参数资料
| 型号： | ISL8033IRZ |
| 厂商： | Intersil |
| 文件页数： | 14/18页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 3A DL 24QFN |
| 标准包装： | 75 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 2 |
| 输出电压： | 0.8 V ~ 6 V |
| 输入电压： | 2.85 V ~ 6 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 1.1MHz |
| 电流 - 输出： | 3A |
| 同步整流器： | 是 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-VFQFN 裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 24-QFN（4x4） |
ISL8033, ISL8033A
Typical Operating Performance ISL8033A
Unless otherwise noted, operating conditions are: T A = +25°C, V IN = 5V, EN = V IN , L1 = 0.68μH, L2 = 1 μ H, C1 = C2 = C4 = 2x22μF, V OUT1 = 1.2V, V OUT2 =
1.8V, I OUT1 = I OUT2 = 0A to 3A. (Continued)
V OUT1 RIPPLE 50mV/DIV
IL1 2A/DIV
FIGURE 38. LOAD TRANSIENT CHANNEL 1
Theory of Operation
The ISL8033 is a dual 3A step-down switching regulator optimized
for battery-powered or mobile applications. The regulator operates
at 1MHz fixed switching frequency under heavy load condition. The
ISL8033A operates at 2.5MHz to allow small external inductor and
capacitors to be used for minimal printed-circuit board (PCB) area.
The two channels are 180° out-of-phase operation. The supply
current is typically only 8μA when the regulator is shutdown.
PWM Control Scheme
Pulling the SYNC pin HI (>1.5V) forces the converter into PWM
mode in the next switching cycle regardless of output current.
Each of the channels of the ISL8033, ISL8033A employ the
current-mode pulse-width modulation (PWM) control scheme for
fast transient response and pulse-by-pulse current limiting, as
shown in the “Theory of Operation” on page 14. The current loop
consists of the oscillator, the PWM comparator COMP, current
sensing circuit, and the slope compensation for the current loop
stability. The current sensing circuit consists of the resistance of
the P-channel MOSFET when it is turned on and the current sense
amplifier CSA1. The gain for the current sensing circuit is
typically 0.20V/A. The control reference for the current loops
comes from the error amplifier EAMP of the voltage loop.
The PWM operation is initialized by the clock from the oscillator.
The P-channel MOSFET is turned on at the beginning of a PWM
cycle and the current in the MOSFET starts to ramp-up. When the
sum of the current amplifier CSA1 (or CSA2 on Channel 2) and the
compensation slope (0.46V/μs) reaches the control reference of
the current loop, the PWM comparator COMP sends a signal to the
PWM logic to turn off the P-MOSFET and to turn on the N-channel
MOSFET. The N-MOSFET stays on until the end of the PWM cycle.
Figure 40 shows the typical operating waveforms during the PWM
operation. The dotted lines illustrate the sum of the compensation
ramp and the current-sense amplifier CSA_ output.
14
V OUT2 RIPPLE 50mV/DIV
IL2 2A/DIV
FIGURE 39. LOAD TRANSIENT CHANNEL 2
The output voltage is regulated by controlling the reference
voltage to the current loop. The bandgap circuit outputs a 0.8V
reference voltage to the voltage control loop. The feedback signal
comes from the VFB pin. The soft-start block only affects the
operation during the start-up and will be discussed separately.
The error amplifier is a transconductance amplifier that converts
the voltage error signal to a current output. The voltage loop is
internally compensated with the 27pF and 390k Ω RC network.
The maximum EAMP voltage output is precisely clamped to the
bandgap voltage (1.172V).
V EAMP
V CSA1
Duty
Cycle
I L
V OUT
FIGURE 40. PWM OPERATION WAVEFORMS
Synchronization Control (ISL8033)
The frequency of operation can be synchronized up to 6MHz by an
external signal applied to the SYNC pin. The 1st falling edge on the
SYNC triggered the rising edge of the PWM ON pulse of Channel 1. The
2nd falling edge of the SYNC triggers the rising edge of the PWM ON
pulse of the Channel 2. This process alternates indefinitely allowing
180° output phase operation between the two channels.
FN6854.2
March 24, 2011
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| ISL8033IRZ-T | 功能描述:IC REG BUCK SYNC ADJ 3A DL 24QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 类型:降压（降压） 输出类型:两者兼有 输出数:1 输出电压:5V，1 V ~ 10 V 输入电压:3.5 V ~ 28 V PWM 型:电流模式 频率 - 开关:220kHz ~ 1MHz 电流 - 输出:600mA 同步整流器:无 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:16-SSOP（0.154"，3.90mm 宽） 包装:带卷 (TR) 供应商设备封装:16-QSOP |
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