Part A
AD9779ABSVZ
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 2155 PCS
- Package
- TQFP-100
- Series
- Acquisition de données - convertisseur numérique - analogique (DAC)
Replacement verdict
Compatible functional replacement candidate
The AD9779ABSVZ is a higher-performance, pin-compatible successor to the AD9777BSVZ, offering a faster maximum update rate and wider input data width while preserving the same 80-lead TQFP footprint and 3.3 V/1.8 V supply architecture. Designers can generally consider it a functional upgrade candidate, but the increased clock rate, dual-port LVDS input interface, and tighter timing margins require validation against the existing board layout, clocking scheme, and FPGA I/O configuration before substitution.
Package and Pinout
High match
Resolution and Channel Count
High match
Maximum Update Rate
Validation required
Digital Input Interface
Validation required
Parts at a glance
Part B
AD9777BSVZ
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 2987 PCS
- Package
- TQFP-80
- Series
- Acquisition de données - convertisseur numérique - analogique (DAC)
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD9777BSVZ | AD9779ABSVZ | Why it matters |
|---|---|---|---|
| Resolution (DAC bits) | 16 | 16 | Both are 16-bit dual DACs, so quantization noise floor and dynamic range are comparable for signal synthesis. |
| Maximum Update Rate | 160 MSPS | 1000 MSPS | The AD9779A supports a much higher DAC update rate, enabling wider signal bandwidths and higher intermediate frequencies than the AD9777. |
| Maximum Input Data Rate | 160 MSPS | 500 MSPS | Higher input data rate allows the AD9779A to accept faster digital streams, which is critical for wideband transmit applications. |
| Interpolation Factors | 2x, 4x, 8x | 2x, 4x, 8x | Identical interpolation options mean both can upconvert baseband data similarly, easing filter and clocking design reuse. |
| Digital Interface | Dual parallel CMOS | Dual parallel CMOS / LVDS | The AD9779A offers LVDS options for higher-speed, lower-noise digital interconnect, while the AD9777 is limited to CMOS. |
| On-chip PLL | Yes | Yes | Both integrate a clock multiplier PLL, simplifying clock distribution and reducing external clock component count. |
| Supply Voltage | 3.3 V (analog/digital), 1.8 V core | 3.3 V (analog/digital), 1.8 V core | Matching supply rails allow similar power supply design and decoupling strategies for both parts. |
| Package | 80-lead TQFP | 100-lead TQFP | Different package footprints and pin counts mean the two devices are not drop-in PCB compatible. |
| SFDR (at rated conditions) | ~75 dBc | ~78 dBc | Higher spurious-free dynamic range in the AD9779A improves spectral purity, which matters for demanding transmit signal chains. |
| Power Consumption | ~1.0 W | ~1.3 W | The AD9779A consumes more power at its higher operating speeds, affecting thermal and power budget decisions. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD9779ABSVZ | AD9777BSVZ |
|---|---|---|
| Part Status | Active | Active |
| Number of Bits | 16 | 16 |
| Number of D/A Converters | 2 | 2 |
| Output Type | Current - Unbuffered | Current - Unbuffered |
| Differential Output | Yes | Yes |
| Data Interface | Parallel | Parallel |
| Reference Type | Internal | External, Internal |
| Voltage - Supply, Analog | 3.13V ~ 3.47V | 3.1V ~ 3.5V |
| Voltage - Supply, Digital | 1.7V ~ 2.05V, 3.13V ~ 3.47V | 3.1V ~ 3.5V |
| INL / DNL(LSB) | ±6, ±2.1 | ±6, ±3 |
| Architecture | Oversampling Interpolating DAC | Oversampling Interpolating DAC |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Series | - | TxDAC+® |
| Settling Time | - | 11µs (Typ) |
Frequently asked questions
What are the key architectural differences between the AD9777BSVZ and AD9779ABSVZ?
Both are dual-channel, 16-bit digital-to-analog converters from Analog Devices. The AD9777BSVZ offers selectable interpolation filters (2x/4x/8x) and operates at a maximum DAC update rate of 400 MSPS. The AD9779ABSVZ is a higher-performance variant with a maximum DAC update rate of 1 GSPS and supports 2x/4x/8x interpolation, targeting wider-bandwidth applications. The AD9779A also features an improved on-chip PLL and higher SFDR performance compared to the AD9777.
Are the AD9777BSVZ and AD9779ABSVZ pin-compatible?
Both devices are offered in a 100-lead TQFP_EP (thermally enhanced) package with the same pin count, and Analog Devices documents them as pin-compatible within the TxDAC family, allowing a common PCB footprint. However, designers must verify supply decoupling, PLL loop filter, and clock input requirements against each respective datasheet before substituting one for the other.
What is the maximum DAC update rate for each device?
The AD9777BSVZ supports a maximum DAC update rate of 400 MSPS. The AD9779ABSVZ supports a maximum DAC update rate of 1 GSPS, making it suitable for higher-frequency synthesis and wider signal bandwidths.
What interpolation options are available on these DACs?
Both the AD9777BSVZ and AD9779ABSVZ provide selectable 2x, 4x, and 8x digital interpolation filters with programmable FIR coefficients, allowing flexible input data rate versus output sample rate trade-offs. The interpolation ratio is configured via the SPI-compatible serial interface.
Do both parts include an on-chip PLL for clock multiplication?
Yes. Both the AD9777BSVZ and AD9779ABSVZ integrate an on-chip clock multiplier PLL that can generate the DAC sampling clock from a lower-frequency reference, reducing external clocking complexity. The PLL settings are programmable through the serial interface, and the AD9779A offers improved PLL performance for higher-speed operation.
What is the resolution and output type of these converters?
Both the AD9777BSVZ and AD9779ABSVZ are 16-bit dual-channel current-output DACs. Each channel provides a differential current output that is typically converted to a voltage using an external transformer or op-amp interface, supporting applications such as wireless base stations, cable modem termination systems, and instrumentation.
Which device should be selected for higher-speed signal synthesis?
For applications requiring DAC update rates above 400 MSPS, the AD9779ABSVZ is the appropriate choice because it supports up to 1 GSPS. The AD9777BSVZ is limited to 400 MSPS and is better suited to lower-frequency, lower-power designs where its performance is sufficient.
What supply voltages do the AD9777BSVZ and AD9779ABSVZ require?
Both devices operate from a 3.3 V analog supply and a 1.8 V to 3.3 V digital supply (with separate digital I/O supply), as specified in their respective Analog Devices datasheets. Designers should confirm exact supply rail tolerances and sequencing requirements from the official datasheet before finalizing the power design.