lt5537 Linear Technology Corporation, lt5537 Datasheet - Page 14

• Manufacturer Part Number: lt5537
• Description: Wide Dynamic Range Rf/if Log Detector
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
LT5537
Enable Pin Operation
The enable circuit of the LT5537 is shown in a simplified
form in Figure 12. When the voltage at the ENBL pin is ≥1V,
the enable circuit biases the chip up for normal operation.
The current drawn by the ENBL pin is dependent on the
voltage on that pin. At V
is typically 100µA. At V
increases to about 200µA. When the voltage at the ENBL
pin is ≤0.3V, or if the pin is not connected, the chip is
disabled and draws a reduced supply current of about
500µA, with V
14
CC
= 3V.
U
CC
CC
INPUT
U
= ENBL = 5V, the ENBL current
= ENBL = 3V, the ENBL current
W
R2
51Ω
Figure 14. Layout of the Evalulation Board
100pF
100pF
Figure 13. Application Board Schematic
C1
C2
U
1
2
3
4
ENBL
IN
IN
CAP
+
–
+
LT5537
33nF
C6
CAP
OUT
V
V
CC
EE
–
8
7
6
5
5537 F19
R1
33k
C3
1nF
Figure 12. Equivalent ENBL Input Circuit
C4
1µF
ENBL
ENBL
OUTPUT
V
CC
25k
5537 F04
5537fa