RT9027A [RICHTEK]
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| 型号： | RT9027A |
| 厂家： | 
RICHTEK TECHNOLOGY CORPORATION |
| 描述： | 暂无描述 |
| 文件： | 总12页 (文件大小：235K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
RT9027A/B
Linear Fan Driver
General Description
Features
z VOUT Follows 1.6 Times of VSET
The RT9027A/B is a high performance positive voltage
regulator designed for very low dropout voltage up to 0.5
Amps. TheVSET voltage must be larger than 1Vto guarantee
that VOUT is 1.6 times of VSET. When VSET is less than 1V,
the IC will be shutdown. The FON pin turns VOUT to fully-
on when FON is given low. For RT9027B (EN version),
FON pin is equivalent to EN pin. The RT9027A/B provides
excellent regulation over variations in line, load and
temperature. The RT9027A/B is available in the SOP-8
package.
z 150mV Dropout @ 0.5A
z Over Current and Over Temperature Protection
z FON Pin Turns VOUT Fully On
z RoHS Compliant and 100% Lead (Pb)-Free
Applications
z Notebook Computer FanDriver
z Battery Powered System
z Motherboard
z Peripheral Card
Ordering Information
RT9027
Pin Configurations
Package Type
S : SOP-8
(TOP VIEW)
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
FON
VIN
GND
GND
GND
GND
8
7
6
5
2
3
4
VOUT
VSET
A : FON Function
B : EN Function
RT9027A
Note :
EN
VIN
GND
GND
GND
GND
8
Richtek products are :
2
3
4
7
6
5
` RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
` Suitable for use in SnPb or Pb-free soldering processes.
VOUT
VSET
RT9027B
SOP-8
Typical Application Circuit
3
2
V
VIN
IN
V
VOUT
GND
OUT
C
2.2uF
C
2.2uF
IN
OUT
RT9027A/B
4
1
VSET
V
SET
5 to 8
FON/EN
FON/EN
DS9027A/B-02 April 2011
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1
RT9027A/B
Functional Pin Description
Pin No. Pin Name
Pin Function
Internal pulled high. For RT9027A, the IC will be fully turned on when this pin’s voltage is
below 0.4V.
Internal pulled high. For RT9027B, the IC will be shutdown when this pin’s voltage is
below 0.4V.
FON
EN
1
2
3
VIN
Input Voltage Pin.
Output Voltage Pin.
VOUT
This pin is used for output voltage setting. It is necessary to make this pin higher than 1V
to guarantee VOUT to be 1.6 times of VSET. The IC will be shutdown when this pin voltage
is below 1V.
4
VSET
GND
5 to 8
Ground.
Function Block Diagram
VIN
BIAS+Thermal
Shutdown
V
IN
POR
V
POR
SET
VSET
(Enable)
OCP
-
EA
+
VOUT
Logic
FON/EN
GND
0.6
1
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DS9027A/B-02 April 2011
RT9027A/B
Absolute Maximum Ratings (Note 1)
z Supply Input Voltage, VIN ---------------------------------------------------------------------------------------------- 6V
z EN, FON, VSET Voltage ----------------------------------------------------------------------------------------------- 6V
z PowerDissipation, PD @ TA = 25°C
SOP-8 ---------------------------------------------------------------------------------------------------------------------- 1.053W
z Package Thermal Resistance (Note 2)
SOP-8, θJA ----------------------------------------------------------------------------------------------------------------- 95°C/W
z Lead Temperature (Soldering, 10 sec.) ----------------------------------------------------------------------------- 260°C
z Junction Temperature --------------------------------------------------------------------------------------------------- 150°C
z StorageTemperature Range ------------------------------------------------------------------------------------------- −65°C to 150°C
z ESD Susceptibility (Note 3)
HBM ------------------------------------------------------------------------------------------------------------------------ 2kV
MM -------------------------------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions (Note 4)
z Supply Input Voltage, VIN ---------------------------------------------------------------------------------------------- 4.5V to 5.5V
z Junction Temperature Range ------------------------------------------------------------------------------------------ −40°C to 125°C
z Ambient Temperature Range ------------------------------------------------------------------------------------------ −40°C to 85°C
Electrical Characteristics
(VSET = 2V, VIN = 5V, IOUT = 0.5A, CIN = COUT = 2.2uF, TA = 25°C, unless otherwise specified)
Parameter
Input Voltage
Symbol
Test Conditions
Min
Typ
Max
Unit
Input Voltage Range
Quiescent Current
V
4.5
--
--
5.5
--
V
IN
I
Q
I
= 0A
300
10
uA
OUT
RT9027A
RT9027B
V
= 0V
--
---
--
SET
Shutdown
Current
I
uA
SHDN
V
= 0V
--
10
EN
Output Voltage
V
/V
1.552
1.6
0.2
0.2
1.648
0.5
V
OUT SET
Line Regulation
Load Regulation
ΔVLINE
--
--
%
ΔVLOAD
0.8
I
= 0.5A, V = 5V, V
= 3.3V
--
1.6
--
0.15
2
0.3
3.5
--
Ω
A
A
R
OUT
IN
SET
ON
Current Limit
Short Current
I
LIM
I
SC
1.1
2.5
0.7
0.8
0.1
V
V
V
V
UVLO Threshold
Rising
Rising
--
--
IN
V
V
UVLO Hysteresis
--
--
IN
UVLO Threshold
UVLO Hysteresis
--
--
SET
SET
--
--
To be continued
DS9027A/B-02 April 2011
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3
RT9027A/B
Parameter
Symbol
Test Conditions
Min
Typ
Max
Unit
FON Function (RT9027A)
Logic-Low Voltage
--
1.6
--
--
--
0.4
--
V
V
FON Threshold
Logic-High Voltage
VFON = 0
1.5
15
uA
FON Bias Pin Current
EN Function (RT9027B)
Logic-Low Voltage VIL
Logic-High Voltage VIH
--
1.6
--
--
--
0.4
--
V
V
EN Threshold
EN Bias Pin Current
IEN
VEN = 0
10
15
uA
Over Temperature Protection
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
TSD
--
--
140
30
--
--
°C
°C
Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for
stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational
sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may
remain possibility to affect device reliability.
Note 2. θJA is measured in the natural convection at TA = 25°C on a high effective four layers thermal conductivity test board of
JEDEC 51-7 thermal measurement standard.
Note 3. Devices are ESD sensitive. Handling precaution is recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
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DS9027A/B-02 April 2011
RT9027A/B
Typical Operating Characteristics
Output Voltage vs. VSET Voltage
Output Voltage vs. Output Current
6
1.615
1.610
1.605
1.600
1.595
1.590
1.585
1.580
1.575
5
4
IOUT = 0A
IOUT = 0.5A
3
2
1
0
VSET = 1V
0.8
1
1.2 1.4 1.6 1.8
2
2.2 2.4 2.6 2.8
3
3.2
0
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Output Current (A)
VSET Voltage (V)
Output Voltage vs. Output Current
Output Voltage vs. Output Current
3.220
3.215
3.210
3.205
3.200
3.195
3.190
3.185
3.180
4.815
4.810
4.805
4.800
4.795
4.790
4.785
4.780
4.775
VSET = 2V
VSET = 3V
0
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Output Current (A)
0
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Output Current (A)
Output Voltage vs. Input Voltage
Output Voltage vs. Input Voltage
1.600
1.599
1.598
1.597
1.596
1.595
1.594
1.593
1.592
1.591
1.590
3.210
3.208
3.206
3.204
3.202
3.200
3.198
3.196
3.194
3.192
3.190
IOUT = 0.5A
IOUT = 0A
IOUT = 0.5A
IOUT = 0A
VSET = 1V
VSET = 2V
4.5 4.6 4.7 4.8 4.9
5
5.1 5.2 5.3 5.4 5.5
4.5 4.6 4.7 4.8 4.9
5
5.1 5.2 5.3 5.4 5.5
Input Voltage (V)
Input Voltage (V)
DS9027A/B-02 April 2011
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5
RT9027A/B
Output Voltage vs. Temperature
Output Voltage vs. Temperature
1.64
1.63
1.62
1.61
1.60
1.59
1.58
1.57
1.56
3.24
3.23
3.22
3.21
3.20
3.19
3.18
3.17
3.16
VSET = 1V, IOUT = 0A
75 100 125
VSET = 2V, IOUT = 0A
-50
-25
0
25
50
-50
-25
0
25
50
75
100
125
(°C)
(°C)
Temperature
Temperature
Output Voltage vs. Temperature
VIN UVLO Threshold vs. Temperature
4.83
4.82
4.81
4.80
4.79
4.78
4.77
4.76
4.75
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Rising
Falling
VSET = 3V, IOUT = 0A
50 75 100 125
-50
-25
0
25
-50
-25
0
25
50
75
100
125
Temperature (°C)
(°C)
Temperature
VSET Threshold vs. Temperature
EN Threshold vs. Temperature
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
Rising
Falling
Rising
Falling
-50
-25
0
25
50
75
100
125
-50
-25
0
25
50
75
100
125
(°C)
Temperature
Temperature (°C)
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DS9027A/B-02 April 2011
RT9027A/B
Current Limit vs. VSET Voltage
Dropout Voltage vs. Output Current
120
100
80
60
40
20
0
2.4
2.3
2.2
2.1
2.0
1.9
1.8
1.7
1.6
125°C
85°C
25°C
-40°C
0
50 100 150 200 250 300 350 400 450 500
Output Current (mA)
0.8
1
1.2 1.4 1.6 1.8
2
2.2 2.4 2.6 2.8
3
3.2
VSET Voltage (V)
Quiescent Current vs. Input Voltage
Current Limit vs. Temperature
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
400
380
360
340
320
300
280
260
240
220
200
VSET = 1V
VSET = 2V
VOUT = 3.2V
VOUT = 1.6V
-50
-25
0
25
50
75
100
125
4.5 4.6 4.7 4.8 4.9
5
5.1 5.2 5.3 5.4 5.5
(°C)
Temperature
Input Voltage (V)
Quiescent Current vs. Temperature
Shutdown Current vs. Input Voltage
350
330
310
290
270
250
230
210
190
170
150
15
14
13
12
11
10
9
VSET = 1V
VSET = 2V
VOUT = 3.2V
VOUT = 1.6V
8
7
6
EN = 0V
5
-50
-25
0
25
50
75
100
125
4.5 4.6 4.7 4.8 4.9
5
5.1 5.2 5.3 5.4 5.5
Temperature
(°C)
Input Voltage (V)
DS9027A/B-02 April 2011
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RT9027A/B
Shutdown Current vs. Temperature
Start Up for EN
15
14
13
12
11
10
9
VIN
(5V/Div)
VSET = 1V
VSET = 2V
VEN
(5V/Div)
VOUT
(1V/Div)
8
7
IOUT
VSET = 1V, VIN = VEN = 5V
VOUT = 1.6V, IOUT = 500mA
(0.5A/Div)
6
EN = 0V
100 125
5
-50
-25
0
25
50
75
Time (5us/Div)
Temperature
(°C)
Start Up from VIN
Start Up from VSET
VIN
(5V/Div)
VIN
(5V/Div)
VSET
(1V/Div)
VOUT
(1V/Div)
VOUT
(1V/Div)
IOUT
(0.5A/Div)
IOUT
(0.5A/Div)
VSET = 1V, VIN = VEN = 5V
VOUT = 1.6V, IOUT = 500mA
VSET = 1V, VIN = VEN = 5V
VOUT = 1.6V, IOUT = 500mA
Time (2.5ms/Div)
Time (50us/Div)
Short-Circuit Protection
Short-Circuit Protection
VOUT
VOUT
(2V/Div)
(2V/Div)
IOUT
(0.5A/Div)
IOUT
(1A/Div)
VSET = 1V, VIN = VEN = 5V
VOUT = 1.6V
VSET = 2V, VIN = VEN = 5V
VOUT = 3.2V
Time (1ms/Div)
Time (1ms/Div)
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DS9027A/B-02 April 2011
RT9027A/B
Line Transient Response
Line Transient Response
VSET = 1V, VEN = 5V, VOUT = 1.6V, IOUT = 10mA
VSET = 1V, VEN = 5V, VOUT = 1.6V, IOUT = 500mA
5.5
4.5
5.5
4.5
VIN
(V)
VIN
(V)
VOUT
VOUT
(10mV/Div)
(10mV/Div)
Time (100us/Div)
Time (100us/Div)
Line Transient Response
Line Transient Response
VSET = 2V, VEN = 5V, VOUT = 3.2V, IOUT = 10mA
VSET = 2V, VEN = 5V, VOUT = 3.2V, IOUT = 500mA
5.5
VIN
5.5
VIN
(V)
(V)
4.5
4.5
VOUT
VOUT
(10mV/Div)
(10mV/Div)
Time (100us/Div)
Time (100us/Div)
Load Transient Response
Load Transient Response
VSET = 2V, VIN = VEN = 5V, VOUT = 3.2V
IOUT = 50mA to 0.5A
VSET = 1V, VIN = VEN = 5V, VOUT = 1.6V
IOUT = 50mA to 0.5A
VOUT
(10mV/Div)
VOUT
(10mV/Div)
IOUT
(0.5A/Div)
IOUT
(0.5A/Div)
Time (250us/Div)
Time (250us/Div)
DS9027A/B-02 April 2011
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9
RT9027A/B
Application Information
Output Voltage Setting
Thermal Shutdown Protection
The output voltage of RT9027AB is adjustable from 1.6V
to VIN by VSET voltage. It is set by internal voltage divider
resisters shown in function block diagram. The VOUT
voltage level is set as 1.6 times of VSET voltage level
when VSET is higher than 1V. When VSET is less than
0.8V, the IC will be shutdown.
RT9027AB over temperature protection function limits
power dissipation to prevent this die from over temperature
damage. When the RT9027B operation junction
temperature exceeds 140°C, the over temperature
protection circuit starts the thermal shutdown function
and turns the pass transistor off. The pass transistor turns
on again after the junction temperature cools by 30°C.
For RT9027A, it lowers its OTP trip level to 110°C. It limits
IC case temperature under 100°C and provides maximum
safety to customer while output short circuit occurring.
Fully Turn On and Enable Logic Function
For RT9027A, pin1 named FON features fully turn on
function. When the FON pin is in logic low level, the IC
goes into fully turn on mode. During this condition, the
pass transistor will be fully turned on. The FON pin is
pulled to high level internally. For the enable function, it is
acceptable to use the VSET pin to control the IC. When
the VSET pin is in logic low level (<0.8V), the IC will be
shutdown.
Thermal Considerations
For continuous operation, do not exceed absolute
maximum operation junction temperature 125°C. The
power dissipation definition in device is:
PD = (VIN − VOUT) x IOUT + VIN x IQ
For RT9027B, there is an ENpin for power on/off control.
When the EN pin is in logic low level, the IC will be
shutdown.During this condition, the pass transistor, error
amplifier, and band gap are turned off, reducing the supply
current to 10uA typical. The IC goes into operation mode
when the EN pin is in logic high level condition. The EN
pin is pulled to high level internally.
The maximum power dissipation depends on the thermal
resistance of IC package, PCB layout, the rate of
surroundings airflow and temperature difference between
junction to ambient. The maximum power dissipation can
be calculated by following formula :
P
D(MAX) = (TJ(MAX) − TA) / θJA
Where TJ(MAX) is the maximum operation junction
temperature 125°C, TA is the ambient temperature and the
θJA is the junction to ambient thermal resistance. For
recommended operating conditions specification of
RT9027A/B, where TJ(MAX) is the maximum junction
temperature of the die (125°C) and TA is the maximum
ambient temperature.
Capacitor Selection
Good bypassing is recommended from input to ground to
improve the AC performance. A 2.2uF input ceramic
capacitor or greater located as close as possible to the IC
is recommended. The RT9027AB is specifically designed
to use ceramic output capacitors as low as 2.2uF. The
ceramic capacitors offer significant cost and space savings,
along with high frequency noise filtering.
Since the multiple GND pins of the SOP-8 package are
internally shorted and connected to lead frame, it is efficient
to dissipate the heat by adding copper area on GND
footprint. Figure 1 shows the relation about thermal
resistance θJA vs. copper area on a standard JEDEC 51-
7 (4 layer, 2S2P) thermal test board at TA = 25°C. For
example, with 10mm x 10mm copper area PCB, we can
obtain the lower thermal resistance about 45°C/W.
Current Limit and Short Circuit Protection
The RT9027A contains an independent current limit and
short circuit current protection to prevent the IC from
damaging in unexpected applications. The current limit
monitors and controls the pass transistor’ s gate voltage,
limiting the output current to a certain level (2A typ.). When
the output voltage is less than 0.4V, the short circuit current
protection starts the current fold back function and limits
the output current at 0.8A (typ.).
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DS9027A/B-02 April 2011
RT9027A/B
The maximum power dissipation at TA = 25°C can be
calculated by following formula :
PD(MAX) = (125°C − 25°C) / 45°C/W = 2.22W for SOP-8
package
100
90
80
70
60
50
40
30
20
10
0
0
20
40
60
80
100
Copper Area (mm2)
Figure 1
The maximum power dissipation depends on operating
ambient temperature for fixedTJ(MAX) and thermal resistance
θJA . For RT9027AB packages, the Figure 2 of de-rating
curves allows the designer to see the effect of rising
ambient temperature on the maximum power allowed.
2.4
JEDEC 4-layers PCB
100mm2
2.2
50mm2
2
1.8
25mm2
1.6
1.4
15mm2
1.2
1
min. layout
0.8
0.6
0.4
0.2
0
0
25
50
75
100
125
(°C)
Ambiemt Temperature
Figure 2.De-rating Curves for RT9027AB Package
DS9027A/B-02 April 2011
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11
RT9027A/B
Outline Dimension
H
A
M
J
B
F
C
I
D
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
B
C
D
F
H
I
4.801
3.810
1.346
0.330
1.194
0.170
0.050
5.791
0.400
5.004
3.988
1.753
0.508
1.346
0.254
0.254
6.200
1.270
0.189
0.150
0.053
0.013
0.047
0.007
0.002
0.228
0.016
0.197
0.157
0.069
0.020
0.053
0.010
0.010
0.244
0.050
J
M
8-Lead SOP Plastic Package
Richtek Technology Corporation
Headquarter
Richtek Technology Corporation
Taipei Office (Marketing)
5F, No. 20, Taiyuen Street, Chupei City
Hsinchu, Taiwan, R.O.C.
5F, No. 95, Minchiuan Road, Hsintien City
Taipei County, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Tel: (8862)86672399 Fax: (8862)86672377
Email: marketing@richtek.com
Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit design,
specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be guaranteed
by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek.
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12
DS9027A/B-02 April 2011
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