Product Summary

The UC2845BNG is a high performance current mode pwm controller. The UC2845BNG provides the necessary features to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. Internally implemented circuits include a trimmed oscillator for precise DUTY CYCLE CONTROL under voltage lock out featuring start - up current less than 0.5mA, a precision reference trimmed for accuracy at the error ampinput, logic to insure latched operation, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high peak current. The out put stage, suitable for driving N-Channel MOSFETs, is low in the offstate. The UC2845BNG has UVLO thresholds of 16V (on) and 10V (off), ideally suited off-line applications.

Parametrics

UC2845BNG absolute maximum ratings: (1)Supply Voltage (low impedance source), Vi: 30 V; (2)Supply Voltage (Ii < 30mA), Vi: Self Limiting; (3)Output Current, IO: ±1 A; (4)Output Energy (capacitive load), EO: 5 mJ; (5)Analog Inputs: -0.3 to 5.5 V; (6)Error Amplifier Output Sink Current: 10 mA; (7)Power Dissipation at Tamb ≤ 25℃ (Minidip), Ptot: 1.25 W; (8)Power Dissipation at Tamb ≤ 25℃ (SO8), Ptot: 800 mW; (9)Storage Temperature Range, Tstg: -65 to 150℃; (10)Junction Operating Temperature, TJ: -40 to 150℃; (11)Lead Temperature (soldering 10s), TL: 300℃.

Features

UC2845BNG features: (1)trimmed oscillator for precise fre-quency control; (2)oscillator frequency guaranteed at 250kHz; (3)current mode operation to 500khz; (4)automatic feed forward compensa-tion; (5)latching pwm for cycle-by-cycle current limiting; (6)internally trimmed reference with undervoltage lockout; (7)high current totempoleoutput; (8)undervoltage lockout with hyster-esis; (9)low start-upandoperatingcurrent.

Diagrams

UC2845BNG block diagram

Image Part No Mfg Description Data Sheet Download Pricing
(USD)		 Quantity
UC2845BNG
UC2845BNG
ON Semiconductor
Current Mode PWM Controllers ANA SMPS PWM CONTROLLER
Data Sheet
0-1: $0.38
1-25: $0.34
25-100: $0.29
100-250: $0.25
Image Part No Mfg Description Data Sheet Download Pricing
(USD)		 Quantity
UC28023DW
UC28023DW
Texas Instruments
Current Mode PWM Controllers Economy High Speed
Data Sheet
0-1: $2.77
1-25: $1.96
25-100: $1.78
100-250: $1.55
UC28023DWG4
UC28023DWG4
Texas Instruments
Current Mode PWM Controllers Economy High Speed
Data Sheet
0-1: $2.47
1-25: $2.03
25-100: $1.78
100-250: $1.55
UC28023DWR
UC28023DWR
Texas Instruments
Current Mode PWM Controllers Economy High Speed
Data Sheet
0-1490: $1.09
1490-2000: $1.06
2000-5000: $1.01
UC28023DWRG4
UC28023DWRG4
Texas Instruments
Current Mode PWM Controllers Economy High Speed
Data Sheet
0-1490: $1.09
1490-2000: $1.06
2000-5000: $1.01
UC28023N
UC28023N
Texas Instruments
Current Mode PWM Controllers Economy High Speed
Data Sheet
0-1: $2.47
1-25: $2.03
25-100: $1.78
100-250: $1.55
UC28023NG4
UC28023NG4
Texas Instruments
Current Mode PWM Controllers Economy High Speed
Data Sheet
0-1: $2.47
1-25: $2.03
25-100: $1.78
100-250: $1.55