obtain high efficiency and reduce overall
system cost. This device includes undervoltage lock-
out, cycle-by-cycle current limit, hiccup-mode output
short-circuit protection, and overtemperature shutdown.
The MAX5090 delivers up to 2A output current. External
shutdown is included, featuring 19µA (typ) shutdown
current. The MAX5090A/MAX5090B versions have fixed
output voltages of 3.3V and 5V, respectively, while the
MAX5090C features an adjustable 1.265V to 11V output
voltage.
The MAX5090 is available in a space-saving 16-pin thin
QFN package (5mm x 5mm) and operates over the
automotive temperature range (-40°C to +125°C).
Applications
Automotive
Industrial
Distributed Power
Typical Operating Circuit
Features
Wide Input Voltage Range: 6.5V to 76V
Fixed (3.3V, 5V) and Adjustable (1.265V to 11V)
Output-Voltage Versions
2A Output Current
Efficiency Up to 92%
Internal 0.26High-Side DMOS FET
310µA Quiescent Current at No Load
19µA Shutdown Current
Internal Frequency Compensation
Fixed 127kHz Switching Frequency
External Frequency Synchronization
Thermal Shutdown and Short-Circuit Current Limit
-40°C to +125°C Automotive Temperature Range
16-Pin (5mm x 5mm) Thin QFN Package
Capable of Dissipating 2.67W at +70°C
Ordering Information
PART
TEMP
RANGE
PIN-
PACKAGE*
OUTPUT
VOLTAGE
(V)
MAX5090AATE+ -40°C to +125°C 16 TQFN-EP**
3.3
MAX5090AATE -40°C to +125°C 16 TQFN-EP**
3.3
MAX5090BATE+ -40°C to +125°C 16 TQFN-EP**
5.0
MAX5090BATE -40°C to +125°C 16 TQFN-EP**
5.0
Ordering Information continued at end of data sheet.
*The package code is T1655-3.
**EP = Exposed pad.
+Denotes lead-free package.
Pin Configuration
VIN
7.5V TO 76V
CIN
68µF
CBYPASS
0.47µF
RIN
10
VIN
ON/OFF
DRAIN
LX
MAX5090B
SYNC
SGND
PGND
BST
FB
SS
VD
CBST
0.22µF
100µH
D1
PDS5100H
3.3µF
CSS
0.047µF
VOUT
5V/2A
COUT
100µF
TOP VIEW
12 11 10 9
DRAIN 13
DRAIN 14
N.C. 15
N.C. 16
EP
MA5090
1234
8 FB
7 SS
6 SYNC
5 VD
TQFN
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.






MAX5090C Datasheet, Funktion
2A, 76V, High-Efficiency MAXPower Step-Down
DC-DC Converters
Typical Operating Characteristics (continued)
(VIN = 12V, VON/OFF =12V, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C. See the Typical
Operating Circuit, if applicable.)
LOAD-TRANSIENT RESPONSE
(MAX5090AATE)
MAX5090 toc19
VOUT = 3.3V
LX WAVEFORMS
(MAX5090AATE)
MAX5090 toc20
LX WAVEFORMS
(MAX5090AATE)
MAX5090 toc21
www.DataSheet4U.com
A
VOUT = 3.3V
A
VOUT = 3.3V
A
B
400µs/div
A: VOUT, 200mV/div, AC-COUPLED
B: IOUT, 500mA/div, 0.1A TO 1A
LX WAVEFORM
(MAX5090AATE)
MAX5090 toc22
VOUT = 3.3V
A
B
0
4µs/div
A: SWITCH VOLTAGE (LX PIN), 20mV/div (VIN = 48V)
B: INDUCTOR CURRENT, 2A/div (I0 = 2A)
STARTUP WAVEFORM
(IOUT = 0)
MAX5090 toc23
A
B
4µs/div
A: SWITCH VOLTAGE, 20V/div (VIN = 48V)
B: INDUCTOR CURRENT, 200mA/div (I0 = 75mA)
STARTUP WAVEFORM
(IOUT = 2A)
MAX5090 toc24
A
B
4µs/div
A: SWITCH VOLTAGE, 20V/div (VIN = 48V)
B: INDUCTOR CURRENT, 200mA/div (IOUT = 0)
PEAK SWITCH CURRENT
vs. INPUT VOLTAGE
7.0
MAX5090AATE
6.0
VOUT = 3.3V
5% DROP IN VOUT
PULSED OUTPUT LOAD
5.0
B
CSS = 0.047µF
A: VON/OFF, 2V/div
B: VOUT, 1V/div
4ms/div
SYNCHRONIZATION
MAX5090 toc26
fSYNC = 119kHz
SYNC
2V/div
B
CSS = 0.047µF
A: VON/OFF, 2V/div
B: VOUT, 1V/div
4ms/div
SYNCHRONIZATION
MAX5090 toc27
fSYNC = 200kHz
SYNC
2V/div
4.0
3.0
LX LX
2.0
10V/div
10V/div
1.0
6.5 16 26 36 46 56 66 76
2µs/div
1µs/div
INPUT VOLTAGE (V)
6 _______________________________________________________________________________________

6 Page









MAX5090C pdf, datenblatt
2A, 76V, High-Efficiency MAXPower Step-Down
DC-DC Converters
ESRIN
=
VESR
IOUT
+
IL
2

CIN
=
IOUT ×
VQ
D(1D)
× fSW
where:
IL
=
(VIN VOUT) × VOUT
VIN × fSW × L
www.DataSheet4U.com
D = VOUT
VIN
IOUT is the maximum output current of the converter
and fSW is the oscillator switching frequency (127kHz).
For example, at VIN = 48V, VOUT = 3.3V, the ESR and
input capacitance are calculated for the input peak-to-
peak ripple of 100mV or less, yielding an ESR and
capacitance value of 40mand 100µF, respectively.
Low-ESR ceramic multilayer chip capacitors are recom-
mended for size-optimized application. For ceramic
capacitors assume the contribution from ESR and capaci-
tor discharge is equal to 10% and 90%, respectively.
The input capacitor must handle the RMS ripple current
without significant rise in the temperature. The maxi-
mum capacitor RMS current occurs at approximately
50% duty cycle. Ensure that the ripple specification of
the input capacitor exceeds the worst-case capacitor
RMS ripple current. Use the following equations to cal-
culate the input capacitor RMS current:
ICRMS = IPRMS2 IAVGin2
where:
IPRMS =
(IPK2
+
IDC 2 + IPK xIDC )
x
D
3
IAVGin
= VOUT x
VIN x
IOUT
η
IPK = IOUT +
IL
2
IDC =
IOUT
IL
2
D = VOUT
VIN
IPRMS is the input switch RMS current, IAVGin is the
input average current, and η is the converter efficiency.
The ESR of the aluminum electrolytic capacitor increas-
es significantly at cold temperatures. Use a 1µF or
greater value ceramic capacitor in parallel with the alu-
minum electrolytic input capacitor, especially for input
voltages below 8V.
800
700
600
500
400
300
200
100
0
-40
25 100 125
TEMPERATURE (°C)
150
Figure 3. Forward-Voltage Drop vs. Temperature of the Internal
Body Diode of MAX5090
Output Filter Capacitor
The output capacitor COUT forms double pole with the
inductor and a zero with its ESR. The MAX5090’s inter-
nal fixed compensation is designed for a 100µF capaci-
tor, and the ESR must be from 20mto 100m. The
use of an aluminum or tantalum electrolytic capacitor is
recommended. See Table 2 to choose an output
capacitor for stable operation.
The output ripple is comprised of VOQ (caused by the
capacitor discharge), and VOESR (caused by the ESR
of the capacitor). Use low-ESR tantalum or aluminum
electrolytic capacitors at the output. Use the following
equations to calculate the contribution of output capac-
itance and its ESR on the peak-to-peak output ripple
voltage:
VOESR = ∆IL x ESR
VOQ
IL
8 xCOUT x
fSW
The MAX5090 has a programmable soft-start time (tSS).
The output rise time is directly proportional to the out-
put capacitor, output voltage, and the load. The output
rise time also depends on the inductor value and the
current-limit threshold. It is important to keep the output
rise time at startup the same as the soft-start time (tSS)
to avoid output overshoot. Large output capacitors take
longer than the programmed soft-start time (tSS) and
cause error-amplifier saturation. This results in output
overshoot. Use greater than 2ms soft-start time for a
100µF output capacitor.
12 ______________________________________________________________________________________

12 Page





SeitenGesamt 17 Seiten
PDF Download[ MAX5090C Schematic.PDF ]

Link teilen




Besondere Datenblatt

TeilenummerBeschreibungHersteller
MAX5090AHigh-Efficiency MAXPower Step-Down DC-DC ConvertersMaxim Integrated Products
Maxim Integrated Products
MAX5090BHigh-Efficiency MAXPower Step-Down DC-DC ConvertersMaxim Integrated Products
Maxim Integrated Products
MAX5090CHigh-Efficiency MAXPower Step-Down DC-DC ConvertersMaxim Integrated Products
Maxim Integrated Products

TeilenummerBeschreibungHersteller
CD40175BC

Hex D-Type Flip-Flop / Quad D-Type Flip-Flop.

Fairchild Semiconductor
Fairchild Semiconductor
KTD1146

EPITAXIAL PLANAR NPN TRANSISTOR.

KEC
KEC


www.Datenblatt-PDF.com       |      2020       |      Kontakt     |      Suche