Other Parts Discussed in Thread: DAC7563, OPA2140, TPS7A49, TPS7A30
Hi,
1º.- I need to adapt the output of an analog signal of a DAC7563 from 0..5V to -5V..5V (the load is around 2.5Kohms). This is my design:
I need to design the power supply, but I'm not sure wether Vb+ = 5V and Vb- = -5V it's enough. In the datasheet says that the input voltage range in Common-mode voltage (Vcm) is:
Common mode voltage range (min) = (Vb-) -0.1 = -5 -0.1 = -5.1V
Common mode voltage range (max) = (Vb+) -3.5 = 5-3.5 = 1.5V
According to my design:
V+(max) = 20/(10+20)*Vouta(max = 5V) = 3.33 V, then I need: 5-3.33 = 1.67 V more in Vb+, therefore Vb+ = 5 + 1.67 = 6.67Volts.
Definitely, I need at least 6.67 Volts to not limit the input.
Is this calculation correct?
Can I use for example Vb+ = 10V and Vb-= -10V to feed the op2140? I'm not to be at the edge
2º.- My problem know is how to get -10V and +10V because I only have a power supply of 12 Volts@1A in my design.
I've got 3 units of dac7563, 3 units of opa2140, 1 unit of ref5025, 1 unit of TPS7A49 to get 10V and 1 unit of TPS7A30 to get -10V, so the power consumption it'll be around 100mWatts. The power consumption actually isn't a problem.
Any ideas?
I found these uModule step-down regulators from Linear Technology LTM8020 or LTM8022 that can produce negative output voltages from positive inputs.
Is there some Texas Instruments power module similar from these type of uModules from Linear Technology?
Thank you so much. Best regards.