首页 |元器件品牌

LT1762EMS8#PBF [Linear]

LT1762 - 150mA, Low Noise, LDO Micropower Regulators; Package: MSOP; Pins: 8; Temperature Range: -40°C to 85°C;
LT1762EMS8#PBF
型号： LT1762EMS8#PBF
厂家： Linear    Linear
描述：

LT1762 - 150mA, Low Noise, LDO Micropower Regulators; Package: MSOP; Pins: 8; Temperature Range: -40°C to 85°C

光电二极管 输出元件 调节器
文件： 总16页 (文件大小：404K)
中文：  中文翻译
下载：  下载PDF数据表文档文件
 查看货源
LT1762 Series  
150mA, Low Noise, LDO  
Micropower Regulators  
U
FEATURES  
DESCRIPTIO  
The LT®1762 series are micropower, low noise, low  
dropout regulators. The devices are capable of supplying  
150mAofoutputcurrentwithadropoutvoltageof270mV.  
Designed for use in battery-powered systems, the low  
25µA quiescent current makes them an ideal choice.  
Quiescent current is well controlled; it does not rise in  
dropout as it does with many other regulators.  
■
Low Noise: 20µVRMS (10Hz to 100kHz)  
■
Low Quiescent Current: 25µA  
■
Wide Input Voltage Range: 1.8V to 20V  
Output Current: 150mA  
■
■
Very Low Shutdown Current: < 1  
Low Dropout Voltage: 270mV  
No Protection Diodes Needed  
Fixed Output Voltages: 2.5V, 3V, 3.3V, 5V  
Adjustable Output from 1.22V to 20V  
Stable with 2.2µF Output Capacitor  
Stable with Aluminum, Tantalum or  
Ceramic Capacitors  
Reverse Battery Protection  
No Reverse Current  
Overcurrent and Overtemperature Protected  
8-Lead MSOP Package  
µA  
■
■
■
■
■
■
A key feature of the LT1762 regulators is low output noise.  
With the addition of an external 0.01µF bypass capacitor,  
output noise drops to 20µVRMS over a 10Hz to 100kHz  
bandwidth. The LT1762 regulators are stable with output  
capacitors as low as 2.2µF. Small ceramic capacitors can  
be used without the series resistance required by other  
regulators.  
■
■
■
■
Internal protection circuitry includes reverse battery pro-  
tection, current limiting, thermal limiting and reverse  
current protection. The parts come in fixed output volt-  
ages of 2.5V, 3V, 3.3V and 5V, and as an adjustable device  
with a 1.22V reference voltage. The LT1762 regulators are  
available in the 8-lead MSOP package.  
U
APPLICATIO S  
■
Cellular Phones  
■
Battery-Powered Systems  
■
Frequency Synthesizers  
Noise-Sensitive Instrumentation Systems  
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.  
All other trademarks are the property of their respective owners.  
■
U
TYPICAL APPLICATIO  
3.3V Low Noise Regulator  
Dropout Voltage  
400  
3.3V AT 150mA  
20µV NOISE  
IN  
OUT  
V
350  
300  
250  
200  
150  
100  
50  
IN  
RMS  
+
3.7V TO  
20V  
SENSE  
1µF  
10µF  
LT1762-3.3  
0.01µF  
1762 TA01  
SHDN  
GND  
BYP  
0
0
20 40 60 80 100 120 140 160  
OUTPUT CURRENT (mA)  
1762 TA02  
1762fa  
1
LT1762 Series  
W W  
U W  
U
W U  
ABSOLUTE MAXIMUM RATINGS  
PACKAGE/ORDER INFORMATION  
(Note 1)  
ORDER PART  
NUMBER  
IN Pin Voltage........................................................ ±20V  
OUT Pin Voltage .................................................... ±20V  
Input to Output Differential Voltage ....................... ±20V  
SENSE Pin Voltage ............................................... ±20V  
ADJ Pin Voltage ...................................................... ±7V  
BYP Pin Voltage.................................................... ±0.6V  
SHDN Pin Voltage................................................. ±20V  
Output Short-Circut Duration.......................... Indefinite  
Operating Junction Temperature Range  
TOP VIEW  
OUT  
SENSE/ADJ*  
BYP  
1
2
3
4
8 IN  
7 NC  
6 NC  
5 SHDN  
LT1762EMS8  
LT1762EMS8-2.5  
LT1762EMS8-3  
LT1762EMS8-3.3  
LT1762EMS8-5  
GND  
MS8 PACKAGE  
8-LEAD PLASTIC MSOP  
*PIN 2: SENSE FOR LT1762-2.5/  
LT1762-3/LT1762-3.3/LT1762-5  
ADJ FOR LT1762  
MS8 PART MARKING  
LTHF  
LTHG  
LTHH  
LTHJ  
LTHK  
(Note 2) ............................................ –40°C to 125°C  
Storage Temperature Range ................. –65°C to 150°C  
Lead Temperature (Soldering, 10 sec).................. 300°C  
TJMAX = 150°C, θJA = 125°C/ W  
SEE THE APPLICATIONS  
INFORMATION SECTION.  
Order Options Tape and Reel: Add #TR  
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF  
Lead Free Part Marking: http://www.linear.com/leadfree/  
Consult factory for Industrial and Military grade parts.  
ELECTRICAL CHARACTERISTICS  
The  
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are T = 25°C. (Note 2)  
A
PARAMETER  
CONDITIONS  
= 150mA  
MIN  
TYP  
MAX  
UNITS  
Minimum Operating Voltage  
I
●
●
●
●
●
●
1.8  
2.3  
V
LOAD  
Regulated Output Voltage  
(Note 4)  
LT1762-2.5  
LT1762-3  
LT1762-3.3  
LT1762-5  
LT1762  
V
= 3V, I  
= 1mA  
LOAD  
2.475  
2.435  
2.5  
2.5  
2.525  
2.565  
V
V
IN  
3.5V < V < 20V, 1mA < I  
< 150mA  
LOAD  
IN  
V
= 3.5V, I  
IN  
= 1mA  
LOAD  
2.970  
2.925  
3
3
3.030  
3.075  
V
V
IN  
4V < V < 20V, 1mA < I  
< 150mA  
LOAD  
V
= 3.8V, I  
= 1mA  
LOAD  
3.267  
3.220  
3.3  
3.3  
3.333  
3.380  
V
V
IN  
4.3V < V < 20V, 1mA < I  
< 150mA  
LOAD  
IN  
V
= 5.5V, I  
IN  
= 1mA  
LOAD  
4.950  
4.875  
5
5
5.050  
5.125  
V
V
IN  
6V < V < 20V, 1mA < I  
< 150mA  
LOAD  
ADJ Pin Voltage  
(Notes 3, 4)  
V
= 2V, I  
= 1mA  
LOAD  
1.208  
1.190  
1.22  
1.22  
1.232  
1.250  
V
V
IN  
2.22V < V < 20V, 1mA < I  
< 150mA  
LOAD  
IN  
Line Regulation  
LT1762-2.5  
LT1762-3  
LT1762-3.3  
LT1762-5  
∆V = 3V to 20V, I  
IN  
= 1mA  
●
●
●
●
●
1
1
1
1
1
5
5
5
5
5
mV  
mV  
mV  
mV  
mV  
IN  
LOAD  
∆V = 3.5V to 20V, I  
= 1mA  
= 1mA  
= 1mA  
LOAD  
LOAD  
LOAD  
∆V = 3.8V to 20V, I  
IN  
∆V = 5.5V to 20V, I  
IN  
LT1762 (Note 3) ∆V = 2V to 20V, I  
= 1mA  
IN  
LOAD  
Load Regulation  
LT1762-2.5  
V
V
= 3.5V, ∆I  
= 3.5V, ∆I  
= 1mA to 150mA  
= 1mA to 150mA  
4
4
5
9
1
12  
25  
mV  
mV  
IN  
IN  
LOAD  
LOAD  
●
●
●
●
●
LT1762-3  
V
V
= 4V, ∆I  
= 4V, ∆I  
= 1mA to 150mA  
= 1mA to 150mA  
15  
30  
mV  
mV  
IN  
IN  
LOAD  
LOAD  
LT1762-3.3  
LT1762-5  
V
V
= 4.3V, ∆I  
= 4.3V, ∆I  
= 1mA to 150mA  
= 1mA to 150mA  
17  
33  
mV  
mV  
IN  
IN  
LOAD  
LOAD  
V
V
= 6V, ∆I  
= 6V, ∆I  
= 1mA to 150mA  
= 1mA to 150mA  
25  
50  
mV  
mV  
IN  
IN  
LOAD  
LOAD  
LT1762 (Note 3)  
V
V
= 2.22V, ∆I  
= 2.22V, ∆I  
= 1mA to 150mA  
= 1mA to 150mA  
6
12  
mV  
mV  
IN  
IN  
LOAD  
LOAD  
1762fa  
2
LT1762 Series  
ELECTRICAL CHARACTERISTICS  
The  
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are T = 25°C. (Note 2)  
A
PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
Dropout Voltage  
I
I
= 1mA  
= 1mA  
0.09  
0.15  
0.19  
V
V
LOAD  
LOAD  
V
= V  
●
●
●
●
IN  
OUT(NOMINAL)  
(Notes 5, 6)  
I
I
= 10mA  
= 10mA  
0.15  
0.21  
0.27  
0.21  
0.25  
V
V
LOAD  
LOAD  
I
I
= 50mA  
= 50mA  
0.27  
0.31  
V
V
LOAD  
LOAD  
I
I
= 150mA  
= 150mA  
0.33  
0.40  
V
V
LOAD  
LOAD  
GND Pin Current  
I
I
I
I
I
= 0mA  
= 1mA  
= 10mA  
= 50mA  
= 150mA  
●
●
●
●
●
25  
70  
350  
1.3  
4
65  
120  
500  
1.8  
7
µA  
µA  
LOAD  
LOAD  
LOAD  
LOAD  
LOAD  
V
= V  
IN  
OUT(NOMINAL)  
(Notes 5, 7)  
µA  
mA  
mA  
Output Voltage Noise  
ADJ Pin Bias Current  
Shutdown Threshold  
C
= 10µF, C  
= 0.01µF, I  
= 150mA, BW = 10Hz to 100kHz  
20  
30  
µV  
RMS  
OUT  
BYP  
LOAD  
(Notes 3, 8)  
100  
2
nA  
V
V
= Off to On  
= On to Off  
●
●
0.8  
0.65  
V
V
OUT  
OUT  
0.25  
SHDN Pin Current  
(Note 9)  
V
V
= 0V  
= 20V  
0.1  
1
µA  
µA  
SHDN  
SHDN  
Quiescent Current in Shutdown  
Ripple Rejection  
V
V
= 6V, V  
= 0V  
0.1  
65  
1
µA  
IN  
SHDN  
– V  
= 1V (Avg), V  
= 0.5V , f = 120Hz,  
P-P RIPPLE  
50  
dB  
IN  
OUT  
RIPPLE  
I
= 150mA  
LOAD  
Current Limit  
V
V
= 7V, V  
= V  
= 0V  
400  
mA  
mA  
IN  
IN  
OUT  
OUT(NOMINAL)  
+ 1V, ∆V  
= –0.1V  
●
●
160  
OUT  
Input Reverse Leakage Current  
V
= –20V, V  
= 0V  
OUT  
1
mA  
IN  
Reverse Output Current  
(Note 10)  
LT1762-2.5  
LT1762-3  
LT1762-3.3  
LT1762-5  
V
V
V
V
V
= 2.5V, V < 2.5V  
10  
10  
10  
10  
5
20  
20  
20  
20  
10  
µA  
µA  
µA  
µA  
µA  
OUT  
OUT  
OUT  
OUT  
OUT  
IN  
= 3V, V < 3V  
IN  
= 3.3V, V < 3.3V  
IN  
= 5V, V < 5V  
IN  
LT1762 (Note 3)  
= 1.22V, V < 1.22V  
IN  
Note 5: To satisfy requirements for minimum input voltage, the LT1762  
(adjustable version) is tested and specified for these conditions with an  
external resistor divider (two 250k resistors) for an output voltage of  
2.44V. The external resistor divider will add a 5µA DC load on the output.  
Note 1: Stresses beyond those listed under Absolute Maximum Ratings  
may cause permanent damage to the device. Exposure to any Absolute  
Maximum Rating condition for extended periods may affect device  
reliability and lifetime.  
Note 6: Dropout voltage is the minimum input to output voltage differential  
needed to maintain regulation at a specified output current. In dropout, the  
Note 2: The LT1762 regulators are tested and specified under pulse load  
conditions such that T ≈ T . The LT1762 is 100% tested at 25°C.  
J
A
output voltage will be equal to: V – V  
.
Performance at –40°C and 125°C is assured by design, characterization  
IN  
DROPOUT  
and correlation with statistical process controls.  
Note 7: GND pin current is tested with V = V  
and a current  
IN  
OUT(NOMINAL)  
source load. This means the device is tested while operating in its dropout  
region. This is the worst-case GND pin current. The GND pin current will  
decrease slightly at higher input voltages.  
Note 8: ADJ pin bias current flows into the ADJ pin.  
Note 9: SHDN pin current flows into the SHDN pin.  
Note 10: Reverse output current is tested with the IN pin grounded and the  
OUT pin forced to the rated output voltage. This current flows into the OUT  
pin and out the GND pin.  
Note 3: The LT1762 (adjustable version) is tested and specified for these  
conditions with the ADJ pin connected to the OUT pin.  
Note 4: Operating conditions are limited by maximum junction  
temperature. The regulated output voltage specification will not apply for  
all possible combinations of input voltage and output current. When  
operating at maximum input voltage, the output current range must be  
limited. When operating at maximum output current, the input voltage  
range must be limited.  
1762fa  
3
LT1762 Series  
TYPICAL PERFORMANCE CHARACTERISTICS  
U W  
Typical Dropout Voltage  
Guaranteed Dropout Voltage  
Dropout Voltage  
500  
450  
400  
350  
300  
250  
200  
150  
100  
50  
500  
450  
400  
350  
300  
250  
200  
150  
100  
50  
500  
450  
400  
350  
300  
250  
200  
150  
100  
50  
= TEST POINTS  
T
≤ 125°C  
≤ 25°C  
J
I
= 150mA  
L
T
J
= 125°C  
= 25°C  
I
= 50mA  
= 10mA  
= 1mA  
T
L
J
I
T
J
L
I
L
0
–50  
0
0
0
25  
50  
75 100 125  
–25  
40  
120  
140 160  
0
20  
60 80 100  
40  
120  
140 160  
0
20  
60 80 100  
TEMPERATURE (°C)  
LOAD CURRENT (mA)  
LOAD CURRENT (mA)  
1762 G03  
1762 G01  
1762 G02  
LT1762-2.5  
Output Voltage  
LT1762-3  
Output Voltage  
Quiescent Current  
40  
35  
30  
25  
20  
15  
10  
5
2.54  
2.53  
2.52  
2.51  
2.50  
2.49  
2.48  
2.47  
2.46  
3.060  
3.045  
3.030  
3.015  
3.000  
2.985  
2.970  
2.955  
2.940  
V
R
R
= 6V  
I
= 1mA  
I = 1mA  
L
IN  
L
L
L
= ∞, I = 0 (LT1762-2.5/-3/-3.3/-5)  
L
= 250k, I = 5µA (LT1762)  
L
V
SHDN  
= V  
IN  
0
–50  
–25  
0
25  
50  
75  
125  
–25  
0
25  
50  
75  
125  
–25  
0
25  
50  
75  
125  
100  
–50  
100  
–50  
100  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
1762 G04  
1762 G05  
1762 G06  
LT1762-3.3  
Output Voltage  
LT1762-5  
Output Voltage  
LT1762  
ADJ Pin Voltage  
3.360  
3.345  
3.330  
3.315  
3.300  
3.285  
3.270  
3.255  
3.240  
5.100  
5.075  
5.050  
5.025  
5.000  
4.975  
4.950  
4.925  
4.900  
1.240  
1.235  
1.230  
1.225  
1.220  
1.215  
1.210  
1.205  
1.200  
I
= 1mA  
I = 1mA  
L
L
I = 1mA  
L
–25  
0
25  
50  
75  
125  
–25  
0
25  
50  
75  
125  
–25  
0
25  
50  
75  
125  
–50  
100  
–50  
100  
–50  
100  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
1762 G07  
1762 G08  
1762 G09  
1762fa  
4
LT1762 Series  
U W  
TYPICAL PERFORMANCE CHARACTERISTICS  
LT1762-2.5  
Quiescent Current  
LT1762-3  
Quiescent Current  
LT1762-3.3  
Quiescent Current  
400  
350  
300  
250  
200  
150  
100  
50  
400  
350  
300  
250  
200  
150  
100  
50  
400  
350  
300  
250  
200  
150  
100  
50  
T
= 25°C  
= ∞  
T
= 25°C  
R = ∞  
L
T
= 25°C  
= ∞  
J
L
J
J
L
R
R
V
= 0V  
9
V
= 0V  
9
SHDN  
8
SHDN  
V
= V  
SHDN  
V
= V  
5
V
SHDN  
= 0V  
9
V
= V  
5
IN  
6
SHDN  
IN  
SHDN  
4
IN  
0
0
0
0
1
2
3
6
7
8
10  
0
1
2
3
4
5
7
10  
0
1
2
3
4
6
7
8
10  
INPUT VOLTAGE (V)  
INPUT VOLTAGE (V)  
INPUT VOLTAGE (V)  
1762 G10  
1762 G12  
1762 G11  
LT1762-5  
Quiescent Current  
LT1762  
Quiescent Current  
LT1762-2.5  
GND Pin Current  
30  
25  
20  
15  
10  
5
400  
350  
300  
250  
200  
150  
100  
50  
800  
700  
600  
500  
400  
300  
200  
100  
0
T = 25°C  
J
T
= 25°C  
= ∞  
J
L
V
SHDN  
= V  
IN  
V
= V  
SHDN  
R
IN  
*FOR V  
= 2.5V  
OUT  
R
L
= 100Ω  
L
I
= 25mA*  
T
= 25°C  
= 250k  
J
L
R
L
= 250Ω  
R
L
I
= 10mA*  
V
= V  
IN  
SHDN  
R
= 2.5k  
L
V
= 0V  
SHDN  
I
L
= 1mA*  
V
SHDN  
= 0V  
0
0
0
2
4
6
8
10 12 14 16 18 20  
0
1
2
3
4
5
6
7
8
9
10  
0
1
2
3
4
5
6
7
8
9
10  
INPUT VOLTAGE (V)  
INPUT VOLTAGE (V)  
INPUT VOLTAGE (V)  
1762 G14  
1762 G13  
1762 G15  
LT1762-3  
GND Pin Current  
LT1762-3.3  
LT1762-5  
GND Pin Current  
GND Pin Current  
800  
700  
600  
500  
400  
300  
200  
100  
0
800  
700  
600  
500  
400  
300  
200  
100  
0
800  
700  
600  
500  
400  
300  
200  
100  
0
T
= 25°C  
T = 25°C  
J
J
V
= V  
V
= V  
IN SHDN  
IN  
SHDN  
*FOR V  
= 3V  
*FOR V  
= 3.3V  
OUT  
R
L
= 200Ω  
OUT  
L
R
L
= 120Ω  
L
R
L
= 132Ω  
L
I
= 25mA*  
I
= 25mA*  
I
= 25mA*  
T
= 25°C  
IN  
J
V
= V  
SHDN  
*FOR V  
= 5V  
OUT  
R
L
= 330Ω  
R
L
= 300Ω  
= 10mA*  
L
L
I
= 10mA*  
I
R
L
= 500Ω  
L
I
= 10mA*  
R
L
= 5k  
= 1mA*  
L
R
I
= 3.3k  
R
= 3k  
= 1mA*  
L
L
L
I
= 1mA*  
I
L
0
1
2
3
4
5
6
7
8
9
10  
0
1
2
3
4
5
6
7
8
9
10  
0
1
2
3
4
5
6
7
8
9
10  
INPUT VOLTAGE (V)  
INPUT VOLTAGE (V)  
INPUT VOLTAGE (V)  
1762 G16  
1762 G17  
1762 G18  
1762fa  
5
LT1762 Series  
TYPICAL PERFORMANCE CHARACTERISTICS  
U W  
LT1762  
GND Pin Current  
LT1762-2.5  
GND Pin Current  
LT1762-3  
GND Pin Current  
800  
700  
600  
500  
400  
300  
200  
100  
0
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
T
= 25°C  
IN  
J
V
T
= 25°C  
T
= 25°C  
J
IN  
J
V
= V  
SHDN  
= V  
V
= V  
SHDN  
IN  
SHDN  
*FOR V  
= 1.22V  
OUT  
*FOR V  
= 2.5V  
*FOR V  
= 3V  
OUT  
OUT  
R
L
= 48.8Ω  
L
R
L
= 20Ω  
L
R
L
= 16.7Ω  
I
= 25mA*  
L
I
= 150mA*  
I
= 150mA*  
R
L
= 122Ω  
= 10mA*  
L
I
R
= 25Ω  
= 100mA*  
R
= 30Ω  
L
L
I
I = 100mA*  
L
L
R
= 60Ω  
L
R
= 1.22k  
R
L
= 50Ω  
= 50mA*  
L
L
I = 50mA*  
L
I
L
= 1mA*  
I
4
4
0
1
2
3
5
6
7
8
9
10  
0
1
2
3
5
6
7
8
9
10  
0
1
2
3
4
5
6
7
8
9
10  
INPUT VOLTAGE (V)  
INPUT VOLTAGE (V)  
INPUT VOLTAGE (V)  
1762 G20  
1762 G21  
1762 G19  
LT1762-3.3  
GND Pin Current  
LT1762-5  
GND Pin Current  
LT1762  
GND Pin Current  
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
T
= 25°C  
T
= 25°C  
T
= 25°C  
J
IN  
J
V
J
= V  
V
= V  
V
= V  
SHDN  
IN  
SHDN  
IN  
SHDN  
*FOR V  
= 3.3V  
*FOR V  
= 5V  
*FOR V  
= 1.22V  
OUT  
OUT  
OUT  
R
= 8.07Ω  
L
R
L
= 33.3Ω  
L
R
L
= 22Ω  
L
I = 150mA*  
L
I
= 150mA*  
I
= 150mA*  
R
L
= 12.2Ω  
L
I
= 100mA*  
R
= 50Ω  
= 100mA*  
R
L
= 33Ω  
L
L
I
I
= 100mA*  
L
R
L
= 24.4Ω  
L
I
= 50mA*  
R
= 100Ω  
= 50mA*  
R
L
= 66Ω  
= 50mA*  
L
L
I
I
L
4
4
0
1
2
3
5
6
7
8
9
10  
0
1
2
3
5
6
7
8
9
10  
4
0
1
2
3
5
6
7
8
9
10  
INPUT VOLTAGE (V)  
INPUT VOLTAGE (V)  
INPUT VOLTAGE (V)  
1762 G23  
1762 G24  
1762 G22  
SHDN Pin Threshold  
(Off-to-On)  
SHDN Pin Threshold  
(On-to-Off)  
GND Pin Current vs I  
LOAD  
1.0  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
0.1  
0
1.0  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
0.1  
0
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
0
I
= 1mA  
L
V
IN  
= V + 1V  
OUT(NOMINAL)  
I
= 150mA  
L
I
= 1mA  
L
40  
120  
–50  
0
25  
TEMPERATURE (°C)  
50  
75 100 125  
0
20  
60 80 100  
140 160  
–25  
–50  
0
25  
50  
75 100 125  
–25  
OUTPUT CURRENT (mA)  
TEMPERATURE (°C)  
1762 G25  
1762 G27  
1762 G26  
1762fa  
6
LT1762 Series  
U W  
TYPICAL PERFORMANCE CHARACTERISTICS  
SHDN Pin Input Current  
ADJ Pin Bias Current  
SHDN Pin Input Current  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
0
1.6  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
0
140  
120  
100  
80  
V
= 20V  
SHDN  
60  
40  
20  
0
4
–50  
0
25  
50  
75  
125  
0
1
2
3
5
6
7
8
9
10  
–25  
100  
–25  
0
25  
50  
75  
125  
–50  
100  
TEMPERATURE (°C)  
SHDN PIN VOLTAGE (V)  
TEMPERATURE (°C)  
1762 G28  
1762 G30  
1762 G29  
Current Limit  
Current Limit  
Reverse Output Current  
500  
450  
400  
350  
300  
250  
200  
150  
100  
50  
500  
450  
400  
350  
300  
250  
200  
150  
100  
50  
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
V
= 0V  
V
= 7V  
IN  
OUT  
T = 25°C, V = 0V  
OUT  
J
IN  
V
= 0V  
CURRENT FLOWS  
INTO OUTPUT PIN  
V
OUT  
= V  
SENSE  
LT1762  
(LT1762-2.5/-3/-3.3/-5)  
= V (LT1762)  
V
OUT  
ADJ  
LT1762-2.5  
LT1762-3  
LT1762-3.3  
LT1762-5  
0
0
0
2
3
4
5
6
7
50  
TEMPERATURE (°C)  
125  
1
–50  
0
25  
75 100  
–25  
4
0
1
2
3
5
6
7
8
9
10  
INPUT VOLTAGE (V)  
OUTPUT VOLTAGE (V)  
1762 G31  
1762 G32  
1762 G33  
Reverse Output Current  
Input Ripple Rejection  
Input Ripple Rejection  
80  
70  
60  
50  
40  
30  
20  
10  
0
80  
70  
60  
50  
40  
30  
20  
10  
0
30  
25  
20  
15  
10  
5
V
V
V
V
V
V
= 0V  
C
BYP  
= 0.01µF  
IN  
= 1.22V (LT1762)  
= 2.5V (LT1762-2.5)  
= 3V (LT1762-3)  
= 3.3V (LT1762-3.3)  
= 5V (LT1762-5)  
OUT  
OUT  
OUT  
OUT  
OUT  
C
BYP  
= 1000pF  
C
BYP  
= 100pF  
C
= 10µF  
OUT  
LT1762-2.5/-3/-3.3/-5  
LT1762  
I
= 150mA  
L
I
= 150mA  
C
= 2.2µF  
L
OUT  
V
= V  
+
IN  
OUT(NOMINAL)  
V
= V  
+
IN  
OUT(NOMINAL)  
1V + 50mV  
C
RIPPLE  
RMS  
1V + 50mV  
C
RIPPLE  
RMS  
= 10µF  
= 0  
BYP  
OUT  
0
10  
100  
1k  
10k  
100k  
1M  
10  
100  
1k  
10k  
100k  
1M  
–50  
0
25  
50  
75 100 125  
–25  
FREQUENCY (Hz)  
FREQUENCY (Hz)  
TEMPERATURE (°C)  
1762 G35  
1762 G36  
1762 G34  
1762fa  
7
LT1762 Series  
U W  
TYPICAL PERFORMANCE CHARACTERISTICS  
LT1762  
Minimum Input Voltage  
Ripple Rejection  
Load Regulation  
2.50  
2.25  
2.00  
1.75  
1.50  
1.25  
1.00  
0.75  
0.50  
0.25  
0
5
0
68  
66  
64  
62  
60  
58  
56  
54  
52  
V
= 1.22V  
OUT  
LT1762  
I
= 150mA  
L
LT1762-3  
LT1762-2.5  
–5  
I
= 1mA  
L
–10  
–15  
–20  
–25  
LT1762-3.3  
LT1762-5  
V
= V  
+
OUT (NOMINAL)  
IN  
1V + 0.5V RIPPLE  
P-P  
V
= V  
+ 1V  
50  
IN  
OUT(NOMINAL)  
AT f = 120Hz  
∆I = 1mA TO 150mA  
L
I
L
= 150mA  
–50  
0
25  
50  
75 100 125  
–25  
–25  
0
25  
50  
75  
125  
–25  
0
25  
75  
125  
–50  
100  
–50  
100  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
TEMPERATURE (°C)  
1762 G38  
1762 G37  
1762 G39  
Output Noise Spectral Density  
BYP  
C
= 0  
Output Noise Spectral Density  
10  
1
10  
1
C
I
= 10µF  
C
L
= 10µF  
OUT  
L
OUT  
= 150mA  
I
= 150mA  
LT1762-3.3  
LT1762-3  
C
= 1000pF  
BYP  
LT1762-5  
LT1762-5  
LT1762  
C
= 100pF  
BYP  
LT1762-2.5  
LT1762  
0.1  
0.1  
C
BYP  
= 0.01µF  
0.01  
0.01  
10  
100  
1k  
FREQUENCY (Hz)  
10k  
100k  
10  
100  
1k  
10k  
100k  
FREQUENCY (Hz)  
1762 G41  
1762 G40  
RMS Output Noise vs  
Bypass Capacitor  
RMS Output Noise vs  
Load Current (10Hz to 100kHz)  
160  
140  
120  
100  
80  
160  
140  
120  
100  
80  
C
= 10µF  
C
L
= 10µF  
OUT  
OUT  
C
= 0  
I
= 150mA  
BYP  
LT1762-5  
C
= 0.01µF  
f = 10Hz TO 100kHz  
BYP  
LT1762-5  
LT1762-3.3  
LT1762-3  
LT1762  
60  
60  
LT1762  
40  
40  
LT1762-2.5  
LT1762-5  
LT1762  
20  
20  
0
0
0.01  
10  
100  
1000  
10000  
0.1  
1
10  
100  
1000  
C
(pF)  
LOAD CURRENT (mA)  
BYP  
1762 G42  
1762 G43  
1762fa  
8
LT1762 Series  
U W  
TYPICAL PERFORMANCE CHARACTERISTICS  
LT1762-5  
LT1762-5  
10Hz to 100kHz Output Noise  
10Hz to 100kHz Output Noise  
C
= 100pF  
C
BYP  
= 0  
BYP  
V
V
OUT  
100µV/DIV  
OUT  
100µV/DIV  
1ms/DIV  
1ms/DIV  
C
L
= 10µF  
C
L
= 10µF  
OUT  
= 150mA  
OUT  
= 150mA  
I
1762 G44  
I
1762 G45  
LT1762-5  
10Hz to 100kHz Output Noise  
= 1000pF  
LT1762-5  
10Hz to 100kHz Output Noise  
C
C
BYP  
= 0.01µF  
BYP  
V
V
OUT  
100µV/DIV  
OUT  
100µV/DIV  
1ms/DIV  
1ms/DIV  
C
I
= 10µF  
C
L
= 10µF  
OUT  
OUT  
= 150mA  
= 150mA  
1762 G46  
I
1762 G47  
L
LT1762-5  
Transient Response  
C = 0.01µF  
BYP  
LT1762-5  
Transient Response  
C
BYP  
= 0  
0.3  
0.2  
0.1  
0
V
C
C
= 6V  
V
C
C
= 6V  
IN  
IN  
IN  
IN  
0.04  
0.02  
0
= 10µF  
= 10µF  
= 10µF  
= 10µF  
OUT  
OUT  
–0.1  
–0.2  
–0.3  
150  
100  
50  
–0.02  
–0.04  
150  
100  
50  
0
0
80  
TIME (µs)  
0
40  
120  
160  
200  
800  
TIME (µs)  
0
400  
1200  
1600  
2000  
1762 G49  
1762 G48  
1762fa  
9
LT1762 Series  
U
U
U
PIN FUNCTIONS  
GND (Pin 4): Ground.  
OUT (Pin 1): Output. The output supplies power to the  
load. A minimum output capacitor of 2.2µF is required to  
prevent oscillations. Larger output capacitors will be  
required for applications with large transient loads to limit  
peak voltage transients. See the Applications Information  
section for more information on output capacitance and  
reverse output characteristics.  
SHDN (Pin5): Shutdown. The SHDN pin is used to put the  
LT1762 regulators into a low power shutdown state. The  
output will be off when the SHDN pin is pulled low. The  
SHDN pin can be driven either by 5V logic or open-  
collector logic with a pull-up resistor. The pull-up resistor  
is required to supply the pull-up current of the open-  
collector gate, normally several microamperes, and the  
SHDN pin current, typically 1µA. If unused, the SHDN pin  
must be connected to VIN. The device will be in low power  
shutdown state if the SHDN pin is not connected.  
SENSE (Pin 2): Output Sense. For fixed voltage versions  
of the LT1762 (LT1762-2.5/LT1762-3/LT1762-3.3/  
LT1762-5), the SENSE pin is the input to the error ampli-  
fier. Optimum regulation will be obtained at the point  
where the SENSE pin is connected to the OUT pin of the  
regulator. In critical applications, small voltage drops are  
caused by the resistance (RP) of PC traces between the  
regulator and the load. These may be eliminated by con-  
necting the SENSE pin to the output at the load as shown  
in Figure 1 (Kelvin Sense Connection). Note that the  
voltage drop across the external PC traces will add to the  
dropout voltage of the regulator. The SENSE pin bias  
current is 10µA at the nominal rated output voltage. The  
SENSEpincanbepulledbelowground(asinadualsupply  
system where the regulator load is returned to a negative  
supply) and still allow the device to start and operate.  
IN (Pin 8): Input. Power is supplied to the device through  
the IN pin. A bypass capacitor is required on this pin if the  
device is more than six inches away from the main input  
filter capacitor. In general, the output impedance of a  
battery rises with frequency, so it is advisable to include a  
bypass capacitor in battery-powered circuits. A bypass  
capacitor in the range of 1µF to 10µF is sufficient. The  
LT1762 regulators are designed to withstand reverse  
voltages on the IN pin with respect to ground and the OUT  
pin. In the case of a reverse input, which can happen if a  
battery is plugged in backwards, the device will act as if  
there is a diode in series with its input. There will be no  
reverse current flow into the regulator and no reverse  
voltage will appear at the load. The device will protect both  
itself and the load.  
ADJ (Pin 2): Adjust. For the adjustable LT1762, this is the  
input to the error amplifier. This pin is internally clamped  
to ±7V. It has a bias current of 30nA which flows into the  
pin (see curve of ADJ Pin Bias Current vs Temperature in  
the Typical Performance Characteristics). The ADJ pin  
voltage is 1.22V referenced to ground and the output  
voltage range is 1.22V to 20V.  
R
P
8
5
1
2
IN  
OUT  
LT1762  
+
+
BYP (Pins 3): Bypass. The BYP pin is used to bypass the  
reference of the LT1762 regulators to achieve low noise  
performance from the regulator. The BYP pin is clamped  
internally to ±0.6V (one VBE). A small capacitor from the  
output to this pin will bypass the reference to lower the  
output voltage noise. A maximum value of 0.01µF can be  
usedforreducingoutputvoltagenoisetoatypical20µVRMS  
over a 10Hz to 100kHz bandwidth. If not used, this pin  
must be left unconnected.  
SHDN SENSE  
GND  
LOAD  
V
IN  
4
R
P
1762 F01  
Figure 1. Kelvin Sense Connection  
1762fa  
10  
LT1762 Series  
U
W U U  
APPLICATIONS INFORMATION  
TheLT1762seriesare150mAlowdropoutregulatorswith  
micropowerquiescentcurrentandshutdown.Thedevices  
are capable of supplying 150mA at a dropout voltage of  
270mV. Output voltage noise can be lowered to 20µVRMS  
over a 10Hz to 100kHz bandwidth with the addition of a  
0.01µFreferencebypasscapacitor. Additionally, therefer-  
ence bypass capacitor will improve transient response of  
the regulator, lowering the settling time for transient load  
conditions. The low operating quiescent current (25µA)  
drops to less than 1µA in shutdown. In addition to the low  
quiescentcurrent, theLT1762regulatorsincorporatesev-  
eral protection features which make them ideal for use in  
battery-powered systems. The devices are protected  
against both reverse input and reverse output voltages. In  
battery backup applications where the output can be held  
up by a backup battery when the input is pulled to ground,  
the LT1762-X acts like it has a diode in series with its  
output and prevents reverse current flow. Additionally, in  
dual supply applications where the regulator load is re-  
turnedtoanegativesupply,theoutputcanbepulledbelow  
groundbyasmuchas20Vandstillallowthedevicetostart  
and operate.  
at 1.22V referenced to ground. The current in R1 is then  
equalto1.22V/R1andthecurrentinR2isthecurrentinR1  
plus the ADJ pin bias current. The ADJ pin bias current,  
30nA at 25°C, flows through R2 into the ADJ pin. The  
output voltage can be calculated using the formula in  
Figure 2. The value of R1 should be no greater than 250k  
to minimize errors in the output voltage caused by the ADJ  
pinbiascurrent.Notethatinshutdowntheoutputisturned  
off and the divider current will be zero. Curves of ADJ Pin  
Voltage vs Temperature and ADJ Pin Bias Current vs  
Temperature appear in the Typical Performance Charac-  
teristics section.  
The adjustable device is tested and specified with the ADJ  
pin tied to the OUT pin for an output voltage of 1.22V.  
Specifications for output voltages greater than 1.22V will  
be proportional to the ratio of the desired output voltage to  
1.22V: VOUT/1.22V. For example, load regulation for an  
output current change of 1mA to 150mA is –1mV typical  
at VOUT = 1.22V. At VOUT = 12V, load regulation is:  
(12V/1.22V)(–1mV) = –9.8mV  
Bypass Capacitance and Low Noise Performance  
Adjustable Operation  
The LT1762 regulators may be used with the addition of a  
bypass capacitor from VOUT to the BYP pin to lower output  
voltage noise. A good quality low leakage capacitor is  
recommended. This capacitor will bypass the reference of  
the regulator, providing a low frequency noise pole. The  
noise pole provided by this bypass capacitor will lower the  
output voltage noise to as low as 20µVRMS with the  
addition of a 0.01µF bypass capacitor. Using a bypass  
capacitor has the added benefit of improving transient  
response. With no bypass capacitor and a 10µF output  
capacitor, a 10mA to 150mA load step will settle to within  
1% of its final value in less than 100µs. With the addition  
of a 0.01µF bypass capacitor, the output will stay within  
1% for a 10mA to 150mA load step (see LT1762-5  
Transient Response in the Typical Performance Charac-  
teristics). However, regulatorstart-uptimeisproportional  
to the size of the bypass capacitor, slowing to 15ms with  
a 0.01µF bypass capacitor and 10µF output capacitor.  
The adjustable version of the LT1762 has an output  
voltage range of 1.22V to 20V. The output voltage is set by  
theratiooftwoexternalresistorsasshowninFigure2.The  
device servos the output to maintain the ADJ pin voltage  
IN  
OUT  
LT1762  
V
OUT  
+
V
IN  
R2  
R1  
ADJ  
GND  
1762 F02  
R2  
⎞
⎟
⎠
R1  
⎛
VOUT = 1.22V 1+  
+ I  
ADJ)(  
R2  
)
(
⎜
⎝
VADJ = 1.22V  
IADJ = 30nA AT 25°C  
OUTPUT RANGE = 1.22V TO 20V  
Figure 2. Adjustable Operation  
1762fa  
11  
LT1762 Series  
U
W U U  
APPLICATIONS INFORMATION  
small package, but they tend to have strong voltage and  
temperature coefficients as shown in Figures 4 and 5.  
When used with a 5V regulator, a 16V 10µF Y5V capacitor  
can exhibit an effective value as low as 1µF to 2µF for the  
DC bias voltage applied and over the operating tempera-  
ture range. The X5R and X7R dielectrics result in more  
stable characteristics and are more suitable for use as the  
output capacitor. The X7R type has better stability across  
temperature, while the X5R is less expensive and is  
available in higher values. Care still must be exercised  
when using X5R and X7R capacitors; the X5R and X7R  
codesonlyspecifyoperatingtemperaturerangeandmaxi-  
mum capacitance change over temperature. Capacitance  
change due to DC bias with X5R and X7R capacitors is  
better than Y5V and Z5U capacitors, but can still be  
Output Capacitance and Transient Response  
The LT1762 regulators are designed to be stable with a  
wide range of output capacitors. The ESR of the output  
capacitor affects stability, most notably with small capaci-  
tors. A minimum output capacitor of 2.2µF with an ESR of  
3Ω or less is recommended to prevent oscillations. The  
LT1762-X is a micropower device and output transient  
response will be a function of output capacitance. Larger  
values of output capacitance decrease the peak deviations  
and provide improved transient response for larger load  
current changes. Bypass capacitors, used to decouple  
individual components powered by the LT1762-X, will  
increase the effective output capacitor value. With larger  
capacitors used to bypass the reference (for low noise  
operation), larger values of output capacitors are needed.  
For 100pF of bypass capacitance, 3.3µF of output capaci-  
tor is recommended. With a 330pF bypass capacitor or  
larger, a 4.7µF output capacitor is recommended. The  
shaded region of Figure 3 defines the range over which the  
LT1762 regulators are stable. The minimum ESR needed  
is defined by the amount of bypass capacitance used,  
while the maximum ESR is 3Ω.  
20  
BOTH CAPACITORS ARE 16V,  
1210 CASE SIZE, 10µF  
0
X5R  
–20  
–40  
–60  
Y5V  
–80  
Extra consideration must be given to the use of ceramic  
capacitors. Ceramic capacitors are manufactured with a  
variety of dielectrics, each with different behavior across  
temperature and applied voltage. The most common di-  
electrics used are specified with EIA temperature charac-  
teristiccodesofZ5U,Y5V,X5RandX7R.TheZ5UandY5V  
dielectrics are good for providing high capacitances in a  
4.0  
–100  
0
8
12 14  
2
4
6
10  
16  
DC BIAS VOLTAGE (V)  
1762 F04  
Figure 4. Ceramic Capacitor DC Bias Characteristics  
40  
20  
3.5  
3.0  
X5R  
0
–20  
STABLE REGION  
2.5  
2.0  
–40  
Y5V  
1.5  
1.0  
0.5  
0
C
= 0  
BYP  
C
= 100pF  
BYP  
–60  
C
= 330pF  
BYP  
C
≥ 3300pF  
BYP  
–80  
BOTH CAPACITORS ARE 16V,  
1210 CASE SIZE, 10µF  
–100  
1
3
6
9 10  
8
2
4
5
7
50  
TEMPERATURE (°C)  
100 125  
–50 –25  
0
25  
75  
OUTPUT CAPACITANCE (µF)  
1762 F03  
1762 F05  
Figure 3. Stability  
Figure 5. Ceramic Capacitor Temperature Characteristics  
1762fa  
12  
LT1762 Series  
U
W U U  
APPLICATIONS INFORMATION  
significant enough to drop capacitor values below appro-  
The GND pin current can be found by examining the GND  
priate levels. Capacitor DC bias characteristics tend to Pin Current curves in the Typical Performance Character-  
improve as component case size increases, but expected  
capacitance at operating voltage should be verified.  
istics.Powerdissipationwillbeequaltothesumofthetwo  
components listed above.  
Voltage and temperature coefficients are not the only  
The LT1762 series regulators have internal thermal limit-  
sources of problems. Some ceramic capacitors have a ing designed to protect the device during overload condi-  
piezoelectric response. A piezoelectric device generates tions. For continuous normal conditions, the maximum  
voltage across its terminals due to mechanical stress, junction temperature rating of 125°C must not be  
similar to the way a piezoelectric accelerometer or micro- exceeded. It is important to give careful consideration to  
phone works. For a ceramic capacitor the stress can be allsourcesofthermalresistancefromjunctiontoambient.  
induced by vibrations in the system or thermal transients. Additional heat sources mounted nearby must also be  
The resulting voltages produced can cause appreciable  
amounts of noise, especially when a ceramic capacitor is  
used for noise bypassing. A ceramic capacitor produced  
Figure 6’s trace in response to light tapping from a pencil.  
considered.  
For surface mount devices, heat sinking is accomplished  
by using the heat spreading capabilities of the PC board  
and its copper traces. Copper board stiffeners and plated  
through-holes can also be used to spread the heat gener-  
ated by power devices.  
LT1762-5  
C
C
I
= 10µF  
= 0.01µf  
= 100mA  
OUT  
BYP  
LOAD  
The following table lists thermal resistance for several  
different board sizes and copper areas. All measurements  
were taken in still air on 3/32" FR-4 board with one ounce  
copper.  
V
OUT  
500µV/DIV  
Table 1. Measured Thermal Resistance  
100ms/DIV  
1762 F05  
COPPER AREA  
THERMAL RESISTANCE  
TOPSIDE* BACKSIDE  
BOARD AREA (JUNCTION-TO-AMBIENT)  
Figure 6. Noise Resulting from Tapping on a Ceramic Capacitor  
2500mm2  
1000mm2  
225mm2  
100mm2  
50mm2  
2500mm2  
2500mm2  
2500mm2  
2500mm2  
2500mm2  
2500mm2  
2500mm2  
2500mm2  
2500mm2  
2500mm2  
110°C/W  
115°C/W  
120°C/W  
130°C/W  
140°C/W  
Similar vibration induced behavior can masquerade as  
increased output voltage noise.  
Thermal Considerations  
The power handling capability of the device will be limited  
by the maximum rated junction temperature (125°C). The  
power dissipated by the device will be made up of two  
components:  
*Device is mounted on topside.  
Calculating Junction Temperature  
Example: Given an output voltage of 3.3V, an input voltage  
rangeof4Vto6V, anoutputcurrentrangeof0mAto50mA  
and a maximum ambient temperature of 50°C, what will  
the maximum junction temperature be?  
1. Output current multiplied by the input/output voltage  
differential: (IOUT)(VIN – VOUT), and  
2. GND pin current multiplied by the input voltage:  
(IGND)(VIN).  
The power dissipated by the device will be equal to:  
I
OUT(MAX)(VIN(MAX) – VOUT) + IGND(VIN(MAX))  
1762fa  
13  
LT1762 Series  
U
W U U  
APPLICATIONS INFORMATION  
20V. For fixed voltage versions, the output will act like a  
large resistor, typically 500kΩ or higher, limiting current  
flow to less than 100µA. For adjustable versions, the  
output will act like an open circuit; no current will flow out  
of the pin. If the input is powered by a voltage source, the  
output will source the short-circuit current of the device  
and will protect itself by thermal limiting. In this case,  
grounding the SHDN pin will turn off the device and stop  
the output from sourcing the short-circuit current.  
where,  
IOUT(MAX) = 150mA  
V
IN(MAX) = 6V  
IGND at (IOUT = 150mA, VIN = 6V) = 5mA  
So,  
P = 150mA(6V – 3.3V) + 5mA(6V) = 0.44W  
The thermal resistance will be in the range of 110°C/W to  
140°C/W depending on the copper area. So the junction  
temperature rise above ambient will be approximately  
equal to:  
The ADJ pin of the adjustable device can be pulled above  
or below ground by as much as 7V without damaging the  
device. Iftheinputisleftopencircuitorgrounded, theADJ  
pin will act like an open circuit when pulled below ground  
and like a large resistor (typically 100k) in series with a  
diode when pulled above ground.  
0.44W(125°C/W) = 55°C  
The maximum junction temperature will then be equal to  
the maximum junction temperature rise above ambient  
plus the maximum ambient temperature or:  
In situations where the ADJ pin is connected to a resistor  
divider that would pull the ADJ pin above its 7V clamp  
voltage if the output is pulled high, the ADJ pin input  
current must be limited to less than 5mA. For example, a  
resistor divider is used to provide a regulated 1.5V output  
fromthe1.22Vreferencewhentheoutputisforcedto20V.  
The top resistor of the resistor divider must be chosen to  
limitthecurrentintotheADJpintolessthan5mAwhenthe  
ADJ pin is at 7V. The 13V difference between output and  
ADJpindividedbythe5mAmaximumcurrentintotheADJ  
pin yields a minimum top resistor value of 2.6k.  
T
JMAX = 50°C + 55°C = 105°C  
Protection Features  
The LT1762 regulators incorporate several protection  
featureswhichmakethemidealforuseinbattery-powered  
circuits. In addition to the normal protection features  
associated with monolithic regulators, such as current  
limiting and thermal limiting, the devices are protected  
against reverse input voltages, reverse output voltages  
and reverse voltages from output to input.  
In circuits where a backup battery is required, several  
different input/output conditions can occur. The output  
voltage may be held up while the input is either pulled to  
ground, pulledtosomeintermediatevoltageorisleftopen  
circuit. Current flow back into the output will follow the  
curve shown in Figure 7.  
Current limit protection and thermal overload protection  
areintendedtoprotectthedeviceagainstcurrentoverload  
conditions at the output of the device. For normal opera-  
tion, the junction temperature should not exceed 125°C.  
The input of the device will withstand reverse voltages of  
20V.Currentflowintothedevicewillbelimitedtolessthan  
1mA (typically less than 100µA) and no negative voltage  
will appear at the output. The device will protect both itself  
and the load. This provides protection against batteries  
which can be plugged in backward.  
When the IN pin of the LT1762-X is forced below the OUT  
pin or the OUT pin is pulled above the IN pin, input current  
will typically drop to less than 2µA. This can happen if the  
input of the device is connected to a discharged (low  
voltage) battery and the output is held up by either a  
backup battery or a second regulator circuit. The state of  
the SHDN pin will have no effect on the reverse output  
current when the output is pulled above the input.  
The output of the LT1762-X can be pulled below ground  
withoutdamagingthedevice.Iftheinputisleftopencircuit  
or grounded, the output can be pulled below ground by  
1762fa  
14  
LT1762 Series  
U
W U U  
APPLICATIONS INFORMATION  
100  
T
= 25°C  
IN  
J
V
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
= 0V  
LT1762  
CURRENT FLOWS  
INTO OUTPUT PIN  
V
= V  
OUT  
SENSE  
(LT1762-2.5/LT1762-3  
LT1762-3.3/LT1762-5)  
LT1762-2.5  
V
= V  
OUT  
ADJ  
(LT1762)  
LT1762-3  
LT1762-5  
LT1762-3.3  
4
0
1
2
3
5
6
7
8
9
10  
OUTPUT VOLTAGE (V)  
1762 F07  
Figure 7. Reverse Output Current  
U
PACKAGE DESCRIPTION  
MS8 Package  
8-Lead Plastic MSOP  
(LTC DWG # 05-08-1660)  
0.118 ± 0.004*  
(3.00 ± 0.102)  
8
7
6
5
0.118 ± 0.004**  
(3.00 ± 0.102)  
0.193 ± 0.006  
(4.90 ± 0.15)  
1
2
3
4
0.040 ± 0.006  
(1.02 ± 0.15)  
0.034 ± 0.004  
(0.86 ± 0.102)  
0.007  
(0.18)  
0° – 6° TYP  
SEATING  
PLANE  
0.012  
(0.30)  
REF  
0.021 ± 0.006  
(0.53 ± 0.015)  
0.006 ± 0.004  
(0.15 ± 0.102)  
MSOP (MS8) 1098  
0.0256  
(0.65)  
BSC  
* DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH,  
PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE  
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.  
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE  
1762fa  
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.  
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-  
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.  
15  
LT1762 Series  
U
TYPICAL APPLICATION  
Paralleling of Regulators for Higher Output Current  
R1  
0.1Ω  
3.3V  
300mA  
IN  
OUT  
FB  
+
+
C1  
10µF  
C2  
10µF  
V
IN  
> 3.7V  
C4  
0.01µF  
LT1762-3.3  
SHDN  
BYP  
GND  
R2  
0.1Ω  
IN  
OUT  
C5  
0.01µF  
LT1762  
R6  
2k  
BYP  
ADJ  
SHDN  
SHDN  
GND  
R7  
1.21k  
R3  
2.2k  
R4  
2.2k  
8
3
2
R5  
10k  
+
1
1/2 LT1490  
–
4
1762 TA03  
C3  
0.01µF  
RELATED PARTS  
PART NUMBER  
LT1120  
DESCRIPTION  
125mA Low Dropout Regulator with 20µA I  
COMMENTS  
Includes 2.5V Reference and Comparator  
Q
LT1121  
150mA Micropower Low Dropout Regulator  
700mA Micropower Low Dropout Regulator  
30µA I , SOT-223 Package  
Q
LT1129  
50µA Quiescent Current  
LT1175  
500mA Negative Low Dropout Micropower Regulator  
45µA I , 0.26V Dropout Voltage, SOT-223 Package  
Q
LT1521  
300mA Low Dropout Micropower Regulator with Shutdown  
15µA I , Reverse Battery Protection  
Q
LT1529  
3A Low Dropout Regulator with 50µA I  
500mV Dropout Voltage  
Q
LT1611  
Inverting 1.4MHz Switching Regulator  
5V to –5V at 150mA, Low Output Noise, SOT-23 Package  
SOT-23 Package, Internally Compensated  
Burst ModeTM Operation, Monolithic, 100% Duty Cycle  
LT1613  
1.4MHz Single-Cell Micropower DC/DC Converter  
High Efficiency Synchronous Step-Down Switching Regulator  
LTC1627  
LT1761 Series  
LT1763 Series  
100mA, Low Noise, Low Dropout Micropower Regulators in SOT-23 20µA Quiescent Current, 20µV  
Noise  
Noise  
RMS  
RMS  
500mA, Low Noise, LDO Micropower Regulators  
30µA Quiescent Current, 20µV  
Burst Mode is a trademark of Linear Technology Corporation.  
1762fa  
LT 1006 REV A • PRINTED IN USA  
LinearTechnology Corporation  
1630 McCarthy Blvd., Milpitas, CA 95035-7417  
16  
●
●
(408)432-1900 FAX:(408)434-0507 www.linear-tech.com  
© LINEAR TECHNOLOGY CORPORATION 1999  

相关型号：

SI9130DB

 5- and 3.3-V Step-Down Synchronous Converters

Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY

SI9135LG-T1

 SMBus Multi-Output Power-Supply Controller

Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY

SI9135LG-T1-E3

 SMBus Multi-Output Power-Supply Controller

Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY

SI9135_11

 SMBus Multi-Output Power-Supply Controller

Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY

SI9136_11

 Multi-Output Power-Supply Controller

Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY

SI9130CG-T1-E3

 Pin-Programmable Dual Controller - Portable PCs

Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY

SI9130LG-T1-E3

 Pin-Programmable Dual Controller - Portable PCs

Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY

SI9130_11

 Pin-Programmable Dual Controller - Portable PCs

Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY

SI9137

 Multi-Output, Sequence Selectable Power-Supply Controller for Mobile Applications

Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY

SI9137DB

 Multi-Output, Sequence Selectable Power-Supply Controller for Mobile Applications

Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY

SI9137LG

 Multi-Output, Sequence Selectable Power-Supply Controller for Mobile Applications

Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY

SI9122E

 500-kHz Half-Bridge DC/DC Controller with Integrated Secondary Synchronous Rectification Drivers

Warning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
©2020 ICPDF网 联系我们和版权申明