RT9171
DS9171-02 May 2001 www.richtek-ic.com.tw
1
2A Fixed and Adjustable Low Dropout
Positive Voltage Regulators
General Description
The RT9171 is a high performance positive voltage
regulator designed for applications requiring low
dropout at fully rated current. Additionally, the
RT9171 provides excellent regulation over variations
in line and load. Outstanding features include low
dropout performance at rated current, fast transient
response, internal current-limiting, and thermal-
shutdown protection of the output device. The
RT9171 three-terminal regulator offers fixed 2.5V
and 3.3V output voltages, and adjustable voltage
options available in TO-252 and TO-263 packages.
Applications
z
Active SCSI Termination
z
Low Voltage Microcontrollers
z
Switching Power Supply Post-Regulator
Ordering Information
RT9171-
Features
z
Low Dropout, 1.6V Max.
z
Full Current Rating Over Line and Temperature
z
Fast Transient Response
z ±
±±
±1 %%%% Output Voltage Accuracy
z
Adjustable and Fixed Output Voltage
z
TO- 252 and TO- 263 Packages
Pin Configurations
Part Number Pin Configurations
RT9171-CL
(Plastic TO-252)
TOP VIEW
1. ADJ/GND
2. VOUT (TAB)
3. VIN
RT9171-CM
(Plastic TO-263)
TOP VIEW
1. ADJ/GND
2. VOUT (TAB)
3. VIN
Typical Application Circuit
Operating temperature range
C: Commercial standard
Package type
L : TO-252
M : TO-263
Output voltage
Default : Adjustable
25 : 2.5V output voltage
33 : 3.3V output voltage
123
1
2
3
RT9171
ADJ
VOUT
V
REF
R1
120
1%
R2
195
1%
V
OUT
= 3.3V
I
ADJ
V
IN
= 5V
+
C2
22µF
TANT
+
C1
10µFF
Adj ustable Volt ag e Regul ator
(1) C1 needed if device is far from filter capacitors.
(2) C2 required for stability.
V
OUT
= V
REF
(1+ ) + I
ADJ R2
R1
R2
VIN
RT9171
www.richtek-ic.com.tw DS9171-02 May 2001
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Pin Description
Pin Name Pin Function
ADJ / GND Adjust Output or Ground
VOUT Output Voltage
VIN Power Input
Absolute Maximum Ratings
z Input Voltage 9V
z Operating Junction Temperature Range −40°C to 125°C
z Storage Temperature Range −65°C to 150°C
z Lead Temperature (Soldering, 10 sec.) 260°C
z Package Thermal Resistance
TO-252, θ
JC
15°C/W
TO-252, θ
JA
56°C/W
TO-263, θ
JC
8°C/W
TO-263, θ
JA
19.4°C/W
Electrical Characteristics
(TA = 25°C, unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Units
I
OUT
= 10mA, (V
IN
- V
OUT
) = 2V
T
A
= 25°C
1.238 1.250 1.262
Reference Voltage
(1)
RT9171
V
REF
10mA < I
OUT
< 2A,
1.6V < V
IN
- V
OUT
< 9V
1.225 1.250 1.270
V
RT9171-25
2.475 2.5 2.525
Output Voltage
RT9171-33
V
OUT
VIN = V
OUT
+2V, I
OUT
= 10mA
3.267 3.3 3.333
V
Line Regulation
(1)
∆V
LINE
I
OUT
= 10mA
1.6V ≤ V
IN
- V
OUT
to VIN = 9V
-- 0.1 0.3 %
Load Regulation
(1)
∆V
LOAD
(V
IN
− V
OUT
) = 2V, 0mA ≤ I
OUT
≤ 2A -- 0.2 0.4 %
I
OUT
= 100mA -- 1.1 1.2
Dropout Voltage
(2)
V
DROP
I
OUT
= 2A -- 1.4 1.6
V
Current Limit
I
LIMIT
V
IN
= 5V
2.2 3 -- A
Minimum Load Current RT9171
(V
IN
- V
OUT
) = 2V -- 5 10 mA
Ripple Rejection PSRR
f
RIPPLE
= 120H
Z
, (VIN - V
OUT
) = 2V,
V
RIPPLE
= 1V
P-P
-- 72 -- dB
Adjust Pin Current
I
ADJ
-- 65 120 µA
Adjust Pin Current Change
∆I
ADJ
10mA ≤ I
OUT
≤ 1A, V
IN
= 5V -- 0.2 5 µA
Notes: (1) Low duty cycle pulse testing with Kelvin connections.
(2) ΔV
OUT
and
ΔV
REF
= 1%.
RT9171
DS9171-02 May 2001 www.richtek-ic.com.tw
3
Package Information
Dimensions In Millimeters Dimensions In Inches
Symbol
Min Max Min Max
A 2.184 2.388
0.086 0.094
B 0.889 2.032
0.035 0.080
b 0.508 0.889 0.020 0.035
b1 1.016 Ref. 0.040 Ref.
b2 0.457 0.584 0.018 0.023
C 0.457 0.584
0.018 0.023
D 6.350 6.731
0.250 0.265
D1 5.207 5.461
0.205 0.215
E 5.334 6.223
0.210 0.245
e 2.108 2.438 0.083 0.096
L1 9.398 10.414
0.370 0.410
L2 0.508 --
0.020 --
L3 0.635 1.016
0.025 0.040
U 3.810 Ref. 0.150 Ref.
V 3.048 Ref. 0.120 Ref.
3-Lead TO-252 Plastic Surface Mount Package
U
V
L1
C
A
b2
L2
D
D1
B
E
b
b1
e
L3
RT9171
www.richtek-ic.com.tw DS9171-02 May 2001
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Dimensions In Millimeters Dimensions In Inches
Symbol
Min Max Min Max
A 4.064 4.826 0.160 0.190
B 1.143 1.676 0.045 0.066
b 0.660 0.914 0.026 0.036
b1 1.143 1.397 0.045 0.055
b2 0.305 0.584 0.012 0.023
C 1.143 1.397 0.045 0.055
D 9.652 10.668 0.380 0.420
E 8.128 9.652 0.320 0.380
e 2.286 2.794 0.090 0.110
L1 14.605 15.875 0.575 0.625
L2 2.286 2.794 0.090 0.110
U 6.223 Ref. 0.245 Ref.
V 7.620 Ref. 0.300 Ref.
3-Lead TO- 263 Surface Mount
C
A
b2
b1
MARK
b
L1
D
E
B
L2
e
V
U
RT9171
DS9171-02 May 2001 www.richtek-ic.com.tw
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RT9171
www.richtek-ic.com.tw DS9171-02 May 2001
6
RICHTEK TECHNOLOGY CORP.
Headquarter
6F, No. 35, Hsintai Road, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5510047 Fax: (8863)5537749
RICHTEK TECHNOLOGY CORP.
Taipei Office (Marketing)
8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City
Taipei County, Taipei, R.O.C.
Tel: (8862)89191466 Fax: (8862)89191465
Email: marketing@richtek-ic.com.tw
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