SLUS224 Data sheet

SLUS224H September 1994 – October 2024 UC1842A , UC1843A , UC1844A , UC1845A , UC2842A , UC2843A , UC2844A , UC2845A , UC3842A , UC3842M , UC3843A , UC3844A , UC3845A

PRODUCTION DATA

5.5 Electrical Characteristics

Unless otherwise stated, these specifications apply for T_A = –55°C to 125°C (UC184xA), T_A = –40°C to 125°C (UC284xAQ), T_A = –40°C to 85°C (UC284xA), T_A = 0°C to 70°C (UC384xA); T_A = T_J; V_CC = 15 V⁽⁴⁾; R_T = 10 kΩ; C_T = 3.3 nF.

PARAMETER		TEST CONDITIONS		MIN	TYP	MAX	UNIT
REFERENCE
	Output voltage	T_J = 25°C, I_O = 1 mA	UC184xA, UC284xA	4.95	5	5.05	V
	Output voltage	T_J = 25°C, I_O = 1 mA	UC384xA	4.9	5	5.1	V
	Line regulation	12 ≤ V_IN ≤ 25 V			6	20	mV
	Load regulation	1 ≤ I_O ≤ 20 mA			6	25	mV
	Temperature stability	See ⁽¹⁾⁽⁶⁾			0.2	0.4	mV/°C
	Total output variation	Line, Load, Temperature	UC184xA, UC284xA	4.9		5.1	V
	Total output variation	Line, Load, Temperature	UC384xA	4.82		5.18	V
	Output noise voltage	10 Hz ≤ f ≤ 10 kHz; T_J = 25°C⁽¹⁾			50		µV
	Long-term stability	T_A = 125°C, 1000 hrs⁽¹⁾			5	25	mV
	Output short circuit			–30	–100	–180	mA
OSCILLATOR
	Initial accuracy	T_J = 25°C⁽⁵⁾		47	52	57	kHz
	Voltage stability	12 ≤ V_CC ≤ 25 V			0.2%	1%
	Temperature stability	T_MIN ≤ T_A ≤ T_MAX⁽¹⁾			5%
	Amplitude	V_RT/CT peak to peak⁽¹⁾			1.7		V
	Discharge current	T_J = 25°C, V_RT/CT = 2 V⁽⁷⁾		7.8	8.3	8.8	mA
		V_RT/CT = 2 V⁽⁷⁾	UC184xA, UC284xA	7.5		8.8
		V_RT/CT = 2 V⁽⁷⁾	UC384xA	7.6		8.8
ERROR AMPLIFIER
	Input voltage	V_COMP = 2.5 V	UC184xA, UC284xA	2.45	2.5	2.55	V
	Input voltage	V_COMP = 2.5 V	UC384xA	2.42	2.5	2.58	V
	Input bias current				–0.3	–1	µA
	Input bias current				–0.3	–2	µA
A_VOL	Open-loop gain	2 ≤ V_O ≤ 4 V		65	90		dB
	Unity gain bandwidth	T_J = 25°C⁽¹⁾		0.7	1		MHz
CMRR	Common mode rejection ratio	12 ≤ V_CC ≤ 25 V		60	70		dB
	Output sink current	V_FB = 2.7 V, V_COMP = 1.1 V		2	6		mA
	Output source current	V_FB = 2.3 V, V_COMP = 5 V		–0.5	–0.8		mA
	V_OUT high	V_FB = 2.3 V, R_L = 15 kΩ to ground		5	6		V
	V_OUT low	V_FB = 2.7 V, R_L = 15 kΩ to VREF			0.7	1.1	V
CURRENT SENSE
	Gain	See ⁽²⁾⁽³⁾		2.85	3	3.15	V/V
	Maximum input signal	V_COMP = 5 V⁽²⁾		0.9	1	1.1	V
PSRR	Power supply rejection ratio	12 ≤ V_CC ≤ 25 V⁽²⁾			70		dB
	Input bias current				–2	–10	µA
	Delay to output	V_ISENSE = 0 to 2 V⁽¹⁾			150	300	ns
OUTPUT
	Output low level	I_SINK = 20 mA			0.1	0.4	V
	Output low level	I_SINK = 200 mA			1.5	2.2	V
	Output high level	I_SOURCE = 20 mA		13	13.5		V
	Output high level	I_SOURCE = 200 mA		12	13.5		V
	Rise time	T_J = 25°C, C_L = 1 nF⁽¹⁾			25	150	ns
	Fall time	T_J = 25°C, C_L = 1 nF⁽¹⁾			25	150	ns
	UVLO saturation	V_CC = 5 V, I_SINK = 10 mA			0.7	1.2	V
UNDERVOLTAGE LOCKOUT
	Start threshold	UC1842A, UC1844A, UC2842A, and UC2844A		15	16	17	V
		UC3842A and UC3844A		14.5	16	17.5
		UCx843A and UCx845A		7.8	8.4	9
	Minimum operation voltage after turnon	UC1842A, UC1844A, UC2842A, and UC2844A		9	10	11	V
		UC3842A and UC3844A		8.5	10	11.5
		UCx843A and UCx845A		7	7.6	8.2
PWM
	Maximum duty cycle	UCx842A, UCx843A		92%	96%	100%
	Maximum duty cycle	UCx844A, UCx845A		46%	48%	50%
	Minimum duty cycle					0%
TOTAL STANDBY CURRENT
	Start-up current				0.3	0.5	mA
	Operating supply current	V_FB = V_ISENSE = 0 V			11	17	mA
	V_CC Zener voltage	I_CC = 25 mA		30	39		V

(1) Verified by design, but not 100% production tested.

(2) Parameter measured at trip point of latch with V_FB = 0.

(3) Gain defined as: A = ΔV_COMP / ΔV_ISENSE; 0 ≤ V_ISENSE ≤ 0.8 V.

(4) Adjust V_CC above the start threshold before setting at 15 V.

(5) Output frequency equals oscillator frequency for the UCx842A and UCx843A. Output frequency is one half oscillator frequency for the UCx844A and UCx845A.

(6) Temperature stability, sometimes referred to as average temperature coefficient, is described by: Temperature stability = ( V_REF(max) – V_REF(min)) / (T_J(max) – T_J(min) ). V_REF(max) and V_REF(min) are the maximum and minimum reference voltage measured over the appropriate temperature range. Note that the extremes in voltage do not necessarily occur at the extremes in temperature.

(7) This parameter is measured with R_T = 10 kΩ to V_REF. This contributes approximately 300 µA of current to the measurement. The total current flowing into the RT/CT pin is approximately 300 µA higher than the measured value.