Rainbow Electronics MAX5153 - Manual (Page 9)

_______________Detailed Description
The MAX5152/MAX5153 dual, 13-bit, voltage-output
DACs are easily configured with a 3-wire serial inter-
face. These devices include a 16-bit data-in/data-out
shift register, and each DAC has a double-buffered
input comprised of an input register and a DAC register
(see
Functional Diagram ). Both DACs use an inverted
R-2R ladder network that produces a weighted voltage
proportional to the input voltage value. Each DAC has
its own reference input to facilitate independent full-
scale values. Figure 1 depicts a simplified circuit dia-
gram of one of the two DACs.
Reference Inputs
The reference inputs accept both AC and DC values
with a voltage range extending from 0V to (V
DD - 1.4V).
Determine the output voltage using the following equa-
tion:
V OUT = V REF x NB / 8192
where NB is the numeric value of the DAC’s binary input
code (0 to 8191) and V
REF is the reference voltage.
The reference input impedance ranges from 14k
Ω
(1555
hex) to several giga ohms (with an input code of 0000
hex). This reference input capacitance is code depen-
dent and typically ranges from 15pF with an input code
of all zeros to 50pF with an input code of all ones.
Output Amplifier
The output amplifier’s inverting input is available to the
user, allowing force and sense capability for remote
sensing and specific gain configurations. The inverting
input can be connected to the output to provide a unity-
gain buffered output. The output amplifiers have a typi-
cal slew rate of 0.75V/µs and settle to 1/2LSB within
25µs, with a load of 10k
Ω
in parallel to 100pF. Loads
less than 2k
Ω
degrade performance.
MAX5152/MAX5153
Low-Power, Dual, 13-Bit Voltage-Output DACs
with Configurable Outputs
_______________________________________________________________________________________ 9
______________________________________________________________Pin Description
PIN
Analog Ground AGND 1
FUNCTION NAME
DAC A Output Voltage OUTA 2
Reference for DAC A REFA 4
DAC A Output Amplifier Feedback Input. Inverting input of the output amplifier. FBA 3
Chip-Select Input CS 6
Serial Clock Input SCLK 8
Serial Data Input DIN 7
Active-Low Clear Input. Resets all registers to zero. DAC outputs go to 0V. CL 5
Serial Data Output DOUT 10
Power-Down Lockout. The device cannot be powered down when PDL is low. PDL 12
User-Programmable Output UPO 11
DAC B Output Amplifier Feedback Input. Inverting input of the output amplifier. FBB 14
Positive Power Supply V DD 16
DAC B Output Voltage OUTB 15
Reference Input for DAC B REFB 13
Digital Ground DGND 9
OUT_
FB_
SHOWN FOR ALL 1s ON DAC
D0 D10 D11 D12
2R 2R 2R 2R 2R
R R R
REF_
AGND
Figure 1. Simplified DAC Circuit Diagram