XC9250/XC9251
Series
30V Driver Transistor Built-In Step-Down DC/DC Converters
ETR05023-004a
■GENERAL
DESCRIPTION
The XC9250/XC9251 series are 30V operation step-down DC/DC converter ICs with an internal driver transistor. The internal Nch driver
transistor is driven by bootstrap to achieve a stable, high-efficiency power supply up to an output current of 2.0A. Low ESR capacitors such as
ceramic capacitors can be used for the load capacitor (C
L
).
A 0.8V reference voltage source is incorporated in the IC, and the output voltage can be set to a value from 1.2V to 12.0V using external
resistors (R
FB1
, R
FB2
).
300kHz or 500kHz can be selected for the switching frequency. The generation of unneeded noise can be suppressed by synchronizing to an
external CLK in a range of
±25%
of the free running frequency using the SYNC pin. In automatic PWM/PFM control, the IC operates by PFM
control when the load is light to achieve high efficiency over the full load range from light to heavy.
The soft start time can be set as desired by adding an external capacitance to the SS pin.
With the built-in UVLO function, the driver transistor is forced OFF when input voltage becomes 4.5V or lower.
Internal protection circuits include over current protection, integral latch protection, short-circuit protection, and thermal shutdown circuits to
enable safe use.
■APPLICATIONS
●
Car navigation systems
●
Car audios
●
Industrial equipment
■FEATURES
Input Voltage
FB Voltage
Oscillation Frequency
Maximum Output Current
Control Method
:
:
:
:
:
7½30V
0.8V±2％
300kHz, 500kHz
2.0A
PWM (XC9250)
PWM/PFM (XC9251)
Soft-start
Protection Circuit
:
:
External Capacitor
(set by external capacitor C)
Over Current Protection 3.2A (TYP.)
Integral Latch Method (XC9250/51A)
Automatic Recovery (XC9250/51B)
Thermal Shutdown
Low ESR Ceramic Capacitor
Operating Ambient Temperature
Package
Environmentally Friendly
:
:
:
:
Ceramic Capacitor
-40℃ ~ +105℃
SOP-8FD
EU RoHS Compliant, Pb Free
*Performance depends on external components and wiring on the PCB.
■TYPICAL
APPLICATION CIRCUIT
■TYPICAL
PERFORMANCE
CHARACTERISTICS
XC9250x085/XC9251x085
(V
IN
=12V , V
OUT
=5V)
L=15
μ
H(CLF12555-150M), C
IN1
=10
μ
F(GRM32ER71H106KA12L),
SBD=CMS15, C
L
=22
μ
F×2(GRM32ER71E226KE15L)
100
90
Efficiency :EFFI[%]
80
70
60
50
40
30
20
10
0
1
10
100
1000
10000
XC9251
XC9250
Output Current :I
OUT
[mA]
1/28
XC9250/XC9251
Series
■PRODUCT
CLASSIFICATION
●Ordering
Information
XC9250①②③④⑤⑥-⑦
XC9251①②③④⑤⑥-⑦
PWM
PWM/PFM Auto
DESIGNATOR
①
②③
④
⑤⑥-⑦
(*1)
(*1)
ITEM
Functional selection
Adjustable Output Voltage
Oscillation Frequency
Package (Order Unit)
SYMBOL
A
B
08
3
5
QR-G
DESCRIPTION
Refer to Selection Guide
Output voltage can be adjusted in 1.2V to 12V
300kHz
500kHz
SOP-8FD (1,000/Reel)
The “-G” suffix denotes Halogen and Antimony free as well as being fully RoHS compliant.
●Selection
Guide
TYPE
A
B
CURRENT
LIMITTER
YES
YES
THERMAL
SHUTDOWN
YES
YES
LATCH
PROTECTION
YES
(*1)
NO
CHIP ENABLE
YES
YES
SYNCHRONIZED with
EXTERNAL CLOCK
YES
YES
UVLO
YES
YES
TYPE
A
B
(*1)
SOFT-START
YES
YES
The over-current protection latch is an integral latch type.
■PIN
CONFIGURATION
* The dissipation pad for this IC should be solder-plated for mounting strength and heat
dissipation.
Please refer to the reference mount pattern and metal masking.
The dissipation
pad should be connected to the GND (No. 6) pin.
4/28
XC9250/XC9251
Series
■PIN
ASSIGNMENT
PIN NUMBER
SOP-8FD
1
2
3
4
5
6
7
8
PIN NAME
V
IN
CE
SYNC
FB
SS
GND
BST
Lx
FUNCTIONS
Power Input
Chip Enable
External CLK Sync Pin
Output Voltage Sense
Soft-start Adjustment
Ground
Bootstrap
Switching Output
■FUNCTION
PIN NAME
SIGNAL
L
CE
H
OPEN
L
SYNC
H
CLK
OPEN
(*1)
STATUS
Stand-by
Active
Undefined State
(*1)
Operates with internal clock frequency
Synchronizes with External Clock Signal
Undefined State
(*1)
Please do not leave the CE and SYNC pin open.
■ABSOLUTE
MAXIMUM RATINGS
PARAMETER
V
IN
Pin Voltage
BST Pin Voltage
FB Pin Voltage
SYNC Pin Voltage
CE Pin Voltage
SS Pin Voltage
Lx Pin Voltage
Lx Pin Current
Power Dissipation
Surge Voltage
Operating Ambient Temperature
Storage Temperature
SYMBOL
V
IN
V
BST
V
FB
V
SYNC
V
CE
V
CSS
V
Lx
I
Lx
Pd
V
SURGE
Topr
Tstg
RATINGS
-0.3
½
+36
-0.3 or V
LX
-0.3
(*1)
½
V
LX
+6.5 or +36
(*2)
-0.3
½
+6.5
-0.3
½
+6.5
-0.3
½
+36
-0.3
½
+6.5
-0.3
½
V
IN
+0.3 or +36
(*3)
4.2
300
1500 (PCB mounted)
46
(*4)
-40
½
+105
-55
½
+125
Ta=25℃
UNITS
V
V
V
V
V
V
V
A
mW
V
℃
℃
* All voltages are described based on the GND pin.
(*1)
(*2)
(*3)
(*4)
The minimum value should be either -0.3 or V
LX
-0.3 in the highest.
The maximum value should be either V
LX
+6.5 or +36 in the lowest.
The maximum value should be either V
IN
+0.3 or +36 in the lowest.
Applied Time≦400ms
5/28
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