1. Product Overview: SPT9713 Digital-to-Current Converter (D/C)

️· Function: The SPT9713 is a high-speed digital-to-current converter. It takes digital input data and converts it into analog current outputs (Iout+ and Iout-).
️· Key Features:
- High-speed conversion.
- Internal voltage reference (can be bypassed for external reference).
- Output currents are proportional to digital input.
- Latchable architecture: Data is latched on the rising edge of the latch enable signal.
- Replacing AD9713: Designed as a drop-in replacement for the AD9713.

2. Technical Specifications & Formulas

️· Full-Scale Output Current: `I_out(FS) = (Control Amp In / R Set) * 128`
- Control Amp In: Voltage reference input.
- R_Set: Connection for external resistance (nominally 7.5 kΩ). This value dictates the full-scale current.
️· Output Voltage Calculation: (For a given resistive load R_L)
- `R_eff = R_out || R_L` (Parallel combination of output resistance and load resistance)
- `V_out = R_eff * I_out(FS)`
️· Internal Voltage Reference: Typically -1.20V with a tolerance of ±0.05V and drift of 50 ppm/°C.
️· Package Dimensions Dimensions for 28-lead PLCC packaging

3. Pin Assignments and Functions

Pin Name	Function
Out+	Analog Current Output
Out–	Complementary Analog Current Output
D1–D12	Digital Input Bits (D12 is LSB)
Latch Enable	Latch Control Line
Ref In	Voltage Reference Input
Ref Out	Internal Voltage Reference Output (connect to Control Amp In if not using external reference)
Ref GND	Ground Return For Internal Voltage Reference and Amplifier
Control Amp In	Normally connected to Ref Out.
Control Amp Out	Output of Internal Control Amplifier.
R Set	Connection for external resistance
Analog Return	Analog Ground
Analog V EE	Analog Negative Supply
Digital V EE	Digital Negative Supply
Digital V CC	Digital Positive Supply
DGND	Digital Ground

4. Ordering Information:

️· SPT9713AIP: ±0.75/±1.0 DNL/INL, –40 to +85 °C, 28L PLCC.
️· SPT9713BIP: ±1.25/±1.5 DNL/INL, –40 to +85 °C, 28L PLCC.

Key Analysis and Takeaways

️· Target Application: This converter is likely used in applications requiring precise analog current control, such as:
- Motor control
- LED drivers
- Programmable voltage sources (using current-to-voltage conversion)
- Precision signal generation
️· Design Considerations:
- The external resistance, R_Set, is crucial for setting the full-scale output current.
- The output load resistance (R_L) affects the output voltage and accuracy. Careful selection is needed.
- The data sheet emphasizes its drop-in replacement capability for the AD9713, suggesting compatibility in existing designs.
️· DNL/INL: DNL (Differential Non-Linearity) and INL (Integral Non-Linearity) are important parameters that describe the accuracy of the digital-to-analog conversion. Lower values are better. The different part numbers (AIP and BIP) offer different levels of these specifications.