XC9257/XC9258
Series
ETR05040-001
COT Control, 1.0A Synchronous Step-Down DC/DC Converters
■GENERAL
DESCRIPTION
☆GreenOperation-compatible
The XC9257/XC9258 series is a group of synchronous-rectification type DC/DC converters with a built-in P-channel MOS driver
transistor and N-channel MOS switching transistor, designed to allow the use of ceramic capacitors. Output voltage is internally
set in a range from 0.8V to 3.6V (accuracy: ±2.0%) increments of 0.05V. The device provides a high efficiency, stable power
supply with an output current of 1.0A to be configured using only a coil and two capacitors connected externally. Oscillation
frequency is set to 1.2MHz or 6.0MHz can be selected for suiting to your particular application.
As for operation mode HiSAT-COT
(*)
control excellent in transient response, the XC9257 series is PWM control, the XC9258
series is automatic PWM/PFM switching control, allowing fast response, low ripple and high efficiency over the full range of loads
(from light load to heavy load).
During stand-by, all circuits are shutdown to reduce current consumption to as low as 1.0μA or less. As for the soft-start function
as fast as 0.3ms in typical for quick turn-on. With the built-in UVLO (Under Voltage Lock Out) function, the internal P-channel MOS
driver transistor is forced OFF when input voltage becomes 2.00V or lower. The B types integrate C
L
High Speed discharge
function which enables the electric charge at the output capacitor C
L
to be discharged via the internal discharge.
Two types of package SOT-25, USP-6C are available.
(*)
HiSAT-COT is an original Torex term for High Speed Transient Response.
■APPLICATIONS
●Smart
phones / Mobile phones
●Bluetooth
●Portable
game consoles
●Digital
still cameras / Camcorders
●Point-of-Load
(POL)
●Wearable
devices
■FEATURES
Input Voltage Range
Output Voltage Range
Oscillation Frequency
Output Current
Control Methods
:
:
:
:
:
2.5V∼5.5V
0.8V∼3.6V (±2.0%)
1.2MHz, 6.0MHz
1A
HiSAT-COT Control
100% Duty Cycle
PWM Control (XC9257)
PWM/PFM Auto (XC9258)
Thermal Shutdown
Current Limit (Pendent character)
Short Circuit Protection (Type B)
Soft-Start
UVLO
C
L
High Speed Discharge (Type B)
Ceramic Capacitor
- 40℃
∼
+ 105℃
SOT-25, USP-6C
EU RoHS Compliant, Pb Free
Protection Circuits
:
Functions
:
Capacitor
Operating Ambient Temperature
Packages
Environmentally Friendly
:
:
:
:
■TYPICAL
APPLICATION CIRCUIT
■TYPICAL
PERFORMANCE
CHARACTERISTICS
XC9257B18C/XC9258B18C
L =LTF5022T-4R7N2R0(4.7μH)
C
IN
= 10μF(GRM155R61A106M) C
L
= 10μF(GRM155R61A106M)
100
90
80
Efficiency: EFFI (%)
V
IN
=3.7V
70
60
50
40
30
20
10
0
0.1
V
IN
=3.7V
V
IN
=5.0V
V
IN
=5.0V
XC9258
XC9257
1
10
100
1000
Output Current: I
OUT
(mA)
1/27
XC9257/XC9258
Series
■
BLOCK DIAGRAM
1)
XC9257/XC9258 Series Type A (SOT-25)
2) XC9257/XC9258 Series Type B (SOT-25)
(*) The XC9257 offers a fixed PWM control, a Control Logic of PWM/PFM Selector is fixed at “PWM” internally.
The XC9258 control scheme is a fixed PWM/PFM automatic switching, a Control Logic of PWM/PFM Selector is fixed at “PWM/PFM
automatic switching” internally.
Diodes inside the circuit are an ESD protection diode and a parasitic diode.
2)
XC9257/XC9258 Series Type B (USP-6C)
2)
XC9257/XC9258 Series Type B (USP-6C)
C
FB
R1
V
OUT
Phase
Compensation
Error Amp.
+
-
Comparator
-
+
S
R
Minimum
On Time
Generator
Q
Logic
High Side
Current Limit
V
IN
C
FB
R1
V
OUT
Phase
Compensation
+
-
Comparator
-
+
S
R
Minimum
On Time
Generator
Q
Short
Protection
High Side
Current Limit
V
IN
Error Amp.
R2
V
SS
Vref with
Soft Start
CE Control Logic,
UVLO,
Thermal Shutdown
Synch.
Buffer
Driver
Lx
Logic
R2
V
SS
Vref with
Soft Start
CE Control Logic,
UVLO,
Thermal Shutdown
Synch.
Buffer
Driver
Lx
V
IN
V
OUT
PWM/PFM
Selector
V
SS
V
IN
V
OUT
PWM/PFM
Selector
V
SS
CE
CE
(*)
The XC9257 offers a fixed PWM control, a Control Logic of PWM/PFM Selector is fixed at “PWM” internally.
The XC9258 control scheme is a fixed PWM/PFM automatic switching, a Control Logic of PWM/PFM Selector is fixed at “PWM/PFM
automatic switching” internally.
Diodes inside the circuit are an ESD protection diode and a parasitic diode.
2/27
XC9257/XC9258
Series
■PRODUCT
CLASSIFICATION
1) Ordering Information
XC9257①②③④⑤⑥-⑦ PWM Control
XC9258①②③④⑤⑥-⑦ PWM/PFM Automatic switching control
DESIGNATOR
①
ITEM
Type
SYMBOL
A
B
DESCRIPTION
Refer to Selection Guide
Output voltage options
e.g. 1.2V
→ ②=1, ③=2
1.25V
→ ②=1, ③=C
0.05V increments : 0.05=A, 0.15=B, 0.25=C,
0.35=D, 0.45=E, 0.55=F,
0.65=H, 0.75=K, 0.85=L,
0.95=M
1.2MHz
6.0MHz
SOT-25 (3,000pcs/Reel)
USP-6C (3,000pcs/Reel)
②③
Output Voltage
08∼36
④
(*1)
Oscillation Frequency
Packages (Order Unit)
C
E
MR-G
ER-G
⑤⑥-⑦
(*1)
The “-G” suffix denotes Halogen and Antimony free as well as being fully EU RoHS compliant.
2) Selection Guide
TYPE
A
B
OUTPUT VOLTAGE
Fixed
Fixed
C
L
AUTO-DISCHARGE
No
Yes
SHORT PROTECTION
(LATCH)
No
Yes
UVLO
Yes
Yes
TYPE
A
B
CHIP ENABLE
Yes
Yes
CURRENT LIMIT
Yes
Yes
SOFT-START TIME
Fixed
Fixed
THERMAL SHUTDOWN
Yes
Yes
3/27
XC9257/XC9258
Series
■PIN
CONFIGURATION
* The dissipation pad for the USP-6C package should be solder-plated in recommended mount pattern and metal masking so
as to enhance mounting strength and heat release. If the pad needs to be connected to other pins, it should be connected
to the GND (No. 2 and 5) pin.
■PIN
ASSIGNMENT
PIN NUMBER
SOT-25
1
2
3
4
5
USP-6C
6
2,5
4
3
1
PIN NAME
V
IN
V
SS
CE
V
OUT
Lx
FUNCTIONS
Power Input
Ground
Chip Enable
Output Voltage Monitor
Switching Output
■FUNCTION
CE PIN Function
PIN NAME
CE
SIGNAL
L
H
STATUS
Stand-by
Active
Please do not leave the CE pin open.
4/27
XC9257/XC9258
Series
■ABSOLUTE
MAXIMUM RATINGS
Ta=25℃
PARAMETER
V
IN
Pin Voltage
Lx Pin Voltage
V
OUT
Pin Voltage
CE Pin Voltage
SOT-25
Power Dissipation
USP-6C
Operating Ambient Temperature
Storage Temperature
(*1)
(*2)
SYMBOL
V
IN
V
Lx
V
OUT
V
CE
RATINGS
-0.3∼+6.2
-0.3∼V
IN
+0.3 or +6.2
(*1)
-0.3∼V
IN
+0.3 or +4.0
(*2)
-0.3∼+6.2
250
600 (PCB mounted)
120
1000 (PCB mounted)
-40∼+105
-55∼+125
UNITS
V
V
V
V
Pd
mW
Topr
Tstg
℃
℃
* All voltages are described based on the GND (V
SS
) pin.
The maximum value should be either V
IN
+0.3V or +6.2V in the lowest.
The maximum value should be either V
IN
+0.3V or +4.0V in the lowest.
5/27
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