CAT523 Datasheet, PDF (10/15 Pages) Catalyst Semiconductor – Configured Digitally Programmable Potentiometer (DPP): Programmable Voltage Applications

CAT523
Not Recommended for New Design
+5V
V_DD
V_REF
V_REFH
FINE ADJUST
DPP
127R_C
CAT523
COARSE ADJUST
DPP
GND
V_REFL
+V
R_C
+
V_OFFSET
–
V_REF
R_C = _{256 x 1µA}
Fine adjust gives ±1 LSB change in V_OFFSET
when V_OFFSET = V_REF/2
Coarse-Fine Offset Control by Averaging DPP
Outputs for Single Power Supply Systems
+5V
2.2kΩ
V_DD
4.7µF
V_REFH
CONTROL
& DATA
DPP1
CAT523
+5V
10kΩ
+5V
V_DD
+V_REF
V_REFH
FINE ADJUST
DPP
127R_C
CAT523
COARSE ADJUST
R_C
DPP
GND
V_REFL
R₀
-V_REF
(+V_REF) - (V_OFFSET+)
R_C =
1µA
R₀ =
(-V_REF) + (V_OFFSET+)
1µA
V_OFFSET
+V
+
–
-V
Coarse-Fine Offset Control by Averaging DPP
Outputs for Dual Power Supply Systems
LM385-2.5
+15V
+
–
10kΩ
I_SINK = 2 - 255mA
2N7000
39Ω 1W
39Ω 1W
1mA steps
DPP2
GND
V_REFL
5MΩ
+
–
5MΩ
2N7000
3.9kΩ
5µA steps
10kΩ
10kΩ
–
+
TIP30
Doc. No. MD-2005 Rev. I
-15V
Current Sink with 4 Decades of Resolution
10
© 2008 SCILLC. All rights reserved.
Characteristics subject to change without notice