Code of Civil Procedure section 580b provides that no deficiency judgment shall lie after a sale of real property under a deed of trust given to the vendor to secure payment of the balance of the purchase price of that real property. Section 580b was drafted in contemplation of the standard purchase money transaction, in which the vendor of real property retains an interest in the land sold to secure payment of part of the purchase price.

  In Weinstein v. Rocha the court confirmed the breadth of section 580b. It held that a written settlement agreement, wherein the parties intended to modify the terms of a promissory note given to the seller to secure payment of part of the purchase price, was simply a modification of the note, not a separate obligation. The settlement agreement did not change the nature of the note — a seller financed note secured by a deed of trust.

  Seller’s remedy, therefore, was limited to foreclosure of the security. If that security is valueless by virtue of the foreclosure of a senior lien, section 580b applies and prevents any deficiency judgment on the note.