Datasheet

UCC1895, UCC2895, UCC3895
SLUS157P –DECEMBER 1999–REVISED JUNE 2013 www.ti.com
ELECTRICAL CHARACTERISTICS (continued)
V
DD
= 12 V, R
T
= 82 kΩ, C
T
= 220 pF, R
DELAB
= 10 kΩ, R
DELCD
= 10 kΩ, C
REF
= 0.1 μF, C
VDD
= 0.1 μF and no load on the
outputs, T
A
= T
J
. T
A
= 0°C to 70°C for UCC3895x, T
A
= –40°C to +85°C for UCC2895x and T
A
= –55°C to +125°C for the
UCC1895x. (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
No-load comparator turn-off threshold 0.45 0.5 0.55
No-load comparator turn-on threshold 0.55 0.6 0.69 V
No-load comparator hysteresis 0.035 0.1 0.165
OSCILLATOR
f
OSC
Frequency T
J
= 25°C 473 500 527 kHZ
Frequency total variation( Over line, temperature 2.5% 5%
V
IH_SYNC
SYNC input threshold, SYNC 2.05 2.1 2.4
V
OH_SYNC
High-level output voltage, SYNC I
SYNC
= –400 μA, V
CT
= 2.6 V 4.1 4.5 5 V
V
OL_SYNC
Low-level output voltage, SYNC I
SYNC
= 100 μA, V
CT
= 0 V 0 0.5 1
Sync output pulse width LOAD
SYNC
= 3.9 kΩ and 30 pF in parallel 85 135 ns
V
RT
Timing resistor voltage 2.9 3 3.1
V
CT(peak)
Timing capacitor peak voltage 2.25 2.35 2.55 v
V
CT(valley)
Timing capacitor valley voltage 0 0.2 0.4
CURRENT SENSE
I
CS(bias)
Current sense bias current 0 V < CS < 2.5 V –4.5 20 µA
0 V ADS < 2.5 V
Peak current threshold 1.9 2 2.1 V
Overcurrent threshold 2.4 2.5 2.6 V
Current sense to output delay 0 V ≤ CS ≤ 2.3 V 75 110 ns
DELAB = DELCD = REF
SOFT-START/SHUTDOWN
I
SOURCE
Softstart source current SS/DISB = 3.0 V –40 –35 –30 µA
CS = 1.9 V
I
SINK
Softstart sink current SS/DISB = 3.0 V, 325 350 375 µA
CS = 2.6 V
Softstart/disable comparator 0.44 0.5 0.56 V
threshold
ADAPTIVE DELAY SET (ADS)
DELAB/DELCD output voltage ADS = CS = 0 V 0.45 0.5 0.55
V
ADS = 0 V 1.9 2 2.1
CS = 2 V
t
DELAY
Output delay
(2)(3)
ADS = CS = 0 V 450 560 620 ns
ADS bias current 0 V < ADS < 2.5 V –20 20 µA
0 V < CS < 2.5 V
(2) Ensured by design. Not production tested.
(3) Output delay is measured between OUTA and OUTB, or OUTC and OUTD. Output delay is defined as shown below where: t
f(OUTA)
=
falling edge of OUTA signal, t
r(OUTB)
= rising edge of OUTB signal (see Figure 1 and Figure 2).
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