3A, 18V, 350kHz , Synchronous Buck Regulator
NR885E
General Descriptions
The NR885E is synchronous buck regulator ICs
integrates High-side and Low-side power MOSFETs.
With the current mode control, ultra low ESR capacitors
such as ceramic capacitors can be used. The ICs have
protection functions such as Over-Current Protection
(OCP), Under-Voltage Lockout (UVLO) and Thermal
Shutdown (TSD). An adjustable Soft-Start by an external
capacitor prevents the excessive inrush current at turn-on
the regulator. The ICs integrate phase compensation
circuit which reduces the number of external components
and simplifies the design of customer application. The
ON/OFF pin (EN Pin) turns the regulator on or off and
helps to achieve low power consumption requirements.
The NR885E is available in an 8-pin SOIC package with
an exposed thermal pad on the back side.
Dec./02/2014
Package
Exposed SOIC 8
Thermally enhanced 8-Pin package
Features & Benefits
Current mode PWM control
Up to 95% efficiency
Stable with low ESR ceramic output capacitors
Built-in protection function
Over Current Protection (OCP)
Thermal Shutdown (TSD)
Under Voltage Lockout (UVLO)
Built-in phase compensation
Adjustable Soft-Start with an external capacitor
Turn ON/OFF the regulator function
Electrical Characteristics
3A output current
Operating input range V
IN
= 4.5V½18V
Output adjustable V
O
= 0.8V½14V
Fixed 350kHz frequency
Applications
LCD TV / Blu-Ray / Set top box
Green Electronic products
Other power supply
Basic Connection of NR885E
NR885E
C1, C2: 10μF / 25V
C4, C5: 22μF / 16V
C9: 0.1μF
C3: 0.1μF
R1: 100kΩ
L1: 10μH
R3: 22Ω
R4: 8.2 kΩ, R5: 4.3kΩ (Vo=3.3V)
R6: 3.9kΩ
Rev.1.1
SANKEN ELECTRIC CO., LTD.
http://www.sanken-ele.co.jp
1
3A, 18V, 350kHz , Synchronous Buck Regulator
NR885E
Series Lineup
Product No.
NR885E
(1)
(2)
Dec./02/2014
f
SW
350kHz
V
IN
4.5V to 18V
(1)
V
O
0.8V to 14V
(2)
I
O
3A
The minimum input voltage shall be either of 4.5V or V
O
+3V, whichever is higher.
The I/O condition limited by the Minimum on-time (T
ON(MIN)
).
Absolute Maximum Ratings
Parameter
DC input voltage
Power dissipation
Junction temperature
Storage temperature
Thermal resistance
(junction- Pin No. 4)
Thermal resistance
(junction-ambient air)
(3)
(4)
(3)
Symbol
V
IN
P
D
T
J
T
S
θ
JP
θ
JA
Ratings
20
1.76
40
to 150
40
to 150
26
71
Units
V
W
°C
°C
°C /W
°C /W
Condition
Glass-epoxy board mounting
in a 30×30mm.
(copper area in a 25×25mm)
Max T
J
=150°C
(4)
Glass-epoxy board mounting
in a 30×30mm.
(copper area in a 25×25mm)
Limited by thermal shutdown.
The temperature detection of thermal shutdown is about 160°C
Recommended Operating Conditions
Parameter
DC input voltage
DC output current
Output voltage
(5)
(6)
(7)
Symbol
V
IN
Io
Vo
Ratings
MIN
Vo+3
0
0.8
MAX
18
3.0
14
Units
V
A
V
Condition
(7)
Ambient operating temperature
Top
85
°C
40
(5)
The minimum value of input voltage is taken as the larger one of either 4.5V or V
O
+3V.
In the case of V
IN
=V
O
+1½V
O
+3V , it is set to I
O
= Max. 2A
(6)
Recommended circuit refers to Typical Application Circuit.
(7)
To be used within the allowable package power dissipation characteristics.
Rev.1.1
SANKEN ELECTRIC CO., LTD.
http://www.sanken-ele.co.jp
2
3A, 18V, 350kHz , Synchronous Buck Regulator
NR885E
Electrical Characteristics
Parameter
Reference voltage
Output voltage temperature
coefficient
Switching frequency
Line regulation
Load regulation
Over current protection
threshold
Supply Current
Shutdown Supply Current
Source current
at low level
voltage
High level
voltage
Sink current
Threshold voltage
(8)
(8)
(8)
Dec./02/2014
Ta = 25°C
Symbol
V
REF
⊿V
REF
/⊿T
f
SW
V
Line
V
Load
I
S
I
IN
I
IN(off)
I
EN/SS
V
SSH
I
EN
V
C/EH
D
MAX
T
ON(MIN)
0.7
―
―
151
―
Ratings
MIN
0.784
―
280
―
―
3.1
―
0
6
―
TYP
0.800
±0.05
350
50
50
―
6
―
10
3.0
50
1.4
90
150
165
20
MAX
0.816
―
420
―
―
6.0
―
10
14
―
100
2.1
―
―
―
―
Units
V
Test conditions
(8)
V
IN
= 12V，I
O
= 1.0A
V = 12V, I
O
= 1.0A
mV/°C
IN
40°C
to +85°C
V
IN
=12V, V
O
=3.3V,
kHz
I
O
=1A
V
IN
= 6.3V½18V,
mV
V
O
= 3.3V, I
O
= 1A
V
IN
= 12V, V
O
= 3.3V,
mV
I
O
= 0.1A½3.0A
A
mA
μA
μA
V
μA
V
%
nsec
°C
°C
V
IN
= 12V, V
O
= 3.3V
V
IN
= 12V
V
EN
=10kΩ pull up to V
IN
V
IN
=12V, I
O
=0A,
V
EN
=0V
V
SS
=0V, V
IN
=12V
V
IN
=12V
V
EN
= 10V
V
IN
=12V
SS Pin
EN Pin
Max on-duty
Minimum on-time
(9)
Thermal shutdown threshold
(8)
TSD
temperature
Thermal shutdown
(8)
restart hysteresis
TSD_hys
of temperature
(8)
Guaranteed by design, not tested.
(9)
The I/O characteristic are limited by the T
ON(MIN)
.
Rev.1.1
SANKEN ELECTRIC CO., LTD.
http://www.sanken-ele.co.jp
3
3A, 18V, 350kHz , Synchronous Buck Regulator
NR885E
Typical Performance Characteristics
NR885E Typical Performance Characteristics
Efficiency
効率(Vo=1.8V)
V
O
=1.8V
Dec./02/2014
Efficiency [%]
EFF(%)
100
90
80
70
60
50
40
30
20
10
0
0
0.5
V
IN
=5V
6V
8V
10V
12V
15V
18V
1
1.5
2
2.5
3
Output Current: I
O
[A]
NR880K ES1 HSOP8 S1 RT(Vo=3.3V)
V
O
=3.3V
3.5
Io(A)
Efficiency [%]
EFF(%)
100
90
80
70
60
50
40
30
20
10
0
0
V
IN
=6V
8V
10V
12V
15V
18V
0.5
1
1.5
2
2.5
3
Io(A)
3.5
Output Current: I
O
[A]
Efficiency[%]
Efficiency [%]
V
O
=5V
Vo=5V
100
90
80
70
60
50
40
30
20
10
0
0.0
V
IN
=8V
10V
12V
15V
18V
0.5
1.0
2.5
3.0
3.5
Output Current: I
O
[A]
負荷電流Io[A]
1.5
2.0
Efficiency[%]
Efficiency [%]
V
O
=12V
Vo=12V
100
90
80
70
60
50
40
30
20
10
0
0.0
V
IN
=14V
15V
18V
0.5
1.0
1.5
2.0
2.5
Output Current: I
O
[A]
3.0
3.5
負荷電流Io[A]
Rev.1.1
SANKEN ELECTRIC CO., LTD.
http://www.sanken-ele.co.jp
4
3A, 18V, 350kHz , Synchronous Buck Regulator
NR885E
NR885E Typical Performance Characteristics
Output startup
V
O
=3.3V, Load = Constant Resistance
出力電圧Vo
Output Voltage
[V]
[V]
Dec./02/2014
Over Current Protection
Vo=3.3V
V
O
=3.3V
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Output Voltage
[V]
I
o
= 0A
0.5A
1A
2A
3A
V
IN
= 8V
10V
12V
15V
18V
Input Voltage
V
IN
[V]
Output Current I
O
[A]
出力電流Io [A]
Load Regulation:
V
Load
½(kHz)
Switching Frequency {kHz}
NR880K ES1
V =3.3V
HSOP8 S1 RT(Vo=3.3V)
O
Switching Frequency:
f
SW
NR880K ES1 HSOP8 S1 RT(Vo=3.3V)
Vo(V)
Output Voltage
[V]
V
O
=3.3V
3.35
3.33
3.31
3.29
3.27
3.25
0
0.5
1
1.5
2
2.5
V
IN
= 6V
8V
10V
12V
15V
18V
400
390
380
370
360
350
340
330
320
310
300
0
0.5
1
1.5
2
V
IN
= 6V
8V
10V
12V
15V
18V
2.5
3
3.5
Io(A)
3
Output Current I
O
[A]
3.5
Io(A)
Output Current I
O
[A]
Shutdown Supply Current :
I
IN(off)
NR880K ES1 DIP28 S1
=0V
vs VIN at RT
V
Iqoff
EN
A)
Supply Current :
I
IN
Io=0A
V
O
=3.3V
7
無負荷時動½電流Iq [mA ]
EN:Open
10
9
8
7
6
5
4
3
2
1
0
0
2
4
6
8
10
12
14
16
Iqoff(
Current
[μA]
μ
6
5
4
3
2
1
0
Input Voltage V
IN
[V]
18
20
VIN(V)
Current
[mA]
0
2
4
6
8
10
12
14
16
18
入力電圧Vin [V]
Input Voltage V
IN
[V]
Rev.1.1
SANKEN ELECTRIC CO., LTD.
http://www.sanken-ele.co.jp
5
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