Datasheet

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ELECTRICAL CHARACTERISTICS
UCD8220
SLUS652D – MARCH 2005 – REVISED OCTOBER 2006
V
DD
= 12 V, 4.7-F capacitor from V
DD
to AGND, 1 µ F from PVDD to PGND, 0.22-F capacitor from 3V3 to AGND,
T
A
= T
J
= -40C to 105C, (unless otherwise noted).
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
SUPPLY SECTION
Supply current, OFF V
DD
= 4.2 V 300 500 A
Supply current, ON (UCD8220), outputs not switching, CLK = low 2 3 mA
LOW VOLTAGE UNDERVOLTAGE LOCKOUT (UCD8220 only)
V
DD
UVLO ON 4.25 4.5 4.75
V
V
DD
UVLO OFF 4.05 4.25 4.45
V
DD
UVLO hysteresis 150 250 350 mV
REFERENCE / EXTERNAL BIAS SUPPLY
3V3 initial set point T
A
= 25C, I
LOAD
= 0 3.267 3.3 3.333
V
3V3 set point over temperature 3.234 3.3 3.366
3V3 load regulation I
LOAD
= 1 mA to 10 mA, VDD = 5 V - 1 6.6
mV
3V3 line regulation VDD = 4.75 V to 12 V, I
LOAD
= 10 mA - 1 6.6
Short circuit current VDD = 4.75 to 12 V 11 20 35 mA
3V3 OK threshold, ON 3.3 V rising 2.9 3.0 3.1
V
3V3 OK threshold, OFF 3.3 V falling 2.7 2.8 2.9
CLOCK INPUT (CLK)
HIGH, positive-going input threshold
1.65 - 2.08
voltage (VIT+)
LOW negative-going input threshold
1.16 - 1.5 V
voltage (VIT-)
Input voltage hysteresis,
0.6 - 0.8
(VIT+ - VIT-)
Frequency OUTx = 1 MHz - - 2 MHz
Minimum allowable off time
(1)
20 ns
SLOPE COMPENSATION (ISET)
ISET Voltage V
ISET
, 3V3 = 3.3 V, +/-2% 1.78 1.84 1.90 V
R
ISET
= 6.19 k Ω to AGND, CS = 0.25 V, CTRL = 2.5 V 1.48 2.12 2.76
m, V
SLOPE
(I-Mode) R
ISET
= 100 k Ω to AGND, CS = 0.25 V, CTRL = 2.5 V 0.099 0.142 0.185
R
ISET
= 499 k Ω to AGND, CS = 0.25 V, CTRL = 2.5 V 0.019 0.028 0.037
V/s
R
ISET
= 4.99 k Ω to 3V3, CTRL = 2.5 V 1.44 2.06 2.68
m, V
SLOPE
(V-Mode) R
ISET
= 100 k Ω to 3V3, CTRL = 2.5 V 0.079 0.114 0.148
R
ISET
= 402 k Ω to 3v3, CTRL = 2.5 V 0.019 0.027 0.035
ISET resistor range Current mode control; R
ISET
connected to AGND 6.19 499
k Ω
ISET resistor range Voltage mode control; R
ISET
connected to 3V3 4.99 402
Voltage mode control with Feed-Forward; R
ISET
connected to
ISET current range 3.7 300 µ A
VIN
PWM
PWM offset at CTRL input 3V3 = 3.3 V +/-2% 0.45 0.51 0.6 V
CTRL buffer gain
(1)
Gain from CTRL to PWM comparator input 0.5 V/V
CURRENT LIMIT (ILIM)
ILIM internal current limit threshold ILIM = OPEN 0.466 0.5 0.536 V
ILIM maximum current limit threshold ILIM = 3.3 V 0.975 1.025 1.075
V
ILIM current limit threshold ILIM = 0.75 V 0.700 0.725 0.750
ILIM minimum current limit threshold ILIM = 0.25 V 0.21 0.23 0.25 V
(1) Ensured by design. Not 100% tested in production.
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