LTC2220-1 Datasheet, PDF (9/28 Pages) Linear Technology – 12-Bit,185Msps ADC

LTC2220-1
PI FU CTIO S
(CMOS Mode)
A_IN+ (Pins 1, 2): Positive Differential Analog Input.
A_IN– (Pins 3, 4): Negative Differential Analog Input.
REFHA (Pins 5, 6): ADC High Reference. Bypass to
Pins 7, 8 with 0.1µF ceramic chip capacitor, to Pins 11, 12
with a 2.2µF ceramic capacitor and to ground with 1µF
ceramic capacitor.
REFLB (Pins 7, 8): ADC Low Reference. Bypass to Pins 5,
6 with 0.1µF ceramic chip capacitor. Do not connect to
Pins 11, 12.
REFHB (Pins 9, 10): ADC High Reference. Bypass to
Pins 11, 12 with 0.1µF ceramic chip capacitor. Do not
connect to Pins 5, 6.
REFLA (Pins 11, 12): ADC Low Reference. Bypass to
Pins 9, 10 with 0.1µF ceramic chip capacitor, to Pins 5, 6
with a 2.2µF ceramic capacitor and to ground with 1µF
ceramic capacitor.
V_DD (Pins 13, 14, 15, 62, 63): 3.3V Supply. Bypass to
GND with 0.1µF ceramic chip capacitors.
GND (Pins 16, 61, 64): ADC Power Ground.
ENC⁺ (Pin 17): Encode Input. Conversion starts on the
positive edge.
ENC^– (Pin 18): Encode Complement Input. Conversion
starts on the negative edge. Bypass to ground with 0.1µF
ceramic for single-ended ENCODE signal.
SHDN (Pin 19): Shutdown Mode Selection Pin. Connect-
ing SHDN to GND and OE to GND results in normal
operation with the outputs enabled. Connecting SHDN to
GND and OE to V_DD results in normal operation with the
outputs at high impedance. Connecting SHDN to V_DD and
OE to GND results in nap mode with the outputs at high
impedance. Connecting SHDN to V_DD and OE to V_DD
results in sleep mode with the outputs at high impedance.
OE (Pin 20): Output Enable Pin. Refer to SHDN pin
function.
DB0 - DB11 (Pins 21, 22, 23, 24, 27, 28, 29, 30, 31, 32,
35, 36): Digital Outputs, B Bus. DB11 is the MSB. At high
impedance in full rate CMOS mode.
OGND (Pins 25, 33, 41, 50): Output Driver Ground.
OV_DD (Pins 26, 34, 42, 49): Positive Supply for the
Output Drivers. Bypass to ground with 0.1µF ceramic chip
capacitor.
OFB (Pin 37): Over/Under Flow Output for B Bus. High
when an over or under flow has occurred. At high imped-
ance in full rate CMOS mode.
CLKOUTB (Pin 38): Data Valid Output for B Bus. In demux
mode with interleaved update, latch B bus data on the
falling edge of CLKOUTB. In demux mode with simulta-
neous update, latch B bus data on the rising edge of
CLKOUTB. This pin does not become high impedance in
full rate CMOS mode.
CLKOUTA (Pin 39): Data Valid Output for A Bus. Latch A
bus data on the falling edge of CLKOUTA.
DA0 - DA11 (Pins 40, 43, 44, 45, 46, 47, 48, 51, 52, 53,
54, 55): Digital Outputs, A Bus. DA11 is the MSB.
OFA (Pin 56): Over/Under Flow Output for A Bus. High
when an over or under flow has occurred.
LVDS (Pin 57): Output Mode Selection Pin. Connecting
LVDS to 0V selects full rate CMOS mode. Connecting
LVDS to 1/3V_DD selects demux CMOS mode with simulta-
neous update. Connecting LVDS to 2/3V_DD selects demux
CMOS mode with interleaved update. Connecting LVDS to
V_DD selects LVDS mode.
MODE (Pin 58): Output Format and Clock Duty Cycle
Stabilizer Selection Pin. Connecting MODE to 0V selects
offset binary output format and turns the clock duty cycle
stabilizer off. Connecting MODE to 1/3V_DD selects offset
binary output format and turns the clock duty cycle stabi-
lizer on. Connecting MODE to 2/3V_DD selects 2’s comple-
ment output format and turns the clock duty cycle stabi-
lizer on. Connecting MODE to V_DD selects 2’s complement
output format and turns the clock duty cycle stabilizer off.
SENSE (Pin 59): Reference Programming Pin. Connecting
SENSE to V_CM selects the internal reference and a ±0.5V
input range. Connecting SENSE to V_DD selects the internal
reference and a ±1V input range. An external reference
greater than 0.5V and less than 1V applied to SENSE
selects an input range of ±V_SENSE. ±1V is the largest valid
input range.
V_CM (Pin 60): 1.6V Output and Input Common Mode Bias.
Bypass to ground with 2.2µF ceramic chip capacitor.
GND (Exposed Pad): ADC Power Ground. The exposed
pad on the bottom of the package needs to be soldered to
ground.
2220_1fa
9