NCP3126
http://onsemi.com
4
Table 3. ELECTRICAL CHARACTERISTICS (−40°C < T
J
< 125°C; V
IN
= 12 V, BST−VSW = 12 V, BST = 12 V, V
SW
= 24 V, for
min/max values unless otherwise noted.)
Characteristic
Conditions Min Typ Max Unit
Input Voltage Range V
IN
− GND 4.5 13.2 V
Boost Voltage Range VBST − GND 4.5 26.5 V
SUPPLY CURRENT
Quiescent Supply Current
VFB = 1.0 V, No Switching, V
IN
= 13.2 V 1.0 − 10.0 mA
Shutdown Supply Current VFB = 1.0 V, COMP = 0 V, V
IN
= 13.2 V − 4.0 − mA
Boost Quiescent Current VFB = 1.0 V, No Switching, V
IN
= 13.2 V 0.1 − 1.0 mA
UNDER VOLTAGE LOCKOUT
V
IN
UVLO Threshold V
IN
Rising Edge 3.8 − 4.3 V
V
IN
UVLO Hysteresis − − 430 − mV
SWITCHING REGULATOR
VFB Feedback Voltage,
Control Loop in Regulation
T
J
= 0 to 25°C, 4.5 V < V
CC
< 13.2 V
−40°C v T
J
v 125°C, 4.5 v V
CC
v 13.2 V
792
784
800
800
808
816
mV
Oscillator Frequency T
J
= 0 to 25°C, 4.5 V < V
CC
< 13.2 V
−40°C v T
J
v 125°C, 4.5 v V
CC
v 13.2 V
300
290
350
350
400
410
kHz
Ramp−Amplitude Voltage 0.8 1.1 1.4 V
Minimum Duty Ratio − 5.5 − %
Maximum Duty Ratio 70 75 80 %
PWM COMPENSATION
Transconductance
3.0 − 5 ms
Open Loop DC Gain C
O
= 1 nF 55 70 − dB
Output Source Current
Output Sink Current
V
FB
< 0.8 V
V
FB
> 0.8 V
60
60
125
125
200
200
mA
Input Bias Current − 0.160 1.0
mA
ENABLE
Enable Threshold
0.3 0.4 0.5 V
SOFT−START
Delay to Soft−Start
3 − 15 ms
SS Source Current VFB < 0.8 V − 10.5 −
mA
Switch Over Threshold VFB = 0.8 V − 100 − % of Vref
OVER−CURRENT PROTECTION
OCSET Current Source
Sourced from ISET pin, before SS − 10 −
mA
OC Switch−Over Threshold − 700 − mV
Fixed OC Threshold − 375 mV
PWM OUTPUT STAGE
High−Side Switch On−Resistance
V
IN
= 12 V (Note 5)
V
IN
= 5 V (Note 5)
80
105
140
175
mW
Low−Side Switch On−Resistance V
IN
= 12 V (Note 5)
V
IN
= 5 V (Note 5)
45
65
75
100
mW
5. Guaranteed by design.
