Rainbow Electronics MAX5259 User Manual

Page 14

MAX5258/MAX5259

+3V/+5V, Low-Power, 8-Bit Octal DAC
with Rail-to-Rail Output Buffers

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Don’t Care

8-Bit Data

Load All DACs with Shift-Register Data

(LDAC = X)

All eight DAC registers are updated with shift-register data. This command allows all DACs to be set to any analog
value within the reference range. This command can be used to substitute CLEAR if code 00 (hex) is programmed,
which clears all DACs. This command brings the device out of shutdown.

Address

8-Bit Data

Load Input Register, DAC Registers Unchanged (Single Update Operation)

(LDAC = X)

When performing a single update operation, A2-A0 selects the respective input register. At the rising edge of CS, the
selected input register is loaded with the current shift-register data. All DAC outputs remain unchanged. This pre-
loads individual data in the input register without changing the DAC outputs.

Address

8-Bit Data

Load Input and DAC Registers

(LDAC = X)

This command directly loads current shift-register data in the selected input and DAC registers at the rising edge of
CS. A2-A0 set the DAC address.

For example, to load all eight DAC registers simultaneously with individual settings, eight commands are required.
First perform seven single input register update operations (C2 = 1, C1 = 0, C0 = 1) for DACs A, B, C, D, E, F, and G
(C2 = 1, C1 = 0, C0 = 1). The final command loads input register H and updates all eight DAC registers from their
respective input registers. This command brings the device out of shutdown.

Address

8-Bit Data

Software “

LDAC

” Command

(LDAC = X)

All DAC registers are updated with the contents of their respective input registers at the rising edge of CS. This is a
synchronous software command that performs the same function as the asynchronous LDAC.