Datasheet
Single-chip Type with Built-in FET Switching Regulator Series
Step-down Switching regulators
with Built-in Power MOSFET
BU9000xGWZ series
●General
Description
The BU9000xGWZ are a high efficiency 6MHz
synchronous step-down switching regulator with ultra
low current PFM mode.
It provides up to 1.0A load current and an input voltage
range from 3.0V to 5.5V, optimized for battery powered
portable applications.
BU9000xGWZ has a mode control pin that allows the
user to select Forced PWM (Pulse Width Modulation)
mode or PFM (Pulse Frequency Modulation) and PWM
auto change mode utilized power save operation at light
load current.
●Applications
Smart phones, Cell phones, Portable applications,
Micro DC/DC modules, and USB accessories
●Package(s)
UCSP35L1
W(Typ.) x D(Typ.) x H(Max.)
1.30mm x 0.90mm x 0.40mm
●Typical
Application Circuit(s)
●Features
Fast transient response
Automatic PFM/PWM operation
Forced PWM operation
Internal Soft Start
Under voltage lockout
Over current protection
Thermal shutdown
Figure 1. Typical Application Circuit(s)
Output
voltage
3.30V
1.20V
1.80V
2.50V
3.00V
1.25V
1.00V
1.30V
Operating mode
MODE=L
Automatic
PFM/PWM
Forced PFM
MODE=H
●Lineup
Part No.
BU90002GWZ
BU90003GWZ
BU90004GWZ
BU90005GWZ
BU90006GWZ
BU90007GWZ
BU90008GWZ
BU90009GWZ
Input voltage
4.0V to 5.5V
2.3V to 5.5V
2.3V to 5.5V
2.3V to 5.5V
2.3V to 5.5V
2.3V to 5.5V
2.3V to 5.5V
2.3V to 5.5V
Switching frequency
5.4MHz to 6.6MHz
3.6MHz to 4.4MHz
4.8MHz to 6.0MHz
5.4MHz to 6.6MHz
5.4MHz to 6.6MHz
3.6MHz to 4.4MHz
3.2MHz to 4.0MHz
3.8MHz to 4.8MHz
Forced PWM
Automatic
PFM/PWM
●Pin
Configuration(s)
(BOTTOM VIEW)
●Pin
Description(s)
Pin No.
A1
A2
A3
B1
B2
B3
Symbol
VIN
EN
GND
MODE
LX
FB
Function
Power supply input pin
Enable pin
GND pin
Forced PWM mode pin
Inductor connection pin
Feedback voltage input pin
Figure 2. Pin Configuration(s)
○Product
structure：Silicon monolithic integrated circuit
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© 2012 ROHM Co., Ltd. All rights reserved.
TSZ22111・14・001
○This
product is not designed protection against radioactive rays
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TSZ02201-0F2F0AG00010-1-2
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BU9000xGWZ series
●Block
Diagram(s)
Datasheet
MODE
B1
TSD
FB
VOUT
L
： PWM/PFM
MODE
H
： PWM
MODE
VIN
A1
2.3½5.5V
UVLO
PWM/PFM
control
B3
EN
ERROR COMP
VREF
Switching
Control Logic
and
Gate Driver
B2
1.5½0.47uH
LX
VOUT
4.7½10uF
EN
H
： ON
L
： OFF
A2
SHUTDOWN
Frequency
control
A3
GND
Figure 3. Block Diagram(s)
●Description
of Block(s)
The BU9000xGWZ are a synchronous step-down DC/DC converter that achieves fast transient response from light load to
heavy load by hysteretic PWM control system and current constant PFM control system.
○PWM
control
BU9000xGWZ operates by hysteretic PWM control. This scheme ensures fast switching, high efficiency, and fast transient
response.
When the output voltage is below the VREF voltage, the error comparator output is low to high and turning on P-channel
MOSFET until above the VREF voltage and minimum on time.
○PFM
control
At light load the regulator and MODE=low, the regulator operates with reduced switching frequency and improves the
efficiency.During PFM operation, the output voltage slightly higher than typical output voltage.
Figure 4. Operation of PFM mode and PWM mode
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BU9000xGWZ series
●Description
of operations
1) Shutdown
If the EN input pin set to low (<0.4V), all circuit are shut down and the regulator is standby mode.
Do not leave the EN pin floating.
Datasheet
2) Soft start function
The regulator has a soft start circuit that reduces in-rush current at start-up. Typical start up times with a 4.7uF output
capacitor is 120usec.
3) Current limit
The BU9000xGWZ has a current limit circuit that protects itself and external components during overload condition.
4) UVLO
The BU9000xGWZ has a Under Voltage Lock Out circuit that turn off device when VIN>2.05V(typ.)
5) FORCED PWM MODE
Setting MODE pin high (>1.4V) places the regulator in forced PWM.This control provides noise reduction and output
stability.Do not leave the MODE pin floating.
6) FORCED PFM MODE ( BU90005GWZ)
Setting MODE pin low (<0.4V) places the regulator in forced PFM. It is effective in light load mode.
7) TSD
The BU9000xGWZ has a thermal shutdown feature to protect the device if the junction temperature exceeds 150℃.In
thermal shutdown, the DRIVER is disabled.
This circuit is only to cut off the IC from thermal runaway, and has not been design to protect or guarantee the IC. Therefore,
the user should not plan to activate this circuit with continued operation in mind.
●Absolute
Maximum Ratings
(Ta=25℃)
Parameter
Maximum input power supply voltage
Maximum voltage at EN, FB, LX, MODE
Power dissipation
Operating temperature range
Storage temperature range
Junction temperature
Symbol
VIN
VEN, VFB,
VLX, VMODE
Rating
7
7
0.39(*1)
-40 to +85
-55 to +125
+125
Unit
V
V
W
℃
℃
℃
Pd
Topr
Tstg
Tjmax
(*1) When mounted on the specified PCB (55mm x 63mm), Deducted by 3.9m W/c when used over Ta=25c
●Recommended
Operating Rating(s)
Parameter
Symbol
Rating
Min.
4.0
2.3
Typ.
-
-
Max.
5.5
5.5
Unit
Serise
BU90002GWZ
BU90003½BU90009GWZ
Input voltage
VIN
V
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BU9000xGWZ series
●Electrical
Characteristic(s)
(unless otherwise specified VIN=3.6V, Ta=25℃)
Item
【Switching
regulator】
Output voltage accuracy
VOUTA
IoutMAX1
IoutMAX2
IoutMAX3
IoutMAX4
【Soft
start】
Soft start time
【Frequency
control】
5.4
4.8
Switching frequency
fosc
3.6
3.2
3.8
【Driver】
PchFET on resistance
NchFET on resistance
【Control】
EN pin control
voltage
MODE pin
control voltage
【UVLO】
Protect threshold voltage
Hysteresis
【Current
limit】
Current limit threshold
【Output
discharge】
Output discharge resistance
【Circuit
current】
Uvth
Uvhy
ILIMIT
DRES
1.95
50
1.5
15
2.05
100
1.7
30
2.15
150
1.9
60
V
mV
A
Ohm
Operation
Non Operation
Operation
Non Operation
VENH
VENL
VMODEH
VMODEL
1.4
0
1.4
0
-
-
-
-
VIN
0.4
VIN
0.4
V
V
V
V
Forced PWM
Datasheet
Symbol
Min.
-2
-2
-
-
-
-
Rating
Typ.
-
-
-
-
-
-
Max.
+2
+3
1.0
0.8
0.6
0.1
Unit
Condition
%
A
A
A
A
MODE:H(PWM Operation)
MODE:L(PFM Operation)
3.0V≦VIN＜5.5V
2.7V≦VIN＜3.0V
2.3V≦VIN＜2.7V
MODE:L(PFM Operation)
(BU90005GWZ,)
Maximum load current
Tss
65
55
120
110
6.0
5.4
4.0
3.6
4.3
250
300
220
250
240
220
6.6
6.0
4.4
4.0
4.8
400
450
350
380
usec
usec
MHz
MHz
MHz
MHz
MHz
mOhm
mOhm
mOhm
mOhm
( BU90002GWZ, BU90003GWZ,
BU90004GWZ, BU90005GWZ,
BU90006GWZ, BU90007GWZ,
BU90009GWZ )
( BU90008GWZ )
No load, MODE:H
( BU90002GWZ,BU90005GWZ,
BU90006GWZ)
No load, MODE:H
( BU90004GWZ )
No load, MODE:H
( BU90003GWZ, BU90007GWZ )
No load, MODE:H
( BU90008GWZ )
No load, MODE:H
( BU90009GWZ )
RonP1
RonP2
RonN1
RonN2
-
-
VIN=5.0V
VIN=3.6V
VIN=5.0V
VIN=3.6V
Automatic PFM/PWM
(BU90005GWZ : Forced PFM)
PMOS current detect,
Open loop
EN=0V, FB=0.5V
No load, EN:H, MODE:L,
VOUT=3.6V forced
Not switching
( BU90003GWZ, BU90004GWZ,
BU90005GWZ, BU90007GWZ,
BU90008GWZ, BU90009GWZ )
IINS1
-
45
65
uA
IINS2
Operating quiescent current
IQ1
-
55
80
uA
No load, EN:H, MODE:L,
VOUT=3.6V forced
Not switching
( BU90002GWZ,BU90006GWZ )
-
5.2
-
mA
No load, EN:H, MODE:H,
PWM operation
L:LQM21MPN1R0NG0
( BU90003GWZ )
IQ2
Shutdown current
SHD
-
-
5.6
0
-
1
mA
uA
No load, EN:H, MODE:H,
PWM operation
L:LQM21MPN1R0NG0
( BU90004GWZ )
EN=0V
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BU9000xGWZ series
●Electrical
Characteristic curves (Reference data)
BU90002GWZ (3.3V OUTPUT)
Parts
L:LQM21MPN1R0NG0 (2.0mm×1.6mm×1.0mm Murata)
COUT:GRM155R60J475M(1.0mm×0.5mm×0.5mm Murata)
Datasheet
EN
2V/div
EN
2V/div
VOUT
2V/div
20us
VOUT
2V/div
IL
500mA/div
100us
Figure 5. Start up
Figure 6. Shut down
Vout
50mV/div
ac coupled
Vout
50mV/div
ac coupled
10us
4us
IOUT
50mA/div
IOUT
200mA/div
Figure 7. Load transient response 5mA to 50mA
tr=tf=100ns, MODE : Low
Figure 8. Load transient response 50mA to 350mA
tr=tf=100ns, MODE : Low
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TSZ02201-0F2F0AG00010-1-2
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