MP2403互换的同步降压型DC-DC稳压器MXT2485

Electrical Characteristic
(VIN = 12V, TA = 25℃, unless otherwise specified )
Parameter
VIN Input Supply Voltage VIN Supply Current VIN Shutdown Supply Current Feedback Voltage Feedback OVP Threshold Voltage (4) High-Side MOSFET RDS(ON) (4) Low-Side MOSFET RDS(ON) High-Side MOSFET Leakage Current (4) High-Side MOSFET Current Limit (4) Low-Side MOSFET Current Limit COMP to Current sense Transconductance
MXT2485
36V, 3A, 250KHz Synchronous Step-Down DC/DC Converter
General Description
The MXT2485 is a synchronous step-down DC/DC converter that provides wide 4.6V to 36V input voltage range and 3A continuous load current capability. Fault protection includes cycle-by-cycle current limit, input UVLO, output over voltage protection and thermal shutdown. Besides, adjustable soft-start function prevents inrush current at turn-on. This device uses current mode control scheme that provides fast transient response. In shutdown mode, the supply current is less than 1uA.
Pin Configuration
Top View
BS VIN SW GND 1 2 3 4 GND Exposed Pad 8 7 6 5 SS EN COMP FB

Ordering Information
Part Number Package Shipment
Tape & Reel / 3000 MXT2485ADJSBCR SOP8-EP
(3)
Symbol Test Conditions
VEN = VIN, VFB=1.0V VEN = 0V 4.6V≦VIN≦36V -40℃≦TA≦85℃
Min
4.6
Typ
1.1 0.3 0.80 0.95 150 80 5 1.5 7
Max
36 3 0.82 0.8Βιβλιοθήκη Baidu5 1
Unit
V mA μA V V mΩ mΩ uA A A A/V
7
3 EN SW
VOUT R1 C7
(optional)
ＭＸＴ２４８５
8 SS GND
C2 R2
C4 0.1uF
4, Exposed pad
COMP
6 C3 C6
(optional)
R3
Figure 1 Typical Application Circuit
VOUT 5.0V 3.3V 2.5V 1.8V R1 53.5K 31.25K 21.5K 12.5K R2 10K 10K 10K 10K R3 7.5K 5.6K 4.7K 3.3K C3 3.3nF 3.3nF 3.3nF 3.3nF L1 10-15uH 6.8-10uH 4.7-6.8uH 4.7uH C2 22uF x 2 Ceramic 22uF x 2 Ceramic 47uF Ceramic 47uF x 2 Ceramic
Features

Wide Input Voltage from 4.6V to 36V 3A Output Current Adjustable Output Voltage from 0.8V to 28V High Efficiency Up to 95% Fixed 250KHz Switching Frequency Current Mode Operation Adjustable Soft-Start Cycle-by-Cycle current limit Input Under Voltage Lockout Over-Temperature Protection Thermal Enhanced SOP-8 Package RoHS Compliant
VFB
0.78 0.765 0.9
VEN = 0V, VSW = 0V 4 From drain to source GCS
10
3
MXT2485
Electrical Characteristic (continued)
(VIN = 12V, TA = 25℃, unless otherwise specified ) Error Amplifier Transconductance GEA Δ ICOMP = ±10μA 200 VFB = 0V VFB = 0.7V VIN Rising VCOMP = 0V, VSS = 0V CSS = 0.1uF 80 820 400 250 55 90 180 4.3 200 6 15 1.5 160 300 μA/V V/V KHz KHz % ns V mV uA ms V ℃
*SB: SOP8-EP C: Green, -40 ~85℃ R: Tape & Reel
1
MXT2485
Typical Application Circuit
VIN 4.6 to 36V 2 C1 10uF VIN BS 1 C5 10nF L1 D1 B340 FB 5
(optional)
ON OFF
Application
The MXT2485 is available in an SOP8-EP package, provides a very compact system solution and good thermal conductance.

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2
MXT2485
Absolute Maximum Ratings (1)
Input Supply Voltage VIN …………………………………………………………………………... -0.3V ~ +39V EN Voltage VEN …………………………………………………………………………………….. -0.3V ~ +39V SW Voltage VSW ………………………………………………………………………………. -1V ~ (VIN + 0.3V) Boost Voltage VBS …………………………………………………………………... (VSW – 0.3V) ~ (VSW + 6V). All Other Pins Voltage ………………………………………………………………………………… -0.3V ~ 6V Maximum Junction Temperature …………………………………………………………………………. 150℃ Storage Temperature …………………………………………………………………………….. -65℃ ~ 150℃ Lead Temperature( Soldering 10 sec ) …………………………………………………………………… 260℃ ESD Classification ( HBM ) ……………………………………………………………………………… Class 2
Recommended Operating Conditions (2)
Input Supply Voltage VIN ………………………………………………………………………………4.6V ~ 36V Output Voltage VOUT ………………………………………………………………………………….. 0.8V ~ 28V Ambient Temperature TA ………………………………………………………………………….. -40℃ ~ 85℃
Pin Function Description
Pin NO. Pin Name
1 2 3 4/EP 5 6 7 8 BS VIN SW GND FB COMP EN SS
Pin Description
High Side Gate Drive Boost Input. A 10nF or greater capacitor must be connected from this pin to SW. It can boost the gate drive to fully turn on the internal high side NMOS. Power Supply Input Pin. Drive 4.6V to 36V voltage to this pin to power on this chip. Connecting a 10uF ceramic bypass capacitor between VIN and GND to eliminate noise. Power Switching Output. It is the output pin that internal high side NMOS switching to supply power. Ground Pin. Connecting EP(exposed pad) to Pin 4. Voltage Feedback Input Pin. Connecting FB and VOUT with a resistive voltage divider. This IC senses feedback voltage via FB and regulate it at 0.8V. Compensation Pin. This pin is used to compensate the regulation control loop. Connect a series RC network from COMP pin to GND. Enable Input Pin. This pin provides a digital control to turn the converter on or off. Connect to VIN with a 100KΩ resistor for self-startup. Soft-Start Input Pin. This pin controls the soft-start period. Connect a capacitor from SS to GND to set the soft start period.
Thermal Characteristics
SOP-8(Exposed Pad), θJA ……………………………………………………………………………….. 75℃/W SOP-8(Exposed Pad), θJC ……………………………………………………………………………….. 15℃/W
Notes: (1) Stresses exceed those ratings may damage the device. (2) If out of its operation conditions, the device is not guaranteed to function.