RT9185B [ETC]
SHDN. EN. BP. FTR and POK2 ; SHDN 。 EN 。 BP 。 FTR和POK2\n
| 型号： | RT9185B |
| 厂家： | 
ETC |
| 描述： | SHDN. EN. BP. FTR and POK2
|
| 文件： | 总16页 (文件大小：349K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
RT9185
Triple, Ultra-Fast CMOS LDO Regulator
General Description
Features
ꢁ Fixed Output Voltages: 3.35V at 1.5A, 2.55V at
The RT9185 series are an efficient, precise triple-
channel CMOS LDO regulator specifically designed
for mother-board application. The device is intended
to powering the standby voltage in which 3.3V_PCI,
2.5V_Clock and 1.8V_ICH2 or 1.5V_ICH4 core
voltage of the PC based computer system.
Moreover, it is also optimized for CD/DVD-ROM,
CD/RW, XDSL Router or IA equipments applications.
The regulator outputs are capable of sourcing 1.5A,
0.8A and 0.3A of output current respectively.
0.8A and 1.5V or 1.8V at 0.3A
ꢁ Low Quiescent Current (Typically 0.4mA)
ꢁ Operating Voltage Ranges: 3.5V~5.5V
ꢁ Ultra-Fast Transient Response
ꢁ Tight Load and Line Regulation
ꢁ Current Limiting Protection
ꢁ Thermal Shutdown Protection
ꢁ Only low-ESR Ceramic Capacitors Required
for Stability
ꢁ Custom Voltage Available
The RT9185 also works with low-ESR ceramic
capacitors, reducing the amount of board space
necessary for power applications. The other features
include faster transient response, low dropout voltage,
high output accuracy, current limiting and thermal
shutdown protections.
Applications
ꢁ Mother-board Power Supply
ꢁ CD/DVD-ROM, CD/RW
ꢁ XDSL Router
ꢁ IA Equipments
ꢁ Cable Modems
The RT9185 regulators are available in fused SOP-8,
5-lead TO-252 and 5-lead TO-263 packages.
Pin Configurations
Part Number
Pin Configurations
Ordering Information
RT9185 ꢀꢀꢀꢀ
RT9185ꢀCS
(Plastic SOP-8)
Package Type
GND
GND
1
2
8
7
VOUT1
VDD
S : SOP-8
L5 : TO-252-5
M5 : TO-263-5
VOUT2
VOUT3
3
4
6
5
GND
GND
Operating Temperature Range
C: Commercial Standard
TOP VIEW
1. VOUT1
2. VDD
3. GND (TAB)
4. VOUT2
5. VOUT3
RT9185ꢀCL5
(Plastic TO-252-5)
VOUT3
A : 1.8V
B : 1.5V
Other voltage versions please
contact RichTek for detail.
1
2
3
4
5
TOP VIEW
1. VOUT1
2. VDD
RT9185ꢀCM5
(Plastic TO-263-5)
3. GND (TAB)
4. VOUT2
5. VOUT3
1 2
3 4 5
DS9185-02 July 2003
www.richtek.com
1
RT9185
Typical Application Circuit
V
V
(1.5V or 1.8V / 0.3A)
(2.55V / 0.8A)
V
(3.35V / 1.5A)
VOUT1
VOUT3
VOUT2
OUT3
OUT1
C4
1µF
C2
4.7µF
RT9185
V
(5VSB)
VDD
OUT2
DD
GND
C1
2.2µF
C3
4.7µF
Pin Description
Pin Name
VOUT1
VDD
Pin Function
Channel 1 Output Voltage
Supply Input
GND
Common Ground
VOUT2
VOUT3
Channel 2 Output Voltage
Channel 3 Output Voltage
Function Block Diagram
Current
VDD
Limiting
+
_
Thermal
Sensor
_
+
VOUT1
Error Amp
Reference
Current
Limiting
Current
VDD
VDD
Limiting
+
+
_
_
_
_
+
+
VOUT3
GND
VOUT2
Error Amp
Error Amp
www.richtek.com
DS9185-02 July 2003
2
RT9185
Absolute Maximum Ratings (Note 1)
ꢁ Supply Input Voltage
7V
ꢁ Package Thermal Resistance
SOP-8, θ
20°C/W
10°C/W
5.5°C/W
260°C
150°C
JC
TO-252-5, θ
JC
TO-263-5, θ
JC
ꢁ Lead Temperature (Soldering, 10 sec.)
ꢁ Junction Temperature
ꢁ Storage Temperature Range
ꢁ ESD Susceptibility (Note 2)
HBM
−65°C to 150°C
2kV
MM
200V
Recommended Operating Conditions (Note 3)
ꢁ Supply Input Voltage
3.5V to 5.5V
ꢁ Junction Temperature Range
−40°C to 125°C
Electrical Characteristics
(VDD = 5V, CIN = 1µF, TA = 25°C, for each LDO unless otherwise specified)
Parameter
Symbol
Test Conditions
Min
Typ
Max Units
VOUT1
IOUT = 1mA
3.315 3.35 3.415
VOUT2
IOUT = 1mA
RT9185A
RT9185B
2.525 2.55
2.60
1.836
1.530
--
Output Voltage Accuracy
V
1.782
1.485
1.5
1.8
1.5
1.9
VOUT3
IOUT = 1mA
ILIM1
ILIM2
ILIM3
R
R
R
LOAD = 1Ω
LOAD = 1Ω
LOAD = 1Ω
0.8
0.3
1.3
0.5
--
--
Current Limiting
A
Quiescent Current (triple LDOs)
(Note 5)
IDD
IOUT = 0mA
--
0.4
0.8
mA
∆VDROP1 IOUT = 1.0A
∆VDROP2 IOUT = 0.8A
--
--
600
700
1085 mV
Dropout Voltage
--
mV
mV
Line Regulation (triple LDOs)
IOUT = 1mA, VDD = 4V to 6V
VOUT1, 1mA < IOUT <1.0A
VOUT2, 1mA < IOUT <0.8A
VOUT3, 1mA < IOUT < 0.3A
∆VLINE
--
--
2
10
55
55
45
--
∆VLOAD1
∆VLOAD2
30
30
Load Regulation (Note 4)
--
mV
--
∆VLOAD3
TC
20
30
Temperature Coefficient
Thermal Shutdown
--
PPM
TSD
125
165
--
°C
DS9185-02 July 2003
www.richtek.com
3
RT9185
Note 1. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device.
These are stress ratings only, and 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 affect device reliability.
Note 2. Devices are ESD sensitive. Handling precaution recommended. The human body model is a 100pF capacitor
discharged through a 1.5KΩ resistor into each pin.
Note 3. The device is not guaranteed to function outside its operating conditions.
Note 4. Regulation is measured at constant junction temperature by using a 20mS current pulse. Devices are tested for load
regulation in the load range from 1mA to 1.5A, 0.8A and 0.3A for each LDO respectively.
Note 5. Quiescent, or ground current, is the difference between input and output currents. It is defined by IQ = IIN – IOUT
under no load condition (IOUT = 0mA). The total current drawn from the supply is the sum of the load current plus the
ground pin current.
www.richtek.com
4
DS9185-02 July 2003
RT9185
Typical Operating Characteristics
Quiescent Current
Temperature Stability
600
500
400
300
200
4.2
VDD = 5V
3.8
VOUT1 = 3.3V
VOUT2
3.4
VOUT1
3
VOUT2 = 2.5V
VOUT3
2.6
2.2
VOUT3 = 1.8V/1.5V
1.8
1.4
-40
-15
5
25
45
65
85
105 125
-40
-15
5
25
45
65
85
105 125
Temperature °
Temperature ( C)
°C
Current Limit vs. Temperature
PSRR
-10
-20
-30
-40
-50
-60
-70
-80
2.5
TA=25°C
VDD = 5V
VDD = 5V
VOUT1
VOUT2
C1 =2.2µF, C2 = 4.7µF
C3 =4.7µF, C4 = 1µF
IO1, IO2, IO3 = 10mA
2
1.5
1
VOUT3
VOUT2
VOUT3
0.5
VOUT1
0
-35
-40
10
10
100
100
1K
1000
Frequency (Hz)
10K
10000
100K
1M
100000 10000
-15
5
25
45
65
85
105 125
(°C)
Temperature
Dropout Valtage vs. Temperature
VDD = 5V
Short Thermal Shutdown
1
0.8
0.6
0.4
0.2
VDD = 5V
C1 = 2.2µF
3
2.5
2
TA = 25°C
VOUT2 = 2.5V
VOUT1 = 3.3V
1.5
1
0.5
0
-35
-40
-15
5
25
45
65
85
105 125
Time 25mS/Div
(°C)
Temperature
DS9185-02 July 2003
www.richtek.com
5
RT9185
Load Transient Response
Load Transient Response
C = 2.2µF
3
C = 2.2µF
2
V
= 5V
OUT2
V
= 5V
OUT1
1
1
DD
DD
C = 4.7µF
C = 4.7µF
100 V
= 2.5V
100 V
= 3.3V
T = 25°C
A
T = 25°C
A
50
50
0
0
-50
-50
≈
≈
≈
≈
≈
≈
1
0
1
0
Time 500µS/Div
Time 500µS/Div
Line Transient Response
Load Transient Response
C = 2.2µF
V
V
A
= 4.5V to 5.5V
= 3.3V
OUT1
C =2.2µF
4
1
V
=5V
OUT3
DD
1
DD
C = 4.7µF
C =1µF
2
10
5
100 V
=1.5V
I
= 500mA
T = 25°C
OUT1
T =25°C
A
50
0
0
-5
-50
≈
≈
≈
400
200
0
5.5
4.5
Time 100µS/Div
Time 500µS/Div
Line Transient Response
Line Transient Response
C = 2.2µF
C = 4.7µF
OUT1
C = 2.2µF
V
V
A
= 4.5V to 5.5V
= 2.5V
V
V
= 4.5V to 5.5V
= 1.5V
OUT1
1
3
1
DD
OUT2
T = 25°C
DD
C = 4.7µF
4
20
10
20
10
I
= 400mA
I
= 150mA
T = 25°C
OUT1
A
0
0
-10
-10
≈
≈
≈
5.5
4.5
5.5
4.5
Time 100µS/Div
Time 100µS/Div
www.richtek.com
6
DS9185-02 July 2003
RT9185
Power Dissipation vs. Copper Area
Power Dissipation vs. Copper Area
500
400
300
200
100
0
500
400
300
200
100
0
TJ = 125°C
TJ = 125°C
TA = 25°C
TA = 50°C
TA = 25°C
TO-252
TA = 65°C
TA = 50°C
TA = 65°C
2.5
SOP-8
1
1.5
2
2.5
3
2
3
3.5
4
4.5
5
Power Dissipation (W)
Power Dissipation (W)
Power Dissipation vs. Copper Area
300
250
200
150
100
TJ = 125°C
TA = 65°C
TA = 50°C
TA = 25°C
TO-263-5
7.5
2.5
3.5
4.5
5.5
6.5
8.5
Power Dissipation (W)
DS9185-02 July 2003
www.richtek.com
7
RT9185
Applications Information
Like any low-dropout regulator, the RT9185 requires
input and output decoupling capacitors. The device is
specifically designed for portable applications
requiring minimum board space and smallest
components. These capacitors must be correctly
selected for good performance (see Capacitor
Characteristics Section). Please note that linear
regulators with a low dropout voltage have high
internal loop gains which require care in guarding
against oscillation caused by insufficient decoupling
capacitance.
The output capacitor’s ESR is critical because it
forms a zero to provide phase lead which is required
for loop stability.
NO LOAD STABILITY
The device will remain stable and in regulation with
no external load. This is specially important in CMOS
RAM keep-alive applications.
INPUT-OUTPUT (DROPOUT) VOLTAGE
A
regulator’s minimum input-to-output voltage
differential (dropout voltage) determines the lowest
usable supply voltage. In battery-powered systems,
this determines the useful end-of-life battery voltage.
Because the device uses a PMOS, its dropout
voltage is a function of drain-to-source on-resistance,
INPUT CAPACITOR
An input capacitance of ≅2.2µF is required between
the device input pin and ground directly (the amount
of the capacitance may be increased without limit).
The input capacitor MUST be located less than 1 cm
from the device to assure input stability (see PCB
Layout Section). A lower ESR capacitor allows the
use of less capacitance, while higher ESR type (like
aluminum electrolytic) require more capacitance.
R
DS(ON), multiplied by the load current:
VDROUPOUT = VDD – VOUT = RDS(ON) × IOUT
CURRENT LIMIT
The RT9185 monitors and controls the PMOS’ gate
voltage, limiting the output current to 1.9A, 1.3A and
0.5A (typ) respectively. The outputs can be shorted
to ground for an indefinite period of time without
damaging the part.
Capacitor types (aluminum, ceramic and tantalum)
can be mixed in parallel, but the total equivalent input
capacitance/ESR must be defined as above to stable
operation.
SHORT-CIRCUIT PROTECTION
The device is short circuit protected and in the event
of a peak over-current condition, the short-circuit
control loop will rapidly drive the output PMOS pass
element off. Once the power pass element shuts
down, the control loop will rapidly cycle the output on
and off until the average power dissipation causes
the thermal shutdown circuit to respond to servo the
on/off cycling to a lower frequency. Please refer to
the section on thermal information for power
dissipation calculations.
There are no requirements for the ESR on the input
capacitor, but tolerance and temperature coefficient
must be considered when selecting the capacitor to
ensure the capacitance will be ≅2.2µF over the entire
operating temperature range.
OUTPUT CAPACITOR
The RT9185 is designed specifically to work with
very small ceramic output capacitors. The
recommended minimum capacitance (temperature
characteristics X7R, X5R, Z5U, or Y5V) are 2.2µF to
4.7µF range with 10mΩ to 50mΩ range ceramic
capacitors between each LDO output and GND for
transient stability, but it may be increased without
limit. Higher capacitance values help to improve
transient.
CAPACITOR CHARACTERISTICS
It is important to note that capacitance tolerance and
variation with temperature must be taken into
consideration when selecting a capacitor so that the
minimum required amount of capacitance is provided
over the full operating temperature range. In general,
www.richtek.com
8
DS9185-02 July 2003
RT9185
a good tantalum capacitor will show very little
capacitance variation with temperature, but a ceramic
may not be as good (depending on dielectric type).
Aluminum electrolytics also typically have large
temperature variation of capacitance value.
Tantalums also have good temperature stability: a
good quality tantalum will typically show
a
capacitance value that varies less than 10~15%
across the full temperature range of 125°C to −40°C.
ESR will vary only about 2X going from the high to
low temperature limits.
Equally important to consider is a capacitor’s ESR
change with temperature: this is not an issue with
ceramics, as their ESR is extremely low. However, it
is very important in tantalum and aluminum
electrolytic capacitors. Both show increasing ESR at
colder temperatures, but the increase in aluminum
electrolytic capacitors is so severe they may not be
feasible for some applications.
The increasing ESR at lower temperatures can cause
oscillations when marginal quality capacitors are
used (if the ESR of the capacitor is near the upper
limit of the stability range at room temperature).
Aluminum:
This capacitor type offers the most capacitance for
the money. The disadvantages are that they are
larger in physical size, not widely available in surface
mount, and have poor AC performance (especially at
higher frequencies) due to higher ESR and ESL.
Ceramic:
For values of capacitance in the 10µF to 100µF
range, ceramics are usually larger and more costly
than tantalums but give superior AC performance for
by-passing high frequency noise because of very low
ESR (typically less than 10mΩ). However, some
dielectric types do not have good capacitance
Compared by size, the ESR of an aluminum
electrolytic is higher than either Tantalum or ceramic,
and it also varies greatly with temperature. A typical
aluminum electrolytic can exhibit an ESR increase of
as much as 50X when going from 25°C down to
−40°C.
characteristics as
temperature.
a
function of voltage and
Z5U and Y5V dielectric ceramics have capacitance
that drops severely with applied voltage. A typical
Z5U or Y5V capacitor can lose 60% of its rated
capacitance with half of the rated voltage applied to it.
The Z5U and Y5V also exhibit a severe temperature
effect, losing more than 50% of nominal capacitance
at high and low limits of the temperature range.
It should also be noted that many aluminum
electrolytics only specify impedance at a frequency of
120Hz, which indicates they have poor high
frequency performance. Only aluminum electrolytics
that have an impedance specified at a higher
frequency (between 20kHz and 100kHz) should be
used for the device. Derating must be applied to the
manufacturer’s ESR specification, since it is typically
only valid at room temperature.
X7R and X5R dielectric ceramic capacitors are
strongly recommended if ceramics are used, as they
typically maintain a capacitance range within ±20% of
nominal over full operating ratings of temperature
and voltage. Of course, they are typically larger and
more costly than Z5U/Y5U types for a given voltage
and capacitance.
Any applications using aluminum electrolytics should
be thoroughly tested at the lowest ambient operating
temperature where ESR is maximum.
Tantalum:
Solid tantalum capacitors are recommended for use
on the output because their typical ESR is very close
to the ideal value required for loop compensation.
They also work well as input capacitors if selected to
meet the ESR requirements previously listed.
DS9185-02 July 2003
www.richtek.com
9
RT9185
THERMAL CONSIDERATIONS
The RT9185 is a triple channel CMOS regulator
designed to provide two output voltage from one
package. Each output pin the RT9185 can deliver a
current of up to 1.5A, 0.8A and 0.3A respectively
over the full operating junction temperature range.
However, the maximum output current must be
derated at higher ambient temperature to ensure the
junction temperature does not exceed 125°C. With all
possible conditions, the junction temperature must be
within the range specified under operating conditions.
Each regulator contributes power dissipation to the
overall power dissipation of the package. Power
dissipation can be calculated based on the output
current and the voltage drop across each regulator.
TRACE RESISTANCE
RP
RT9185
VDD
VOUT1
VOUT3
VOUT2
I
O
+
+
LOAD
DROP = I * RP
O
GND
GND PLANE
The GND pin of the RT9185 performs the dual
function of providing an electrical connection to
ground and channeling heat away. Connect the GND
pin to ground using a large pad or ground plane.
Good board layout practices must be used or
instability can be induced because of ground loops
and voltage drops. The input and output capacitors
MUST be directly connected to the input, output, and
ground pins of the device using traces which have no
other currents flowing through them. The best way to
do this is to layout CIN and COUT near the device with
short traces to the VDD, VOUT, and ground pins.
PD = (VDD –VOUT1) IOUT1 + (VDD – VOUT2) IOUT2
(VDD – VOUT3) IOUT3 + VIN IGND
+
Although the device is rated for 1.5A, 0.8A and 0.3A
of output current, the application may limit the
amount of output current based on the total power
dissipation and the ambient temperature. The final
operating junction temperature for any set of
conditions can be estimated by the following thermal
equation:
The regulator ground pin should be connected to the
external circuit ground so that the regulator and its
capacitors have a “single point ground”.
PD (MAX) = ( TJ (MAX) − TA ) / θ
JA
It should be noted that stability problems have been
seen in applications where “vias” to an internal
ground plane were used at the ground points of the
device and the input and output capacitors. This was
caused by varying ground potentials at these nodes
resulting from current flowing through the ground
plane. Using a single point ground technique for the
regulator and it’s capacitors fixed the problem. Since
high current flows through the traces going into VIN
and coming from VOUT, Kelvin connect the capacitor
leads to these pins so there is no voltage drop in
series with the input and output capacitors.
Where TJ (MAX) is the maximum junction temperature
of the die (125°C) and TA is the maximum ambient
temperature. θJA is the thermal resistance from the
junction to the surrounding environment which is
combined with θJC + θCA. Where θJC is junction to
case thermal resistance which for fused SOP-8 is
20°C/W, TO-252-5 is 10°C/W and TO-263-5 is
5.5°C/W, θ
is case to ambient thermal resistance
CA
which depend on PCB board area and air flow.
PCB LAYOUT
The RT9185 is a fixed output voltage regulator which
the voltage are sensed at the output pin. A long PCB
trace to load will cause a voltage drop between load
and RT9185. Be careful with PCB layout which
minimum the output trace length and maximum the
trace width.
Optimum performance can only be achieved when
the device is mounted on a PC board according to
the diagram below:
www.richtek.com
10
DS9185-02 July 2003
RT9185
GND
+
+
VOUT1
VOUT3
+
+
GND
VDD
VOUT2
GND
SOP-8 Board Layout
GND
+
+
VOUT1
VOUT3
+
+
GND
VDD
VOUT2
GND
TO-252-5/TO-263-5 Board Layout
DS9185-02 July 2003
www.richtek.com
11
RT9185
Package Information
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
0.178
0.102
5.791
0.406
5.004
3.988
1.753
0.508
1.346
0.254
0.254
6.198
1.270
0.189
0.150
0.053
0.013
0.047
0.007
0.004
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
www.richtek.com
12
DS9185-02 July 2003
RT9185
E
C2
b3
L3
V
D
H
L
b
P
L2
A
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
2.388
0.889
5.461
0.889
6.223
6.731
10.414
1.780
Min
0.086
Max
0.094
0.035
A
b
2.184
0.381
4.953
0.457
5.334
6.350
9.000
0.508
0.015
b3
C2
D
0.195
0.018
0.210
0.250
0.215
0.035
0.245
0.265
E
H
0.354
0.020
0.410
0.070
L
0.020 Ref.
L2
L3
P
0.508 Ref.
0.035
0.080
--
0.889
2.032
1.270 Ref.
0.050 Ref.
V
4.572
--
0.180
5-Lead TO-252 Plastic Package
DS9185-02 July 2003
www.richtek.com
13
RT9185
C
D
U
B
V
E
L1
L2
b
e
b2
A
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
10.668
1.676
9.652
4.826
1.397
Min
Max
D
B
9.652
1.143
8.128
4.064
1.143
0.380
0.045
0.320
0.160
0.045
0.420
0.066
0.380
0.190
0.055
E
A
C
U
V
6.223 Ref.
7.620 Ref.
0.245 Ref.
0.300 Ref.
L1
L2
b
14.605
2.286
0.660
0.305
1.524
15.875
2.794
0.914
0.584
1.829
0.575
0.090
0.026
0.012
0.060
0.625
0.110
0.036
0.023
0.072
b2
e
5-Lead TO-263 Plastic Surface Mount Package
www.richtek.com
14
DS9185-02 July 2003
RT9185
DS9185-02 July 2003
www.richtek.com
15
RT9185
RICHTEK TECHNOLOGY CORP.
Headquarter
RICHTEK TECHNOLOGY CORP.
Taipei Office (Marketing)
5F, No. 20, Taiyuen Street, Chupei City
8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City
Hsinchu, Taiwan, R.O.C.
Taipei County, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Tel: (8862)89191466 Fax: (8862)89191465
Email: marketing@richtek-ic.com.tw
www.richtek.com
16
DS9185-02 July 2003
相关型号：
©2020 ICPDF网 联系我们和版权申明