DS1123LE-50+ Maxim Integrated Products, DS1123LE-50+ Datasheet - Page 12

• Manufacturer Part Number: DS1123LE-50+
• Description: IC TIMING ELEMENT PROG 16-TSSOP
• Manufacturer: Maxim Integrated Products

Specifications of DS1123LE-50+

• Number Of Taps/steps: 256
• Function: Programmable
• Delay To 1st Tap: 16.5nS
• Tap Increment: 0.5nS
• Available Total Delays: 127.5ns
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Number Of Independent Delays: -

3.3V, 8-Bit, Programmable Timing Element
Figure 7. Reference Delay Timing, MS = 0
Figure 8. Delay Parameters
IN do not benefit from the REF output’s tendency to track
OUT over temperature and voltage. Figure 9 shows INL’s
effect on delay performance graphically.
To configure the DS1123L as a monostable vibrator, set
MS = 1. This causes the reference output (PWM) to be
set high between t
input. After time period t
returns low, and the monostable vibrator can be retrig-
gered. See Figure 10 for the timing of the OUT and
PWM signals. When MS = 1 and the DS1123L is trig-
gered by an external free-running oscillator, reference
output becomes a pulse-width modulator (PWM). When
using the DS1123L as a PWM, the free-running oscillator
should not be generated by connecting OUT to the input.
This causes the PWM period to change in addition to the
duty cycle as different values are programmed, which is
most likely not the desired functionality.
12
Configuring the DS1123L as a Monostable
DELAY
t
DMAX
t
REF
t
_____________________________________________________________________
D0
0
IN
t
REF0
REF
DS1123L
and t
D
D
has elapsed, the output
when it is triggered by the
REF
OUT
Vibrator or PWM
OUT
REF
IN
t
DREF
255
STEP
t
D0
t
REF
t
WI
The minimum pulse width that can be practically gener-
ated is approximately 5ns. This is because a 5ns pulse
is approximately the shortest pulse that can be pro-
duced with the DS1123L’s output driver. The mono-
stable vibrator cannot be retriggered, so subsequent
triggering pulses into IN should not be present until
after the output has returned low.
To configure the DS1123L as an adjustable oscillator,
set MS = 1 and externally connect OUT to IN. Setting
MS = 1 by itself inverts the input signal in addition to
delaying it (see Figure 10). Connecting OUT to the
input then causes the circuit to oscillate with the period
being twice the programmed delay. Table 2 shows the
oscillator frequency ranges that the different speed
grades of DS1123Ls provide.
Figure 9. Integral Nonlinearity
Configuring the DS1123L as an Oscillator
t
MEASURED
MEASURED
DMAX
DELAY
t
DREF
t
REF
t
D0
0
64
MEASURED DELAY
t
FOR ALL STEPS
DMAX
EXAGGERATED
128
LINE FIT BETWEEN
MEASURED MAX
AND MIN DELAY
192
INL
255
STEP