LT1173 データシートの表示（PDF） - Linear Technology
部品番号
コンポーネント説明
メーカー
LT1173 Datasheet PDF : 16 Pages
| |||
LT1173
APPLICATI S I FOR ATIO
Using the Gain Block
The gain block (GB) on the LT1173 can be used as an error
amplifier, low battery detector or linear post regulator. The
gain block itself is a very simple PNP input op amp with an
open collector NPN output. The negative input of the gain
block is tied internally to the 1.245V reference. The posi-
tive input comes out on the SET pin.
Arrangement of the gain block as a low battery detector is
straightforward. Figure 12 shows hookup. R1 and R2 need
only be low enough in value so that the bias current of the
SET input does not cause large errors. 100kΩ for R2 is
adequate. R3 can be added to introduce a small amount of
hysteresis. This will cause the gain block to “snap” when
the trip point is reached. Values in the 1M-10M range are
optimal. The addition of R3 will change the trip point,
however.
+5V
V IN
LT1173
100k
R1
VBAT
1.245V
REF
–
AO
TO
SET
+
PROCESSOR
R2
GND
R3
R1 = VLB – 1.245V
11.7µA
VLB = BATTERY TRIP POINT
R2 = 100kΩ
R3 = 4.7MΩ
LT1173 • TA16
Figure 12. Setting Low Battery Detector Trip Point
Table 1. Component Selection for Common Converters
INPUT
VOLTAGE
OUTPUT
VOLTAGE
OUTPUT
CURRENT (MIN)
CIRCUIT
FIGURE
2.0-3.1
5
90mA
5
2.0-3.1
5
10mA
5
2.0-3.1
12
50mA
5
2.0-3.1
12
10mA
5
5
12
90mA
5
5
12
30mA
5
5
15
50mA
5
5
30
25mA
5
6.5-9.5
5
50mA
6
12-20
5
300mA
6
20-30
5
300mA
6
5
–5
75mA
7
12
–5
250mA
7
–5
5
150mA
8
–5
12
75mA
8
G = Gowanda
C = Coiltronics
* Add 68Ω from ILIM to VIN
** Add 100Ω from ILIM to VIN
INDUCTOR
VALUE
47µH
220µH
47µH
150µH
120µH
150µH
120µH
100µH
47µH
220µH
470µH
100µH
470µH
100µH
100µH
INDUCTOR
PART NUMBER
G GA10-472K, C CTX50-1
G GA10-223K, C CTX
G GA10-472K, C CTX50-1
G GA10-153K
G GA10-123K
G GA10-153K
G GA10-123K C CTX100-4
G GA10-103K, C CTX100-4
G GA10-472K, C CTX50-1
G GA20-223K
G GA20-473K
G GA10-103K, C CTX100-4
G GA40-473K
G GA10-103K, C CTX100-4
G GA10-103K, C CTX100-4
CAPACITOR
VALUE
100µF
22µF
47µF
22µF
100µF
47µF
47µF
10µF, 50V
100µF
220µF
470µF
100µF
220µF
220µF
47µF
NOTES
*
*
**
**
**
**
**
**
11
Share Link: 