LTC2220/LTC2221
12
22201fa
(CMOS Mode)
AIN+ (Pins 1, 2): Positive Differential Analog Input.
AIN– (Pins 3, 4): Negative Differential Analog Input.
REFHA (Pins 5, 6): ADC High Reference. Bypass to
Pins 7, 8 with 0.1
F ceramic chip capacitor, to Pins 11, 12
with a 2.2
F ceramic capacitor and to ground with 1F
ceramic capacitor.
REFLB (Pins 7, 8): ADC Low Reference. Bypass to Pins 5,
6 with 0.1
F ceramic chip capacitor. Do not connect to
Pins 11, 12.
REFHB (Pins 9, 10): ADC High Reference. Bypass to
Pins 11, 12 with 0.1
F ceramic chip capacitor. Do not
connect to Pins 5, 6.
REFLA (Pins 11, 12): ADC Low Reference. Bypass to
Pins 9, 10 with 0.1
F ceramic chip capacitor, to Pins 5, 6
with a 2.2
F ceramic capacitor and to ground with 1F
ceramic capacitor.
VDD (Pins 13, 14, 15, 62, 63): 3.3V Supply. Bypass to
GND with 0.1
F 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 0.1
F
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 VDD results in normal operation with the
outputs at high impedance. Connecting SHDN to VDD and
OE to GND results in nap mode with the outputs at high
impedance. Connecting SHDN to VDD and OE to VDD
results in sleep mode with the outputs at high impedance.
OE (Pin 20): Output Enable Pin. Refer to SHDN pin
function.
UU
U
PI FU CTIO S
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.
OVDD (Pins 26, 34, 42, 49): Positive Supply for the
Output Drivers. Bypass to ground with 0.1
F 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 1/3VDD selects demux CMOS mode with simulta-
neous update. Connecting LVDS to 2/3VDD selects demux
CMOS mode with interleaved update. Connecting LVDS to
VDD 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 1/3VDD selects offset
binary output format and turns the clock duty cycle stabi-
lizer on. Connecting MODE to 2/3VDD selects 2’s comple-
ment output format and turns the clock duty cycle stabi-
lizer on. Connecting MODE to VDD selects 2’s complement
output format and turns the clock duty cycle stabilizer off.