ltc2640-lz8 Linear Technology Corporation, ltc2640-lz8 Datasheet - Page 14

• Manufacturer Part Number: ltc2640-lz8
• Description: Single 12-/10-/8-bit Spi Vout Dacs With Bidirectional Reference
• Manufacturer: Linear Technology Corporation

LTC2640
TYPICAL PERFORMANCE CHARACTERISTICS
LTC2640
PIN FUNCTIONS
CS/LD (Pin 1): Serial Interface Chip Select/Load Input.
When CS/LD is low, SCK is enabled for shifting data on
SDI into the register. When CS/LD is taken high, SCK
is disabled and the specifi ed command (see Table 1) is
executed.
SCK (Pin 2): Serial Interface Clock Input. CMOS and TTL
compatible.
SDI (Pin 3): Serial Interface Data Input. Data on SDI is
clocked into the DAC on the rising edge of SCK. The LTC2640
accepts input word lengths of either 24 or 32 bits.
GND (Pin 4): Ground.
V
(LTC2640-L) or 4.5V ≤ V
to GND with a 0.1μF capacitor.
REF (Pin 6): Reference Voltage Input or Output. When
External Reference mode is selected, REF is an input
(0V ≤ V
14
CC
–10
–12
–14
–16
–18
–2
–4
–6
–8
(Pin 5): Supply Voltage Input. 2.7V ≤ V
0
1k
Multiplying Bandwidth
V
V
V
CODE = FULL SCALE
CC
REF(DC)
REF(AC)
REF
= 5V
≤ V
= 2V
= 0.2V
10k
CC
FREQUENCY (Hz)
P-P
) where the voltage supplied sets the
100k
CC
≤ 5.5V (LTC2640-H). Bypass
2640 G33
1000k
500
400
300
200
100
0
100
Noise Voltage vs Frequency
CC
INTERNAL REF .
CODE = MIDSCALE
≤ 5.5V
1k
FREQUENCY (Hz)
LTC2640-H
(V
LTC2640-L
(V
CC
CC
10k
full-scale voltage. When Internal Reference is selected,
the 10ppm/°C 1.25V (LTC2640-L) or 2.048V (LTC2640-H)
internal reference is available at the pin. This output may
be bypassed to GND with up to 10μF (0.33μF is recom-
mended), and must be buffered when driving external DC
load current.
V
CLR (Pin 8, LTC2640-Z): Asynchronous Clear Input. A
logic low at this level-triggered input clears all registers
and causes the DAC voltage output to reset to Zero. CMOS
and TTL compatible.
REF_SEL (Pin 8, LTC2640-M): Selects default Reference
at power up. Tie to V
or GND to select an External Reference. After power-up,
the logic state at this pin is ignored and the reference may
be changed only by software command.
= 5V)
= 4V)
OUT
(Pin 7): DAC Analog Voltage Output.
100k
2640 G34
T
A
1M
= 25°C, unless otherwise noted.
10μV/DIV
CC
to select the Internal Reference,
0.1Hz to 10Hz Voltage Noise
LTC2640-L, V
INTERNAL REF .
CODE = MIDSCALE
CC
= 4V
1s/DIV
2640 G35
2640fa