max555ccbtd Maxim Integrated Products, Inc., max555ccbtd Datasheet - Page 6

• Manufacturer Part Number: max555ccbtd
• Description: Max555 300msps, 12-bit Dac With Complementary Voltage Outputs
• Manufacturer: Maxim Integrated Products, Inc.

weighted currents), which are applied directly to the out-
put of the resistor-divider network. The second group,
bits D5–D3 (three binary weighted currents), is applied
to the middle of the divider network. The middle of the
network divides the current seen at the output by 8. The
third group, bits D2–D0 (three additional binary weighted
current sources), is applied to the input of the resistive
network, dividing the current seen at the output by 64.
Glitching is reduced by decoding the four MSBs into 15
identical current sources and synchronizing data with a
master/slave register at every current switch. Data bits
are transferred to the output on the positive-going edge
of the clock, with the BYPASS input asserted low. In the
asynchronous mode with the BYPASS input asserted
high, the latches are transparent and data is trans-
300Msps, 12-Bit DAC with
Complementary Voltage Outputs
Figure 1. Functional Diagram
6
_______________________________________________________________________________________
MSB (D11)
ROFFSET
LSB (D0)
BYPASS
12 INPUTS
(1V FS)
REF/2
CLK
CLK
REF
400Ω
2
REGISTER
MASTER
DIGITAL SECTION
400Ω
800Ω
4
DECODER
4 TO 15
8
15
CONTROL AMPLIFIER
REGISTER
SLAVE
I = V
IN
/R
IN
15
8
800Ω
AV
EE
ferred to the output regardless of the clock state. All
digital inputs are ECL compatible. The clock input is
differential.
The control amplifier forces a reference current, which is
replicated in the current sources. This reference current is
nominally 1.25mA. It can be supplied by an external cur-
rent source, or by an external voltage source of 1.000V
applied to the REF input.
A reference input of V
scale output voltage of V
for the VOUT output. The output coding is summarized
in Table 1.
SWITCHING
SOURCES
NETWORK
CURRENT
AND
LBIAS
I1
I2
I3
I3
I2
I1
V
FS
DV
17
17
= 4096 / 4095 x VOUT (code 0)
3
3
3
3
EE
RESISTOR-DIVIDER NETWORK
÷ 8
÷ 8
MAX555
AV
REF
EE
FS
= 1.000V will produce a full-
ALTCOMPIB
ALTCOMPC
= -1.000V, where:
LOOPCRNT
÷ 8
÷ 8
AGND
50Ω
50Ω
IO
IO
DGND
VOUT
LGND
VOUT