RT9261B38CX [RICHTEK]
VFM Step-up DC/DC Converter; VFM升压型DC / DC转换器型号: | RT9261B38CX |
厂家: | RICHTEK TECHNOLOGY CORPORATION |
描述: | VFM Step-up DC/DC Converter |
文件: | 总10页 (文件大小:193K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
Preliminary
RT9261B
VFM Step-up DC/DC Converter
General Description
Features
The RT9261B Series are VFM Step-up DC/DC
converter ICs with ultra low supply current by CMOS
process and suitable for use with battery-powered
instruments.
z Minimal Number of External Components
(Only an Inductor, a Diode, and a Capacitor)
z Ultra Low Input Current (6.5µA at Switch Off)
z Capable of Supplying 50mA Output Current
with Internal Switch
The RT9261B IC consists of an oscillator, a VFM
control circuit, a driver transistor (LX switch), a
reference voltage unit, an error amplifier, resistors
for voltage detection, and a LX switch protection
circuit. A low ripple and high efficiency step-up
DC/DC converter can be constructed with the
RT9261B IC and only three external components.
z
2% Output Voltage Accuracy
z Low Ripple and Low Noise
z Low Start-up Voltage, 0.8V at 1mA
z 80% Efficiency with Low Cost Inductor
z +50 ppm/°C Low Temperature-Drift
z SOT-89 and SOT-25 Small Packages
Applications
The CE pin enables the circuit to set the standby
supply current at a maximum of 0.5µA.
z Power source for battery-powered equipment
z Power source for cameras, camcorders, VCRs,
PDAs, pagers, electronic data banks, and hand-
held communication equipment
Ordering Information
RT9261B-ꢀꢀ ꢀ ꢀ
Package type
B : SOT-25
z Power source for appliances, which require
higher voltage than that of batteries used in the
appliances
X : SOT-89
Operating temperature range
C: Commercial standard
Pin Configurations
Part Number
Pin Configurations
Output voltage
15 : 1.5V
16 : 1.6V
:
TOP VIEW
RT9261B-ꢀꢀCX
(Plastic SOT-89)
1. GND
2. VOUT (TAB)
3. LX
1
5
1
2
2
3
49 : 4.9V
50 : 5.0V
TOP VIEW
RT9261B-ꢀꢀCB
(Plastic SOT-25)
4
1. CE
2. VOUT
3. NC
4. GND
5. LX
3
DS9261B-03 September 2001
www.richtek-ic.com.tw
1
RT9261B
Preliminary
Typical Application Circuit
D1
1N5819
RT9261B
L1
LX
VOUT
GND
V
OUT
V
IN
+
Co
µ
22 F
-
D1
1N5819
L1
RT9261B
LX
V
OUT
VOUT
GND
V
IN
CE
+
Co
µ
22 F
-
* L1 ranges from 27µH to 120µH
Pin Description
Pin No.
Pin Name
Pin Function
-xxCX
-xxCB
1
2
4
2
5
1
3
GND
VOUT
LX
Ground
Output Voltage
3
Pin for Switching
--
--
CE
Chip Enable (Active High)
No Connection
NC
Function Block Diagram
VLX Limiter
Vref
LX
LXSW
Buffer
VOUT
GND
-
+
VFM Control
Error Amp.
OSC 190kHz
Chip Enable
CE
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DS9261B-03 September 2001
2
Preliminary
RT9261B
Absolute Maximum Ratings
z Output Voltage
z LX Pin Voltage
8V
8V
-0.3 to V
(1)
z CE Pin Voltage
+0.3V
OUT
z LX Pin Output Current
400mA
z Power Dissipation, P @ T = 25°C
D
A
SOT-89
SOT-25
0.5W
0.25W
z Package Thermal Resistance
SOT-89, θ
SOT-89, θ
SOT-25, θ
100°C/W
300°C/W
250°C/W
JC
JA
JA
z Operating Temperature Range
z Storage Temperature Range
z Lead Temperature (Soldering, 10 sec.)
Notes: (1) Applicable to RT9261B-xxCB
-20 to +85°C
-65°C to 150°C
260°C
Electrical Characteristics (Refer to Fig. 1)
Parameter
Output Voltage Accuracy
Input Voltage
Symbol
∆V
Test Conditions
Min Typ Max Units
-2
--
--
--
+2
7
%
V
V
V
OUT
V
V
V
IN
Start-up Voltage
--
0.8
--
1
I
I
= 1mA, V : 0 → 2V
IN
ST
OUT
Hold-on Voltage
0.7
--
--
= 1mA, V : 2 → 0V
HO
OUT
IN
(1)
24
36
36
45
V
≤ 3.5V
OUT
To be measured at V in
IN
Input Current 1
Input Current 2
µA
µA
(2)
continuous switching
--
3.5V < V
≤ 5V
OUT
To be measured at V
switch off condition
in
(1) (2)
OUT
--
6.5
10
(1)
To be measured at V in
IN
--
--
18
20
36
45
V
≤ 3.5V
OUT
Input Current 3
µA
no load (guaranteed by I
1
(2)
(2)
3.5V < V
≤ 5V
(1)
OUT
and I )
2
120
160
--
--
--
--
--
V
OUT
≤ 3.5V
LX Switching Current
LX Leakage Current
mA
I
I
V
LX
= 0.4V
SWITCHING
3.5V < V
≤ 5V
OUT
--
0.5
µA
V
LX
= 6V
LEAKAGE
Maximum Oscillator Frequency
Oscillator Duty Cycle
Efficiency
140
65
190
75
80
0.8
240 KHz
F
MAX
85
--
%
%
V
D
On (V “L”) side
OSC
LX
--
LX switch on
0.65
1.0
V
LX
Voltage Limit
Notes:
(1) V = 1.8V, V = 0V, I = 1mA, Topt = 25°C, and External Circuit of Typical Application
OUT
IN
SS
(2) V = 3V, V = 0V, I = 1mA, Topt = 25°C, and External Circuit of Typical Application
IN
SS
OUT
DS9261B-03 September 2001
www.richtek-ic.com.tw
3
RT9261B
Preliminary
Electrical Characteristics (Refer to Fig. 2)
Parameter
Output Voltage Accuracy
Input Voltage
Symbol
∆V
Test Conditions
Min
-2
--
Typ Max Units
--
--
+2
7
%
V
OUT
V
V
V
IN
Start-up Voltage
Hold-on Voltage
--
0.8
--
1
V
I
I
= 1mA, V : 0 → 2V
IN
ST
OUT
0.7
--
--
V
= 1mA, V : 2 → 0V
HO
OUT
IN
Efficiency
80
24
36
--
%
(1)
--
36
45
V
≤ 3.5V
OUT
To be measured at V in
IN
Input Current 1
Input Current 2
µA
µA
(2)
continuous switching
--
3.5V < V
≤ 5V
OUT
To be measured at V
(1) (2)
OUT
--
6.5
10
in switch off condition
(1)
To be measured at V in
IN
--
--
18
20
36
45
V
≤ 3.5V
OUT
Input Current 3
µA
no load (guaranteed by I
1
(2)
(2)
3.5V < V
≤ 5V
(1)
OUT
and I )
2
120
160
--
--
--
--
--
--
--
--
--
--
V
OUT
≤ 3.5V
LX Switching Current
mA
I
I
V
= 0.4V
= 6V
SWITCHING
LX
3.5V < V
≤ 5V
OUT
LX Leakage Current
CE “H” Level
0.5
--
µA
V
V
LX
V
IN
V
IN
LEAKAGE
= V
= V
* 0.9
* 0.9
0.4×V
OUT
OUT
OUT
OUT
CE “L” Level
--
--
0.2
0.5
--
V
CE “H” Input Current
CE “ L” Input Current
µA
µA
CE = V
CE = 0V
-0.5
Maximum Oscillator Frequency
Oscillator Duty Cycle
140
65
190 240 KHz
F
MAX
75
85
%
V
D
On (V “L”) side
OSC
LX
LX switch on
0.65
0.8
1.0
V
LX
Voltage Limit
Notes:
(1) V = 1.8V, V = 0V, I = 1mA, Topt = 25°C, and External Circuit of Typical Application
OUT
IN
SS
(2) V = 3V, V = 0V, I = 1mA, Topt = 25°C, and External Circuit of Typical Application
IN
SS
OUT
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DS9261B-03 September 2001
4
Preliminary
RT9261B
Typical Operating Charateristics
Start-up/Hold-on Voltage vs. Output Current
Output Voltage vs. Output Current
2.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
3.0V
2.5V
2.0V
2
1.5V
1.0V
1.5
Vstart
1
Vhold
0.5
VOUT = 3.3V
VOUT = 3.3V
L = 47uH
L = 47uH
0
0
0
0
30
60
90
120
150
180
0
50
100
150
200
Output Current (mA)
Output Current (mA)
Output Current vs. Ripple Voltage
Output Current vs. Ripple Voltage
300
250
200
150
100
50
90
80
70
60
50
40
30
20
10
0
3.0V
2.0V
2.5V
2.0V
3.0V
2.5V
1.5V
1.5V
VOUT = 3.3V
COUT = 20uF
L = 47uH
VOUT = 3.3V
OUT = 68uF
L = 47uH
1.0V
50
C
1.0V
50
0
100
150
200
0
100
150
200
Output Current (mA)
Output Current (mA)
Efficiency vs. output Current
Output Current vs. Ripple Voltage
90
80
70
60
50
40
30
20
10
0
25
20
15
10
5
3.0V
2.5V
2.0V
1.0V
1.5V
2.5V
3.0V
1.0V
VOUT = 3.3V
OUT = 170uF
VOUT = 3.3V
L = 47uH
C
2.0V
1.5V
L = 47uH
0
50
100
150
200
0
50
100
150
200
Output Current (mA)
DS9261B-03 September 2001
www.richtek-ic.com.tw
5
RT9261B
Preliminary
Start-up/Hold-on Voltage vs. Output Current
Output Voltage vs. Output Current
2.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
3.0V
2
2.5V
1.5V
2.0V
1.0V
1.5
Vstart
1
Vhold
0.5
VOUT = 3.3V
L = 100uH
VOUT = 3.3V
L = 100uH
0
0
50
100
150
200
0
0
0
20
40
60
80
100 120
Output Current (mA)
Output Current (mA)
Output Current vs. Ripple Voltage
Output Current vs. Ripple Voltage
300
250
200
150
100
50
90
80
70
60
50
40
30
20
10
0
2.0V
3.0V
2.5V
2.5V
3.0V
2.0V
1.0V
VOUT = 3.3V
COUT = 20uF
L = 100uH
VOUT = 3.3V
OUT = 68uF
L = 100uH
C
1.5V
1.0V
1.5V
50
0
50
100
150
200
0
100
150
200
Output Current (mA)
Output Current (mA)
Output Current vs. Ripple Voltage
Efficiency vs. output Current
100
90
80
70
60
50
40
30
20
10
0
18
16
14
12
10
8
2.5V
3.0V
3.0V
2.0V
1.0V
2.5V
2.0V
1.5V
1.0V
6
4
VOUT = 3.3V
OUT = 170uF
L = 100uH
1.5V
2
C
VOUT = 3.3V
L = 100uH
0
50
100
150
200
0
50
100
150
200
Output Current (mA)
Output Current (mA)
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DS9261B-03 September 2001
6
Preliminary
RT9261B
Package Information
D
A
D1
H
B
C
C1
e
e
A
b
b1
b
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
1.397
0.356
2.388
0.406
--
Max
Min
0.055
0.014
0.094
0.016
--
Max
A
b
1.600
0.483
2.591
0.533
4.242
1.194
4.597
1.753
1.549
0.432
0.063
0.019
0.102
0.021
0.167
0.047
0.181
0.069
0.061
0.017
B
b1
C
C1
D
0.787
4.394
1.397
1.448
0.381
0.031
0.173
0.055
0.057
0.015
D1
e
H
3-Lead SOT-89 Surface Mount
DS9261B-03 September 2001
www.richtek-ic.com.tw
7
RT9261B
Preliminary
D
b
C
B
H
A
L
e
A1
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
A1
B
0.889
0.000
1.397
0.356
2.591
2.692
0.838
0.102
0.356
1.295
0.152
1.803
0.559
2.997
3.099
1.041
0.254
0.610
0.035
0.000
0.055
0.014
0.102
0.106
0.033
0.004
0.014
0.051
0.006
0.071
0.022
0.118
0.122
0.041
0.010
0.024
b
C
D
e
H
L
SOT- 25 Surface Mount Package
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DS9261B-03 September 2001
8
Preliminary
RT9261B
DS9261B-03 September 2001
www.richtek-ic.com.tw
9
RT9261B
Preliminary
RICHTEK TECHNOLOGY CORP.
Headquarter
RICHTEK TECHNOLOGY CORP.
Taipei Office (Marketing)
6F, No. 35, Hsintai Road, 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)5510047 Fax: (8863)5537749
Tel: (8862)89191466 Fax: (8862)89191465
Email: marketing@richtek-ic.com.tw
www.richtek-ic.com.tw
DS9261B-03 September 2001
10
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