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UTC L2800 LINEAR INTEGRATED CIRCUIT
SWITCHING REGULATOR
CONTROLLER(LOW VOLTAGE)
DESCRIPTION
The UTC L2800 is a single-channel switching
regulator control IC for low voltage applications
incorporating a soft start function and short circuit
detection function. The device has a low minimum
operating voltage of 1.8V and is ideal for the power
supply of battery-operated electronic equipment.
FEATURES
*Wide supply voltage operating range: 1.8V~15V
*Low current consumption: Typically 5.5mA in
operation,1µA or less in stand-by
*High speed operation is possible: Maximum 1MHz
*The error amplifier gain is set inside the IC,so
peripheral components are minimized.
*Incorporates a soft start circuit.
*Incorporates a timer-latch type short circuit detection
circuit (SCP).
*Totem-pole type output with adjustable on/off current
(for NPN transistors)
*Incorporates a stand-by function.
PIN CONFIGURATION
SOP-8
TSSOP-8
-IN 1
SCP
Vcc
BR/CTL
2
3
4
FB
8
OSC
7
6
GND
5
OUT
UTC UNISONIC TECHNOLOGIES CO., LTD.
QW-R121-010,A
1
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UTC L2800 LINEAR INTEGRATED CIRCUIT
PIN DESCRIPTION
PIN NO. SYMBOL I/O DESCRIPTION
1 -IN I Error amplifier inverting input pin
2 SCP - Soft start and SCP setting capacitor connection pin
3 VCC - Power supply pin
4 BR/CTL I Output current setting and control pin
5 OUT O Totem-pole type output pin
6 GND - Ground pin
7 OSC - Capacitor and resistor connection pin for setting the oscillation frequency
8 FB O Error amplifier output pin
BLOCK DIAGRAM
Vcc OSC
3 7
-IN
FB
Reference
voltage supply
1.25V
1
8
-
+
Error Amp.
0.5V
6 2 4
0.6V
0.1V
36kΩ
500Ω
Soft start
SCP
Sawtooth
wave oscillator
0.1V
PWM
Comp.
+
+
+
DTC 0.6V
Output drive
control circuit
0.3V
BR/CTLSCPGND
30kΩ
5
OUT
ABSOLUTE MAXIMUM RATINGS (Ta=25℃)
Power Supply Voltage Vcc 16 V
Output Source Current IO+ -50 mA
Output Sink Current IO- 50 mA
Power Dissipation
Storage Temperature Tstg -55 ~ +125
Operating Temperature Top -30 ~ +85
* When mounted on a 10cm square double-sided epoxy board.
PARAMETER SYMBOL RATINGS UNIT
SOP-8
TSSOP-8
PD
570*
580*
mW
°C
°C
UTC UNISONIC TECHNOLOGIES CO., LTD.
QW-R121-010,A
2
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UTC L2800 LINEAR INTEGRATED CIRCUIT
RECOMMENDED OPERATING CONDITIONS (Ta=25°C)
PARAMETER SYMBOL MIN TYP MAX UNIT
Power Supply Voltage Vcc 1.8 15 V
Error Amplifier Input Voltage VI -0.2 1.0 V
BR/CTL Pin Input Voltage VBR -0.2 Vcc V
Output Source Current IO+ -40 mA
Output Sink Current IO- 40 mA
SCP Pin Capacitance CPE 0.1
Phase Compensation Capacitance CP 0.1
Output Current Setting Resistance RB 150 390 5000
Timing Resistance RT 1.0 3.0 10.0
Timing Capacitance CT 100 270 10000 pF
Oscillation Frequency fosc 10 500 1000 kHz
Operating Temperature Top -30 +25 +85
ELECTRICAL CHARACTERISTICS
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Circuit to prevent
malfuncition at low input
oltage (U.V.L.O)
Soft Start
Short Circuit
Detection(S.C.P.)
Sawtooth Wave
Oscillator(OSC)
Error Amplifier
Idle Period Adjustment
Section
Output Section
Reset Voltage VR 0.9 V
Threshold Voltage VTH
Charging Current Ics VSCP=0V -1.5 -1.0 -0.7
Voltage at soft start
completion
Charging Current Icpc VSCP=0V -1.5 -1.0 -0.7
Threshold Voltage VtPC 0.7 0.8 0.9 V
Oscillation Frequency
Frequency Input
Stability
Frequency Variation
With Temperature
Input Threshold Voltage VT VFB=450mV 480 500 520 mV
VT Input Stability VTdV Vcc=2V ~ 15V 5 20 mV
VT Variation With
Temperature
Input Bias Current IB VIN=0V -1.0 -0.2 1.0
Voltage Gain Av 70 100 145 V/V
Frequency Bandwidth BW AV=0dB 6 MHz
Voltage Range
Output Source Current IOM+ -40 -24
Output Sink Current I
Maximum Duty Cycle tDUTY
Output Voltage
Output Source Current IO+
Output Sink Current IOPull Down Resistance RO 20 30 40
(Ta=25°C, VCC=+2V)
Vts 0.7 0.8 0.9 V
fosc
RT=3.0kΩ, CT=270pF
fdV Vcc=2V ~ 15V 2 10 %
fdT
Ta=-30°C ~ +85°C
Ta=-30°C ~ +85°C
VTdT
VOM+ 0.78 0.87 V Maximum Output
OM
V
OM
VOH1
VOH2
VOL1
VOL2
-
V
FB=0.45V
-
R
T=3.0kΩ, CT=270pF
VFB=0.8V
RB=390Ω, Io=-15mA
RB=750Ω, Vcc=1.8V
Io= -10mA
RB=390Ω, Io=15mA
RB=750Ω, Vcc=1.8V
Io=10mA
RB=390Ω, Vo=0.9V
RB=390Ω, Vo=0.3V
1.1 1.3 1.5 V
400 500 600 kHz
5 %
1 %
0.05 0.2 V
24 40
65 75 85 %
1.0 1.2 V
0.8 1.0 V
0.1 0.2 V
0.1 0.2 V
-30 -20 mA
30 60 mA
µF
µF
Ω
kΩ
°C
µA
µA
µA
µA
µA
kΩ
UTC UNISONIC TECHNOLOGIES CO., LTD.
QW-R121-010,A
3