The SP9601 is a very low power 12-Bit Digital-to-Analog Converter. It features ±4.5V output
swings when using ±5 volt supplies. The converter uses a standard 3–wire serial interface
compatible with SPI™, QSPI™ and Microwire™. The output settling-time is specified at 30µs. The
SP9601 is available in 8–pin 0.15" SOIC and DIP packages, specified over commercial and
industrial temperature ranges.
These are stress ratings only and functional operation of the device
at these or any other above those indicated in the operation
sections of the specifications below is not implied. Exposure to
absolute maximum rating conditions for extended periods of time
may affect reliability.
The SP9601 consists of four main functional
blocks – the input shift register, DAC register,
12-Bit D/A converter and a bipolar output voltage amplifier, Figure 1.
The input shift register is used to convert the
serial input data stream to a parallel 12–Bit
digital word. The input data is shifted on positive clock (SCLK) edges when the Chip Select
(CS) signal is in the “low” state. The MSB is
loaded first and LSB last. No shifting of the
input data occurs when the Chip Select (CS)
signal is in the “high” state.
PIN ASSIGNMENTS
Pin 1- V
– Voltage Output.
OUT
Pin 2- VDD – +5V Power Supply Input.
Pin 3- SCLK – Serial Clock Input.
Pin 4- DIN – Serial Data Input.
Pin 5- CS – Chip Select Input.
Pin 6- VSS– –5V Power Supply Input.
Pin 7- GND – Ground.
Pin 8- V
– Reference Input.
REF
FEATURES...
The SP9601 is a low power 12–Bit Digital-toAnalog Converter. The converter features ±4.5V
output swings with ±5V supplies. The input
coding format used is standard offset binary,
Table 1.
This Digital-to Analog Converter uses a standard 3–wire interface compatible with SPI™,
QSPI™ and Microwire™. The output settling
time is specified at 30µs to full 12-bit accuracy
when driving a 5KΩ, 50pF load combination.
The SP9601 Digital-to-Analog Converter is
ideally suited for applications such as ATE,
process controllers, robotics and instrumentation. The SP9601 is available in an 8-pin 0.15"
SOIC and 0.3" PDIP packages, specified over
commercial and industrial temperature ranges.
The DAC register is used to store the digital
word which is sent to the DAC. Its value is
updated on the positive transition of the Chip
Select (CS) signal.
In order to reduce the DAC full scale output
sensitivity to the large weighting of the MSB's
found in conventional R-2R resistor ladders, the
3 MSB's are decoded into 8 equally weighted
levels. This reduces the contribution of each bit
by a factor of 4, thus, reducing the output sensitivity to mismatches in resistors and switches by
the same amount. Linearity errors and stability
are both improved for the same reasons.
The DAC itself is implemented with precision
thin-film resistors and CMOS transmission gate
switches. The resistor network is laser-trimmed
to achieve better than 12–Bit accuracy. The D/
A converter is used to convert the 12-bit input
word to a precision voltage.
The operational amplifier is a rail-to-rail input,
rail-to-rail output CMOS amplifier. It is capable
of supplying 5mA of load current in the ±3 volt
output range. The initial offset voltage is lasertrimmed to improve accuracy. Settling time is
30µs for a full scale output transition to 0.024%
accuracy.
The bipolar voltage output of the SP9601 is
created on chip from the DAC output voltage
(V
) by using an operational amplifier and
DAC
two feedback resistors connected as shown in
Figure 2. This configuration produces a ±4.5V
bipolar output range with standard offset binary
coding, Table 1.
USING THE SP9601
External Reference
The DAC input resistance is code dependent
and is minimum at code 1877 and nearly infinite
at code 0. Because of the code-dependent nature
of the reference a high quality, low output impedance amplifier should be used to drive the
V
input.
REF
Serial Clock and Update Rate
The SP9601 maximum serial clock rate (SCLK)
is given by 1/(tCH+tCL) which is approximately
12.5 MHz. The digital word update rate is limited by the chip select period, which is 12 X
SCLK periods plus the CS high pulse width t
This is equal to a 1 µs or 1 MHz update rate.
CSW
However, the DAC settling time to 12–Bits is 30
µs, which for full scale output transitions would
limit the update rate to 33 kHz.
Logic Interface
The SP9601 is designed to be compatible with
TTL and CMOS logic levels. However, driving
the digital inputs with TTL level signals will
increase the power consumption of the part by
300 µA. In order to achieve the lowest power
consumption use rail-to-rail CMOS levels to
drive the digital inputs.
Midscale Preset
By holding CS pin low during Power-up, the
DAC output can be forced to 0V. Following
Power-up, the CS pin should be kept low as the
first digital word is shifted into the shift register.
When CS pin is set high, the digital word in the
shift register (loaded by the last 12 clock cycles)
is latched into the DAC register. Thus, the DAC
can be forced to go from midscale (1000 0000
0000, on Power-up) to any digital state, without
entering an unknown state.
Model .................................................................................. Temperature Range .......................................................................................Package
Monolithic 12-Bit DAC Voltage Output:
SP9601JN ................................................................................ 0˚C to +70˚C........................................................................ 8-pin, 0.3" Plastic DIP
SP9601KN ............................................................................... 0˚C to +70˚C........................................................................ 8-pin, 0.3" Plastic DIP
SP9601JS ................................................................................0˚C to +70˚C ...............................................................................8–pin, 0.15" SOIC
SP9601KS ...............................................................................0°C to +70°C ................................................................................ 8–pin, 0.15" SOIC
SP9601AN ............................................................................... –40˚C to +85˚C ................................................................... 8-pin, 0.3" Plastic DIP
SP9601BN ............................................................................... –40˚C to +85˚C ................................................................... 8-pin, 0.3" Plastic DIP
SP9601AS ...............................................................................–40˚C to +85˚C .......................................................................... 8–pin, 0.15" SOIC
SP9601BS ...............................................................................–40°C to +85 °C ............................................................................8–pin, 0.15" SOIC
Corporation
SIGNAL PROCESSING EXCELLENCE
Sipex Corporation
Headquarters and
Sales Office
22 Linnell Circle
Billerica, MA 01821
TEL: (978) 667-8700
FAX: (978) 670-9001
e-mail: sales@sipex.com
Sales Office
233 South Hillview Drive
Milpitas, CA 95035
TEL: (408) 934-7500
FAX: (408) 935-7600
Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the
application or use of any product or circuit described hereing; neither does it convey any license under its patent rights nor the rights of others.