ltc6993-1 Linear Technology Corporation, ltc6993-1 Datasheet - Page 10

• Manufacturer Part Number: ltc6993-1
• Description: Electrical Specifications Subject To Change
• Manufacturer: Linear Technology Corporation

LTC6993-1/LTC6993-2
LTC6993-3/LTC6993-4
pin FuncTions
V
ply should be kept free from noise and ripple. It should be
bypassed directly to the GND pin with a 0.1µF capacitor.
DIV (Pin 2/Pin 4): Programmable Divider and Polarity
Input. The DIV pin voltage (V
into a 4-bit result (DIVCODE). V
a resistor divider between V
to ensure an accurate result. The DIV pin and resistors
should be shielded from the OUT pin or any other traces
that have fast edges. Limit the capacitance on the DIV pin
to less than 100pF so that V
DIVCODE (POL) determines the polarity of the OUT pins.
When POL = 0 the output produces a positive pulse. When
POL = 1 the output produces a negative pulse.
SET (Pin 3/Pin 3): Pulse Width Setting Input. The voltage
on the SET pin (V
amount of current sourced from the SET pin (I
grams the master oscillator frequency. The I
range is 1.25µA to 20µA. The output pulse will continue
indefinitely if I
and will terminate when I
connected between SET and GND is the most accurate
way to set the pulse width. For best performance, use
a precision metal or thin film resistor of 0.5% or better
tolerance and 50ppm/°C or better temperature coefficient.
For lower accuracy applications an inexpensive 1% thick
film resistor may be used.
Limit the capacitance on the SET pin to less than 10pF
to minimize jitter and ensure stability. Capacitance less
0
+
(Pin 1/Pin 5): Supply Voltage (2.25V to 5.5V). This sup-
SET
SET
drops below approximately 500nA,
) is regulated to 1V above GND. The
SET
DIV
+
(DCB/S6)
and GND. Use 1% resistors
DIV
increases again. A resistor
settles quickly. The MSB of
DIV
) is internally converted
may be generated by
SET
SET
current
) pro-
than 100pF maintains the stability of the feedback circuit
regulating the V
TRIG (Pin 4/Pin 1): Trigger Input. Depending on the ver-
sion, a rising or falling edge on TRIG will initiate the output
pulse. LTC6993-1 and LTC6993-2 are rising-edge sensitive.
LTC6993-3 and LTC6993-4 are falling-edge sensitive.
The LTC6993-2 and LTC6993-4 are retriggerable, allowing
the pulse width to be extended by additional trigger signals
that occur while the output is active. The LTC6993-1/
LTC6993-3 will ignore additional trigger inputs until the
output pulse has terminated.
GND (Pin 5/Pin 2): Ground. Tie to a low inductance ground
plane for best performance.
OUT (Pin 6/Pin 6): Output. The OUT pin swings from
GND to V
30Ω. When driving an LED or other low impedance load a
series output resistor should be used to limit source/sink
current to 20mA.
+
with an output resistance of approximately
V
+
SET
R
SET
TRIG
GND
SET
voltage.
LTC6993
69931234 PF
OUT
DIV
V
+
C1
0.1µF
V
+
R1
R2
69931234p