Document
GT1504
150Khz, 2A PWM Buck Switching Regulator ■ General Description
The GT1504 is a monolithic integrated circuit that provide all the active functions for a step-down switching regulator, capable of driving a 2A load without additional transistor component. Requiring a minimum number of external component, the board space can be saved easily. The external shutdown function can be controlled by TTL logic level and then come into standby mode. The internal compensation makes feedback control have good line and load regulation without external design. Regarding protected function, thermal shutdown is to prevent over temperature operating from damage, and current limit is against over current operating of the output switch. The GT1504 operates at a switching frequency of 150Khz thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. Other features include a guaranteed +4% tolerance on output voltage under specified input voltage and output load conditions, and +15% on the oscillator frequency. The output version included fixed 3.3V, 5V, 12V, and an adjustable type. The packages are available in a standard 8-lead SOP8.
GT1504
150Khz, 2A PWM Buck Switching Regulator ■ Ordering Information ■
GT1504 XX X X
Output version -ADJ : Adjustable -33 : 3.3V -50 : 5.0V -12 : 12V Package BLANK: SOP-8L Packing Blank : Tube A : Taping
■ Features
- 3.3V, 5V, 12V and adjustable output versions - Adjustable version output voltage range, 1.23V to 37V +4% max over line and load condiction - SOP-8L packages - Voltage mode non-synchronous PWM control - Thermal-shutdown and current-limit protection - ON/OFF shutdown control input - Input voltage range up to 40V - Output load current: 2A - 150 kHz fixed frequency internal oscillator - Low power standby mode - Built-in switching transistor on chip
■ Applications
Simple High-efficiency step-down(buck) regulator Efficient preregulator for linear regulators On-card switching regulators Positive to negative converter Battery Charger
■ Block Diagram
SD
VIN
200mV Current Source bias 220 mV
1.235V Reference
2.5V Regulator
Start up
■ Pin Assignments
+ Comp _
■ Pin Descriptions
(Top View) VIN 1 Out 2 FB 3 SD 4 SOP-8L 8 GND 7 GND 6 GND 5 GND Name VIN Out Gnd FB SD
Comp +
Description Operating voltage input. Switching output. Ground. Output voltage feedback control. ON/OFF Shutdown.
FB
+ _
Amp Comp + Pre-driver
2A Switch
Output
150kHz OSC. Thermal Limit
Gnd
GMOS Technology Crop. www.gmos-semi.com 1/9 GMOS Technology Corp. www.gmos-semi.com 2/9
GT1504
150Khz, 2A PWM Buck Switching Regulator ■ Absolute Maximum Ratings
Symbol VCC VSD V FB VOUT PD TOP VOP
GT1504
150Khz, 2A PWM Buck Switching Regulator
Parameter Supply Voltage ON/OFF Pin input voltage Feedback Pin voltage Output voltage to Ground Power dissipation Storage temperature Operating temperature Operating voltage
Rating +45 -0.3 to +25 -0.3 to +25 -1 Internally limited -65 to +150 -40 to +125 +4.5 to +25
Unit V V V V W
o o
■ Electrical Characteristics (Continued)
Symbol VFB GT1504-ADJ
Parameter Output Feedback Efficiency Output voltage Efficiency Output voltage Efficiency Output voltage Efficiency
Conditions 5V < VIN < 40V 0.2A < ILOAD < 2A V OUT programmed for 3V V IN = 12V, ILOAD=2A 5.5V < VIN < 40V 0.2A < ILOAD < 2A V IN = 12V, ILOAD=2A 8V < VIN < 40V 0.2A < ILOAD < 2A V IN = 12V, ILOAD=2A 15V < VIN < 40V 0.2A < ILOAD < 2A VIN = 15V, ILOAD = 2A
Typ.
Limit
Unit V VMIN V MAX %
1.235
1.193/1.18 1.267/1.28
TST
C C
η VOUT GT1504-3.3V
75 3.3 75 5 80 12 90 11.52/11.4 12.48/12.6 4.8/4.75 5.2/5.25 3.168/3.135 3.432/3.465
V
V VMIN V MAX % V VMIN V MAX % V VMIN V MAX %
■ Electrical Characteristics (All Output Voltage Versions)
Unless otherwise specified, V
IN =12V
η Max. -50 -100 173 173 Unit GT1504-5V nA Khz GT1504-12V Khz V % 3.3 A uA mA 10 150 200 0.6 mA uA VOUT
for 3.3V, 5V, adjustable version and V
IN=24V
for the 12V version. I LOA D = 0.2A
Symbol IB
Parameter Feedback bias current oscillator frequency
Conditions V FB=1.3V (Adjustable version only)
Min.
Typ. -10
η VOUT
FOSC
127 110
150
Oscillator frequency short circuit protect Fscp
VSAT DC
of When current limit occurred and V FB <0.55V IOUT =1.5A saturation voltage no outside circuit V FB=0V force driver on Max. Duty Cycle(ON) V FB=0V force driver on Min. Duty cycle(OFF) V FB=12V force driver off peak current current limit 2.4 no outside circuit V FB=0 force driver on no outside circuit Output = 0V Output Leakage V FB=12 force driver off Output = -1V Current V IN =24V Quiescent Current Standby Quiescent Current ON/OFF pin logic input threshold voltage
30 1.25 100 0 2.8
70 1.4 1.5
η
Specifications with boldface type are for full operating temperature range, the other type are for T =25_C. J
ICL
3.6 -200
IL IQ ISTBY VIL VIH IH IL Ts
-5 5 70
V FB=12 force driver off ON/OFF pin=5V V IN =24V Low (regulator ON) High (regulator.