ISL9491ERZ Renesas

DATASHEET ISL9491, ISL9491A FN6531 Rev 1.00 Single Output LNB Supply Voltage Regulator for Satellite Set-Top Box August 12, 2015 Applications These devices are designed for supplying power and Features control signals from advanced satellite set-top box Single Chip Power Solution (STB) modules to the low noise blocks (LNBs) of single antenna ports. Each device consists of a current-mode - Operation for 1-Tuner/1-Dish Applications boost converter and a low-noise linear regulator along Switch-Mode Power Converter for Lowest with the circuitry required for tone injection and pin Dissipation controllable interface. The device makes the total LNB - Boost PWMs with >92% Efficiency supply design simple, efficient and compact with low external component count. - Pin Controllable Enable and Output The current-mode boost converters provide the linear 2.5V/3.3V/5V Logic Compatible regulator with input voltage that is set to the voltage at FAULT Signal the VOUT pin plus a minimal drop to insure minimum DIRECTV SWM Compliant power dissipation across the internal LDO. This VSET Pin to Toggle between Vertical and Horizontal maintains constant voltage drop across the linear pass Polarizations element while permitting adequate voltage range for tone injection. External Tone Input Internal Overcurrent and Over-Temperature The final regulated output voltage is available at the Protection cathode of the back diode to support the operation of an antenna port for a single tuner. The outputs can be Pb-Free (ROHs Compliant) set to various voltage level for the desired polarization reception by means of the logic presented to the Applications VSET0 and VSET1 pins. An EN pin is to be driven high LNB Power Supply and Control for Satellite Set-Top to enable the outputs for the PWM and linear Box combination setting EN low disables the output, forcing a shutdown mode. Pin Configuration The external modulation input (EXTM) can accept a ISL9491, ISL9491A tone modulated DiSEqC command and transfer it (16 LD QFN) symmetrically to the output to meet DiSEqC 1.x TOP VIEW protocol. An external DiSEqC tank circuit can also be implemented to support DiSEqC 2.x. Ordering Information 16 15 14 13 PART TEMP. VCC 1 12 ILIMIT NUMBER PART RANGE PACKAGE PKG. (Note) MARKING (C) (Pb-free) DWG. CS 2 11 TCAP 94 91ERZ ISL9491ERZ* -20 to +85 16 Ld QFN L16.4x4 PGND 3 10 VSET1 94 91AERZ ISL9491AERZ* -20 to +85 16 Ld QFN L16.4x4 GATE 4 9 VSET0 (No longer available or 576 8 supported) *Add -T suffix for tape and reel. Please refer to TB347 for details on reel specifications. NOTE: These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations). Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020. FN6531 Rev 1.00 Page 1 of 14 August 12, 2015 EXTM BYPASS EN VOUT VSW VSENSE SGND FAULTISL9491, ISL9491A Functional Pin Description SYMBOL FUNCTION VSW Input of the linear post-regulator. PGND Dedicated ground for the output gate driver of respective PWM. CS Current sense input connect the sense resistor R at this pin for desired peak overcurrent value for the boost SC FET. SGND Small signal ground for the IC. TCAP Capacitor for setting rise and fall time of the output voltage. Typical value is 0.1F. BYPASS Connect a bypass capacitor of 1F for the internal 5V. VCC Main power supply to the chip. GATE This pin connects to the Gate of the Boost FET. VOUT Output voltage for the LNB meant to be connected to the anode of a back diode in series with the LNB output. VSENSE This pin provides for a sensing and pull-down function for the VLNB and is meant to be connected to the cathode of the back diode. EXTM This is an input for externally modulated DiSEqC tone signal, which is transferred symmetrically onto VLNB. VSET0, Output voltage selection pins. VSET1 EN When this pin is low, the output is disabled in a low power standby state. Setting EN = 1 enables the output voltage. FAULT This an open drain output to be pulled up to the logic high through a resistor. A low indicates that the output voltage is out of regulation. ILIMIT The ILIMIT is used to set the value of the output current limit from the linear. A resistor from ILIMIT to GND programs this limit. FN6531 Rev 1.00 Page 2 of 14 August 12, 2015