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AT84AD001B
2153C–BDC–04/04
Description The AT84AD001B is a monolithic dual 8-bit analog-to-digital converter, offering low
1.4W power consumption and excellent digitizing accuracy. It integrates dual on-chip
track/holds that provide an enhanced dynamic performance with a sampling rate of up to
1 Gsps and an input frequency bandwidth of over 1.5 GHz. The dual concept, the inte-
grated demultiplexer and the easy interleaving mode make this device user-friendly for
all dual channel applications, such as direct RF conversion or data acquisition. The
smart function of the 3-wire serial interface eliminates the need for external compo-
nents, which are usually necessary for gain and offset tuning and setting of other
parameters, leading to space and power reduction as well as system flexibility.
Functional Description
The AT84AD001B is a dual 8-bit 1 Gsps ADC based on advanced high-speed
BiCMOS technology.
Each ADC includes a front-end analog multiplexer followed by a Sample and Hold (S/H),
and an 8-bit flash-like architecture core analog-to-digital converter. The output data is
followed by a switchable 1:1 or 1:2 demultiplexer and LVDS output buffers (100Ω).
Two over-range bits are provided for adjustment of the external gain control on each
channel.
A 3-wire serial interface (3-bit address and 16-bit data) is included to provide several
adjustments:
• Analog input range adjustment (±1.5 dB) with 8-bit data control using a 3-wire bus
interface (steps of 0.18 dB)
• Analog input switch: both ADCs can convert the same analog input signal I or Q
• Gray or binary encoder output. Output format: DMUX 1:1 or 1:2 with control of the
output frequency on the data ready output signal
• Partial or full standby on channel I or channel Q
• Clock selection:
– Two independent clocks: CLKI and CLKQ
– One master clock (CLKI) with the same phase for channel I and channel Q
– One master clock but with two phases (CLKI for channel I and CLKIB for
channel Q)
• ISA: Internal Settling Adjustment on channel I and channel Q
• FiSDA: Fine Sampling Delay Adjustment on channel Q
• Adjustable Data Ready Output Delay on both channels
• Test mode: decimation mode (by 16), Built-In Test.
A calibration phase is provided to set the two DC offsets of channel I and channel Q
close to code 127.5 and calibrate the two gains to achieve a maximum difference of
0.5 LSB. The offset and gain error can also be set externally via the 3-wire serial
interface.
The AD84AD001B operates in fully differential mode from the analog inputs up to the
digital outputs. The AD84AD001B features a full-power input bandwidth of 1.5 GHz.
